Merge tag 'for-v4.5-rc/omap-critical-fixes-a' of git://git.kernel.org/pub/scm/linux/kernel/git/pjw/omap-pending into fixes

ARM: OMAP2+: critical DRA7xx fix for v4.5-rc

Force the DRA7xx Ethernet internal clock source to stay enabled
per TI erratum i877:

http://www.ti.com/lit/er/sprz429h/sprz429h.pdf

Otherwise, if the Ethernet internal clock source is disabled, the
chip will age prematurely, and the RGMII I/O timing will soon
fail to meet the delay time and skew specifications for 1000Mbps
Ethernet.

This fix should go in as soon as possible.

Basic build, boot, and PM test results are available here:

http://www.pwsan.com/omap/testlogs/omap-critical-fixes-for-v4.5-rc/20160307014209/

* tag 'for-v4.5-rc/omap-critical-fixes-a' of git://git.kernel.org/pub/scm/linux/kernel/git/pjw/omap-pending:
  ARM: dts: dra7: do not gate cpsw clock due to errata i877
  ARM: OMAP2+: hwmod: Introduce ti,no-idle dt property

Signed-off-by: Olof Johansson <olof@lixom.net>

4 files changed, 22 insertions, 1 deletions

diff --git a/Documentation/devicetree/bindings/arm/omap/omap.txt b/Documentation/devicetree/bindings/arm/omap/omap.txt
index a2bd593881ca..66422d663184 100644
--- a/Documentation/devicetree/bindings/arm/omap/omap.txt
+++ b/Documentation/devicetree/bindings/arm/omap/omap.txt
@@ -23,6 +23,7 @@ Optional properties:
   during suspend.
 - ti,no-reset-on-init: When present, the module should not be reset at init
 - ti,no-idle-on-init: When present, the module should not be idled at init
+- ti,no-idle: When present, the module is never allowed to idle.
 
 Example:
 
diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi
index c4d9175b90dc..f82aa44c3cee 100644
--- a/arch/arm/boot/dts/dra7.dtsi
+++ b/arch/arm/boot/dts/dra7.dtsi
@@ -1500,6 +1500,16 @@
 			       0x48485200 0x2E00>;
 			#address-cells = <1>;
 			#size-cells = <1>;
+
+			/*
+			 * Do not allow gating of cpsw clock as workaround
+			 * for errata i877. Keeping internal clock disabled
+			 * causes the device switching characteristics
+			 * to degrade over time and eventually fail to meet
+			 * the data manual delay time/skew specs.
+			 */
+			ti,no-idle;
+
 			/*
 			 * rx_thresh_pend
 			 * rx_pend
diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index e9f65fec55c0..b6d62e4cdfdd 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -2200,6 +2200,11 @@ static int _enable(struct omap_hwmod *oh)
  */
 static int _idle(struct omap_hwmod *oh)
 {
+	if (oh->flags & HWMOD_NO_IDLE) {
+		oh->_int_flags |= _HWMOD_SKIP_ENABLE;
+		return 0;
+	}
+
 	pr_debug("omap_hwmod: %s: idling\n", oh->name);
 
 	if (oh->_state != _HWMOD_STATE_ENABLED) {
@@ -2504,6 +2509,8 @@ static int __init _init(struct omap_hwmod *oh, void *data)
 			oh->flags |= HWMOD_INIT_NO_RESET;
 		if (of_find_property(np, "ti,no-idle-on-init", NULL))
 			oh->flags |= HWMOD_INIT_NO_IDLE;
+		if (of_find_property(np, "ti,no-idle", NULL))
+			oh->flags |= HWMOD_NO_IDLE;
 	}
 
 	oh->_state = _HWMOD_STATE_INITIALIZED;
@@ -2630,7 +2637,7 @@ static void __init _setup_postsetup(struct omap_hwmod *oh)
 	 * XXX HWMOD_INIT_NO_IDLE does not belong in hwmod data -
 	 * it should be set by the core code as a runtime flag during startup
 	 */
-	if ((oh->flags & HWMOD_INIT_NO_IDLE) &&
+	if ((oh->flags & (HWMOD_INIT_NO_IDLE | HWMOD_NO_IDLE)) &&
 	    (postsetup_state == _HWMOD_STATE_IDLE)) {
 		oh->_int_flags |= _HWMOD_SKIP_ENABLE;
 		postsetup_state = _HWMOD_STATE_ENABLED;
diff --git a/arch/arm/mach-omap2/omap_hwmod.h b/arch/arm/mach-omap2/omap_hwmod.h
index 76bce11c85a4..7c7a31169475 100644
--- a/arch/arm/mach-omap2/omap_hwmod.h
+++ b/arch/arm/mach-omap2/omap_hwmod.h
@@ -525,6 +525,8 @@ struct omap_hwmod_omap4_prcm {
  *     or idled.
  * HWMOD_OPT_CLKS_NEEDED: The optional clocks are needed for the module to
  *     operate and they need to be handled at the same time as the main_clk.
+ * HWMOD_NO_IDLE: Do not idle the hwmod at all. Useful to handle certain
+ *     IPs like CPSW on DRA7, where clocks to this module cannot be disabled.
  */
 #define HWMOD_SWSUP_SIDLE			(1 << 0)
 #define HWMOD_SWSUP_MSTANDBY			(1 << 1)
@@ -541,6 +543,7 @@ struct omap_hwmod_omap4_prcm {
 #define HWMOD_SWSUP_SIDLE_ACT			(1 << 12)
 #define HWMOD_RECONFIG_IO_CHAIN			(1 << 13)
 #define HWMOD_OPT_CLKS_NEEDED			(1 << 14)
+#define HWMOD_NO_IDLE				(1 << 15)
 
 /*
  * omap_hwmod._int_flags definitions