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authorLinus Torvalds <torvalds@linux-foundation.org>2017-08-13 12:33:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-08-13 12:33:35 -0700
commit438630ef5b3c8755d642b6ca3bc10625ab0af79b (patch)
tree69ea9bc5b04be9a8e872accee0514382a6326704 /drivers/acpi
parentdd95f1860768e340875d6a325df18d73f2dea304 (diff)
parent9527b82ae3af1ebf465506868fb55e7f862cd9da (diff)
Merge tag 'tty-4.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial fixes from Greg KH: "Here are two tty serial driver fixes for 4.13-rc5. One is a revert of a -rc1 patch that turned out to not be a good idea, and the other is a fix for the pl011 serial driver. Both have been in linux-next with no reported issues" * tag 'tty-4.13-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: Revert "serial: Delete dead code for CIR serial ports" tty: pl011: fix initialization order of QDF2400 E44
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/spcr.c36
1 files changed, 34 insertions, 2 deletions
diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
index 4ac3e06b41d8..98aa8c808a33 100644
--- a/drivers/acpi/spcr.c
+++ b/drivers/acpi/spcr.c
@@ -17,6 +17,16 @@
#include <linux/serial_core.h>
/*
+ * Erratum 44 for QDF2432v1 and QDF2400v1 SoCs describes the BUSY bit as
+ * occasionally getting stuck as 1. To avoid the potential for a hang, check
+ * TXFE == 0 instead of BUSY == 1. This may not be suitable for all UART
+ * implementations, so only do so if an affected platform is detected in
+ * parse_spcr().
+ */
+bool qdf2400_e44_present;
+EXPORT_SYMBOL(qdf2400_e44_present);
+
+/*
* Some Qualcomm Datacenter Technologies SoCs have a defective UART BUSY bit.
* Detect them by examining the OEM fields in the SPCR header, similiar to PCI
* quirk detection in pci_mcfg.c.
@@ -147,8 +157,30 @@ int __init parse_spcr(bool earlycon)
goto done;
}
- if (qdf2400_erratum_44_present(&table->header))
- uart = "qdf2400_e44";
+ /*
+ * If the E44 erratum is required, then we need to tell the pl011
+ * driver to implement the work-around.
+ *
+ * The global variable is used by the probe function when it
+ * creates the UARTs, whether or not they're used as a console.
+ *
+ * If the user specifies "traditional" earlycon, the qdf2400_e44
+ * console name matches the EARLYCON_DECLARE() statement, and
+ * SPCR is not used. Parameter "earlycon" is false.
+ *
+ * If the user specifies "SPCR" earlycon, then we need to update
+ * the console name so that it also says "qdf2400_e44". Parameter
+ * "earlycon" is true.
+ *
+ * For consistency, if we change the console name, then we do it
+ * for everyone, not just earlycon.
+ */
+ if (qdf2400_erratum_44_present(&table->header)) {
+ qdf2400_e44_present = true;
+ if (earlycon)
+ uart = "qdf2400_e44";
+ }
+
if (xgene_8250_erratum_present(table))
iotype = "mmio32";