Add support for RTC mode to low level suspend code. This includes
providing the rtc base address for the assembly code to configuring the
PMIC_PWR_EN line late in suspend to enter RTC+DDR mode.

Signed-off-by: Dave Gerlach <d-gerl...@ti.com>
Signed-off-by: Keerthy <j-keer...@ti.com>
---
 arch/arm/mach-omap2/pm-asm-offsets.c |  2 ++
 arch/arm/mach-omap2/pm33xx-core.c    | 10 +++++++
 arch/arm/mach-omap2/sleep33xx.S      |  8 +++--
 arch/arm/mach-omap2/sleep43xx.S      | 57 ++++++++++++++++++++++++++++++++++--
 drivers/soc/ti/pm33xx.c              |  1 +
 include/linux/platform_data/pm33xx.h |  3 ++
 6 files changed, 77 insertions(+), 4 deletions(-)

diff --git a/arch/arm/mach-omap2/pm-asm-offsets.c 
b/arch/arm/mach-omap2/pm-asm-offsets.c
index b9846b1..d202306 100644
--- a/arch/arm/mach-omap2/pm-asm-offsets.c
+++ b/arch/arm/mach-omap2/pm-asm-offsets.c
@@ -27,6 +27,8 @@ int main(void)
               offsetof(struct am33xx_pm_ro_sram_data, amx3_pm_sram_data_virt));
        DEFINE(AMX3_PM_RO_SRAM_DATA_PHYS_OFFSET,
               offsetof(struct am33xx_pm_ro_sram_data, amx3_pm_sram_data_phys));
+       DEFINE(AMX3_PM_RTC_BASE_VIRT_OFFSET,
+               offsetof(struct am33xx_pm_ro_sram_data, rtc_base_virt));
        DEFINE(AMX3_PM_RO_SRAM_DATA_SIZE,
               sizeof(struct am33xx_pm_ro_sram_data));
 
diff --git a/arch/arm/mach-omap2/pm33xx-core.c 
b/arch/arm/mach-omap2/pm33xx-core.c
index e363b97..f4971e4 100644
--- a/arch/arm/mach-omap2/pm33xx-core.c
+++ b/arch/arm/mach-omap2/pm33xx-core.c
@@ -26,6 +26,7 @@
 static struct powerdomain *cefuse_pwrdm, *gfx_pwrdm, *per_pwrdm, *mpu_pwrdm;
 static struct clockdomain *gfx_l4ls_clkdm;
 static void __iomem *scu_base;
+static struct omap_hwmod *rtc_oh;
 
 static int __init am43xx_map_scu(void)
 {
@@ -153,16 +154,25 @@ static struct am33xx_pm_sram_addr 
*amx3_get_sram_addrs(void)
                return NULL;
 }
 
+void __iomem *am43xx_get_rtc_base_addr(void)
+{
+       rtc_oh = omap_hwmod_lookup("rtc");
+
+       return omap_hwmod_get_mpu_rt_va(rtc_oh);
+}
+
 static struct am33xx_pm_platform_data am33xx_ops = {
        .init = am33xx_suspend_init,
        .soc_suspend = am33xx_suspend,
        .get_sram_addrs = amx3_get_sram_addrs,
+       .get_rtc_base_addr = am43xx_get_rtc_base_addr,
 };
 
 static struct am33xx_pm_platform_data am43xx_ops = {
        .init = am43xx_suspend_init,
        .soc_suspend = am43xx_suspend,
        .get_sram_addrs = amx3_get_sram_addrs,
+       .get_rtc_base_addr = am43xx_get_rtc_base_addr,
 };
 
 static struct am33xx_pm_platform_data *am33xx_pm_get_pdata(void)
diff --git a/arch/arm/mach-omap2/sleep33xx.S b/arch/arm/mach-omap2/sleep33xx.S
index 3ef469f..47a8164 100644
--- a/arch/arm/mach-omap2/sleep33xx.S
+++ b/arch/arm/mach-omap2/sleep33xx.S
@@ -20,6 +20,9 @@
 #define AM33XX_CM_CLKCTRL_MODULEMODE_DISABLE                   0x0003
 #define AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE                    0x0002
 
+/* replicated define because linux/bitops.h cannot be included in assembly */
+#define BIT(nr)                        (1 << (nr))
+
        .arm
        .align 3
 
@@ -225,8 +228,6 @@ ENDPROC(am33xx_resume_from_deep_sleep)
  * Local variables
  */
        .align
-resume_addr:
-       .word   cpu_resume - PAGE_OFFSET + 0x80000000
 kernel_flush:
        .word   v7_flush_dcache_all
 virt_mpu_clkctrl:
@@ -249,6 +250,9 @@ ENTRY(am33xx_pm_sram)
        .word am33xx_emif_sram_table
        .word am33xx_pm_ro_sram_data
 
+resume_addr:
+.word  cpu_resume - PAGE_OFFSET + 0x80000000
+
 .align 3
 ENTRY(am33xx_pm_ro_sram_data)
        .space AMX3_PM_RO_SRAM_DATA_SIZE
diff --git a/arch/arm/mach-omap2/sleep43xx.S b/arch/arm/mach-omap2/sleep43xx.S
index 0553adb..5b9343b 100644
--- a/arch/arm/mach-omap2/sleep43xx.S
+++ b/arch/arm/mach-omap2/sleep43xx.S
@@ -22,6 +22,9 @@
 #include "prm33xx.h"
 #include "prcm43xx.h"
 
+/* replicated define because linux/bitops.h cannot be included in assembly */
+#define BIT(nr)                        (1 << (nr))
+
 #define AM33XX_CM_CLKCTRL_MODULESTATE_DISABLED         0x00030000
 #define AM33XX_CM_CLKCTRL_MODULEMODE_DISABLE           0x0003
 #define AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE            0x0002
@@ -45,6 +48,13 @@
                                        AM43XX_CM_PER_EMIF_CLKCTRL_OFFSET)
 #define AM43XX_PRM_EMIF_CTRL_OFFSET                    0x0030
 
+#define RTC_SECONDS_REG                                        0x0
+#define RTC_PMIC_REG                                   0x98
+#define RTC_PMIC_POWER_EN                              BIT(16)
+#define RTC_PMIC_EXT_WAKEUP_STS                                BIT(12)
+#define RTC_PMIC_EXT_WAKEUP_POL                                BIT(4)
+#define RTC_PMIC_EXT_WAKEUP_EN                         BIT(0)
+
        .arm
        .align 3
 
@@ -144,6 +154,20 @@ sync:
        ldr     r4, [r2, #AMX3_PM_WFI_FLAGS_OFFSET]
 
 cache_skip_flush:
+       /*
+        * If we are trying to enter RTC+DDR mode we must perform
+        * a read from the rtc address space to ensure translation
+        * presence in the TLB to avoid page table walk after DDR
+        * is unavailable.
+        */
+       tst     r4, #WFI_FLAG_RTC_ONLY
+       beq     skip_rtc_va_refresh
+
+       adr     r3, am43xx_pm_ro_sram_data
+       ldr     r1, [r3, #AMX3_PM_RTC_BASE_VIRT_OFFSET]
+       ldr     r0, [r1]
+
+skip_rtc_va_refresh:
        /* Check if we want self refresh */
        tst     r4, #WFI_FLAG_SELF_REFRESH
        beq     emif_skip_enter_sr
@@ -179,6 +203,34 @@ wait_emif_disable:
        bne     wait_emif_disable
 
 emif_skip_disable:
+       tst     r4, #WFI_FLAG_RTC_ONLY
+       beq     skip_rtc_only
+
+       adr     r3, am43xx_pm_ro_sram_data
+       ldr     r1, [r3, #AMX3_PM_RTC_BASE_VIRT_OFFSET]
+
+       ldr     r0, [r1, #RTC_PMIC_REG]
+       orr     r0, r0, #RTC_PMIC_POWER_EN
+       orr     r0, r0, #RTC_PMIC_EXT_WAKEUP_STS
+       orr     r0, r0, #RTC_PMIC_EXT_WAKEUP_EN
+       orr     r0, r0, #RTC_PMIC_EXT_WAKEUP_POL
+       str     r0, [r1, #RTC_PMIC_REG]
+       ldr     r0, [r1, #RTC_PMIC_REG]
+       /* Wait for 2 seconds to lose power */
+       mov     r3, #2
+       ldr     r2, [r1, #RTC_SECONDS_REG]
+rtc_loop:
+       ldr     r0, [r1, #RTC_SECONDS_REG]
+       cmp     r0, r2
+       beq     rtc_loop
+       mov     r2, r0
+       subs    r3, r3, #1
+       bne     rtc_loop
+
+       b       re_enable_emif
+
+skip_rtc_only:
+
        tst     r4, #WFI_FLAG_WAKE_M3
        beq     wkup_m3_skip
 
@@ -244,6 +296,7 @@ wkup_m3_skip:
        mov     r2, #AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE
        str     r2, [r1]
 
+re_enable_emif:
        /* Re-enable EMIF */
        ldr     r1, am43xx_virt_emif_clkctrl
        mov     r2, #AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE
@@ -378,8 +431,6 @@ ENDPROC(am43xx_resume_from_deep_sleep)
  * Local variables
  */
        .align
-resume_addr:
-       .word   cpu_resume - PAGE_OFFSET + 0x80000000
 kernel_flush:
        .word   v7_flush_dcache_all
 ddr_start:
@@ -426,6 +477,8 @@ ENTRY(am43xx_pm_sram)
        .word am43xx_emif_sram_table
        .word am43xx_pm_ro_sram_data
 
+resume_addr:
+       .word   cpu_resume - PAGE_OFFSET + 0x80000000
 .align 3
 
 ENTRY(am43xx_pm_ro_sram_data)
diff --git a/drivers/soc/ti/pm33xx.c b/drivers/soc/ti/pm33xx.c
index 0011c8f..d0dab32 100644
--- a/drivers/soc/ti/pm33xx.c
+++ b/drivers/soc/ti/pm33xx.c
@@ -229,6 +229,7 @@ static int am33xx_push_sram_idle(void)
        ro_sram_data.amx3_pm_sram_data_virt = ocmcram_location_data;
        ro_sram_data.amx3_pm_sram_data_phys =
                gen_pool_virt_to_phys(sram_pool_data, ocmcram_location_data);
+       ro_sram_data.rtc_base_virt = pm_ops->get_rtc_base_addr();
 
        /* Save physical address to calculate resume offset during pm init */
        am33xx_do_wfi_sram_phys = gen_pool_virt_to_phys(sram_pool,
diff --git a/include/linux/platform_data/pm33xx.h 
b/include/linux/platform_data/pm33xx.h
index d231265..fbf5ed7 100644
--- a/include/linux/platform_data/pm33xx.h
+++ b/include/linux/platform_data/pm33xx.h
@@ -42,6 +42,7 @@ struct am33xx_pm_sram_addr {
        unsigned long *resume_offset;
        unsigned long *emif_sram_table;
        unsigned long *ro_sram_data;
+       unsigned long resume_address;
 };
 
 struct am33xx_pm_platform_data {
@@ -49,6 +50,7 @@ struct am33xx_pm_platform_data {
        int     (*soc_suspend)(unsigned int state, int (*fn)(unsigned long),
                               unsigned long args);
        struct  am33xx_pm_sram_addr *(*get_sram_addrs)(void);
+       void __iomem *(*get_rtc_base_addr)(void);
 };
 
 struct am33xx_pm_sram_data {
@@ -60,6 +62,7 @@ struct am33xx_pm_sram_data {
 struct am33xx_pm_ro_sram_data {
        u32 amx3_pm_sram_data_virt;
        u32 amx3_pm_sram_data_phys;
+       void __iomem *rtc_base_virt;
 } __packed __aligned(8);
 
 #endif /* __ASSEMBLER__ */
-- 
1.9.1

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