[PATCH 10/19] ARM: OMAP4: PM: Work-around for ROM code BUG of IVAHD/TESLA

[Tero Kristo]

From: Santosh Shilimkar <santosh.shilimkar at ti.com>

The ROM BUG is when MPU Domain OFF wake up sequence that can compromise
IVA and Tesla execution.

At wakeup from MPU OFF on HS device only (not GP device), when
restoring the Secure RAM, the ROM Code reconfigures the clocks the
same way it is done at Cold Reset.
The IVAHD Clocks and Power Domain settings are:
	IVAHD_CM2 IVAHD_CLKCTRL_MODULE_MODE = DISABLE
	IVAHD_CM2 SL2_CLKCTRL_MODULE_MODE = DISABLE
	IVAHD_CM2 SL2_CLKSTCTRL_CLKTRCTRL = HW_AUTO
	IVAHD_PRM IVAHD_PWRSTCTRL_POWERSTATE = OFF
The TESLA Clocks and Power Domain settings are:
	TESLA_CM1 TESLA_CLKCTRL_MODULE_MODE = DISABLE
	TESLA_CM1 TESLA_CLKSTCTRL_CLKTRCTRL = HW_AUTO
	TESLA_PRM TESLA_PWRSTCTRL_POWERSTATE = OFF

This patch fixes the low power OFF mode code so that the these
registers are saved and restore across MPU OFF state.

Also because of this limitation, MPU OFF alone is not targeted without
device OFF to avoid IVAHD and TESLA execution impact

Signed-off-by: Rajendra Nayak <rnayak at ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar at ti.com>
[t-kristo at ti.com: added omap4 pm errata support]
Signed-off-by: Tero Kristo <t-kristo at ti.com>
---
 arch/arm/mach-omap2/omap-mpuss-lowpower.c |   53 +++++++++++++++++++++++++++++
 arch/arm/mach-omap2/pm.h                  |    2 +
 arch/arm/mach-omap2/pm44xx.c              |    9 +++++
 3 files changed, 64 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/omap-mpuss-lowpower.c b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
index b9a2cc7..208d4a4 100644
--- a/arch/arm/mach-omap2/omap-mpuss-lowpower.c
+++ b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
@@ -52,6 +52,7 @@
 
 #include <plat/omap44xx.h>
 
+#include "iomap.h"
 #include "common.h"
 #include "omap4-sar-layout.h"
 #include "pm.h"
@@ -76,6 +77,24 @@ static DEFINE_PER_CPU(struct omap4_cpu_pm_info, omap4_pm_info);
 static struct powerdomain *mpuss_pd;
 static void __iomem *sar_base;
 
+struct reg_tuple {
+	void __iomem *addr;
+	u32 val;
+};
+
+static struct reg_tuple tesla_reg[] = {
+	{.addr = OMAP4430_CM_TESLA_CLKSTCTRL},
+	{.addr = OMAP4430_CM_TESLA_TESLA_CLKCTRL},
+	{.addr = OMAP4430_PM_TESLA_PWRSTCTRL},
+};
+
+static struct reg_tuple ivahd_reg[] = {
+	{.addr = OMAP4430_CM_IVAHD_CLKSTCTRL},
+	{.addr = OMAP4430_CM_IVAHD_IVAHD_CLKCTRL},
+	{.addr = OMAP4430_CM_IVAHD_SL2_CLKCTRL},
+	{.addr = OMAP4430_PM_IVAHD_PWRSTCTRL}
+};
+
 /*
  * Program the wakeup routine address for the CPU0 and CPU1
  * used for OFF or DORMANT wakeup.
@@ -215,6 +234,34 @@ static void save_l2x0_context(void)
 {}
 #endif
 
+static inline void save_ivahd_tesla_regs(void)
+{
+	int i;
+
+	if (!IS_PM44XX_ERRATUM(PM_OMAP4_ROM_IVAHD_TESLA_ERRATUM))
+		return;
+
+	for (i = 0; i < ARRAY_SIZE(tesla_reg); i++)
+		tesla_reg[i].val = __raw_readl(tesla_reg[i].addr);
+
+	for (i = 0; i < ARRAY_SIZE(ivahd_reg); i++)
+		ivahd_reg[i].val = __raw_readl(ivahd_reg[i].addr);
+}
+
+static inline void restore_ivahd_tesla_regs(void)
+{
+	int i;
+
+	if (!IS_PM44XX_ERRATUM(PM_OMAP4_ROM_IVAHD_TESLA_ERRATUM))
+		return;
+
+	for (i = 0; i < ARRAY_SIZE(tesla_reg); i++)
+		__raw_writel(tesla_reg[i].val, tesla_reg[i].addr);
+
+	for (i = 0; i < ARRAY_SIZE(ivahd_reg); i++)
+		__raw_writel(ivahd_reg[i].val, ivahd_reg[i].addr);
+}
+
 /**
  * omap4_enter_lowpower: OMAP4 MPUSS Low Power Entry Function
  * The purpose of this function is to manage low power programming
@@ -273,11 +320,14 @@ int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
 		omap_sar_overwrite();
 		omap4_cm_prepare_off();
 		omap4_dpll_prepare_off();
+		save_ivahd_tesla_regs();
 		save_state = 3;
 	} else if ((pwrdm_read_next_pwrst(mpuss_pd) == PWRDM_POWER_RET) &&
 		(pwrdm_read_logic_retst(mpuss_pd) == PWRDM_POWER_OFF)) {
+		save_ivahd_tesla_regs();
 		save_state = 2;
 	} else if (pwrdm_read_next_pwrst(mpuss_pd) == PWRDM_POWER_OFF) {
+		save_ivahd_tesla_regs();
 		save_state = 3;
 	}
 
@@ -302,6 +352,9 @@ int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
 	wakeup_cpu = smp_processor_id();
 	set_cpu_next_pwrst(wakeup_cpu, PWRDM_POWER_ON);
 
+	if (omap4_mpuss_read_prev_context_state())
+		restore_ivahd_tesla_regs();
+
 	if (omap4_device_prev_state_off()) {
 		omap4_dpll_resume_off();
 		omap4_cm_resume_off();
diff --git a/arch/arm/mach-omap2/pm.h b/arch/arm/mach-omap2/pm.h
index e78ec63..051aeb9 100644
--- a/arch/arm/mach-omap2/pm.h
+++ b/arch/arm/mach-omap2/pm.h
@@ -131,6 +131,8 @@ extern void enable_omap3630_toggle_l2_on_restore(void);
 static inline void enable_omap3630_toggle_l2_on_restore(void) { }
 #endif		/* defined(CONFIG_PM) && defined(CONFIG_ARCH_OMAP3) */
 
+#define PM_OMAP4_ROM_IVAHD_TESLA_ERRATUM	(1 << 0)
+
 #if defined(CONFIG_PM) && defined(CONFIG_ARCH_OMAP4)
 extern u16 pm44xx_errata;
 #define IS_PM44XX_ERRATUM(id)		(pm44xx_errata & (id))
diff --git a/arch/arm/mach-omap2/pm44xx.c b/arch/arm/mach-omap2/pm44xx.c
index 8238097..67cb799 100644
--- a/arch/arm/mach-omap2/pm44xx.c
+++ b/arch/arm/mach-omap2/pm44xx.c
@@ -263,6 +263,15 @@ static int __init omap4_pm_init(void)
 
 	(void) clkdm_for_each(omap_pm_clkdms_setup, NULL);
 
+	/*
+	 * ROM code initializes IVAHD and TESLA clock registers during
+	 * secure RAM restore phase on omap4430 EMU/HS devices, thus
+	 * IVAHD / TESLA clock registers must be saved / restored
+	 * during MPU OSWR / device off.
+	 */
+	if (cpu_is_omap443x() && omap_type() != OMAP2_DEVICE_TYPE_GP)
+		pm44xx_errata |= PM_OMAP4_ROM_IVAHD_TESLA_ERRATUM;
+
 #ifdef CONFIG_SUSPEND
 	omap_pm_suspend = omap4_pm_suspend;
 #endif
-- 
1.7.4.1