[PATCH 1/5] Reset reason: add a scope value to the reset reason feature

[Juergen Borleis <jbe@pengutronix.de>]

Some systems do have more than one source to detect the reason of a reset.
In this case it depends on the initialization order which reason will be
reported to barebox. To avoid this race, this change adds a scope to the
function call to always accept settings with a wider scope and ignore
all settings with a limited scope.

This change is required to support systems where one reset reason source
is more reliable than other sources. Examples are all i.MX SoCs with
an internal reset reason detector and an external PMIC which has the same
capabilities. For these systems the external PMIC provides the correct
reset cause while the internal unit flags a POR only all the time. In order
to support one binary for more than one machine we cannot just disable the
internal reset reason detector, so we need this scope mechanism.

Assumption in this change is, the reset cause sources with a wider scope are
always reporting the correct reason and not vice versa.

Signed-off-by: Juergen Borleis <jbe@pengutronix.de>
---
 Documentation/user/reset-reason.rst   | 30 ++++++++++++++++++++++++++++
 Documentation/user/system-reset.rst   |  3 ++-
 arch/arm/mach-imx/imx1.c              |  8 ++++----
 arch/arm/mach-omap/am33xx_generic.c   | 14 ++++++-------
 arch/arm/mach-pxa/pxa2xx.c            | 12 ++++++------
 arch/arm/mach-pxa/pxa3xx.c            | 12 ++++++------
 arch/arm/mach-samsung/reset_source.c  |  8 ++++----
 arch/arm/mach-tegra/tegra20-pmc.c     | 14 ++++++-------
 common/Kconfig                        |  8 --------
 common/Makefile                       |  2 +-
 common/{reset_source.c => restart.c}  | 37 +++++++++++++++++++++++------------
 drivers/watchdog/im28wd.c             | 12 ++++++------
 drivers/watchdog/imxwd.c              |  8 ++++----
 include/{reset_source.h => restart.h} | 29 +++++++++++++--------------
 14 files changed, 115 insertions(+), 82 deletions(-)
 rename common/{reset_source.c => restart.c} (54%)
 rename include/{reset_source.h => restart.h} (71%)

diff --git a/Documentation/user/reset-reason.rst b/Documentation/user/reset-reason.rst
index a4872fa..525ade2 100644
--- a/Documentation/user/reset-reason.rst
+++ b/Documentation/user/reset-reason.rst
@@ -3,6 +3,9 @@
 Reset Reason
 ------------
 
+Using the Reset Reason
+~~~~~~~~~~~~~~~~~~~~~~
+
 To handle a device in a secure and safty manner many applications are using
 a watchdog or other ways to reset a system to bring it back into life if it
 hangs or crashes somehow.
@@ -45,3 +48,30 @@ The following values can help to detect the reason why the bootloader runs:
 It depends on your board/SoC and its features if the hardware is able to detect
 these reset reasons. Most of the time only ``POR`` and ``RST`` are supported
 but often ``WDG`` as well.
+
+.. _reset_reason_scope:
+
+Scope of Reset Reason
+~~~~~~~~~~~~~~~~~~~~~
+
+Some machines can detect the reset reason via different devices, for example
+via a SoC internal devices and an externally attached device. Both can provide
+the correct reason - or not. If their reset reason point of view differ, you
+need a ``scope`` to decide what reason is the correct one. Barebox provides
+the reset reason scope via the global variable ``system.reset.scope`` and
+the following values:
+
+* ``unknown``: the software can't define the scope of the reset reason.
+* ``cpu``: the inner core CPU only point of view.
+* ``soc``: the full SoC point of view.
+* ``machine``: the full machine point of view
+
+The scopes are rated: lowest rate is ``unknown`` and ``cpu``. The highest
+rate has the ``machine`` point of view. The ``soc`` point of view in inbetween.
+
+Why can the reset reason differ due to different scopes? Think about a SoC which
+is powered by a PMIC: the reset reason detection inside the SoC has the ``soc``
+scope, the PMIC's reset reason detection has the ``machine`` scope. In this case
+the ``soc`` scope reset reason is always ``POR``, while the ``machine`` scope
+reset reason is ``POR`` only on a real POR, ``RST`` due to an user
+intervention and ``WDG`` because the system has failed somehow.
diff --git a/Documentation/user/system-reset.rst b/Documentation/user/system-reset.rst
index e76e3a2..e902026 100644
--- a/Documentation/user/system-reset.rst
+++ b/Documentation/user/system-reset.rst
@@ -61,4 +61,5 @@ wide reset, like the POR is.
 Drawback of the PMIC solution is, you can't use the SoC's internal mechanisms to
 detect the :ref:`reset_reason` anymore. From the SoC point of view it is always
 a POR when the PMIC handles the system reset. If you are in luck the PMIC
-instead can provide this information if you depend on it.
+instead can provide this information if you depend on it. Refer
+:ref:`reset_reason_scope` for further information.
diff --git a/arch/arm/mach-imx/imx1.c b/arch/arm/mach-imx/imx1.c
index 51bdcbf..a3759df 100644
--- a/arch/arm/mach-imx/imx1.c
+++ b/arch/arm/mach-imx/imx1.c
@@ -18,7 +18,7 @@
 #include <mach/weim.h>
 #include <mach/iomux-v1.h>
 #include <mach/generic.h>
-#include <reset_source.h>
+#include <restart.h>
 
 #define MX1_RSR MX1_SCM_BASE_ADDR
 #define RSR_EXR	(1 << 0)
@@ -30,13 +30,13 @@ static void imx1_detect_reset_source(void)
 
 	switch (val) {
 	case RSR_EXR:
-		reset_source_set(RESET_RST);
+		reset_source_set(RESET_RST, FEATURE_SCOPE_SOC);
 		return;
 	case RSR_WDR:
-		reset_source_set(RESET_WDG);
+		reset_source_set(RESET_WDG, FEATURE_SCOPE_SOC);
 		return;
 	case 0:
-		reset_source_set(RESET_POR);
+		reset_source_set(RESET_POR, FEATURE_SCOPE_SOC);
 		return;
 	default:
 		/* else keep the default 'unknown' state */
diff --git a/arch/arm/mach-omap/am33xx_generic.c b/arch/arm/mach-omap/am33xx_generic.c
index 7ce32f0..8ac1290 100644
--- a/arch/arm/mach-omap/am33xx_generic.c
+++ b/arch/arm/mach-omap/am33xx_generic.c
@@ -26,7 +26,7 @@
 #include <mach/sys_info.h>
 #include <mach/am33xx-generic.h>
 #include <mach/gpmc.h>
-#include <reset_source.h>
+#include <restart.h>
 
 void __noreturn am33xx_reset_cpu(unsigned long addr)
 {
@@ -167,23 +167,23 @@ static void am33xx_detect_reset_reason(void)
 
 	switch (val) {
 	case (1 << 9):
-		reset_source_set(RESET_JTAG);
+		reset_source_set(RESET_JTAG, FEATURE_SCOPE_SOC);
 		break;
 	case (1 << 5):
-		reset_source_set(RESET_EXT);
+		reset_source_set(RESET_EXT, FEATURE_SCOPE_SOC);
 		break;
 	case (1 << 4):
 	case (1 << 3):
-		reset_source_set(RESET_WDG);
+		reset_source_set(RESET_WDG, FEATURE_SCOPE_SOC);
 		break;
 	case (1 << 1):
-		reset_source_set(RESET_RST);
+		reset_source_set(RESET_RST, FEATURE_SCOPE_SOC);
 		break;
 	case (1 << 0):
-		reset_source_set(RESET_POR);
+		reset_source_set(RESET_POR, FEATURE_SCOPE_SOC);
 		break;
 	default:
-		reset_source_set(RESET_UKWN);
+		reset_source_set(RESET_UKWN, FEATURE_SCOPE_SOC);
 		break;
 	}
 }
diff --git a/arch/arm/mach-pxa/pxa2xx.c b/arch/arm/mach-pxa/pxa2xx.c
index b712b38..973e394 100644
--- a/arch/arm/mach-pxa/pxa2xx.c
+++ b/arch/arm/mach-pxa/pxa2xx.c
@@ -14,7 +14,7 @@
 
 #include <common.h>
 #include <init.h>
-#include <reset_source.h>
+#include <restart.h>
 #include <mach/hardware.h>
 #include <mach/pxa-regs.h>
 
@@ -28,15 +28,15 @@ static int pxa_detect_reset_source(void)
 	 * Order is important, as many bits can be set together
 	 */
 	if (reg & RCSR_GPR)
-		reset_source_set(RESET_RST);
+		reset_source_set(RESET_RST, FEATURE_SCOPE_SOC);
 	else if (reg & RCSR_WDR)
-		reset_source_set(RESET_WDG);
+		reset_source_set(RESET_WDG, FEATURE_SCOPE_SOC);
 	else if (reg & RCSR_HWR)
-		reset_source_set(RESET_POR);
+		reset_source_set(RESET_POR, FEATURE_SCOPE_SOC);
 	else if (reg & RCSR_SMR)
-		reset_source_set(RESET_WKE);
+		reset_source_set(RESET_WKE, FEATURE_SCOPE_SOC);
 	else
-		reset_source_set(RESET_UKWN);
+		reset_source_set(RESET_UKWN, FEATURE_SCOPE_SOC);
 
 	return 0;
 }
diff --git a/arch/arm/mach-pxa/pxa3xx.c b/arch/arm/mach-pxa/pxa3xx.c
index 86ca63b..e273996 100644
--- a/arch/arm/mach-pxa/pxa3xx.c
+++ b/arch/arm/mach-pxa/pxa3xx.c
@@ -14,7 +14,7 @@
 
 #include <common.h>
 #include <init.h>
-#include <reset_source.h>
+#include <restart.h>
 #include <mach/hardware.h>
 #include <mach/pxa-regs.h>
 
@@ -28,15 +28,15 @@ static int pxa_detect_reset_source(void)
 	 * Order is important, as many bits can be set together
 	 */
 	if (reg & ARSR_GPR)
-		reset_source_set(RESET_RST);
+		reset_source_set(RESET_RST, FEATURE_SCOPE_SOC);
 	else if (reg & ARSR_WDT)
-		reset_source_set(RESET_WDG);
+		reset_source_set(RESET_WDG, FEATURE_SCOPE_SOC);
 	else if (reg & ARSR_HWR)
-		reset_source_set(RESET_POR);
+		reset_source_set(RESET_POR, FEATURE_SCOPE_SOC);
 	else if (reg & ARSR_LPMR)
-		reset_source_set(RESET_WKE);
+		reset_source_set(RESET_WKE, FEATURE_SCOPE_SOC);
 	else
-		reset_source_set(RESET_UKWN);
+		reset_source_set(RESET_UKWN, FEATURE_SCOPE_SOC);
 
 	return 0;
 }
diff --git a/arch/arm/mach-samsung/reset_source.c b/arch/arm/mach-samsung/reset_source.c
index c1365b2..e122909 100644
--- a/arch/arm/mach-samsung/reset_source.c
+++ b/arch/arm/mach-samsung/reset_source.c
@@ -15,7 +15,7 @@
 #include <common.h>
 #include <init.h>
 #include <io.h>
-#include <reset_source.h>
+#include <restart.h>
 #include <mach/s3c-iomap.h>
 
 /* S3C2440 relevant */
@@ -29,21 +29,21 @@ static int s3c_detect_reset_source(void)
 	u32 reg = readl(S3C_GPIO_BASE + S3C2440_GSTATUS2);
 
 	if (reg & S3C2440_GSTATUS2_PWRST) {
-		reset_source_set(RESET_POR);
+		reset_source_set(RESET_POR, FEATURE_SCOPE_SOC);
 		writel(S3C2440_GSTATUS2_PWRST,
 					S3C_GPIO_BASE + S3C2440_GSTATUS2);
 		return 0;
 	}
 
 	if (reg & S3C2440_GSTATUS2_SLEEPRST) {
-		reset_source_set(RESET_WKE);
+		reset_source_set(RESET_WKE, FEATURE_SCOPE_SOC);
 		writel(S3C2440_GSTATUS2_SLEEPRST,
 					S3C_GPIO_BASE + S3C2440_GSTATUS2);
 		return 0;
 	}
 
 	if (reg & S3C2440_GSTATUS2_WDRST) {
-		reset_source_set(RESET_WDG);
+		reset_source_set(RESET_WDG, FEATURE_SCOPE_SOC);
 		writel(S3C2440_GSTATUS2_WDRST,
 					S3C_GPIO_BASE + S3C2440_GSTATUS2);
 		return 0;
diff --git a/arch/arm/mach-tegra/tegra20-pmc.c b/arch/arm/mach-tegra/tegra20-pmc.c
index eaa5ac7..6493eea 100644
--- a/arch/arm/mach-tegra/tegra20-pmc.c
+++ b/arch/arm/mach-tegra/tegra20-pmc.c
@@ -28,7 +28,7 @@
 #include <linux/reset.h>
 #include <mach/lowlevel.h>
 #include <mach/tegra-powergate.h>
-#include <reset_source.h>
+#include <restart.h>
 
 #include <mach/tegra20-pmc.h>
 
@@ -180,22 +180,22 @@ static void tegra20_pmc_detect_reset_cause(void)
 	switch ((reg & PMC_RST_STATUS_RST_SRC_MASK) >>
 	         PMC_RST_STATUS_RST_SRC_SHIFT) {
 	case PMC_RST_STATUS_RST_SRC_POR:
-		reset_source_set(RESET_POR);
+		reset_source_set(RESET_POR, FEATURE_SCOPE_SOC);
 		break;
 	case PMC_RST_STATUS_RST_SRC_WATCHDOG:
-		reset_source_set(RESET_WDG);
+		reset_source_set(RESET_WDG, FEATURE_SCOPE_SOC);
 		break;
 	case PMC_RST_STATUS_RST_SRC_LP0:
-		reset_source_set(RESET_WKE);
+		reset_source_set(RESET_WKE, FEATURE_SCOPE_SOC);
 		break;
 	case PMC_RST_STATUS_RST_SRC_SW_MAIN:
-		reset_source_set(RESET_RST);
+		reset_source_set(RESET_RST, FEATURE_SCOPE_SOC);
 		break;
 	case PMC_RST_STATUS_RST_SRC_SENSOR:
-		reset_source_set(RESET_THERM);
+		reset_source_set(RESET_THERM, FEATURE_SCOPE_SOC);
 		break;
 	default:
-		reset_source_set(RESET_UKWN);
+		reset_source_set(RESET_UKWN, FEATURE_SCOPE_SOC);
 		break;
 	}
 }
diff --git a/common/Kconfig b/common/Kconfig
index 3dfb5ac..f241482 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -716,14 +716,6 @@ config STATE
 	select OFTREE
 	select PARAMETER
 
-config RESET_SOURCE
-	bool "detect Reset cause"
-	depends on GLOBALVAR
-	help
-	  Provide a global variable at runtine which reflects the possible cause
-	  of the reset and why the bootloader is currently running. It can be
-	  useful for any kind of system recovery or repair.
-
 endmenu
 
 menu "Debugging"
diff --git a/common/Makefile b/common/Makefile
index 2738238..16e6690 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -8,6 +8,7 @@ obj-y				+= misc.o
 obj-y				+= memsize.o
 obj-y				+= resource.o
 obj-y				+= bootsource.o
+obj-y				+= restart.o
 obj-$(CONFIG_AUTO_COMPLETE)	+= complete.o
 obj-$(CONFIG_BANNER)		+= version.o
 obj-$(CONFIG_BAREBOX_UPDATE)	+= bbu.o
@@ -40,7 +41,6 @@ obj-$(CONFIG_OFTREE)		+= oftree.o
 obj-$(CONFIG_PARTITION_DISK)	+= partitions.o partitions/
 obj-$(CONFIG_PASSWORD)		+= password.o
 obj-$(CONFIG_POLLER)		+= poller.o
-obj-$(CONFIG_RESET_SOURCE)	+= reset_source.o
 obj-$(CONFIG_SHELL_HUSH)	+= hush.o
 obj-$(CONFIG_SHELL_SIMPLE)	+= parser.o
 obj-$(CONFIG_STATE)		+= state.o
diff --git a/common/reset_source.c b/common/restart.c
similarity index 54%
rename from common/reset_source.c
rename to common/restart.c
index 80002a9..5b53264 100644
--- a/common/reset_source.c
+++ b/common/restart.c
@@ -1,5 +1,5 @@
 /*
- * (C) Copyright 2012 Juergen Beisert - <kernel@pengutronix.de>
+ * (C) Copyright 2015 Juergen Borleis - <kernel@pengutronix.de>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
@@ -14,9 +14,15 @@
 
 #include <common.h>
 #include <init.h>
-#include <environment.h>
+#include <restart.h>
 #include <globalvar.h>
-#include <reset_source.h>
+
+static const char * const scope_names[] = {
+	[FEATURE_SCOPE_UNKNOWN] = "unknown",
+	[FEATURE_SCOPE_CPU] = "cpu",
+	[FEATURE_SCOPE_SOC] = "soc",
+	[FEATURE_SCOPE_MACHINE] = "machine",
+};
 
 static const char * const reset_src_names[] = {
 	[RESET_UKWN] = "unknown",
@@ -29,7 +35,10 @@ static const char * const reset_src_names[] = {
 	[RESET_EXT] = "EXT",
 };
 
-static enum reset_src_type reset_source;
+/* handle reset cause detection feature */
+
+static int reset_source;
+static int reset_source_scope;
 
 enum reset_src_type reset_source_get(void)
 {
@@ -37,20 +46,22 @@ enum reset_src_type reset_source_get(void)
 }
 EXPORT_SYMBOL(reset_source_get);
 
-void reset_source_set(enum reset_src_type st)
+void reset_source_set(enum reset_src_type st, enum f_scope scope)
 {
-	reset_source = st;
+	if (scope <= reset_source_scope)
+		return; /* just ignore this setting */
 
-	globalvar_add_simple("system.reset", reset_src_names[reset_source]);
+	reset_source = st;
+	reset_source_scope = scope;
 }
 EXPORT_SYMBOL(reset_source_set);
 
-/* ensure this runs after the 'global' device is already registerd */
-static int reset_source_init(void)
+static int reset_feature_init(void)
 {
-	reset_source_set(reset_source);
-
+	globalvar_add_simple_enum("system.reset", &reset_source, reset_src_names,
+					ARRAY_SIZE(reset_src_names));
+	globalvar_add_simple_enum("system.reset.scope", &reset_source_scope,
+					scope_names, ARRAY_SIZE(scope_names));
 	return 0;
 }
-
-coredevice_initcall(reset_source_init);
+coredevice_initcall(reset_feature_init);
diff --git a/drivers/watchdog/im28wd.c b/drivers/watchdog/im28wd.c
index a9093a7..c824a25 100644
--- a/drivers/watchdog/im28wd.c
+++ b/drivers/watchdog/im28wd.c
@@ -21,7 +21,7 @@
 #include <errno.h>
 #include <malloc.h>
 #include <watchdog.h>
-#include <reset_source.h>
+#include <restart.h>
 #include <linux/err.h>
 
 #define MXS_RTC_CTRL 0x0
@@ -164,27 +164,27 @@ static void __maybe_unused imx28_detect_reset_source(const struct imx28_wd *p)
 		if (reg & MXS_RTC_PERSISTENT0_ALARM_WAKE) {
 			writel(MXS_RTC_PERSISTENT0_ALARM_WAKE,
 				p->regs + MXS_RTC_PERSISTENT0 + MXS_RTC_CLR_ADDR);
-			reset_source_set(RESET_WKE);
+			reset_source_set(RESET_WKE, FEATURE_SCOPE_SOC);
 			return;
 		}
-		reset_source_set(RESET_POR);
+		reset_source_set(RESET_POR, FEATURE_SCOPE_SOC);
 		return;
 	}
 	if (reg & MXS_RTC_PERSISTENT0_THM_RST) {
 		writel(MXS_RTC_PERSISTENT0_THM_RST,
 			p->regs + MXS_RTC_PERSISTENT0 + MXS_RTC_CLR_ADDR);
-		reset_source_set(RESET_RST);
+		reset_source_set(RESET_RST, FEATURE_SCOPE_SOC);
 		return;
 	}
 	reg = readl(p->regs + MXS_RTC_PERSISTENT1);
 	if (reg & MXS_RTC_PERSISTENT1_FORCE_UPDATER) {
 		writel(MXS_RTC_PERSISTENT1_FORCE_UPDATER,
 			p->regs + MXS_RTC_PERSISTENT1 + MXS_RTC_CLR_ADDR);
-		reset_source_set(RESET_WDG);
+		reset_source_set(RESET_WDG, FEATURE_SCOPE_SOC);
 		return;
 	}
 
-	reset_source_set(RESET_RST);
+	reset_source_set(RESET_RST, FEATURE_SCOPE_SOC);
 }
 
 static int imx28_wd_probe(struct device_d *dev)
diff --git a/drivers/watchdog/imxwd.c b/drivers/watchdog/imxwd.c
index 5ffbac7..f3decae 100644
--- a/drivers/watchdog/imxwd.c
+++ b/drivers/watchdog/imxwd.c
@@ -19,7 +19,7 @@
 #include <errno.h>
 #include <malloc.h>
 #include <watchdog.h>
-#include <reset_source.h>
+#include <restart.h>
 
 struct imx_wd;
 
@@ -138,17 +138,17 @@ static void imx_watchdog_detect_reset_source(struct imx_wd *priv)
 	u16 val = readw(priv->base + IMX21_WDOG_WSTR);
 
 	if (val & WSTR_COLDSTART) {
-		reset_source_set(RESET_POR);
+		reset_source_set(RESET_POR, FEATURE_SCOPE_SOC);
 		return;
 	}
 
 	if (val & (WSTR_HARDRESET | WSTR_WARMSTART)) {
-		reset_source_set(RESET_RST);
+		reset_source_set(RESET_RST, FEATURE_SCOPE_SOC);
 		return;
 	}
 
 	if (val & WSTR_WDOG) {
-		reset_source_set(RESET_WDG);
+		reset_source_set(RESET_WDG, FEATURE_SCOPE_SOC);
 		return;
 	}
 
diff --git a/include/reset_source.h b/include/restart.h
similarity index 71%
rename from include/reset_source.h
rename to include/restart.h
index 367f93b..4215760 100644
--- a/include/reset_source.h
+++ b/include/restart.h
@@ -10,8 +10,18 @@
  * GNU General Public License for more details.
  */
 
-#ifndef __INCLUDE_RESET_SOURCE_H
-# define __INCLUDE_RESET_SOURCE_H
+#ifndef __INCLUDE_SYSTEM_RESTART_H
+# define __INCLUDE_SYSTEM_RESTART_H
+
+/* define a scope a specific hardware feature can cope with */
+enum f_scope {
+	FEATURE_SCOPE_UNKNOWN,
+	FEATURE_SCOPE_CPU,
+	FEATURE_SCOPE_SOC,
+	FEATURE_SCOPE_MACHINE,
+};
+
+/* reset cause detection feature */
 
 enum reset_src_type {
 	RESET_UKWN,	/* maybe the SoC cannot detect the reset source */
@@ -24,18 +34,7 @@ enum reset_src_type {
 	RESET_EXT,	/* External reset through device pin */
 };
 
-#ifdef CONFIG_RESET_SOURCE
-void reset_source_set(enum reset_src_type);
+void reset_source_set(enum reset_src_type, enum f_scope);
 enum reset_src_type reset_source_get(void);
-#else
-static inline void reset_source_set(enum reset_src_type unused)
-{
-}
-
-static inline enum reset_src_type reset_source_get(void)
-{
-	return RESET_UKWN;
-}
-#endif
 
-#endif /* __INCLUDE_RESET_SOURCE_H */
+#endif /* __INCLUDE_SYSTEM_RESTART_H */
-- 
2.1.4


_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox