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

@@ -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 */

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 */

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

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);

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

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)
 
 /*

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 */
@@ -320,19 +365,39 @@ 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;
 
 	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);

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 */