[PATCH 1/2] ARM: OMAP2+: sleep33/43xx: Make sleep actions configurable

From: Keerthy
Date: Wed Jul 04 2018 - 06:07:53 EST

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From: Dave Gerlach <d-gerlach@xxxxxx>

Add an argument to the sleep33xx and sleep43xx code to allow us to set
flags to determine which portions of the code get called in order to use
the same code for multiple power saving modes. This patch allows us to
decide whether or not we flush and disable caches, save EMIF context,
put the memory into self refresh and disable the EMIF, and/or invoke
the wkup_m3 when entering into WFI.

Signed-off-by: Dave Gerlach <d-gerlach@xxxxxx>
Signed-off-by: Tero Kristo <t-kristo@xxxxxx>
Signed-off-by: Keerthy <j-keerthy@xxxxxx>
---
arch/arm/mach-omap2/pm33xx-core.c | 10 ++++---
arch/arm/mach-omap2/sleep33xx.S | 44 ++++++++++++++++++++++++++++++
arch/arm/mach-omap2/sleep43xx.S | 53 +++++++++++++++++++++++++++++++++---
drivers/soc/ti/pm33xx.c | 15 +++++++++-
include/linux/platform_data/pm33xx.h | 26 +++++++++++++++++-
5 files changed, 138 insertions(+), 10 deletions(-)

diff --git a/arch/arm/mach-omap2/pm33xx-core.c b/arch/arm/mach-omap2/pm33xx-core.c
index 9b3755a..e363b97 100644
--- a/arch/arm/mach-omap2/pm33xx-core.c
+++ b/arch/arm/mach-omap2/pm33xx-core.c
@@ -106,12 +106,13 @@ static void amx3_post_suspend_common(void)
pr_err("PM: GFX domain did not transition: %x\n", status);
}

-static int am33xx_suspend(unsigned int state, int (*fn)(unsigned long))
+static int am33xx_suspend(unsigned int state, int (*fn)(unsigned long),
+ unsigned long args)
{
int ret = 0;

amx3_pre_suspend_common();
- ret = cpu_suspend(0, fn);
+ ret = cpu_suspend(args, fn);
amx3_post_suspend_common();

/*
@@ -128,13 +129,14 @@ static int am33xx_suspend(unsigned int state, int (*fn)(unsigned long))
return ret;
}

-static int am43xx_suspend(unsigned int state, int (*fn)(unsigned long))
+static int am43xx_suspend(unsigned int state, int (*fn)(unsigned long),
+ unsigned long args)
{
int ret = 0;

amx3_pre_suspend_common();
scu_power_mode(scu_base, SCU_PM_POWEROFF);
- ret = cpu_suspend(0, fn);
+ ret = cpu_suspend(args, fn);
scu_power_mode(scu_base, SCU_PM_NORMAL);
amx3_post_suspend_common();

diff --git a/arch/arm/mach-omap2/sleep33xx.S b/arch/arm/mach-omap2/sleep33xx.S
index 322b3bb..3ef469f 100644
--- a/arch/arm/mach-omap2/sleep33xx.S
+++ b/arch/arm/mach-omap2/sleep33xx.S
@@ -8,6 +8,7 @@

#include <generated/ti-pm-asm-offsets.h>
#include <linux/linkage.h>
+#include <linux/platform_data/pm33xx.h>
#include <linux/ti-emif-sram.h>
#include <asm/assembler.h>
#include <asm/memory.h>
@@ -25,6 +26,16 @@
ENTRY(am33xx_do_wfi)
stmfd sp!, {r4 - r11, lr} @ save registers on stack

+ /* Save wfi_flags arg to data space */
+ mov r4, r0
+ adr r3, am33xx_pm_ro_sram_data
+ ldr r2, [r3, #AMX3_PM_RO_SRAM_DATA_VIRT_OFFSET]
+ str r4, [r2, #AMX3_PM_WFI_FLAGS_OFFSET]
+
+ /* Only flush cache is we know we are losing MPU context */
+ tst r4, #WFI_FLAG_FLUSH_CACHE
+ beq cache_skip_flush
+
/*
* Flush all data from the L1 and L2 data cache before disabling
* SCTLR.C bit.
@@ -48,14 +59,33 @@ ENTRY(am33xx_do_wfi)
ldr r1, kernel_flush
blx r1

+ adr r3, am33xx_pm_ro_sram_data
+ ldr r2, [r3, #AMX3_PM_RO_SRAM_DATA_VIRT_OFFSET]
+ ldr r4, [r2, #AMX3_PM_WFI_FLAGS_OFFSET]
+
+cache_skip_flush:
+ /* Check if we want self refresh */
+ tst r4, #WFI_FLAG_SELF_REFRESH
+ beq emif_skip_enter_sr
+
adr r9, am33xx_emif_sram_table

ldr r3, [r9, #EMIF_PM_ENTER_SR_OFFSET]
blx r3

+emif_skip_enter_sr:
+ /* Only necessary if PER is losing context */
+ tst r4, #WFI_FLAG_SAVE_EMIF
+ beq emif_skip_save
+
ldr r3, [r9, #EMIF_PM_SAVE_CONTEXT_OFFSET]
blx r3

+emif_skip_save:
+ /* Only can disable EMIF if we have entered self refresh */
+ tst r4, #WFI_FLAG_SELF_REFRESH
+ beq emif_skip_disable
+
/* Disable EMIF */
ldr r1, virt_emif_clkctrl
ldr r2, [r1]
@@ -69,6 +99,10 @@ wait_emif_disable:
cmp r2, r3
bne wait_emif_disable

+emif_skip_disable:
+ tst r4, #WFI_FLAG_WAKE_M3
+ beq wkup_m3_skip
+
/*
* For the MPU WFI to be registered as an interrupt
* to WKUP_M3, MPU_CLKCTRL.MODULEMODE needs to be set
@@ -79,6 +113,7 @@ wait_emif_disable:
bic r2, r2, #AM33XX_CM_CLKCTRL_MODULEMODE_DISABLE
str r2, [r1]

+wkup_m3_skip:
/*
* Execute an ISB instruction to ensure that all of the
* CP15 register changes have been committed.
@@ -132,10 +167,18 @@ wait_emif_enable:
cmp r2, r3
bne wait_emif_enable

+ /* Only necessary if PER is losing context */
+ tst r4, #WFI_FLAG_SELF_REFRESH
+ beq emif_skip_exit_sr_abt

+ adr r9, am33xx_emif_sram_table
ldr r1, [r9, #EMIF_PM_ABORT_SR_OFFSET]
blx r1

+emif_skip_exit_sr_abt:
+ tst r4, #WFI_FLAG_FLUSH_CACHE
+ beq cache_skip_restore
+
/*
* Set SCTLR.C bit to allow data cache allocation
*/
@@ -144,6 +187,7 @@ wait_emif_enable:
mcr p15, 0, r0, c1, c0, 0
isb

+cache_skip_restore:
/* Let the suspend code know about the abort */
mov r0, #1
ldmfd sp!, {r4 - r11, pc} @ restore regs and return
diff --git a/arch/arm/mach-omap2/sleep43xx.S b/arch/arm/mach-omap2/sleep43xx.S
index 8903814..0553adb 100644
--- a/arch/arm/mach-omap2/sleep43xx.S
+++ b/arch/arm/mach-omap2/sleep43xx.S
@@ -9,7 +9,7 @@
#include <generated/ti-pm-asm-offsets.h>
#include <linux/linkage.h>
#include <linux/ti-emif-sram.h>
-
+#include <linux/platform_data/pm33xx.h>
#include <asm/assembler.h>
#include <asm/hardware/cache-l2x0.h>
#include <asm/memory.h>
@@ -51,6 +51,12 @@
ENTRY(am43xx_do_wfi)
stmfd sp!, {r4 - r11, lr} @ save registers on stack

+ /* Save wfi_flags arg to data space */
+ mov r4, r0
+ adr r3, am43xx_pm_ro_sram_data
+ ldr r2, [r3, #AMX3_PM_RO_SRAM_DATA_VIRT_OFFSET]
+ str r4, [r2, #AMX3_PM_WFI_FLAGS_OFFSET]
+
#ifdef CONFIG_CACHE_L2X0
/* Retrieve l2 cache virt address BEFORE we shut off EMIF */
ldr r1, get_l2cache_base
@@ -58,6 +64,10 @@ ENTRY(am43xx_do_wfi)
mov r8, r0
#endif

+ /* Only flush cache is we know we are losing MPU context */
+ tst r4, #WFI_FLAG_FLUSH_CACHE
+ beq cache_skip_flush
+
/*
* Flush all data from the L1 and L2 data cache before disabling
* SCTLR.C bit.
@@ -128,13 +138,33 @@ sync:
bne sync
#endif

+ /* Restore wfi_flags */
+ adr r3, am43xx_pm_ro_sram_data
+ ldr r2, [r3, #AMX3_PM_RO_SRAM_DATA_VIRT_OFFSET]
+ ldr r4, [r2, #AMX3_PM_WFI_FLAGS_OFFSET]
+
+cache_skip_flush:
+ /* Check if we want self refresh */
+ tst r4, #WFI_FLAG_SELF_REFRESH
+ beq emif_skip_enter_sr
+
adr r9, am43xx_emif_sram_table

ldr r3, [r9, #EMIF_PM_ENTER_SR_OFFSET]
blx r3

+emif_skip_enter_sr:
+ /* Only necessary if PER is losing context */
+ tst r4, #WFI_FLAG_SAVE_EMIF
+ beq emif_skip_save
+
ldr r3, [r9, #EMIF_PM_SAVE_CONTEXT_OFFSET]
- blx r3
+ blx r3
+
+emif_skip_save:
+ /* Only can disable EMIF if we have entered self refresh */
+ tst r4, #WFI_FLAG_SELF_REFRESH
+ beq emif_skip_disable

/* Disable EMIF */
ldr r1, am43xx_virt_emif_clkctrl
@@ -148,6 +178,10 @@ wait_emif_disable:
cmp r2, r3
bne wait_emif_disable

+emif_skip_disable:
+ tst r4, #WFI_FLAG_WAKE_M3
+ beq wkup_m3_skip
+
/*
* For the MPU WFI to be registered as an interrupt
* to WKUP_M3, MPU_CLKCTRL.MODULEMODE needs to be set
@@ -165,6 +199,7 @@ wait_emif_disable:
mov r2, #AM43XX_CM_CLKSTCTRL_CLKTRCTRL_SW_SLEEP
str r2, [r1]

+wkup_m3_skip:
/*
* Execute a barrier instruction to ensure that all cache,
* TLB and branch predictor maintenance operations issued
@@ -218,6 +253,9 @@ wait_emif_enable:
cmp r2, r3
bne wait_emif_enable

+ tst r4, #WFI_FLAG_FLUSH_CACHE
+ beq cache_skip_restore
+
/*
* Set SCTLR.C bit to allow data cache allocation
*/
@@ -226,9 +264,16 @@ wait_emif_enable:
mcr p15, 0, r0, c1, c0, 0
isb

- ldr r1, [r9, #EMIF_PM_ABORT_SR_OFFSET]
- blx r1
+cache_skip_restore:
+ /* Only necessary if PER is losing context */
+ tst r4, #WFI_FLAG_SELF_REFRESH
+ beq emif_skip_exit_sr_abt
+
+ adr r9, am43xx_emif_sram_table
+ ldr r1, [r9, #EMIF_PM_ABORT_SR_OFFSET]
+ blx r1

+emif_skip_exit_sr_abt:
/* Let the suspend code know about the abort */
mov r0, #1
ldmfd sp!, {r4 - r11, pc} @ restore regs and return
diff --git a/drivers/soc/ti/pm33xx.c b/drivers/soc/ti/pm33xx.c
index 652739c..0011c8f 100644
--- a/drivers/soc/ti/pm33xx.c
+++ b/drivers/soc/ti/pm33xx.c
@@ -41,6 +41,8 @@
static struct device *pm33xx_dev;
static struct wkup_m3_ipc *m3_ipc;

+static unsigned long suspend_wfi_flags;
+
static u32 sram_suspend_address(unsigned long addr)
{
return ((unsigned long)am33xx_do_wfi_sram +
@@ -53,7 +55,7 @@ static int am33xx_pm_suspend(suspend_state_t suspend_state)
int i, ret = 0;

ret = pm_ops->soc_suspend((unsigned long)suspend_state,
- am33xx_do_wfi_sram);
+ am33xx_do_wfi_sram, suspend_wfi_flags);

if (ret) {
dev_err(pm33xx_dev, "PM: Kernel suspend failure\n");
@@ -310,6 +312,17 @@ static int am33xx_pm_probe(struct platform_device *pdev)
suspend_set_ops(&am33xx_pm_ops);
#endif /* CONFIG_SUSPEND */

+ /*
+ * For a system suspend we must flush the caches, we want
+ * the DDR in self-refresh, we want to save the context
+ * of the EMIF, and we want the wkup_m3 to handle low-power
+ * transition.
+ */
+ suspend_wfi_flags |= WFI_FLAG_FLUSH_CACHE;
+ suspend_wfi_flags |= WFI_FLAG_SELF_REFRESH;
+ suspend_wfi_flags |= WFI_FLAG_SAVE_EMIF;
+ suspend_wfi_flags |= WFI_FLAG_WAKE_M3;
+
ret = pm_ops->init();
if (ret) {
dev_err(dev, "Unable to call core pm init!\n");
diff --git a/include/linux/platform_data/pm33xx.h b/include/linux/platform_data/pm33xx.h
index f9bed2a..d231265 100644
--- a/include/linux/platform_data/pm33xx.h
+++ b/include/linux/platform_data/pm33xx.h
@@ -12,6 +12,29 @@
#include <linux/kbuild.h>
#include <linux/types.h>

+/*
+ * WFI Flags for sleep code control
+ *
+ * These flags allow PM code to exclude certain operations from happening
+ * in the low level ASM code found in sleep33xx.S and sleep43xx.S
+ *
+ * WFI_FLAG_FLUSH_CACHE: Flush the ARM caches and disable caching. Only
+ * needed when MPU will lose context.
+ * WFI_FLAG_SELF_REFRESH: Let EMIF place DDR memory into self-refresh and
+ * disable EMIF.
+ * WFI_FLAG_SAVE_EMIF: Save context of all EMIF registers and restore in
+ * resume path. Only needed if PER domain loses context
+ * and must also have WFI_FLAG_SELF_REFRESH set.
+ * WFI_FLAG_WAKE_M3: Disable MPU clock or clockdomain to cause wkup_m3 to
+ * execute when WFI instruction executes.
+ * WFI_FLAG_RTC_ONLY: Configure the RTC to enter RTC+DDR mode.
+ */
+#define WFI_FLAG_FLUSH_CACHE BIT(0)
+#define WFI_FLAG_SELF_REFRESH BIT(1)
+#define WFI_FLAG_SAVE_EMIF BIT(2)
+#define WFI_FLAG_WAKE_M3 BIT(3)
+#define WFI_FLAG_RTC_ONLY BIT(4)
+
#ifndef __ASSEMBLER__
struct am33xx_pm_sram_addr {
void (*do_wfi)(void);
@@ -23,7 +46,8 @@ struct am33xx_pm_sram_addr {

struct am33xx_pm_platform_data {
int (*init)(void);
- int (*soc_suspend)(unsigned int state, int (*fn)(unsigned long));
+ int (*soc_suspend)(unsigned int state, int (*fn)(unsigned long),
+ unsigned long args);
struct am33xx_pm_sram_addr *(*get_sram_addrs)(void);
};

--
1.9.1

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