From 7a0c19337c38a1ffa7587272e7784e6431e78eaa Mon Sep 17 00:00:00 2001
From: Paul Walmsley <paul@pwsan.com>
Date: Sun, 21 Oct 2012 01:01:09 -0600
Subject: ARM: OMAP2+: PRM: remove PRM weak functions

Remove the now-unused PRM weak functions from prm_common.c.  These
were formerly used to ensure that some OMAP2/3 PRM code would build on
OMAP4, but none of those functions ever would have worked on OMAP4 due
to an incompatible PRM register layout.  Now all that has been cleaned
up and these can be removed.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Reviewed-by: Russ Dill <Russ.Dill@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
---
 arch/arm/mach-omap2/prm_common.c | 62 ----------------------------------------
 1 file changed, 62 deletions(-)

(limited to 'arch/arm/mach-omap2/prm_common.c')

diff --git a/arch/arm/mach-omap2/prm_common.c b/arch/arm/mach-omap2/prm_common.c
index 6b4d332be2f6..0a100d9465b4 100644
--- a/arch/arm/mach-omap2/prm_common.c
+++ b/arch/arm/mach-omap2/prm_common.c
@@ -318,65 +318,3 @@ err:
 	omap_prcm_irq_cleanup();
 	return -ENOMEM;
 }
-
-/*
- * Stubbed functions so that common files continue to build when
- * custom builds are used
- * XXX These are temporary and should be removed at the earliest possible
- * opportunity
- */
-u32 __weak omap2_prm_read_mod_reg(s16 module, u16 idx)
-{
-	WARN(1, "prm: omap2xxx/omap3xxx specific function called on non-omap2xxx/3xxx\n");
-	return 0;
-}
-
-void __weak omap2_prm_write_mod_reg(u32 val, s16 module, u16 idx)
-{
-	WARN(1, "prm: omap2xxx/omap3xxx specific function called on non-omap2xxx/3xxx\n");
-}
-
-u32 __weak omap2_prm_rmw_mod_reg_bits(u32 mask, u32 bits,
-		s16 module, s16 idx)
-{
-	WARN(1, "prm: omap2xxx/omap3xxx specific function called on non-omap2xxx/3xxx\n");
-	return 0;
-}
-
-u32 __weak omap2_prm_set_mod_reg_bits(u32 bits, s16 module, s16 idx)
-{
-	WARN(1, "prm: omap2xxx/omap3xxx specific function called on non-omap2xxx/3xxx\n");
-	return 0;
-}
-
-u32 __weak omap2_prm_clear_mod_reg_bits(u32 bits, s16 module, s16 idx)
-{
-	WARN(1, "prm: omap2xxx/omap3xxx specific function called on non-omap2xxx/3xxx\n");
-	return 0;
-}
-
-u32 __weak omap2_prm_read_mod_bits_shift(s16 domain, s16 idx, u32 mask)
-{
-	WARN(1, "prm: omap2xxx/omap3xxx specific function called on non-omap2xxx/3xxx\n");
-	return 0;
-}
-
-int __weak omap2_prm_is_hardreset_asserted(s16 prm_mod, u8 shift)
-{
-	WARN(1, "prm: omap2xxx/omap3xxx specific function called on non-omap2xxx/3xxx\n");
-	return 0;
-}
-
-int __weak omap2_prm_assert_hardreset(s16 prm_mod, u8 shift)
-{
-	WARN(1, "prm: omap2xxx/omap3xxx specific function called on non-omap2xxx/3xxx\n");
-	return 0;
-}
-
-int __weak omap2_prm_deassert_hardreset(s16 prm_mod, u8 rst_shift,
-						u8 st_shift)
-{
-	WARN(1, "prm: omap2xxx/omap3xxx specific function called on non-omap2xxx/3xxx\n");
-	return 0;
-}
-
-- 
cgit v1.2.3


From e24c35737413c8626f9c4e8f47e33926b7ab7f23 Mon Sep 17 00:00:00 2001
From: Paul Walmsley <paul@pwsan.com>
Date: Sun, 21 Oct 2012 01:01:11 -0600
Subject: ARM: OMAP2+: PRM: prepare for use of prm_ll_data function pointers

There are several PRM operations which behave similarly across OMAP2+
SoCs, but which have slight differences in their underlying
implementations.  For example, to fetch the SoC's last reset sources,
different registers are read across OMAP2xxx, 3xxx, and 44xx, and
different bits are used on each SoC.  But the information returned is
so similar that a single, common interface for drivers is useful.

This patch creates the support code for this function pointer
registration process.  No function pointers are included yet, but a
subsequent patch will create one for the reset source API.

To illustrate the end goal with the above reset source example, each
per-SoC driver will use its own low-level implementation function --
e.g., prm2xxx.c would contain omap2xxx_prm_read_reset_sources().  This
function would read the appropriate register and remap the register
bits to a standard set of reset source bits.  When the prm2xxx.c
driver is loaded, it would register this function with the common PRM
driver, prm.c.  prm.c would then export a common function,
omap_prm_read_reset_sources().  Calling it would call through to the
function pointer for the currently-registered SoC PRM driver.  This
will allow other drivers to use PRM-provided data and operations
without needing to know which SoC is currently in use.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
---
 arch/arm/mach-omap2/prm.h        | 11 +++++++++
 arch/arm/mach-omap2/prm_common.c | 52 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

(limited to 'arch/arm/mach-omap2/prm_common.c')

diff --git a/arch/arm/mach-omap2/prm.h b/arch/arm/mach-omap2/prm.h
index 39d562169d18..3e51c1d15757 100644
--- a/arch/arm/mach-omap2/prm.h
+++ b/arch/arm/mach-omap2/prm.h
@@ -52,5 +52,16 @@
 #define OMAP_POWERSTATE_SHIFT				0
 #define OMAP_POWERSTATE_MASK				(0x3 << 0)
 
+#ifndef __ASSEMBLER__
+
+/**
+ * struct prm_ll_data - fn ptrs to per-SoC PRM function implementations
+ */
+struct prm_ll_data {};
+
+extern int prm_register(struct prm_ll_data *pld);
+extern int prm_unregister(struct prm_ll_data *pld);
+
+#endif
 
 #endif
diff --git a/arch/arm/mach-omap2/prm_common.c b/arch/arm/mach-omap2/prm_common.c
index 0a100d9465b4..8670a3c4bc5e 100644
--- a/arch/arm/mach-omap2/prm_common.c
+++ b/arch/arm/mach-omap2/prm_common.c
@@ -53,6 +53,13 @@ static struct irq_chip_generic **prcm_irq_chips;
  */
 static struct omap_prcm_irq_setup *prcm_irq_setup;
 
+/*
+ * prm_ll_data: function pointers to SoC-specific implementations of
+ * common PRM functions
+ */
+static struct prm_ll_data null_prm_ll_data;
+static struct prm_ll_data *prm_ll_data = &null_prm_ll_data;
+
 /* Private functions */
 
 /*
@@ -318,3 +325,48 @@ err:
 	omap_prcm_irq_cleanup();
 	return -ENOMEM;
 }
+
+/**
+ * prm_register - register per-SoC low-level data with the PRM
+ * @pld: low-level per-SoC OMAP PRM data & function pointers to register
+ *
+ * Register per-SoC low-level OMAP PRM data and function pointers with
+ * the OMAP PRM common interface.  The caller must keep the data
+ * pointed to by @pld valid until it calls prm_unregister() and
+ * it returns successfully.  Returns 0 upon success, -EINVAL if @pld
+ * is NULL, or -EEXIST if prm_register() has already been called
+ * without an intervening prm_unregister().
+ */
+int prm_register(struct prm_ll_data *pld)
+{
+	if (!pld)
+		return -EINVAL;
+
+	if (prm_ll_data != &null_prm_ll_data)
+		return -EEXIST;
+
+	prm_ll_data = pld;
+
+	return 0;
+}
+
+/**
+ * prm_unregister - unregister per-SoC low-level data & function pointers
+ * @pld: low-level per-SoC OMAP PRM data & function pointers to unregister
+ *
+ * Unregister per-SoC low-level OMAP PRM data and function pointers
+ * that were previously registered with prm_register().  The
+ * caller may not destroy any of the data pointed to by @pld until
+ * this function returns successfully.  Returns 0 upon success, or
+ * -EINVAL if @pld is NULL or if @pld does not match the struct
+ * prm_ll_data * previously registered by prm_register().
+ */
+int prm_unregister(struct prm_ll_data *pld)
+{
+	if (!pld || prm_ll_data != pld)
+		return -EINVAL;
+
+	prm_ll_data = &null_prm_ll_data;
+
+	return 0;
+}
-- 
cgit v1.2.3


From 2bb2a5d30abb0dc99d074877bfad2056142c730b Mon Sep 17 00:00:00 2001
From: Paul Walmsley <paul@pwsan.com>
Date: Sun, 21 Oct 2012 01:01:13 -0600
Subject: ARM: OMAP2+: PRM: create PRM reset source API for the watchdog timer
 driver

The OMAP watchdog timer driver needs to determine what caused the SoC
to reset for its GETBOOTSTATUS ioctl.  So, define a set of standard
reset sources across OMAP SoCs.  For OMAP2xxx, 3xxx, and 4xxx SoCs,
define mappings from the SoC-specific reset source register bits to
the standardized reset source IDs.  Create SoC-specific PRM functions
that read the appropriate per-SoC register and use the mapping to
return the standardized reset bits.  Register the SoC-specific PRM
functions with the common PRM code via prm_register().  Create a
function in the common PRM code, prm_read_reset_sources(), that
calls the SoC-specific function, registered during boot.

This patch does not yet handle some SoCs, such as AM33xx.  Those SoCs
were not handled by the code this will replace.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
---
 arch/arm/mach-omap2/prm-regbits-24xx.h |  4 ++
 arch/arm/mach-omap2/prm-regbits-34xx.h | 10 ++++
 arch/arm/mach-omap2/prm.h              | 44 +++++++++++++++++-
 arch/arm/mach-omap2/prm2xxx.c          | 68 ++++++++++++++++++++++++++++
 arch/arm/mach-omap2/prm2xxx.h          |  4 ++
 arch/arm/mach-omap2/prm2xxx_3xxx.h     |  2 +
 arch/arm/mach-omap2/prm3xxx.c          | 65 ++++++++++++++++++++++++++
 arch/arm/mach-omap2/prm3xxx.h          |  2 +
 arch/arm/mach-omap2/prm44xx.c          | 83 ++++++++++++++++++++++++++++++++--
 arch/arm/mach-omap2/prm44xx.h          |  2 +
 arch/arm/mach-omap2/prm_common.c       | 26 +++++++++++
 11 files changed, 306 insertions(+), 4 deletions(-)

(limited to 'arch/arm/mach-omap2/prm_common.c')

diff --git a/arch/arm/mach-omap2/prm-regbits-24xx.h b/arch/arm/mach-omap2/prm-regbits-24xx.h
index bd70a5a04291..638da6dd41c3 100644
--- a/arch/arm/mach-omap2/prm-regbits-24xx.h
+++ b/arch/arm/mach-omap2/prm-regbits-24xx.h
@@ -209,9 +209,13 @@
 
 /* RM_RSTST_WKUP specific bits */
 /* 2430 calls EXTWMPU_RST "EXTWARM_RST" and GLOBALWMPU_RST "GLOBALWARM_RST" */
+#define OMAP24XX_EXTWMPU_RST_SHIFT			6
 #define OMAP24XX_EXTWMPU_RST_MASK			(1 << 6)
+#define OMAP24XX_SECU_WD_RST_SHIFT			5
 #define OMAP24XX_SECU_WD_RST_MASK			(1 << 5)
+#define OMAP24XX_MPU_WD_RST_SHIFT			4
 #define OMAP24XX_MPU_WD_RST_MASK			(1 << 4)
+#define OMAP24XX_SECU_VIOL_RST_SHIFT			3
 #define OMAP24XX_SECU_VIOL_RST_MASK			(1 << 3)
 
 /* PM_WKEN_WKUP specific bits */
diff --git a/arch/arm/mach-omap2/prm-regbits-34xx.h b/arch/arm/mach-omap2/prm-regbits-34xx.h
index 073d4db8aa5c..838b594d4e13 100644
--- a/arch/arm/mach-omap2/prm-regbits-34xx.h
+++ b/arch/arm/mach-omap2/prm-regbits-34xx.h
@@ -509,15 +509,25 @@
 #define OMAP3430_RSTTIME1_MASK				(0xff << 0)
 
 /* PRM_RSTST */
+#define OMAP3430_ICECRUSHER_RST_SHIFT			10
 #define OMAP3430_ICECRUSHER_RST_MASK			(1 << 10)
+#define OMAP3430_ICEPICK_RST_SHIFT			9
 #define OMAP3430_ICEPICK_RST_MASK			(1 << 9)
+#define OMAP3430_VDD2_VOLTAGE_MANAGER_RST_SHIFT		8
 #define OMAP3430_VDD2_VOLTAGE_MANAGER_RST_MASK		(1 << 8)
+#define OMAP3430_VDD1_VOLTAGE_MANAGER_RST_SHIFT		7
 #define OMAP3430_VDD1_VOLTAGE_MANAGER_RST_MASK		(1 << 7)
+#define OMAP3430_EXTERNAL_WARM_RST_SHIFT		6
 #define OMAP3430_EXTERNAL_WARM_RST_MASK			(1 << 6)
+#define OMAP3430_SECURE_WD_RST_SHIFT			5
 #define OMAP3430_SECURE_WD_RST_MASK			(1 << 5)
+#define OMAP3430_MPU_WD_RST_SHIFT			4
 #define OMAP3430_MPU_WD_RST_MASK			(1 << 4)
+#define OMAP3430_SECURITY_VIOL_RST_SHIFT		3
 #define OMAP3430_SECURITY_VIOL_RST_MASK			(1 << 3)
+#define OMAP3430_GLOBAL_SW_RST_SHIFT			1
 #define OMAP3430_GLOBAL_SW_RST_MASK			(1 << 1)
+#define OMAP3430_GLOBAL_COLD_RST_SHIFT			0
 #define OMAP3430_GLOBAL_COLD_RST_MASK			(1 << 0)
 
 /* PRM_VOLTCTRL */
diff --git a/arch/arm/mach-omap2/prm.h b/arch/arm/mach-omap2/prm.h
index 3e51c1d15757..c30ab5de8d1d 100644
--- a/arch/arm/mach-omap2/prm.h
+++ b/arch/arm/mach-omap2/prm.h
@@ -52,16 +52,58 @@
 #define OMAP_POWERSTATE_SHIFT				0
 #define OMAP_POWERSTATE_MASK				(0x3 << 0)
 
+/*
+ * Standardized OMAP reset source bits
+ *
+ * To the extent these happen to match the hardware register bit
+ * shifts, it's purely coincidental.  Used by omap-wdt.c.
+ * OMAP_UNKNOWN_RST_SRC_ID_SHIFT is a special value, used whenever
+ * there are any bits remaining in the global PRM_RSTST register that
+ * haven't been identified, or when the PRM code for the current SoC
+ * doesn't know how to interpret the register.
+ */
+#define OMAP_GLOBAL_COLD_RST_SRC_ID_SHIFT			0
+#define OMAP_GLOBAL_WARM_RST_SRC_ID_SHIFT			1
+#define OMAP_SECU_VIOL_RST_SRC_ID_SHIFT				2
+#define OMAP_MPU_WD_RST_SRC_ID_SHIFT				3
+#define OMAP_SECU_WD_RST_SRC_ID_SHIFT				4
+#define OMAP_EXTWARM_RST_SRC_ID_SHIFT				5
+#define OMAP_VDD_MPU_VM_RST_SRC_ID_SHIFT			6
+#define OMAP_VDD_IVA_VM_RST_SRC_ID_SHIFT			7
+#define OMAP_VDD_CORE_VM_RST_SRC_ID_SHIFT			8
+#define OMAP_ICEPICK_RST_SRC_ID_SHIFT				9
+#define OMAP_ICECRUSHER_RST_SRC_ID_SHIFT			10
+#define OMAP_C2C_RST_SRC_ID_SHIFT				11
+#define OMAP_UNKNOWN_RST_SRC_ID_SHIFT				12
+
 #ifndef __ASSEMBLER__
 
+/**
+ * struct prm_reset_src_map - map register bitshifts to standard bitshifts
+ * @reg_shift: bitshift in the PRM reset source register
+ * @std_shift: bitshift equivalent in the standard reset source list
+ *
+ * The fields are signed because -1 is used as a terminator.
+ */
+struct prm_reset_src_map {
+	s8 reg_shift;
+	s8 std_shift;
+};
+
 /**
  * struct prm_ll_data - fn ptrs to per-SoC PRM function implementations
+ * @read_reset_sources: ptr to the Soc PRM-specific get_reset_source impl
  */
-struct prm_ll_data {};
+struct prm_ll_data {
+	u32 (*read_reset_sources)(void);
+};
 
 extern int prm_register(struct prm_ll_data *pld);
 extern int prm_unregister(struct prm_ll_data *pld);
 
+extern u32 prm_read_reset_sources(void);
+
 #endif
 
+
 #endif
diff --git a/arch/arm/mach-omap2/prm2xxx.c b/arch/arm/mach-omap2/prm2xxx.c
index 9cdb4e5e3d80..e2860f9c111d 100644
--- a/arch/arm/mach-omap2/prm2xxx.c
+++ b/arch/arm/mach-omap2/prm2xxx.c
@@ -29,6 +29,46 @@
 #include "cm2xxx_3xxx.h"
 #include "prm-regbits-24xx.h"
 
+/*
+ * omap2xxx_prm_reset_src_map - map from bits in the PRM_RSTST_WKUP
+ *   hardware register (which are specific to the OMAP2xxx SoCs) to
+ *   reset source ID bit shifts (which is an OMAP SoC-independent
+ *   enumeration)
+ */
+static struct prm_reset_src_map omap2xxx_prm_reset_src_map[] = {
+	{ OMAP_GLOBALCOLD_RST_SHIFT, OMAP_GLOBAL_COLD_RST_SRC_ID_SHIFT },
+	{ OMAP_GLOBALWARM_RST_SHIFT, OMAP_GLOBAL_WARM_RST_SRC_ID_SHIFT },
+	{ OMAP24XX_SECU_VIOL_RST_SHIFT, OMAP_SECU_VIOL_RST_SRC_ID_SHIFT },
+	{ OMAP24XX_MPU_WD_RST_SHIFT, OMAP_MPU_WD_RST_SRC_ID_SHIFT },
+	{ OMAP24XX_SECU_WD_RST_SHIFT, OMAP_SECU_WD_RST_SRC_ID_SHIFT },
+	{ OMAP24XX_EXTWMPU_RST_SHIFT, OMAP_EXTWARM_RST_SRC_ID_SHIFT },
+	{ -1, -1 },
+};
+
+/**
+ * omap2xxx_prm_read_reset_sources - return the last SoC reset source
+ *
+ * Return a u32 representing the last reset sources of the SoC.  The
+ * returned reset source bits are standardized across OMAP SoCs.
+ */
+static u32 omap2xxx_prm_read_reset_sources(void)
+{
+	struct prm_reset_src_map *p;
+	u32 r = 0;
+	u32 v;
+
+	v = omap2_prm_read_mod_reg(WKUP_MOD, OMAP2_RM_RSTST);
+
+	p = omap2xxx_prm_reset_src_map;
+	while (p->reg_shift >= 0 && p->std_shift >= 0) {
+		if (v & (1 << p->reg_shift))
+			r |= 1 << p->std_shift;
+		p++;
+	}
+
+	return r;
+}
+
 int omap2xxx_clkdm_sleep(struct clockdomain *clkdm)
 {
 	omap2_prm_set_mod_reg_bits(OMAP24XX_FORCESTATE_MASK,
@@ -56,3 +96,31 @@ struct pwrdm_ops omap2_pwrdm_operations = {
 	.pwrdm_read_mem_retst	= omap2_pwrdm_read_mem_retst,
 	.pwrdm_wait_transition	= omap2_pwrdm_wait_transition,
 };
+
+/*
+ *
+ */
+
+static struct prm_ll_data omap2xxx_prm_ll_data = {
+	.read_reset_sources = &omap2xxx_prm_read_reset_sources,
+};
+
+static int __init omap2xxx_prm_init(void)
+{
+	if (!cpu_is_omap24xx())
+		return 0;
+
+	return prm_register(&omap2xxx_prm_ll_data);
+}
+subsys_initcall(omap2xxx_prm_init);
+
+static void __exit omap2xxx_prm_exit(void)
+{
+	if (!cpu_is_omap24xx())
+		return;
+
+	/* Should never happen */
+	WARN(prm_unregister(&omap2xxx_prm_ll_data),
+	     "%s: prm_ll_data function pointer mismatch\n", __func__);
+}
+__exitcall(omap2xxx_prm_exit);
diff --git a/arch/arm/mach-omap2/prm2xxx.h b/arch/arm/mach-omap2/prm2xxx.h
index 6d76716a1ea5..1d97112524f1 100644
--- a/arch/arm/mach-omap2/prm2xxx.h
+++ b/arch/arm/mach-omap2/prm2xxx.h
@@ -123,6 +123,10 @@
 /* Function prototypes */
 extern int omap2xxx_clkdm_sleep(struct clockdomain *clkdm);
 extern int omap2xxx_clkdm_wakeup(struct clockdomain *clkdm);
+
+extern int __init prm2xxx_init(void);
+extern int __exit prm2xxx_exit(void);
+
 #endif
 
 #endif
diff --git a/arch/arm/mach-omap2/prm2xxx_3xxx.h b/arch/arm/mach-omap2/prm2xxx_3xxx.h
index 22a405a1543b..3330b1bf789d 100644
--- a/arch/arm/mach-omap2/prm2xxx_3xxx.h
+++ b/arch/arm/mach-omap2/prm2xxx_3xxx.h
@@ -211,7 +211,9 @@ extern int omap2_clkdm_clear_all_wkdeps(struct clockdomain *clkdm);
  *
  * 3430: RM_RSTST_CORE, RM_RSTST_EMU
  */
+#define OMAP_GLOBALWARM_RST_SHIFT			1
 #define OMAP_GLOBALWARM_RST_MASK			(1 << 1)
+#define OMAP_GLOBALCOLD_RST_SHIFT			0
 #define OMAP_GLOBALCOLD_RST_MASK			(1 << 0)
 
 /*
diff --git a/arch/arm/mach-omap2/prm3xxx.c b/arch/arm/mach-omap2/prm3xxx.c
index e276ff270ac5..1fea656b2ca8 100644
--- a/arch/arm/mach-omap2/prm3xxx.c
+++ b/arch/arm/mach-omap2/prm3xxx.c
@@ -47,6 +47,27 @@ static struct omap_prcm_irq_setup omap3_prcm_irq_setup = {
 	.restore_irqen		= &omap3xxx_prm_restore_irqen,
 };
 
+/*
+ * omap3_prm_reset_src_map - map from bits in the PRM_RSTST hardware
+ *   register (which are specific to OMAP3xxx SoCs) to reset source ID
+ *   bit shifts (which is an OMAP SoC-independent enumeration)
+ */
+static struct prm_reset_src_map omap3xxx_prm_reset_src_map[] = {
+	{ OMAP3430_GLOBAL_COLD_RST_SHIFT, OMAP_GLOBAL_COLD_RST_SRC_ID_SHIFT },
+	{ OMAP3430_GLOBAL_SW_RST_SHIFT, OMAP_GLOBAL_WARM_RST_SRC_ID_SHIFT },
+	{ OMAP3430_SECURITY_VIOL_RST_SHIFT, OMAP_SECU_VIOL_RST_SRC_ID_SHIFT },
+	{ OMAP3430_MPU_WD_RST_SHIFT, OMAP_MPU_WD_RST_SRC_ID_SHIFT },
+	{ OMAP3430_SECURE_WD_RST_SHIFT, OMAP_MPU_WD_RST_SRC_ID_SHIFT },
+	{ OMAP3430_EXTERNAL_WARM_RST_SHIFT, OMAP_EXTWARM_RST_SRC_ID_SHIFT },
+	{ OMAP3430_VDD1_VOLTAGE_MANAGER_RST_SHIFT,
+	  OMAP_VDD_MPU_VM_RST_SRC_ID_SHIFT },
+	{ OMAP3430_VDD2_VOLTAGE_MANAGER_RST_SHIFT,
+	  OMAP_VDD_CORE_VM_RST_SRC_ID_SHIFT },
+	{ OMAP3430_ICEPICK_RST_SHIFT, OMAP_ICEPICK_RST_SRC_ID_SHIFT },
+	{ OMAP3430_ICECRUSHER_RST_SHIFT, OMAP_ICECRUSHER_RST_SRC_ID_SHIFT },
+	{ -1, -1 },
+};
+
 /* PRM VP */
 
 /*
@@ -217,6 +238,30 @@ static void __init omap3xxx_prm_enable_io_wakeup(void)
 					   PM_WKEN);
 }
 
+/**
+ * omap3xxx_prm_read_reset_sources - return the last SoC reset source
+ *
+ * Return a u32 representing the last reset sources of the SoC.  The
+ * returned reset source bits are standardized across OMAP SoCs.
+ */
+static u32 omap3xxx_prm_read_reset_sources(void)
+{
+	struct prm_reset_src_map *p;
+	u32 r = 0;
+	u32 v;
+
+	v = omap2_prm_read_mod_reg(WKUP_MOD, OMAP2_RM_RSTST);
+
+	p = omap3xxx_prm_reset_src_map;
+	while (p->reg_shift >= 0 && p->std_shift >= 0) {
+		if (v & (1 << p->reg_shift))
+			r |= 1 << p->std_shift;
+		p++;
+	}
+
+	return r;
+}
+
 /* Powerdomain low-level functions */
 
 /* Applicable only for OMAP3. Not supported on OMAP2 */
@@ -320,6 +365,10 @@ struct pwrdm_ops omap3_pwrdm_operations = {
  *
  */
 
+static struct prm_ll_data omap3xxx_prm_ll_data = {
+	.read_reset_sources = &omap3xxx_prm_read_reset_sources,
+};
+
 static int __init omap3xxx_prm_init(void)
 {
 	int ret;
@@ -327,12 +376,28 @@ static int __init omap3xxx_prm_init(void)
 	if (!cpu_is_omap34xx())
 		return 0;
 
+	ret = prm_register(&omap3xxx_prm_ll_data);
+	if (ret)
+		return ret;
+
 	omap3xxx_prm_enable_io_wakeup();
 	ret = omap_prcm_register_chain_handler(&omap3_prcm_irq_setup);
 	if (!ret)
 		irq_set_status_flags(omap_prcm_event_to_irq("io"),
 				     IRQ_NOAUTOEN);
 
+
 	return ret;
 }
 subsys_initcall(omap3xxx_prm_init);
+
+static void __exit omap3xxx_prm_exit(void)
+{
+	if (!cpu_is_omap34xx())
+		return;
+
+	/* Should never happen */
+	WARN(prm_unregister(&omap3xxx_prm_ll_data),
+	     "%s: prm_ll_data function pointer mismatch\n", __func__);
+}
+__exitcall(omap3xxx_prm_exit);
diff --git a/arch/arm/mach-omap2/prm3xxx.h b/arch/arm/mach-omap2/prm3xxx.h
index 6821e8321610..a3c28a875410 100644
--- a/arch/arm/mach-omap2/prm3xxx.h
+++ b/arch/arm/mach-omap2/prm3xxx.h
@@ -152,6 +152,8 @@ extern void omap3xxx_prm_ocp_barrier(void);
 extern void omap3xxx_prm_save_and_clear_irqen(u32 *saved_mask);
 extern void omap3xxx_prm_restore_irqen(u32 *saved_mask);
 
+extern u32 omap3xxx_prm_get_reset_sources(void);
+
 #endif /* __ASSEMBLER */
 
 
diff --git a/arch/arm/mach-omap2/prm44xx.c b/arch/arm/mach-omap2/prm44xx.c
index 48d91930796d..a799e9552fbf 100644
--- a/arch/arm/mach-omap2/prm44xx.c
+++ b/arch/arm/mach-omap2/prm44xx.c
@@ -1,7 +1,7 @@
 /*
  * OMAP4 PRM module functions
  *
- * Copyright (C) 2011 Texas Instruments, Inc.
+ * Copyright (C) 2011-2012 Texas Instruments, Inc.
  * Copyright (C) 2010 Nokia Corporation
  * Benoît Cousson
  * Paul Walmsley
@@ -30,6 +30,8 @@
 #include "prminst44xx.h"
 #include "powerdomain.h"
 
+/* Static data */
+
 static const struct omap_prcm_irq omap4_prcm_irqs[] = {
 	OMAP_PRCM_IRQ("wkup",   0,      0),
 	OMAP_PRCM_IRQ("io",     9,      1),
@@ -48,6 +50,33 @@ static struct omap_prcm_irq_setup omap4_prcm_irq_setup = {
 	.restore_irqen		= &omap44xx_prm_restore_irqen,
 };
 
+/*
+ * omap44xx_prm_reset_src_map - map from bits in the PRM_RSTST
+ *   hardware register (which are specific to OMAP44xx SoCs) to reset
+ *   source ID bit shifts (which is an OMAP SoC-independent
+ *   enumeration)
+ */
+static struct prm_reset_src_map omap44xx_prm_reset_src_map[] = {
+	{ OMAP4430_RST_GLOBAL_WARM_SW_SHIFT,
+	  OMAP_GLOBAL_WARM_RST_SRC_ID_SHIFT },
+	{ OMAP4430_RST_GLOBAL_COLD_SW_SHIFT,
+	  OMAP_GLOBAL_COLD_RST_SRC_ID_SHIFT },
+	{ OMAP4430_MPU_SECURITY_VIOL_RST_SHIFT,
+	  OMAP_SECU_VIOL_RST_SRC_ID_SHIFT },
+	{ OMAP4430_MPU_WDT_RST_SHIFT, OMAP_MPU_WD_RST_SRC_ID_SHIFT },
+	{ OMAP4430_SECURE_WDT_RST_SHIFT, OMAP_SECU_WD_RST_SRC_ID_SHIFT },
+	{ OMAP4430_EXTERNAL_WARM_RST_SHIFT, OMAP_EXTWARM_RST_SRC_ID_SHIFT },
+	{ OMAP4430_VDD_MPU_VOLT_MGR_RST_SHIFT,
+	  OMAP_VDD_MPU_VM_RST_SRC_ID_SHIFT },
+	{ OMAP4430_VDD_IVA_VOLT_MGR_RST_SHIFT,
+	  OMAP_VDD_IVA_VM_RST_SRC_ID_SHIFT },
+	{ OMAP4430_VDD_CORE_VOLT_MGR_RST_SHIFT,
+	  OMAP_VDD_CORE_VM_RST_SRC_ID_SHIFT },
+	{ OMAP4430_ICEPICK_RST_SHIFT, OMAP_ICEPICK_RST_SRC_ID_SHIFT },
+	{ OMAP4430_C2C_RST_SHIFT, OMAP_C2C_RST_SRC_ID_SHIFT },
+	{ -1, -1 },
+};
+
 /* PRM low-level functions */
 
 /* Read a register in a CM/PRM instance in the PRM module */
@@ -293,6 +322,31 @@ static void __init omap44xx_prm_enable_io_wakeup(void)
 				    OMAP4_PRM_IO_PMCTRL_OFFSET);
 }
 
+/**
+ * omap44xx_prm_read_reset_sources - return the last SoC reset source
+ *
+ * Return a u32 representing the last reset sources of the SoC.  The
+ * returned reset source bits are standardized across OMAP SoCs.
+ */
+static u32 omap44xx_prm_read_reset_sources(void)
+{
+	struct prm_reset_src_map *p;
+	u32 r = 0;
+	u32 v;
+
+	v = omap4_prm_read_inst_reg(OMAP4430_PRM_OCP_SOCKET_INST,
+				    OMAP4_RM_RSTST);
+
+	p = omap44xx_prm_reset_src_map;
+	while (p->reg_shift >= 0 && p->std_shift >= 0) {
+		if (v & (1 << p->reg_shift))
+			r |= 1 << p->std_shift;
+		p++;
+	}
+
+	return r;
+}
+
 /* Powerdomain low-level functions */
 
 static int omap4_pwrdm_set_next_pwrst(struct powerdomain *pwrdm, u8 pwrst)
@@ -555,14 +609,37 @@ struct pwrdm_ops omap4_pwrdm_operations = {
 	.pwrdm_wait_transition	= omap4_pwrdm_wait_transition,
 };
 
+/*
+ * XXX document
+ */
+static struct prm_ll_data omap44xx_prm_ll_data = {
+	.read_reset_sources = &omap44xx_prm_read_reset_sources,
+};
 
-static int __init omap4xxx_prm_init(void)
+static int __init omap44xx_prm_init(void)
 {
+	int ret;
+
 	if (!cpu_is_omap44xx())
 		return 0;
 
+	ret = prm_register(&omap44xx_prm_ll_data);
+	if (ret)
+		return ret;
+
 	omap44xx_prm_enable_io_wakeup();
 
 	return omap_prcm_register_chain_handler(&omap4_prcm_irq_setup);
 }
-subsys_initcall(omap4xxx_prm_init);
+subsys_initcall(omap44xx_prm_init);
+
+static void __exit omap44xx_prm_exit(void)
+{
+	if (!cpu_is_omap44xx())
+		return;
+
+	/* Should never happen */
+	WARN(prm_unregister(&omap44xx_prm_ll_data),
+	     "%s: prm_ll_data function pointer mismatch\n", __func__);
+}
+__exitcall(omap44xx_prm_exit);
diff --git a/arch/arm/mach-omap2/prm44xx.h b/arch/arm/mach-omap2/prm44xx.h
index ee72ae6bd8c9..c8e1accdc90e 100644
--- a/arch/arm/mach-omap2/prm44xx.h
+++ b/arch/arm/mach-omap2/prm44xx.h
@@ -771,6 +771,8 @@ extern void omap44xx_prm_ocp_barrier(void);
 extern void omap44xx_prm_save_and_clear_irqen(u32 *saved_mask);
 extern void omap44xx_prm_restore_irqen(u32 *saved_mask);
 
+extern u32 omap44xx_prm_get_reset_sources(void);
+
 # endif
 
 #endif
diff --git a/arch/arm/mach-omap2/prm_common.c b/arch/arm/mach-omap2/prm_common.c
index 8670a3c4bc5e..e200e4fb47dc 100644
--- a/arch/arm/mach-omap2/prm_common.c
+++ b/arch/arm/mach-omap2/prm_common.c
@@ -28,6 +28,8 @@
 #include <plat/prcm.h>
 
 #include "prm2xxx_3xxx.h"
+#include "prm2xxx.h"
+#include "prm3xxx.h"
 #include "prm44xx.h"
 
 /*
@@ -326,6 +328,30 @@ err:
 	return -ENOMEM;
 }
 
+/**
+ * prm_read_reset_sources - return the sources of the SoC's last reset
+ *
+ * Return a u32 bitmask representing the reset sources that caused the
+ * SoC to reset.  The low-level per-SoC functions called by this
+ * function remap the SoC-specific reset source bits into an
+ * OMAP-common set of reset source bits, defined in
+ * arch/arm/mach-omap2/prm.h.  Returns the standardized reset source
+ * u32 bitmask from the hardware upon success, or returns (1 <<
+ * OMAP_UNKNOWN_RST_SRC_ID_SHIFT) if no low-level read_reset_sources()
+ * function was registered.
+ */
+u32 prm_read_reset_sources(void)
+{
+	u32 ret = 1 << OMAP_UNKNOWN_RST_SRC_ID_SHIFT;
+
+	if (prm_ll_data->read_reset_sources)
+		ret = prm_ll_data->read_reset_sources();
+	else
+		WARN_ONCE(1, "prm: %s: no mapping function defined for reset sources\n", __func__);
+
+	return ret;
+}
+
 /**
  * prm_register - register per-SoC low-level data with the PRM
  * @pld: low-level per-SoC OMAP PRM data & function pointers to register
-- 
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