Merge tag 'tty-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty / serial driver updates from Greg KH:
 "Here is the tty/serial driver set of changes for 6.14-rc1. Nothing
  major in here, it was delayed a bit due to a regression found in
  linux-next which has now been reverted and verified that it is fixed.

  Other than the reverts, highlights include:

   - 8250 work to get the nbcon mode working (partially reverted)

   - altera_jtaguart minor fixes

   - fsl_lpuart minor updates

   - sh-sci driver minor updatesa

   - other tiny driver updates and cleanups

  All of these have been in linux-next for a while, and now with no
  reports of problems (thanks to the reverts)"

* tag 'tty-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (44 commits)
  Revert "serial: 8250: Switch to nbcon console"
  Revert "serial: 8250: Revert "drop lockdep annotation from serial8250_clear_IER()""
  serial: sh-sci: Increment the runtime usage counter for the earlycon device
  serial: sh-sci: Clean sci_ports[0] after at earlycon exit
  serial: sh-sci: Do not probe the serial port if its slot in sci_ports[] is in use
  serial: sh-sci: Move runtime PM enable to sci_probe_single()
  serial: sh-sci: Drop __initdata macro for port_cfg
  serial: kgdb_nmi: Remove unused knock code
  tty: Permit some TIOCL_SETSEL modes without CAP_SYS_ADMIN
  tty: xilinx_uartps: split sysrq handling
  serial: 8250: Revert "drop lockdep annotation from serial8250_clear_IER()"
  serial: 8250: Switch to nbcon console
  serial: 8250: Provide flag for IER toggling for RS485
  serial: 8250: Use high-level writing function for FIFO
  serial: 8250: Use frame time to determine timeout
  serial: 8250: Adjust the timeout for FIFO mode
  tty: atmel_serial: Use of_property_present() for non-boolean properties
  serial: sc16is7xx: Add polling mode if no IRQ pin is available
  dt-bindings: serial: sc16is7xx: Add description for polling mode
  tty: serial: atmel: make it selectable for ARCH_LAN969X
  ...

24 files changed, 564 insertions, 424 deletions

diff --git a/drivers/tty/mips_ejtag_fdc.c b/drivers/tty/mips_ejtag_fdc.c
index afbf7738c7c4..58b28be63c79 100644
--- a/drivers/tty/mips_ejtag_fdc.c
+++ b/drivers/tty/mips_ejtag_fdc.c
@@ -1154,7 +1154,7 @@ static char kgdbfdc_rbuf[4];
 
 /* write buffer to allow compaction */
 static unsigned int kgdbfdc_wbuflen;
-static char kgdbfdc_wbuf[4];
+static u8 kgdbfdc_wbuf[4];
 
 static void __iomem *kgdbfdc_setup(void)
 {
@@ -1215,7 +1215,7 @@ static int kgdbfdc_read_char(void)
 /* push an FDC word from write buffer to TX FIFO */
 static void kgdbfdc_push_one(void)
 {
-	const char *bufs[1] = { kgdbfdc_wbuf };
+	const u8 *bufs[1] = { kgdbfdc_wbuf };
 	struct fdc_word word;
 	void __iomem *regs;
 	unsigned int i;
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 252849910588..363afe11974f 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2224,7 +2224,7 @@ static int gsm_dlci_negotiate(struct gsm_dlci *dlci)
  *
  *	Some control dlci can stay in ADM mode with other dlci working just
  *	fine. In that case we can just keep the control dlci open after the
- *	DLCI_OPENING retries time out.
+ *	DLCI_OPENING receives DM.
  */
 
 static void gsm_dlci_t1(struct timer_list *t)
@@ -2243,16 +2243,19 @@ static void gsm_dlci_t1(struct timer_list *t)
 		}
 		break;
 	case DLCI_OPENING:
-		if (dlci->retries) {
-			dlci->retries--;
-			gsm_command(dlci->gsm, dlci->addr, SABM|PF);
-			mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
-		} else if (!dlci->addr && gsm->control == (DM | PF)) {
+		if (!dlci->addr && gsm->control == (DM | PF)) {
 			if (debug & DBG_ERRORS)
-				pr_info("DLCI %d opening in ADM mode.\n",
-					dlci->addr);
+				pr_info("DLCI 0 opening in ADM mode.\n");
 			dlci->mode = DLCI_MODE_ADM;
 			gsm_dlci_open(dlci);
+		} else if (dlci->retries) {
+			if (!dlci->addr || !gsm->dlci[0] ||
+			    gsm->dlci[0]->state != DLCI_OPENING) {
+				dlci->retries--;
+				gsm_command(dlci->gsm, dlci->addr, SABM|PF);
+			}
+
+			mod_timer(&dlci->t1, jiffies + gsm->t1 * HZ / 100);
 		} else {
 			gsm->open_error++;
 			gsm_dlci_begin_close(dlci); /* prevent half open link */
@@ -2308,7 +2311,9 @@ static void gsm_dlci_begin_open(struct gsm_dlci *dlci)
 		dlci->retries = gsm->n2;
 		if (!need_pn) {
 			dlci->state = DLCI_OPENING;
-			gsm_command(gsm, dlci->addr, SABM|PF);
+			if (!dlci->addr || !gsm->dlci[0] ||
+			    gsm->dlci[0]->state != DLCI_OPENING)
+				gsm_command(gsm, dlci->addr, SABM|PF);
 		} else {
 			/* Configure DLCI before setup */
 			dlci->state = DLCI_CONFIGURE;
@@ -4251,7 +4256,7 @@ static const struct tty_port_operations gsm_port_ops = {
 static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
 {
 	struct gsm_mux *gsm;
-	struct gsm_dlci *dlci;
+	struct gsm_dlci *dlci, *dlci0;
 	unsigned int line = tty->index;
 	unsigned int mux = mux_line_to_num(line);
 	bool alloc = false;
@@ -4274,10 +4279,20 @@ static int gsmtty_install(struct tty_driver *driver, struct tty_struct *tty)
 	perspective as we don't have to worry about this
 	if DLCI0 is lost */
 	mutex_lock(&gsm->mutex);
-	if (gsm->dlci[0] && gsm->dlci[0]->state != DLCI_OPEN) {
+
+	dlci0 = gsm->dlci[0];
+	if (dlci0 && dlci0->state != DLCI_OPEN) {
 		mutex_unlock(&gsm->mutex);
-		return -EL2NSYNC;
+
+		if (dlci0->state == DLCI_OPENING)
+			wait_event(gsm->event, dlci0->state != DLCI_OPENING);
+
+		if (dlci0->state != DLCI_OPEN)
+			return -EL2NSYNC;
+
+		mutex_lock(&gsm->mutex);
 	}
+
 	dlci = gsm->dlci[line];
 	if (dlci == NULL) {
 		alloc = true;
diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index e5310c65cf52..11e05aa014e5 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -231,8 +231,8 @@ void serial8250_rpm_put_tx(struct uart_8250_port *p);
 
 int serial8250_em485_config(struct uart_port *port, struct ktermios *termios,
 			    struct serial_rs485 *rs485);
-void serial8250_em485_start_tx(struct uart_8250_port *p);
-void serial8250_em485_stop_tx(struct uart_8250_port *p);
+void serial8250_em485_start_tx(struct uart_8250_port *p, bool toggle_ier);
+void serial8250_em485_stop_tx(struct uart_8250_port *p, bool toggle_ier);
 void serial8250_em485_destroy(struct uart_8250_port *p);
 extern struct serial_rs485 serial8250_em485_supported;
 
diff --git a/drivers/tty/serial/8250/8250_bcm2835aux.c b/drivers/tty/serial/8250/8250_bcm2835aux.c
index fdb53b54e99e..0609582a62f7 100644
--- a/drivers/tty/serial/8250/8250_bcm2835aux.c
+++ b/drivers/tty/serial/8250/8250_bcm2835aux.c
@@ -46,7 +46,7 @@ struct bcm2835aux_data {
 	u32 cntl;
 };
 
-static void bcm2835aux_rs485_start_tx(struct uart_8250_port *up)
+static void bcm2835aux_rs485_start_tx(struct uart_8250_port *up, bool toggle_ier)
 {
 	if (!(up->port.rs485.flags & SER_RS485_RX_DURING_TX)) {
 		struct bcm2835aux_data *data = dev_get_drvdata(up->port.dev);
@@ -65,7 +65,7 @@ static void bcm2835aux_rs485_start_tx(struct uart_8250_port *up)
 		serial8250_out_MCR(up, UART_MCR_RTS);
 }
 
-static void bcm2835aux_rs485_stop_tx(struct uart_8250_port *up)
+static void bcm2835aux_rs485_stop_tx(struct uart_8250_port *up, bool toggle_ier)
 {
 	if (up->port.rs485.flags & SER_RS485_RTS_AFTER_SEND)
 		serial8250_out_MCR(up, 0);
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 68baf75bdadc..6f676bb37ac3 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -675,7 +675,6 @@ static void serial_8250_overrun_backoff_work(struct work_struct *work)
 
 	uart_port_lock_irqsave(port, &flags);
 	up->ier |= UART_IER_RLSI | UART_IER_RDI;
-	up->port.read_status_mask |= UART_LSR_DR;
 	serial_out(up, UART_IER, up->ier);
 	uart_port_unlock_irqrestore(port, flags);
 }
diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index 9eb9aa766811..c2b75e3f106d 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -365,7 +365,7 @@ static void omap8250_restore_regs(struct uart_8250_port *up)
 
 	if (up->port.rs485.flags & SER_RS485_ENABLED &&
 	    up->port.rs485_config == serial8250_em485_config)
-		serial8250_em485_stop_tx(up);
+		serial8250_em485_stop_tx(up, true);
 }
 
 /*
@@ -412,7 +412,13 @@ static void omap_8250_set_termios(struct uart_port *port,
 	 */
 	uart_update_timeout(port, termios->c_cflag, baud);
 
-	up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
+	/*
+	 * Specify which conditions may be considered for error
+	 * handling and the ignoring of characters. The actual
+	 * ignoring of characters only occurs if the bit is set
+	 * in @ignore_status_mask as well.
+	 */
+	up->port.read_status_mask = UART_LSR_OE | UART_LSR_DR;
 	if (termios->c_iflag & INPCK)
 		up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
 	if (termios->c_iflag & (IGNBRK | PARMRK))
@@ -838,7 +844,6 @@ static void omap_8250_unthrottle(struct uart_port *port)
 	if (up->dma)
 		up->dma->rx_dma(up);
 	up->ier |= UART_IER_RLSI | UART_IER_RDI;
-	port->read_status_mask |= UART_LSR_DR;
 	serial_out(up, UART_IER, up->ier);
 	uart_port_unlock_irqrestore(port, flags);
 
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 3c3f7c926afb..df4d0d832e54 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -64,23 +64,17 @@
 #define PCIE_DEVICE_ID_NEO_2_OX_IBM	0x00F6
 #define PCI_DEVICE_ID_PLX_CRONYX_OMEGA	0xc001
 #define PCI_DEVICE_ID_INTEL_PATSBURG_KT 0x1d3d
-#define PCI_VENDOR_ID_WCH		0x4348
-#define PCI_DEVICE_ID_WCH_CH352_2S	0x3253
-#define PCI_DEVICE_ID_WCH_CH353_4S	0x3453
-#define PCI_DEVICE_ID_WCH_CH353_2S1PF	0x5046
-#define PCI_DEVICE_ID_WCH_CH353_1S1P	0x5053
-#define PCI_DEVICE_ID_WCH_CH353_2S1P	0x7053
-#define PCI_DEVICE_ID_WCH_CH355_4S	0x7173
+
+#define PCI_DEVICE_ID_WCHCN_CH352_2S	0x3253
+#define PCI_DEVICE_ID_WCHCN_CH355_4S	0x7173
+
 #define PCI_VENDOR_ID_AGESTAR		0x5372
 #define PCI_DEVICE_ID_AGESTAR_9375	0x6872
 #define PCI_DEVICE_ID_BROADCOM_TRUMANAGE 0x160a
 #define PCI_DEVICE_ID_AMCC_ADDIDATA_APCI7800 0x818e
 
-#define PCIE_VENDOR_ID_WCH		0x1c00
-#define PCIE_DEVICE_ID_WCH_CH382_2S1P	0x3250
-#define PCIE_DEVICE_ID_WCH_CH384_4S	0x3470
-#define PCIE_DEVICE_ID_WCH_CH384_8S	0x3853
-#define PCIE_DEVICE_ID_WCH_CH382_2S	0x3253
+#define PCI_DEVICE_ID_WCHIC_CH384_4S	0x3470
+#define PCI_DEVICE_ID_WCHIC_CH384_8S	0x3853
 
 #define PCI_DEVICE_ID_MOXA_CP102E	0x1024
 #define PCI_DEVICE_ID_MOXA_CP102EL	0x1025
@@ -2817,80 +2811,80 @@ static struct pci_serial_quirk pci_serial_quirks[] = {
 	},
 	/* WCH CH353 1S1P card (16550 clone) */
 	{
-		.vendor         = PCI_VENDOR_ID_WCH,
-		.device         = PCI_DEVICE_ID_WCH_CH353_1S1P,
+		.vendor         = PCI_VENDOR_ID_WCHCN,
+		.device         = PCI_DEVICE_ID_WCHCN_CH353_1S1P,
 		.subvendor      = PCI_ANY_ID,
 		.subdevice      = PCI_ANY_ID,
 		.setup          = pci_wch_ch353_setup,
 	},
 	/* WCH CH353 2S1P card (16550 clone) */
 	{
-		.vendor         = PCI_VENDOR_ID_WCH,
-		.device         = PCI_DEVICE_ID_WCH_CH353_2S1P,
+		.vendor         = PCI_VENDOR_ID_WCHCN,
+		.device         = PCI_DEVICE_ID_WCHCN_CH353_2S1P,
 		.subvendor      = PCI_ANY_ID,
 		.subdevice      = PCI_ANY_ID,
 		.setup          = pci_wch_ch353_setup,
 	},
 	/* WCH CH353 4S card (16550 clone) */
 	{
-		.vendor         = PCI_VENDOR_ID_WCH,
-		.device         = PCI_DEVICE_ID_WCH_CH353_4S,
+		.vendor         = PCI_VENDOR_ID_WCHCN,
+		.device         = PCI_DEVICE_ID_WCHCN_CH353_4S,
 		.subvendor      = PCI_ANY_ID,
 		.subdevice      = PCI_ANY_ID,
 		.setup          = pci_wch_ch353_setup,
 	},
 	/* WCH CH353 2S1PF card (16550 clone) */
 	{
-		.vendor         = PCI_VENDOR_ID_WCH,
-		.device         = PCI_DEVICE_ID_WCH_CH353_2S1PF,
+		.vendor         = PCI_VENDOR_ID_WCHCN,
+		.device         = PCI_DEVICE_ID_WCHCN_CH353_2S1PF,
 		.subvendor      = PCI_ANY_ID,
 		.subdevice      = PCI_ANY_ID,
 		.setup          = pci_wch_ch353_setup,
 	},
 	/* WCH CH352 2S card (16550 clone) */
 	{
-		.vendor		= PCI_VENDOR_ID_WCH,
-		.device		= PCI_DEVICE_ID_WCH_CH352_2S,
+		.vendor		= PCI_VENDOR_ID_WCHCN,
+		.device		= PCI_DEVICE_ID_WCHCN_CH352_2S,
 		.subvendor	= PCI_ANY_ID,
 		.subdevice	= PCI_ANY_ID,
 		.setup		= pci_wch_ch353_setup,
 	},
 	/* WCH CH355 4S card (16550 clone) */
 	{
-		.vendor		= PCI_VENDOR_ID_WCH,
-		.device		= PCI_DEVICE_ID_WCH_CH355_4S,
+		.vendor		= PCI_VENDOR_ID_WCHCN,
+		.device		= PCI_DEVICE_ID_WCHCN_CH355_4S,
 		.subvendor	= PCI_ANY_ID,
 		.subdevice	= PCI_ANY_ID,
 		.setup		= pci_wch_ch355_setup,
 	},
 	/* WCH CH382 2S card (16850 clone) */
 	{
-		.vendor         = PCIE_VENDOR_ID_WCH,
-		.device         = PCIE_DEVICE_ID_WCH_CH382_2S,
+		.vendor         = PCI_VENDOR_ID_WCHIC,
+		.device         = PCI_DEVICE_ID_WCHIC_CH382_2S,
 		.subvendor      = PCI_ANY_ID,
 		.subdevice      = PCI_ANY_ID,
 		.setup          = pci_wch_ch38x_setup,
 	},
 	/* WCH CH382 2S1P card (16850 clone) */
 	{
-		.vendor         = PCIE_VENDOR_ID_WCH,
-		.device         = PCIE_DEVICE_ID_WCH_CH382_2S1P,
+		.vendor         = PCI_VENDOR_ID_WCHIC,
+		.device         = PCI_DEVICE_ID_WCHIC_CH382_2S1P,
 		.subvendor      = PCI_ANY_ID,
 		.subdevice      = PCI_ANY_ID,
 		.setup          = pci_wch_ch38x_setup,
 	},
 	/* WCH CH384 4S card (16850 clone) */
 	{
-		.vendor         = PCIE_VENDOR_ID_WCH,
-		.device         = PCIE_DEVICE_ID_WCH_CH384_4S,
+		.vendor         = PCI_VENDOR_ID_WCHIC,
+		.device         = PCI_DEVICE_ID_WCHIC_CH384_4S,
 		.subvendor      = PCI_ANY_ID,
 		.subdevice      = PCI_ANY_ID,
 		.setup          = pci_wch_ch38x_setup,
 	},
 	/* WCH CH384 8S card (16850 clone) */
 	{
-		.vendor         = PCIE_VENDOR_ID_WCH,
-		.device         = PCIE_DEVICE_ID_WCH_CH384_8S,
+		.vendor         = PCI_VENDOR_ID_WCHIC,
+		.device         = PCI_DEVICE_ID_WCHIC_CH384_8S,
 		.subvendor      = PCI_ANY_ID,
 		.subdevice      = PCI_ANY_ID,
 		.init           = pci_wch_ch38x_init,
@@ -3967,11 +3961,11 @@ static const struct pci_device_id blacklist[] = {
 
 	/* multi-io cards handled by parport_serial */
 	/* WCH CH353 2S1P */
-	{ PCI_DEVICE(0x4348, 0x7053), 0, 0, REPORT_CONFIG(PARPORT_SERIAL), },
+	{ PCI_VDEVICE(WCHCN, 0x7053), REPORT_CONFIG(PARPORT_SERIAL), },
 	/* WCH CH353 1S1P */
-	{ PCI_DEVICE(0x4348, 0x5053), 0, 0, REPORT_CONFIG(PARPORT_SERIAL), },
+	{ PCI_VDEVICE(WCHCN, 0x5053), REPORT_CONFIG(PARPORT_SERIAL), },
 	/* WCH CH382 2S1P */
-	{ PCI_DEVICE(0x1c00, 0x3250), 0, 0, REPORT_CONFIG(PARPORT_SERIAL), },
+	{ PCI_VDEVICE(WCHIC, 0x3250), REPORT_CONFIG(PARPORT_SERIAL), },
 
 	/* Intel platforms with MID UART */
 	{ PCI_VDEVICE(INTEL, 0x081b), REPORT_8250_CONFIG(MID), },
@@ -6044,27 +6038,27 @@ static const struct pci_device_id serial_pci_tbl[] = {
 	 * WCH CH353 series devices: The 2S1P is handled by parport_serial
 	 * so not listed here.
 	 */
-	{	PCI_VENDOR_ID_WCH, PCI_DEVICE_ID_WCH_CH353_4S,
+	{	PCI_VENDOR_ID_WCHCN, PCI_DEVICE_ID_WCHCN_CH353_4S,
 		PCI_ANY_ID, PCI_ANY_ID,
 		0, 0, pbn_b0_bt_4_115200 },
 
-	{	PCI_VENDOR_ID_WCH, PCI_DEVICE_ID_WCH_CH353_2S1PF,
+	{	PCI_VENDOR_ID_WCHCN, PCI_DEVICE_ID_WCHCN_CH353_2S1PF,
 		PCI_ANY_ID, PCI_ANY_ID,
 		0, 0, pbn_b0_bt_2_115200 },
 
-	{	PCI_VENDOR_ID_WCH, PCI_DEVICE_ID_WCH_CH355_4S,
+	{	PCI_VENDOR_ID_WCHCN, PCI_DEVICE_ID_WCHCN_CH355_4S,
 		PCI_ANY_ID, PCI_ANY_ID,
 		0, 0, pbn_b0_bt_4_115200 },
 
-	{	PCIE_VENDOR_ID_WCH, PCIE_DEVICE_ID_WCH_CH382_2S,
+	{	PCI_VENDOR_ID_WCHIC, PCI_DEVICE_ID_WCHIC_CH382_2S,
 		PCI_ANY_ID, PCI_ANY_ID,
 		0, 0, pbn_wch382_2 },
 
-	{	PCIE_VENDOR_ID_WCH, PCIE_DEVICE_ID_WCH_CH384_4S,
+	{	PCI_VENDOR_ID_WCHIC, PCI_DEVICE_ID_WCHIC_CH384_4S,
 		PCI_ANY_ID, PCI_ANY_ID,
 		0, 0, pbn_wch384_4 },
 
-	{	PCIE_VENDOR_ID_WCH, PCIE_DEVICE_ID_WCH_CH384_8S,
+	{	PCI_VENDOR_ID_WCHIC, PCI_DEVICE_ID_WCHIC_CH384_8S,
 		PCI_ANY_ID, PCI_ANY_ID,
 		0, 0, pbn_wch384_8 },
 	/*
diff --git a/drivers/tty/serial/8250/8250_pci1xxxx.c b/drivers/tty/serial/8250/8250_pci1xxxx.c
index 838f181f929b..e9c51d4e447d 100644
--- a/drivers/tty/serial/8250/8250_pci1xxxx.c
+++ b/drivers/tty/serial/8250/8250_pci1xxxx.c
@@ -78,6 +78,12 @@
 #define UART_TX_BYTE_FIFO			0x00
 #define UART_FIFO_CTL				0x02
 
+#define UART_MODEM_CTL_REG			0x04
+#define UART_MODEM_CTL_RTS_SET			BIT(1)
+
+#define UART_LINE_STAT_REG			0x05
+#define UART_LINE_XMIT_CHECK_MASK		GENMASK(6, 5)
+
 #define UART_ACTV_REG				0x11
 #define UART_BLOCK_SET_ACTIVE			BIT(0)
 
@@ -94,6 +100,7 @@
 #define UART_BIT_SAMPLE_CNT_16			16
 #define BAUD_CLOCK_DIV_INT_MSK			GENMASK(31, 8)
 #define ADCL_CFG_RTS_DELAY_MASK			GENMASK(11, 8)
+#define FRAC_DIV_TX_END_POINT_MASK		GENMASK(23, 20)
 
 #define UART_WAKE_REG				0x8C
 #define UART_WAKE_MASK_REG			0x90
@@ -134,6 +141,11 @@
 #define UART_BST_STAT_LSR_FRAME_ERR		0x8000000
 #define UART_BST_STAT_LSR_THRE			0x20000000
 
+#define GET_MODEM_CTL_RTS_STATUS(reg)		((reg) & UART_MODEM_CTL_RTS_SET)
+#define GET_RTS_PIN_STATUS(val)			(((val) & TIOCM_RTS) >> 1)
+#define RTS_TOGGLE_STATUS_MASK(val, reg)	(GET_MODEM_CTL_RTS_STATUS(reg) \
+						 != GET_RTS_PIN_STATUS(val))
+
 struct pci1xxxx_8250 {
 	unsigned int nr;
 	u8 dev_rev;
@@ -254,6 +266,47 @@ static void pci1xxxx_set_divisor(struct uart_port *port, unsigned int baud,
 	       port->membase + UART_BAUD_CLK_DIVISOR_REG);
 }
 
+static void pci1xxxx_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	u32 fract_div_cfg_reg;
+	u32 line_stat_reg;
+	u32 modem_ctl_reg;
+	u32 adcl_cfg_reg;
+
+	adcl_cfg_reg = readl(port->membase + ADCL_CFG_REG);
+
+	/* HW is responsible in ADCL_EN case */
+	if ((adcl_cfg_reg & (ADCL_CFG_EN | ADCL_CFG_PIN_SEL)))
+		return;
+
+	modem_ctl_reg = readl(port->membase + UART_MODEM_CTL_REG);
+
+	serial8250_do_set_mctrl(port, mctrl);
+
+	if (RTS_TOGGLE_STATUS_MASK(mctrl, modem_ctl_reg)) {
+		line_stat_reg = readl(port->membase + UART_LINE_STAT_REG);
+		if (line_stat_reg & UART_LINE_XMIT_CHECK_MASK) {
+			fract_div_cfg_reg = readl(port->membase +
+						  FRAC_DIV_CFG_REG);
+
+			writel((fract_div_cfg_reg &
+			       ~(FRAC_DIV_TX_END_POINT_MASK)),
+			       port->membase + FRAC_DIV_CFG_REG);
+
+			/* Enable ADC and set the nRTS pin */
+			writel((adcl_cfg_reg | (ADCL_CFG_EN |
+			       ADCL_CFG_PIN_SEL)),
+			       port->membase + ADCL_CFG_REG);
+
+			/* Revert to the original settings */
+			writel(adcl_cfg_reg, port->membase + ADCL_CFG_REG);
+
+			writel(fract_div_cfg_reg, port->membase +
+			       FRAC_DIV_CFG_REG);
+		}
+	}
+}
+
 static int pci1xxxx_rs485_config(struct uart_port *port,
 				 struct ktermios *termios,
 				 struct serial_rs485 *rs485)
@@ -631,9 +684,14 @@ static int pci1xxxx_setup(struct pci_dev *pdev,
 	port->port.rs485_config = pci1xxxx_rs485_config;
 	port->port.rs485_supported = pci1xxxx_rs485_supported;
 
-	/* From C0 rev Burst operation is supported */
+	/*
+	 * C0 and later revisions support Burst operation.
+	 * RTS workaround in mctrl is applicable only to B0.
+	 */
 	if (rev >= 0xC0)
 		port->port.handle_irq = pci1xxxx_handle_irq;
+	else if (rev == 0xB0)
+		port->port.set_mctrl = pci1xxxx_set_mctrl;
 
 	ret = serial8250_pci_setup_port(pdev, port, 0, PORT_OFFSET * port_idx, 0);
 	if (ret < 0)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 649e74e9b52f..d7976a21cca9 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -578,7 +578,7 @@ static int serial8250_em485_init(struct uart_8250_port *p)
 
 deassert_rts:
 	if (p->em485->tx_stopped)
-		p->rs485_stop_tx(p);
+		p->rs485_stop_tx(p, true);
 
 	return 0;
 }
@@ -1390,7 +1390,6 @@ static void serial8250_stop_rx(struct uart_port *port)
 	serial8250_rpm_get(up);
 
 	up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
-	up->port.read_status_mask &= ~UART_LSR_DR;
 	serial_port_out(port, UART_IER, up->ier);
 
 	serial8250_rpm_put(up);
@@ -1399,10 +1398,11 @@ static void serial8250_stop_rx(struct uart_port *port)
 /**
  * serial8250_em485_stop_tx() - generic ->rs485_stop_tx() callback
  * @p: uart 8250 port
+ * @toggle_ier: true to allow enabling receive interrupts
  *
  * Generic callback usable by 8250 uart drivers to stop rs485 transmission.
  */
-void serial8250_em485_stop_tx(struct uart_8250_port *p)
+void serial8250_em485_stop_tx(struct uart_8250_port *p, bool toggle_ier)
 {
 	unsigned char mcr = serial8250_in_MCR(p);
 
@@ -1423,8 +1423,10 @@ void serial8250_em485_stop_tx(struct uart_8250_port *p)
 	if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX)) {
 		serial8250_clear_and_reinit_fifos(p);
 
-		p->ier |= UART_IER_RLSI | UART_IER_RDI;
-		serial_port_out(&p->port, UART_IER, p->ier);
+		if (toggle_ier) {
+			p->ier |= UART_IER_RLSI | UART_IER_RDI;
+			serial_port_out(&p->port, UART_IER, p->ier);
+		}
 	}
 }
 EXPORT_SYMBOL_GPL(serial8250_em485_stop_tx);
@@ -1439,7 +1441,7 @@ static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t)
 	serial8250_rpm_get(p);
 	uart_port_lock_irqsave(&p->port, &flags);
 	if (em485->active_timer == &em485->stop_tx_timer) {
-		p->rs485_stop_tx(p);
+		p->rs485_stop_tx(p, true);
 		em485->active_timer = NULL;
 		em485->tx_stopped = true;
 	}
@@ -1471,7 +1473,7 @@ static void __stop_tx_rs485(struct uart_8250_port *p, u64 stop_delay)
 		em485->active_timer = &em485->stop_tx_timer;
 		hrtimer_start(&em485->stop_tx_timer, ns_to_ktime(stop_delay), HRTIMER_MODE_REL);
 	} else {
-		p->rs485_stop_tx(p);
+		p->rs485_stop_tx(p, true);
 		em485->active_timer = NULL;
 		em485->tx_stopped = true;
 	}
@@ -1560,6 +1562,7 @@ static inline void __start_tx(struct uart_port *port)
 /**
  * serial8250_em485_start_tx() - generic ->rs485_start_tx() callback
  * @up: uart 8250 port
+ * @toggle_ier: true to allow disabling receive interrupts
  *
  * Generic callback usable by 8250 uart drivers to start rs485 transmission.
  * Assumes that setting the RTS bit in the MCR register means RTS is high.
@@ -1567,11 +1570,11 @@ static inline void __start_tx(struct uart_port *port)
  * stoppable by disabling the UART_IER_RDI interrupt.  (Some chips set the
  * UART_LSR_DR bit even when UART_IER_RDI is disabled, foiling this approach.)
  */
-void serial8250_em485_start_tx(struct uart_8250_port *up)
+void serial8250_em485_start_tx(struct uart_8250_port *up, bool toggle_ier)
 {
 	unsigned char mcr = serial8250_in_MCR(up);
 
-	if (!(up->port.rs485.flags & SER_RS485_RX_DURING_TX))
+	if (!(up->port.rs485.flags & SER_RS485_RX_DURING_TX) && toggle_ier)
 		serial8250_stop_rx(&up->port);
 
 	if (up->port.rs485.flags & SER_RS485_RTS_ON_SEND)
@@ -1605,7 +1608,7 @@ static bool start_tx_rs485(struct uart_port *port)
 	if (em485->tx_stopped) {
 		em485->tx_stopped = false;
 
-		up->rs485_start_tx(up);
+		up->rs485_start_tx(up, true);
 
 		if (up->port.rs485.delay_rts_before_send > 0) {
 			em485->active_timer = &em485->start_tx_timer;
@@ -1931,7 +1934,7 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
 	 */
 	if (!(status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS)) &&
 	    (port->status & (UPSTAT_AUTOCTS | UPSTAT_AUTORTS)) &&
-	    !(port->read_status_mask & UART_LSR_DR))
+	    !(up->ier & (UART_IER_RLSI | UART_IER_RDI)))
 		skip_rx = true;
 
 	if (status & (UART_LSR_DR | UART_LSR_BI) && !skip_rx) {
@@ -2079,11 +2082,20 @@ static void serial8250_break_ctl(struct uart_port *port, int break_state)
 	serial8250_rpm_put(up);
 }
 
-static void wait_for_lsr(struct uart_8250_port *up, int bits)
+/* Returns true if @bits were set, false on timeout */
+static bool wait_for_lsr(struct uart_8250_port *up, int bits)
 {
-	unsigned int status, tmout = 10000;
+	unsigned int status, tmout;
+
+	/*
+	 * Wait for a character to be sent. Fallback to a safe default
+	 * timeout value if @frame_time is not available.
+	 */
+	if (up->port.frame_time)
+		tmout = up->port.frame_time * 2 / NSEC_PER_USEC;
+	else
+		tmout = 10000;
 
-	/* Wait up to 10ms for the character(s) to be sent. */
 	for (;;) {
 		status = serial_lsr_in(up);
 
@@ -2094,11 +2106,11 @@ static void wait_for_lsr(struct uart_8250_port *up, int bits)
 		udelay(1);
 		touch_nmi_watchdog();
 	}
+
+	return (tmout != 0);
 }
 
-/*
- *	Wait for transmitter & holding register to empty
- */
+/* Wait for transmitter and holding register to empty with timeout */
 static void wait_for_xmitr(struct uart_8250_port *up, int bits)
 {
 	unsigned int tmout;
@@ -2786,7 +2798,13 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
 	 */
 	uart_update_timeout(port, termios->c_cflag, baud);
 
-	port->read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
+	/*
+	 * Specify which conditions may be considered for error
+	 * handling and the ignoring of characters. The actual
+	 * ignoring of characters only occurs if the bit is set
+	 * in @ignore_status_mask as well.
+	 */
+	port->read_status_mask = UART_LSR_OE | UART_LSR_DR;
 	if (termios->c_iflag & INPCK)
 		port->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
 	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
@@ -3250,7 +3268,7 @@ void serial8250_init_port(struct uart_8250_port *up)
 	port->ops = &serial8250_pops;
 	port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);
 
-	up->cur_iotype = 0xFF;
+	up->cur_iotype = UPIO_UNKNOWN;
 }
 EXPORT_SYMBOL_GPL(serial8250_init_port);
 
@@ -3285,10 +3303,15 @@ EXPORT_SYMBOL_GPL(serial8250_set_defaults);
 
 static void serial8250_console_putchar(struct uart_port *port, unsigned char ch)
 {
+	serial_port_out(port, UART_TX, ch);
+}
+
+static void serial8250_console_wait_putchar(struct uart_port *port, unsigned char ch)
+{
 	struct uart_8250_port *up = up_to_u8250p(port);
 
 	wait_for_xmitr(up, UART_LSR_THRE);
-	serial_port_out(port, UART_TX, ch);
+	serial8250_console_putchar(port, ch);
 }
 
 /*
@@ -3317,6 +3340,16 @@ static void serial8250_console_restore(struct uart_8250_port *up)
 	serial8250_out_MCR(up, up->mcr | UART_MCR_DTR | UART_MCR_RTS);
 }
 
+static void fifo_wait_for_lsr(struct uart_8250_port *up, unsigned int count)
+{
+	unsigned int i;
+
+	for (i = 0; i < count; i++) {
+		if (wait_for_lsr(up, UART_LSR_THRE))
+			return;
+	}
+}
+
 /*
  * Print a string to the serial port using the device FIFO
  *
@@ -3326,24 +3359,34 @@ static void serial8250_console_restore(struct uart_8250_port *up)
 static void serial8250_console_fifo_write(struct uart_8250_port *up,
 					  const char *s, unsigned int count)
 {
-	int i;
 	const char *end = s + count;
 	unsigned int fifosize = up->tx_loadsz;
+	struct uart_port *port = &up->port;
+	unsigned int tx_count = 0;
 	bool cr_sent = false;
+	unsigned int i;
 
 	while (s != end) {
-		wait_for_lsr(up, UART_LSR_THRE);
+		/* Allow timeout for each byte of a possibly full FIFO */
+		fifo_wait_for_lsr(up, fifosize);
 
 		for (i = 0; i < fifosize && s != end; ++i) {
 			if (*s == '\n' && !cr_sent) {
-				serial_out(up, UART_TX, '\r');
+				serial8250_console_putchar(port, '\r');
 				cr_sent = true;
 			} else {
-				serial_out(up, UART_TX, *s++);
+				serial8250_console_putchar(port, *s++);
 				cr_sent = false;
 			}
 		}
+		tx_count = i;
 	}
+
+	/*
+	 * Allow timeout for each byte written since the caller will only wait
+	 * for UART_LSR_BOTH_EMPTY using the timeout of a single character
+	 */
+	fifo_wait_for_lsr(up, tx_count);
 }
 
 /*
@@ -3385,7 +3428,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
 
 	if (em485) {
 		if (em485->tx_stopped)
-			up->rs485_start_tx(up);
+			up->rs485_start_tx(up, false);
 		mdelay(port->rs485.delay_rts_before_send);
 	}
 
@@ -3412,7 +3455,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
 	if (likely(use_fifo))
 		serial8250_console_fifo_write(up, s, count);
 	else
-		uart_console_write(port, s, count, serial8250_console_putchar);
+		uart_console_write(port, s, count, serial8250_console_wait_putchar);
 
 	/*
 	 *	Finally, wait for transmitter to become empty
@@ -3423,7 +3466,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
 	if (em485) {
 		mdelay(port->rs485.delay_rts_after_send);
 		if (em485->tx_stopped)
-			up->rs485_stop_tx(up);
+			up->rs485_stop_tx(up, false);
 	}
 
 	serial_port_out(port, UART_IER, ier);
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 45f0f779fbf9..976dae3bb1bb 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -128,7 +128,7 @@ config SERIAL_SB1250_DUART_CONSOLE
 config SERIAL_ATMEL
 	bool "AT91 on-chip serial port support"
 	depends on COMMON_CLK
-	depends on ARCH_AT91 || COMPILE_TEST
+	depends on ARCH_AT91 || ARCH_LAN969X || COMPILE_TEST
 	select SERIAL_CORE
 	select SERIAL_MCTRL_GPIO if GPIOLIB
 	select MFD_AT91_USART
diff --git a/drivers/tty/serial/altera_jtaguart.c b/drivers/tty/serial/altera_jtaguart.c
index b9c3c3bed0c1..d47a62d1c9f7 100644
--- a/drivers/tty/serial/altera_jtaguart.c
+++ b/drivers/tty/serial/altera_jtaguart.c
@@ -24,8 +24,6 @@
 #include <linux/io.h>
 #include <linux/altera_jtaguart.h>
 
-#define DRV_NAME "altera_jtaguart"
-
 /*
  * Altera JTAG UART register definitions according to the Altera JTAG UART
  * datasheet: https://www.altera.com/literature/hb/nios2/n2cpu_nii51009.pdf
@@ -173,7 +171,7 @@ static int altera_jtaguart_startup(struct uart_port *port)
 	int ret;
 
 	ret = request_irq(port->irq, altera_jtaguart_interrupt, 0,
-			DRV_NAME, port);
+			dev_name(port->dev), port);
 	if (ret) {
 		dev_err(port->dev, "unable to attach Altera JTAG UART %d interrupt vector=%d\n",
 			port->line, port->irq);
@@ -365,7 +363,7 @@ OF_EARLYCON_DECLARE(juart, "altr,juart-1.0", altera_jtaguart_earlycon_setup);
 
 static struct uart_driver altera_jtaguart_driver = {
 	.owner		= THIS_MODULE,
-	.driver_name	= "altera_jtaguart",
+	.driver_name	= KBUILD_MODNAME,
 	.dev_name	= "ttyJ",
 	.major		= ALTERA_JTAGUART_MAJOR,
 	.minor		= ALTERA_JTAGUART_MINOR,
@@ -451,7 +449,7 @@ static struct platform_driver altera_jtaguart_platform_driver = {
 	.probe	= altera_jtaguart_probe,
 	.remove = altera_jtaguart_remove,
 	.driver	= {
-		.name		= DRV_NAME,
+		.name		= KBUILD_MODNAME,
 		.of_match_table	= of_match_ptr(altera_jtaguart_match),
 	},
 };
@@ -481,4 +479,4 @@ module_exit(altera_jtaguart_exit);
 MODULE_DESCRIPTION("Altera JTAG UART driver");
 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
 MODULE_LICENSE("GPL");
-MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_ALIAS("platform:" KBUILD_MODNAME);
diff --git a/drivers/tty/serial/altera_uart.c b/drivers/tty/serial/altera_uart.c
index c94655453c33..1759137121cc 100644
--- a/drivers/tty/serial/altera_uart.c
+++ b/drivers/tty/serial/altera_uart.c
@@ -24,7 +24,6 @@
 #include <linux/io.h>
 #include <linux/altera_uart.h>
 
-#define DRV_NAME "altera_uart"
 #define SERIAL_ALTERA_MAJOR 204
 #define SERIAL_ALTERA_MINOR 213
 
@@ -518,7 +517,7 @@ OF_EARLYCON_DECLARE(uart, "altr,uart-1.0", altera_uart_earlycon_setup);
  */
 static struct uart_driver altera_uart_driver = {
 	.owner		= THIS_MODULE,
-	.driver_name	= DRV_NAME,
+	.driver_name	= KBUILD_MODNAME,
 	.dev_name	= "ttyAL",
 	.major		= SERIAL_ALTERA_MAJOR,
 	.minor		= SERIAL_ALTERA_MINOR,
@@ -619,7 +618,7 @@ static struct platform_driver altera_uart_platform_driver = {
 	.probe	= altera_uart_probe,
 	.remove = altera_uart_remove,
 	.driver	= {
-		.name		= DRV_NAME,
+		.name		= KBUILD_MODNAME,
 		.of_match_table	= of_match_ptr(altera_uart_match),
 	},
 };
@@ -649,5 +648,5 @@ module_exit(altera_uart_exit);
 MODULE_DESCRIPTION("Altera UART driver");
 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
 MODULE_LICENSE("GPL");
-MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_ALIAS("platform:" KBUILD_MODNAME);
 MODULE_ALIAS_CHARDEV_MAJOR(SERIAL_ALTERA_MAJOR);
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 69b7a3e1e418..04212c823a91 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -248,6 +248,13 @@ struct pl011_dmatx_data {
 	bool			queued;
 };
 
+enum pl011_rs485_tx_state {
+	OFF,
+	WAIT_AFTER_RTS,
+	SEND,
+	WAIT_AFTER_SEND,
+};
+
 /*
  * We wrap our port structure around the generic uart_port.
  */
@@ -261,8 +268,10 @@ struct uart_amba_port {
 	unsigned int		fifosize;	/* vendor-specific */
 	unsigned int		fixed_baud;	/* vendor-set fixed baud rate */
 	char			type[12];
-	bool			rs485_tx_started;
-	unsigned int		rs485_tx_drain_interval; /* usecs */
+	ktime_t			rs485_tx_drain_interval; /* nano */
+	enum pl011_rs485_tx_state	rs485_tx_state;
+	struct hrtimer		trigger_start_tx;
+	struct hrtimer		trigger_stop_tx;
 #ifdef CONFIG_DMA_ENGINE
 	/* DMA stuff */
 	unsigned int		dmacr;		/* dma control reg */
@@ -1260,30 +1269,31 @@ static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
 
 static void pl011_rs485_tx_stop(struct uart_amba_port *uap)
 {
-	/*
-	 * To be on the safe side only time out after twice as many iterations
-	 * as fifo size.
-	 */
-	const int MAX_TX_DRAIN_ITERS = uap->port.fifosize * 2;
 	struct uart_port *port = &uap->port;
-	int i = 0;
 	u32 cr;
 
-	/* Wait until hardware tx queue is empty */
-	while (!pl011_tx_empty(port)) {
-		if (i > MAX_TX_DRAIN_ITERS) {
-			dev_warn(port->dev,
-				 "timeout while draining hardware tx queue\n");
-			break;
-		}
+	if (uap->rs485_tx_state == SEND)
+		uap->rs485_tx_state = WAIT_AFTER_SEND;
 
-		udelay(uap->rs485_tx_drain_interval);
-		i++;
+	if (uap->rs485_tx_state == WAIT_AFTER_SEND) {
+		/* Schedule hrtimer if tx queue not empty */
+		if (!pl011_tx_empty(port)) {
+			hrtimer_start(&uap->trigger_stop_tx,
+				      uap->rs485_tx_drain_interval,
+				      HRTIMER_MODE_REL);
+			return;
+		}
+		if (port->rs485.delay_rts_after_send > 0) {
+			hrtimer_start(&uap->trigger_stop_tx,
+				      ms_to_ktime(port->rs485.delay_rts_after_send),
+				      HRTIMER_MODE_REL);
+			return;
+		}
+		/* Continue without any delay */
+	} else if (uap->rs485_tx_state == WAIT_AFTER_RTS) {
+		hrtimer_try_to_cancel(&uap->trigger_start_tx);
 	}
 
-	if (port->rs485.delay_rts_after_send)
-		mdelay(port->rs485.delay_rts_after_send);
-
 	cr = pl011_read(uap, REG_CR);
 
 	if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND)
@@ -1296,7 +1306,7 @@ static void pl011_rs485_tx_stop(struct uart_amba_port *uap)
 	cr |= UART011_CR_RXE;
 	pl011_write(cr, uap, REG_CR);
 
-	uap->rs485_tx_started = false;
+	uap->rs485_tx_state = OFF;
 }
 
 static void pl011_stop_tx(struct uart_port *port)
@@ -1304,11 +1314,18 @@ static void pl011_stop_tx(struct uart_port *port)
 	struct uart_amba_port *uap =
 	    container_of(port, struct uart_amba_port, port);
 
+	if (port->rs485.flags & SER_RS485_ENABLED &&
+	    uap->rs485_tx_state == WAIT_AFTER_RTS) {
+		pl011_rs485_tx_stop(uap);
+		return;
+	}
+
 	uap->im &= ~UART011_TXIM;
 	pl011_write(uap->im, uap, REG_IMSC);
 	pl011_dma_tx_stop(uap);
 
-	if ((port->rs485.flags & SER_RS485_ENABLED) && uap->rs485_tx_started)
+	if (port->rs485.flags & SER_RS485_ENABLED &&
+	    uap->rs485_tx_state != OFF)
 		pl011_rs485_tx_stop(uap);
 }
 
@@ -1328,10 +1345,19 @@ static void pl011_rs485_tx_start(struct uart_amba_port *uap)
 	struct uart_port *port = &uap->port;
 	u32 cr;
 
+	if (uap->rs485_tx_state == WAIT_AFTER_RTS) {
+		uap->rs485_tx_state = SEND;
+		return;
+	}
+	if (uap->rs485_tx_state == WAIT_AFTER_SEND) {
+		hrtimer_try_to_cancel(&uap->trigger_stop_tx);
+		uap->rs485_tx_state = SEND;
+		return;
+	}
+	/* uap->rs485_tx_state == OFF */
 	/* Enable transmitter */
 	cr = pl011_read(uap, REG_CR);
 	cr |= UART011_CR_TXE;
-
 	/* Disable receiver if half-duplex */
 	if (!(port->rs485.flags & SER_RS485_RX_DURING_TX))
 		cr &= ~UART011_CR_RXE;
@@ -1343,10 +1369,14 @@ static void pl011_rs485_tx_start(struct uart_amba_port *uap)
 
 	pl011_write(cr, uap, REG_CR);
 
-	if (port->rs485.delay_rts_before_send)
-		mdelay(port->rs485.delay_rts_before_send);
-
-	uap->rs485_tx_started = true;
+	if (port->rs485.delay_rts_before_send > 0) {
+		uap->rs485_tx_state = WAIT_AFTER_RTS;
+		hrtimer_start(&uap->trigger_start_tx,
+			      ms_to_ktime(port->rs485.delay_rts_before_send),
+			      HRTIMER_MODE_REL);
+	} else {
+		uap->rs485_tx_state = SEND;
+	}
 }
 
 static void pl011_start_tx(struct uart_port *port)
@@ -1355,13 +1385,44 @@ static void pl011_start_tx(struct uart_port *port)
 	    container_of(port, struct uart_amba_port, port);
 
 	if ((uap->port.rs485.flags & SER_RS485_ENABLED) &&
-	    !uap->rs485_tx_started)
+	    uap->rs485_tx_state != SEND) {
 		pl011_rs485_tx_start(uap);
+		if (uap->rs485_tx_state == WAIT_AFTER_RTS)
+			return;
+	}
 
 	if (!pl011_dma_tx_start(uap))
 		pl011_start_tx_pio(uap);
 }
 
+static enum hrtimer_restart pl011_trigger_start_tx(struct hrtimer *t)
+{
+	struct uart_amba_port *uap =
+	    container_of(t, struct uart_amba_port, trigger_start_tx);
+	unsigned long flags;
+
+	uart_port_lock_irqsave(&uap->port, &flags);
+	if (uap->rs485_tx_state == WAIT_AFTER_RTS)
+		pl011_start_tx(&uap->port);
+	uart_port_unlock_irqrestore(&uap->port, flags);
+
+	return HRTIMER_NORESTART;
+}
+
+static enum hrtimer_restart pl011_trigger_stop_tx(struct hrtimer *t)
+{
+	struct uart_amba_port *uap =
+	    container_of(t, struct uart_amba_port, trigger_stop_tx);
+	unsigned long flags;
+
+	uart_port_lock_irqsave(&uap->port, &flags);
+	if (uap->rs485_tx_state == WAIT_AFTER_SEND)
+		pl011_rs485_tx_stop(uap);
+	uart_port_unlock_irqrestore(&uap->port, flags);
+
+	return HRTIMER_NORESTART;
+}
+
 static void pl011_stop_rx(struct uart_port *port)
 {
 	struct uart_amba_port *uap =
@@ -1953,7 +2014,7 @@ static void pl011_shutdown(struct uart_port *port)
 
 	pl011_dma_shutdown(uap);
 
-	if ((port->rs485.flags & SER_RS485_ENABLED) && uap->rs485_tx_started)
+	if ((port->rs485.flags & SER_RS485_ENABLED && uap->rs485_tx_state != OFF))
 		pl011_rs485_tx_stop(uap);
 
 	free_irq(uap->port.irq, uap);
@@ -2098,7 +2159,7 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios,
 	 * with the given baud rate. We use this as the poll interval when we
 	 * wait for the tx queue to empty.
 	 */
-	uap->rs485_tx_drain_interval = DIV_ROUND_UP(bits * 1000 * 1000, baud);
+	uap->rs485_tx_drain_interval = ns_to_ktime(DIV_ROUND_UP(bits * NSEC_PER_SEC, baud));
 
 	pl011_setup_status_masks(port, termios);
 
@@ -2807,6 +2868,11 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
 		}
 	}
 
+	hrtimer_init(&uap->trigger_start_tx, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	hrtimer_init(&uap->trigger_stop_tx, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	uap->trigger_start_tx.function = pl011_trigger_start_tx;
+	uap->trigger_stop_tx.function = pl011_trigger_stop_tx;
+
 	ret = pl011_setup_port(&dev->dev, uap, &dev->res, portnr);
 	if (ret)
 		return ret;
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 0cf05ac18993..f44f9d20a974 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -1727,26 +1727,16 @@ static void atmel_init_property(struct atmel_uart_port *atmel_port,
 
 	/* DMA/PDC usage specification */
 	if (of_property_read_bool(np, "atmel,use-dma-rx")) {
-		if (of_property_read_bool(np, "dmas")) {
-			atmel_port->use_dma_rx  = true;
-			atmel_port->use_pdc_rx  = false;
-		} else {
-			atmel_port->use_dma_rx  = false;
-			atmel_port->use_pdc_rx  = true;
-		}
+		atmel_port->use_dma_rx = of_property_present(np, "dmas");
+		atmel_port->use_pdc_rx = !atmel_port->use_dma_rx;
 	} else {
 		atmel_port->use_dma_rx  = false;
 		atmel_port->use_pdc_rx  = false;
 	}
 
 	if (of_property_read_bool(np, "atmel,use-dma-tx")) {
-		if (of_property_read_bool(np, "dmas")) {
-			atmel_port->use_dma_tx  = true;
-			atmel_port->use_pdc_tx  = false;
-		} else {
-			atmel_port->use_dma_tx  = false;
-			atmel_port->use_pdc_tx  = true;
-		}
+		atmel_port->use_dma_tx = of_property_present(np, "dmas");
+		atmel_port->use_pdc_tx = !atmel_port->use_dma_tx;
 	} else {
 		atmel_port->use_dma_tx  = false;
 		atmel_port->use_pdc_tx  = false;
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 57b0632a3db6..c91b9d9818cd 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -245,7 +245,7 @@
 
 #define DRIVER_NAME	"fsl-lpuart"
 #define DEV_NAME	"ttyLP"
-#define UART_NR		8
+#define UART_NR		12
 
 /* IMX lpuart has four extra unused regs located at the beginning */
 #define IMX_REG_OFF	0x10
@@ -1965,6 +1965,11 @@ static void lpuart32_shutdown(struct uart_port *port)
 			UARTCTRL_TIE | UARTCTRL_TCIE | UARTCTRL_RIE | UARTCTRL_SBK);
 	lpuart32_write(port, temp, UARTCTRL);
 
+	/* flush Rx/Tx FIFO */
+	temp = lpuart32_read(port, UARTFIFO);
+	temp |= UARTFIFO_TXFLUSH | UARTFIFO_RXFLUSH;
+	lpuart32_write(port, temp, UARTFIFO);
+
 	uart_port_unlock_irqrestore(port, flags);
 
 	lpuart_dma_shutdown(sport);
diff --git a/drivers/tty/serial/kgdb_nmi.c b/drivers/tty/serial/kgdb_nmi.c
index e93850f6447a..2833708e369f 100644
--- a/drivers/tty/serial/kgdb_nmi.c
+++ b/drivers/tty/serial/kgdb_nmi.c
@@ -27,18 +27,6 @@
 #include <linux/kgdb.h>
 #include <linux/kdb.h>
 
-static int kgdb_nmi_knock = 1;
-module_param_named(knock, kgdb_nmi_knock, int, 0600);
-MODULE_PARM_DESC(knock, "if set to 1 (default), the special '$3#33' command " \
-			"must be used to enter the debugger; when set to 0, " \
-			"hitting return key is enough to enter the debugger; " \
-			"when set to -1, the debugger is entered immediately " \
-			"upon NMI");
-
-static char *kgdb_nmi_magic = "$3#33";
-module_param_named(magic, kgdb_nmi_magic, charp, 0600);
-MODULE_PARM_DESC(magic, "magic sequence to enter NMI debugger (default $3#33)");
-
 static atomic_t kgdb_nmi_num_readers = ATOMIC_INIT(0);
 
 static int kgdb_nmi_console_setup(struct console *co, char *options)
@@ -95,95 +83,6 @@ struct kgdb_nmi_tty_priv {
 
 static struct tty_port *kgdb_nmi_port;
 
-static void kgdb_tty_recv(int ch)
-{
-	struct kgdb_nmi_tty_priv *priv;
-	char c = ch;
-
-	if (!kgdb_nmi_port || ch < 0)
-		return;
-	/*
-	 * Can't use port->tty->driver_data as tty might be not there. Timer
-	 * will check for tty and will get the ref, but here we don't have to
-	 * do that, and actually, we can't: we're in NMI context, no locks are
-	 * possible.
-	 */
-	priv = container_of(kgdb_nmi_port, struct kgdb_nmi_tty_priv, port);
-	kfifo_in(&priv->fifo, &c, 1);
-}
-
-static int kgdb_nmi_poll_one_knock(void)
-{
-	static int n;
-	int c;
-	const char *magic = kgdb_nmi_magic;
-	size_t m = strlen(magic);
-	bool printch = false;
-
-	c = dbg_io_ops->read_char();
-	if (c == NO_POLL_CHAR)
-		return c;
-
-	if (!kgdb_nmi_knock && (c == '\r' || c == '\n')) {
-		return 1;
-	} else if (c == magic[n]) {
-		n = (n + 1) % m;
-		if (!n)
-			return 1;
-		printch = true;
-	} else {
-		n = 0;
-	}
-
-	if (atomic_read(&kgdb_nmi_num_readers)) {
-		kgdb_tty_recv(c);
-		return 0;
-	}
-
-	if (printch) {
-		kdb_printf("%c", c);
-		return 0;
-	}
-
-	kdb_printf("\r%s %s to enter the debugger> %*s",
-		   kgdb_nmi_knock ? "Type" : "Hit",
-		   kgdb_nmi_knock ? magic  : "<return>", (int)m, "");
-	while (m--)
-		kdb_printf("\b");
-	return 0;
-}
-
-/**
- * kgdb_nmi_poll_knock - Check if it is time to enter the debugger
- *
- * "Serial ports are often noisy, especially when muxed over another port (we
- * often use serial over the headset connector). Noise on the async command
- * line just causes characters that are ignored, on a command line that blocked
- * execution noise would be catastrophic." -- Colin Cross
- *
- * So, this function implements KGDB/KDB knocking on the serial line: we won't
- * enter the debugger until we receive a known magic phrase (which is actually
- * "$3#33", known as "escape to KDB" command. There is also a relaxed variant
- * of knocking, i.e. just pressing the return key is enough to enter the
- * debugger. And if knocking is disabled, the function always returns 1.
- */
-bool kgdb_nmi_poll_knock(void)
-{
-	if (kgdb_nmi_knock < 0)
-		return true;
-
-	while (1) {
-		int ret;
-
-		ret = kgdb_nmi_poll_one_knock();
-		if (ret == NO_POLL_CHAR)
-			return false;
-		else if (ret == 1)
-			break;
-	}
-	return true;
-}
-
 /*
  * The tasklet is cheap, it does not cause wakeups when reschedules itself,
  * instead it waits for the next tick.
diff --git a/drivers/tty/serial/mpc52xx_uart.c b/drivers/tty/serial/mpc52xx_uart.c
index f55aa353aed9..2204cc3e3b07 100644
--- a/drivers/tty/serial/mpc52xx_uart.c
+++ b/drivers/tty/serial/mpc52xx_uart.c
@@ -1621,7 +1621,7 @@ mpc52xx_console_setup(struct console *co, char *options)
 		 (void *)port->mapbase, port->membase,
 		 port->irq, port->uartclk);
 
-	/* Setup the port parameters accoding to options */
+	/* Setup the port parameters according to options */
 	if (options)
 		uart_parse_options(options, &baud, &parity, &bits, &flow);
 	else
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index a3093e09309f..7b51cdc274fd 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -314,6 +314,7 @@
 #define SC16IS7XX_FIFO_SIZE		(64)
 #define SC16IS7XX_GPIOS_PER_BANK	4
 
+#define SC16IS7XX_POLL_PERIOD_MS	10
 #define SC16IS7XX_RECONF_MD		BIT(0)
 #define SC16IS7XX_RECONF_IER		BIT(1)
 #define SC16IS7XX_RECONF_RS485		BIT(2)
@@ -348,6 +349,8 @@ struct sc16is7xx_port {
 	u8				mctrl_mask;
 	struct kthread_worker		kworker;
 	struct task_struct		*kworker_task;
+	struct kthread_delayed_work	poll_work;
+	bool				polling;
 	struct sc16is7xx_one		p[];
 };
 
@@ -861,6 +864,18 @@ static irqreturn_t sc16is7xx_irq(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static void sc16is7xx_poll_proc(struct kthread_work *ws)
+{
+	struct sc16is7xx_port *s = container_of(ws, struct sc16is7xx_port, poll_work.work);
+
+	/* Reuse standard IRQ handler. Interrupt ID is unused in this context. */
+	sc16is7xx_irq(0, s);
+
+	/* Setup delay based on SC16IS7XX_POLL_PERIOD_MS */
+	kthread_queue_delayed_work(&s->kworker, &s->poll_work,
+				   msecs_to_jiffies(SC16IS7XX_POLL_PERIOD_MS));
+}
+
 static void sc16is7xx_tx_proc(struct kthread_work *ws)
 {
 	struct uart_port *port = &(to_sc16is7xx_one(ws, tx_work)->port);
@@ -1149,6 +1164,7 @@ static int sc16is7xx_config_rs485(struct uart_port *port, struct ktermios *termi
 static int sc16is7xx_startup(struct uart_port *port)
 {
 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
+	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
 	unsigned int val;
 	unsigned long flags;
 
@@ -1211,6 +1227,10 @@ static int sc16is7xx_startup(struct uart_port *port)
 	sc16is7xx_enable_ms(port);
 	uart_port_unlock_irqrestore(port, flags);
 
+	if (s->polling)
+		kthread_queue_delayed_work(&s->kworker, &s->poll_work,
+					   msecs_to_jiffies(SC16IS7XX_POLL_PERIOD_MS));
+
 	return 0;
 }
 
@@ -1232,6 +1252,9 @@ static void sc16is7xx_shutdown(struct uart_port *port)
 
 	sc16is7xx_power(port, 0);
 
+	if (s->polling)
+		kthread_cancel_delayed_work_sync(&s->poll_work);
+
 	kthread_flush_worker(&s->kworker);
 }
 
@@ -1538,6 +1561,11 @@ int sc16is7xx_probe(struct device *dev, const struct sc16is7xx_devtype *devtype,
 	/* Always ask for fixed clock rate from a property. */
 	device_property_read_u32(dev, "clock-frequency", &uartclk);
 
+	s->polling = !!irq;
+	if (s->polling)
+		dev_dbg(dev,
+			"No interrupt pin definition, falling back to polling mode\n");
+
 	s->clk = devm_clk_get_optional(dev, NULL);
 	if (IS_ERR(s->clk))
 		return PTR_ERR(s->clk);
@@ -1665,6 +1693,12 @@ int sc16is7xx_probe(struct device *dev, const struct sc16is7xx_devtype *devtype,
 		goto out_ports;
 #endif
 
+	if (s->polling) {
+		/* Initialize kernel thread for polling */
+		kthread_init_delayed_work(&s->poll_work, sc16is7xx_poll_proc);
+		return 0;
+	}
+
 	/*
 	 * Setup interrupt. We first try to acquire the IRQ line as level IRQ.
 	 * If that succeeds, we can allow sharing the interrupt as well.
@@ -1724,6 +1758,9 @@ void sc16is7xx_remove(struct device *dev)
 		sc16is7xx_power(&s->p[i].port, 0);
 	}
 
+	if (s->polling)
+		kthread_cancel_delayed_work_sync(&s->poll_work);
+
 	kthread_flush_worker(&s->kworker);
 	kthread_stop(s->kworker_task);
 
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 74fa02b23772..c472594c3a9f 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -790,7 +790,6 @@ static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
 {
 	struct uart_state *state = container_of(port, struct uart_state, port);
 	struct uart_port *uport;
-	int ret = -ENODEV;
 
 	/* Initialize structure in case we error out later to prevent any stack info leakage. */
 	*retinfo = (struct serial_struct){};
@@ -799,10 +798,10 @@ static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
 	 * Ensure the state we copy is consistent and no hardware changes
 	 * occur as we go
 	 */
-	mutex_lock(&port->mutex);
+	guard(mutex)(&port->mutex);
 	uport = uart_port_check(state);
 	if (!uport)
-		goto out;
+		return -ENODEV;
 
 	retinfo->type	    = uport->type;
 	retinfo->line	    = uport->line;
@@ -823,10 +822,7 @@ static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
 	retinfo->iomem_reg_shift = uport->regshift;
 	retinfo->iomem_base      = (void *)(unsigned long)uport->mapbase;
 
-	ret = 0;
-out:
-	mutex_unlock(&port->mutex);
-	return ret;
+	return 0;
 }
 
 static int uart_get_info_user(struct tty_struct *tty,
@@ -838,6 +834,61 @@ static int uart_get_info_user(struct tty_struct *tty,
 	return uart_get_info(port, ss) < 0 ? -EIO : 0;
 }
 
+static int uart_change_port(struct uart_port *uport,
+			    const struct serial_struct *new_info,
+			    unsigned long new_port)
+{
+	unsigned long old_iobase, old_mapbase;
+	unsigned int old_type, old_iotype, old_hub6, old_shift;
+	int retval;
+
+	old_iobase = uport->iobase;
+	old_mapbase = uport->mapbase;
+	old_type = uport->type;
+	old_hub6 = uport->hub6;
+	old_iotype = uport->iotype;
+	old_shift = uport->regshift;
+
+	if (old_type != PORT_UNKNOWN && uport->ops->release_port)
+		uport->ops->release_port(uport);
+
+	uport->iobase = new_port;
+	uport->type = new_info->type;
+	uport->hub6 = new_info->hub6;
+	uport->iotype = new_info->io_type;
+	uport->regshift = new_info->iomem_reg_shift;
+	uport->mapbase = (unsigned long)new_info->iomem_base;
+
+	if (uport->type == PORT_UNKNOWN || !uport->ops->request_port)
+		return 0;
+
+	retval = uport->ops->request_port(uport);
+	if (retval == 0)
+		return 0; /* succeeded => done */
+
+	/*
+	 * If we fail to request resources for the new port, try to restore the
+	 * old settings.
+	 */
+	uport->iobase = old_iobase;
+	uport->type = old_type;
+	uport->hub6 = old_hub6;
+	uport->iotype = old_iotype;
+	uport->regshift = old_shift;
+	uport->mapbase = old_mapbase;
+
+	if (old_type == PORT_UNKNOWN)
+		return retval;
+
+	retval = uport->ops->request_port(uport);
+	/* If we failed to restore the old settings, we fail like this. */
+	if (retval)
+		uport->type = PORT_UNKNOWN;
+
+	/* We failed anyway. */
+	return -EBUSY;
+}
+
 static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
 			 struct uart_state *state,
 			 struct serial_struct *new_info)
@@ -847,7 +898,7 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
 	unsigned int change_irq, change_port, closing_wait;
 	unsigned int old_custom_divisor, close_delay;
 	upf_t old_flags, new_flags;
-	int retval = 0;
+	int retval;
 
 	if (!uport)
 		return -EIO;
@@ -886,13 +937,10 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
 	if (!(uport->flags & UPF_FIXED_PORT)) {
 		unsigned int uartclk = new_info->baud_base * 16;
 		/* check needs to be done here before other settings made */
-		if (uartclk == 0) {
-			retval = -EINVAL;
-			goto exit;
-		}
+		if (uartclk == 0)
+			return -EINVAL;
 	}
 	if (!capable(CAP_SYS_ADMIN)) {
-		retval = -EPERM;
 		if (change_irq || change_port ||
 		    (new_info->baud_base != uport->uartclk / 16) ||
 		    (close_delay != port->close_delay) ||
@@ -900,7 +948,7 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
 		    (new_info->xmit_fifo_size &&
 		     new_info->xmit_fifo_size != uport->fifosize) ||
 		    (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
-			goto exit;
+			return -EPERM;
 		uport->flags = ((uport->flags & ~UPF_USR_MASK) |
 			       (new_flags & UPF_USR_MASK));
 		uport->custom_divisor = new_info->custom_divisor;
@@ -910,30 +958,24 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
 	if (change_irq || change_port) {
 		retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
 		if (retval)
-			goto exit;
+			return retval;
 	}
 
-	/*
-	 * Ask the low level driver to verify the settings.
-	 */
-	if (uport->ops->verify_port)
+	 /* Ask the low level driver to verify the settings. */
+	if (uport->ops->verify_port) {
 		retval = uport->ops->verify_port(uport, new_info);
+		if (retval)
+			return retval;
+	}
 
 	if ((new_info->irq >= irq_get_nr_irqs()) || (new_info->irq < 0) ||
 	    (new_info->baud_base < 9600))
-		retval = -EINVAL;
-
-	if (retval)
-		goto exit;
+		return -EINVAL;
 
 	if (change_port || change_irq) {
-		retval = -EBUSY;
-
-		/*
-		 * Make sure that we are the sole user of this port.
-		 */
+		 /* Make sure that we are the sole user of this port. */
 		if (tty_port_users(port) > 1)
-			goto exit;
+			return -EBUSY;
 
 		/*
 		 * We need to shutdown the serial port at the old
@@ -943,69 +985,9 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
 	}
 
 	if (change_port) {
-		unsigned long old_iobase, old_mapbase;
-		unsigned int old_type, old_iotype, old_hub6, old_shift;
-
-		old_iobase = uport->iobase;
-		old_mapbase = uport->mapbase;
-		old_type = uport->type;
-		old_hub6 = uport->hub6;
-		old_iotype = uport->iotype;
-		old_shift = uport->regshift;
-
-		/*
-		 * Free and release old regions
-		 */
-		if (old_type != PORT_UNKNOWN && uport->ops->release_port)
-			uport->ops->release_port(uport);
-
-		uport->iobase = new_port;
-		uport->type = new_info->type;
-		uport->hub6 = new_info->hub6;
-		uport->iotype = new_info->io_type;
-		uport->regshift = new_info->iomem_reg_shift;
-		uport->mapbase = (unsigned long)new_info->iomem_base;
-
-		/*
-		 * Claim and map the new regions
-		 */
-		if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
-			retval = uport->ops->request_port(uport);
-		} else {
-			/* Always success - Jean II */
-			retval = 0;
-		}
-
-		/*
-		 * If we fail to request resources for the
-		 * new port, try to restore the old settings.
-		 */
-		if (retval) {
-			uport->iobase = old_iobase;
-			uport->type = old_type;
-			uport->hub6 = old_hub6;
-			uport->iotype = old_iotype;
-			uport->regshift = old_shift;
-			uport->mapbase = old_mapbase;
-
-			if (old_type != PORT_UNKNOWN) {
-				retval = uport->ops->request_port(uport);
-				/*
-				 * If we failed to restore the old settings,
-				 * we fail like this.
-				 */
-				if (retval)
-					uport->type = PORT_UNKNOWN;
-
-				/*
-				 * We failed anyway.
-				 */
-				retval = -EBUSY;
-			}
-
-			/* Added to return the correct error -Ram Gupta */
-			goto exit;
-		}
+		retval = uart_change_port(uport, new_info, new_port);
+		if (retval)
+			return retval;
 	}
 
 	if (change_irq)
@@ -1021,9 +1003,9 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
 		uport->fifosize = new_info->xmit_fifo_size;
 
  check_and_exit:
-	retval = 0;
 	if (uport->type == PORT_UNKNOWN)
-		goto exit;
+		return 0;
+
 	if (tty_port_initialized(port)) {
 		if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
 		    old_custom_divisor != uport->custom_divisor) {
@@ -1039,15 +1021,17 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
 			}
 			uart_change_line_settings(tty, state, NULL);
 		}
-	} else {
-		retval = uart_startup(tty, state, true);
-		if (retval == 0)
-			tty_port_set_initialized(port, true);
-		if (retval > 0)
-			retval = 0;
+
+		return 0;
 	}
- exit:
-	return retval;
+
+	retval = uart_startup(tty, state, true);
+	if (retval < 0)
+		return retval;
+	if (retval == 0)
+		tty_port_set_initialized(port, true);
+
+	return 0;
 }
 
 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
@@ -3061,26 +3045,25 @@ static ssize_t console_store(struct device *dev,
 	if (ret)
 		return ret;
 
-	mutex_lock(&port->mutex);
+	guard(mutex)(&port->mutex);
 	uport = uart_port_check(state);
-	if (uport) {
-		oldconsole = uart_console_registered(uport);
-		if (oldconsole && !newconsole) {
-			ret = unregister_console(uport->cons);
-		} else if (!oldconsole && newconsole) {
-			if (uart_console(uport)) {
-				uport->console_reinit = 1;
-				register_console(uport->cons);
-			} else {
-				ret = -ENOENT;
-			}
-		}
-	} else {
-		ret = -ENXIO;
+	if (!uport)
+		return -ENXIO;
+
+	oldconsole = uart_console_registered(uport);
+	if (oldconsole && !newconsole) {
+		ret = unregister_console(uport->cons);
+		if (ret < 0)
+			return ret;
+	} else if (!oldconsole && newconsole) {
+		if (!uart_console(uport))
+			return -ENOENT;
+
+		uport->console_reinit = 1;
+		register_console(uport->cons);
 	}
-	mutex_unlock(&port->mutex);
 
-	return ret < 0 ? ret : count;
+	return count;
 }
 
 static DEVICE_ATTR_RO(uartclk);
@@ -3136,7 +3119,6 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u
 {
 	struct uart_state *state;
 	struct tty_port *port;
-	int ret = 0;
 	struct device *tty_dev;
 	int num_groups;
 
@@ -3146,11 +3128,9 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u
 	state = drv->state + uport->line;
 	port = &state->port;
 
-	mutex_lock(&port->mutex);
-	if (state->uart_port) {
-		ret = -EINVAL;
-		goto out;
-	}
+	guard(mutex)(&port->mutex);
+	if (state->uart_port)
+		return -EINVAL;
 
 	/* Link the port to the driver state table and vice versa */
 	atomic_set(&state->refcount, 1);
@@ -3170,10 +3150,8 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u
 	uport->minor = drv->tty_driver->minor_start + uport->line;
 	uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
 				drv->tty_driver->name_base + uport->line);
-	if (!uport->name) {
-		ret = -ENOMEM;
-		goto out;
-	}
+	if (!uport->name)
+		return -ENOMEM;
 
 	if (uport->cons && uport->dev)
 		of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
@@ -3189,10 +3167,9 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u
 
 	uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
 				    GFP_KERNEL);
-	if (!uport->tty_groups) {
-		ret = -ENOMEM;
-		goto out;
-	}
+	if (!uport->tty_groups)
+		return -ENOMEM;
+
 	uport->tty_groups[0] = &tty_dev_attr_group;
 	if (uport->attr_group)
 		uport->tty_groups[1] = uport->attr_group;
@@ -3215,10 +3192,7 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u
 		       uport->line);
 	}
 
- out:
-	mutex_unlock(&port->mutex);
-
-	return ret;
+	return 0;
 }
 
 /**
@@ -3384,7 +3358,7 @@ int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
 	struct serial_ctrl_device *ctrl_dev, *new_ctrl_dev = NULL;
 	int ret;
 
-	mutex_lock(&port_mutex);
+	guard(mutex)(&port_mutex);
 
 	/*
 	 * Prevent serial_port_runtime_resume() from trying to use the port
@@ -3396,10 +3370,8 @@ int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
 	ctrl_dev = serial_core_ctrl_find(drv, port->dev, port->ctrl_id);
 	if (!ctrl_dev) {
 		new_ctrl_dev = serial_core_ctrl_device_add(port);
-		if (IS_ERR(new_ctrl_dev)) {
-			ret = PTR_ERR(new_ctrl_dev);
-			goto err_unlock;
-		}
+		if (IS_ERR(new_ctrl_dev))
+			return PTR_ERR(new_ctrl_dev);
 		ctrl_dev = new_ctrl_dev;
 	}
 
@@ -3420,8 +3392,6 @@ int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
 	if (ret)
 		goto err_unregister_port_dev;
 
-	mutex_unlock(&port_mutex);
-
 	return 0;
 
 err_unregister_port_dev:
@@ -3430,9 +3400,6 @@ err_unregister_port_dev:
 err_unregister_ctrl_dev:
 	serial_base_ctrl_device_remove(new_ctrl_dev);
 
-err_unlock:
-	mutex_unlock(&port_mutex);
-
 	return ret;
 }
 
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 924b803af440..b1ea48f38248 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -165,6 +165,8 @@ struct sci_port {
 static struct sci_port sci_ports[SCI_NPORTS];
 static unsigned long sci_ports_in_use;
 static struct uart_driver sci_uart_driver;
+static bool sci_uart_earlycon;
+static bool sci_uart_earlycon_dev_probing;
 
 static inline struct sci_port *
 to_sci_port(struct uart_port *uart)
@@ -3056,10 +3058,6 @@ static int sci_init_single(struct platform_device *dev,
 		ret = sci_init_clocks(sci_port, &dev->dev);
 		if (ret < 0)
 			return ret;
-
-		port->dev = &dev->dev;
-
-		pm_runtime_enable(&dev->dev);
 	}
 
 	port->type		= p->type;
@@ -3086,11 +3084,6 @@ static int sci_init_single(struct platform_device *dev,
 	return 0;
 }
 
-static void sci_cleanup_single(struct sci_port *port)
-{
-	pm_runtime_disable(port->port.dev);
-}
-
 #if defined(CONFIG_SERIAL_SH_SCI_CONSOLE) || \
     defined(CONFIG_SERIAL_SH_SCI_EARLYCON)
 static void serial_console_putchar(struct uart_port *port, unsigned char ch)
@@ -3260,8 +3253,6 @@ static void sci_remove(struct platform_device *dev)
 	sci_ports_in_use &= ~BIT(port->port.line);
 	uart_remove_one_port(&sci_uart_driver, &port->port);
 
-	sci_cleanup_single(port);
-
 	if (port->port.fifosize > 1)
 		device_remove_file(&dev->dev, &dev_attr_rx_fifo_trigger);
 	if (type == PORT_SCIFA || type == PORT_SCIFB || type == PORT_HSCIF)
@@ -3396,7 +3387,8 @@ static struct plat_sci_port *sci_parse_dt(struct platform_device *pdev,
 static int sci_probe_single(struct platform_device *dev,
 				      unsigned int index,
 				      struct plat_sci_port *p,
-				      struct sci_port *sciport)
+				      struct sci_port *sciport,
+				      struct resource *sci_res)
 {
 	int ret;
 
@@ -3425,6 +3417,11 @@ static int sci_probe_single(struct platform_device *dev,
 	if (ret)
 		return ret;
 
+	sciport->port.dev = &dev->dev;
+	ret = devm_pm_runtime_enable(&dev->dev);
+	if (ret)
+		return ret;
+
 	sciport->gpios = mctrl_gpio_init(&sciport->port, 0);
 	if (IS_ERR(sciport->gpios))
 		return PTR_ERR(sciport->gpios);
@@ -3438,18 +3435,37 @@ static int sci_probe_single(struct platform_device *dev,
 		sciport->port.flags |= UPF_HARD_FLOW;
 	}
 
-	ret = uart_add_one_port(&sci_uart_driver, &sciport->port);
-	if (ret) {
-		sci_cleanup_single(sciport);
-		return ret;
+	if (sci_uart_earlycon && sci_ports[0].port.mapbase == sci_res->start) {
+		/*
+		 * In case:
+		 * - this is the earlycon port (mapped on index 0 in sci_ports[]) and
+		 * - it now maps to an alias other than zero and
+		 * - the earlycon is still alive (e.g., "earlycon keep_bootcon" is
+		 *   available in bootargs)
+		 *
+		 * we need to avoid disabling clocks and PM domains through the runtime
+		 * PM APIs called in __device_attach(). For this, increment the runtime
+		 * PM reference counter (the clocks and PM domains were already enabled
+		 * by the bootloader). Otherwise the earlycon may access the HW when it
+		 * has no clocks enabled leading to failures (infinite loop in
+		 * sci_poll_put_char()).
+		 */
+		pm_runtime_get_noresume(&dev->dev);
+
+		/*
+		 * Skip cleanup the sci_port[0] in early_console_exit(), this
+		 * port is the same as the earlycon one.
+		 */
+		sci_uart_earlycon_dev_probing = true;
 	}
 
-	return 0;
+	return uart_add_one_port(&sci_uart_driver, &sciport->port);
 }
 
 static int sci_probe(struct platform_device *dev)
 {
 	struct plat_sci_port *p;
+	struct resource *res;
 	struct sci_port *sp;
 	unsigned int dev_id;
 	int ret;
@@ -3479,9 +3495,29 @@ static int sci_probe(struct platform_device *dev)
 	}
 
 	sp = &sci_ports[dev_id];
+
+	/*
+	 * In case:
+	 * - the probed port alias is zero (as the one used by earlycon), and
+	 * - the earlycon is still active (e.g., "earlycon keep_bootcon" in
+	 *   bootargs)
+	 *
+	 * defer the probe of this serial. This is a debug scenario and the user
+	 * must be aware of it.
+	 *
+	 * Except when the probed port is the same as the earlycon port.
+	 */
+
+	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	if (sci_uart_earlycon && sp == &sci_ports[0] && sp->port.mapbase != res->start)
+		return dev_err_probe(&dev->dev, -EBUSY, "sci_port[0] is used by earlycon!\n");
+
 	platform_set_drvdata(dev, sp);
 
-	ret = sci_probe_single(dev, dev_id, p, sp);
+	ret = sci_probe_single(dev, dev_id, p, sp, res);
 	if (ret)
 		return ret;
 
@@ -3562,7 +3598,23 @@ sh_early_platform_init_buffer("earlyprintk", &sci_driver,
 			   early_serial_buf, ARRAY_SIZE(early_serial_buf));
 #endif
 #ifdef CONFIG_SERIAL_SH_SCI_EARLYCON
-static struct plat_sci_port port_cfg __initdata;
+static struct plat_sci_port port_cfg;
+
+static int early_console_exit(struct console *co)
+{
+	struct sci_port *sci_port = &sci_ports[0];
+
+	/*
+	 * Clean the slot used by earlycon. A new SCI device might
+	 * map to this slot.
+	 */
+	if (!sci_uart_earlycon_dev_probing) {
+		memset(sci_port, 0, sizeof(*sci_port));
+		sci_uart_earlycon = false;
+	}
+
+	return 0;
+}
 
 static int __init early_console_setup(struct earlycon_device *device,
 				      int type)
@@ -3571,15 +3623,18 @@ static int __init early_console_setup(struct earlycon_device *device,
 		return -ENODEV;
 
 	device->port.type = type;
-	memcpy(&sci_ports[0].port, &device->port, sizeof(struct uart_port));
+	sci_ports[0].port = device->port;
 	port_cfg.type = type;
 	sci_ports[0].cfg = &port_cfg;
 	sci_ports[0].params = sci_probe_regmap(&port_cfg);
+	sci_uart_earlycon = true;
 	port_cfg.scscr = sci_serial_in(&sci_ports[0].port, SCSCR);
 	sci_serial_out(&sci_ports[0].port, SCSCR,
 		       SCSCR_RE | SCSCR_TE | port_cfg.scscr);
 
 	device->con->write = serial_console_write;
+	device->con->exit = early_console_exit;
+
 	return 0;
 }
 static int __init sci_early_console_setup(struct earlycon_device *device,
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index beb151be4d32..92ec51870d1d 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -287,7 +287,7 @@ static void cdns_uart_handle_rx(void *dev_id, unsigned int isrstatus)
 				continue;
 		}
 
-		if (uart_handle_sysrq_char(port, data))
+		if (uart_prepare_sysrq_char(port, data))
 			continue;
 
 		if (is_rxbs_support) {
@@ -495,7 +495,7 @@ static irqreturn_t cdns_uart_isr(int irq, void *dev_id)
 	    !(readl(port->membase + CDNS_UART_CR) & CDNS_UART_CR_RX_DIS))
 		cdns_uart_handle_rx(dev_id, isrstatus);
 
-	uart_port_unlock(port);
+	uart_unlock_and_check_sysrq(port);
 	return IRQ_HANDLED;
 }
 
@@ -1380,9 +1380,7 @@ static void cdns_uart_console_write(struct console *co, const char *s,
 	unsigned int imr, ctrl;
 	int locked = 1;
 
-	if (port->sysrq)
-		locked = 0;
-	else if (oops_in_progress)
+	if (oops_in_progress)
 		locked = uart_port_trylock_irqsave(port, &flags);
 	else
 		uart_port_lock_irqsave(port, &flags);
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 50c0c23ae678..449dbd216460 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -3617,7 +3617,7 @@ void console_sysfs_notify(void)
 		sysfs_notify(&consdev->kobj, NULL, "active");
 }
 
-static struct ctl_table tty_table[] = {
+static const struct ctl_table tty_table[] = {
 	{
 		.procname	= "legacy_tiocsti",
 		.data		= &tty_legacy_tiocsti,
diff --git a/drivers/tty/vt/selection.c b/drivers/tty/vt/selection.c
index 564341f1a74f..0bd6544e30a6 100644
--- a/drivers/tty/vt/selection.c
+++ b/drivers/tty/vt/selection.c
@@ -192,6 +192,20 @@ int set_selection_user(const struct tiocl_selection __user *sel,
 	if (copy_from_user(&v, sel, sizeof(*sel)))
 		return -EFAULT;
 
+	/*
+	 * TIOCL_SELCLEAR, TIOCL_SELPOINTER and TIOCL_SELMOUSEREPORT are OK to
+	 * use without CAP_SYS_ADMIN as they do not modify the selection.
+	 */
+	switch (v.sel_mode) {
+	case TIOCL_SELCLEAR:
+	case TIOCL_SELPOINTER:
+	case TIOCL_SELMOUSEREPORT:
+		break;
+	default:
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+	}
+
 	return set_selection_kernel(&v, tty);
 }
 
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 96842ce817af..be5564ed8c01 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -3345,8 +3345,6 @@ int tioclinux(struct tty_struct *tty, unsigned long arg)
 
 	switch (type) {
 	case TIOCL_SETSEL:
-		if (!capable(CAP_SYS_ADMIN))
-			return -EPERM;
 		return set_selection_user(param, tty);
 	case TIOCL_PASTESEL:
 		if (!capable(CAP_SYS_ADMIN))