From: Jean Pihet <j-pi...@ti.com>
- Reworked and simplified the execution paths for better
readability and to avoid duplication of code,
- Added comments on the entry and exit points and the interaction
with the ROM code for OFF mode restore,
- Reworked the existing comments for better readability.
Tested on N900 and Beagleboard with full RET and OFF modes,
using cpuidle and suspend.
Signed-off-by: Jean Pihet <j-pi...@ti.com>
---
arch/arm/mach-omap2/control.c | 10 +-
arch/arm/mach-omap2/sleep34xx.S | 309 ++++++++++++++++++++++----------------
2 files changed, 188 insertions(+), 131 deletions(-)
diff --git a/arch/arm/mach-omap2/control.c b/arch/arm/mach-omap2/control.c
index 728f268..5cb7276 100644
--- a/arch/arm/mach-omap2/control.c
+++ b/arch/arm/mach-omap2/control.c
@@ -239,7 +239,15 @@ void omap3_save_scratchpad_contents(void)
struct omap3_scratchpad_prcm_block prcm_block_contents;
struct omap3_scratchpad_sdrc_block sdrc_block_contents;
- /* Populate the Scratchpad contents */
+ /*
+ * Populate the Scratchpad contents
+ *
+ * The get_*restore_pointer functions are used to get the resume
+ * function pointer to be called by the ROM code when back from WFI
+ * in OFF mode.
+ * The restore pointer is stored into the scratchpad for later access
+ * by the ROM code.
+ */
scratchpad_contents.boot_config_ptr = 0x0;
if (cpu_is_omap3630())
scratchpad_contents.public_restore_ptr =
diff --git a/arch/arm/mach-omap2/sleep34xx.S b/arch/arm/mach-omap2/sleep34xx.S
index 426af02..55ddd5a 100644
--- a/arch/arm/mach-omap2/sleep34xx.S
+++ b/arch/arm/mach-omap2/sleep34xx.S
@@ -70,6 +70,11 @@
* API functions
*/
+/*
+ * The get_*restore_pointer functions are returning the resume
+ * function pointer to be called by the ROM code when back from WFI
+ * in OFF mode.
+ */
.text
/* Function call to get the restore pointer for resume from OFF */
ENTRY(get_restore_pointer)
@@ -101,7 +106,7 @@ ENTRY(get_es3_restore_pointer_sz)
/*
* L2 cache needs to be toggled for stable OFF mode functionality on 3630.
* This function sets up a flag that will allow for this toggling to take
- * place on 3630. Hopefully some version in the future maynot need this
+ * place on 3630. Hopefully some version in the future maynot need this.
*/
ENTRY(enable_omap3630_toggle_l2_on_restore)
stmfd sp!, {lr} @ save registers on stack
@@ -143,34 +148,156 @@ ENTRY(save_secure_ram_context_sz)
.word . - save_secure_ram_context
/*
+ * ======================
+ * == Idle entry point ==
+ * ======================
+ */
+
+/*
* Forces OMAP into idle state
*
- * omap34xx_suspend() - This bit of code just executes the WFI
- * for normal idles.
+ * omap34xx_suspend() - This bit of code saves the CPU context if needed
+ * and executes the WFI instruction
*
- * Note: This code get's copied to internal SRAM at boot. When the OMAP
- * wakes up it continues execution at the point it went to sleep.
+ * Notes:
+ * - this code gets copied to internal SRAM at boot.
+ * - when the OMAP wakes up it continues at different execution points
+ * depending on the low power mode (non-OFF vs OFF modes),
+ * cf. 'Resume path for xxx mode' comments.
*/
ENTRY(omap34xx_cpu_suspend)
stmfd sp!, {r0-r12, lr} @ save registers on stack
- /* r0 contains restore pointer in sdram */
- /* r1 contains information about saving context */
- ldr r4, sdrc_power @ read the SDRC_POWER register
- ldr r5, [r4] @ read the contents of SDRC_POWER
- orr r5, r5, #0x40 @ enable self refresh on idle req
- str r5, [r4] @ write back to SDRC_POWER register
+ /*
+ * r0 contains restore pointer in sdram
+ * r1 contains information about saving context:
+ * 0 - No context lost
+ * 1 - Only L1 and logic lost
+ * 2 - Only L2 lost
+ * 3 - Both L1 and L2 lost
+ */
+ /* Save context only if required */
cmp r1, #0x0
- /* If context save is required, do that and execute wfi */
- bne save_context_wfi
+ beq omap3_do_wfi
+
+save_context_wfi:
+ mov r8, r0 @ Store SDRAM address in r8
+ mrc p15, 0, r5, c1, c0, 1 @ Read Auxiliary Control Register
+ mov r4, #0x1 @ Number of parameters for restore call
+ stmia r8!, {r4-r5} @ Push parameters for restore call
+ mrc p15, 1, r5, c9, c0, 2 @ Read L2 AUX ctrl register
+ stmia r8!, {r4-r5} @ Push parameters for restore call
+
+ /* Check what that target sleep state is from r1 */
+ cmp r1, #0x2 @ Only L2 lost, no need to save context
+ beq clean_caches
+
+l1_logic_lost:
+ /* Store sp and spsr to SDRAM */
+ mov r4, sp
+ mrs r5, spsr
+ mov r6, lr
+ stmia r8!, {r4-r6}
+ /* Save all ARM registers */
+ /* Coprocessor access control register */
+ mrc p15, 0, r6, c1, c0, 2
+ stmia r8!, {r6}
+ /* TTBR0, TTBR1 and Translation table base control */
+ mrc p15, 0, r4, c2, c0, 0
+ mrc p15, 0, r5, c2, c0, 1
+ mrc p15, 0, r6, c2, c0, 2
+ stmia r8!, {r4-r6}
+ /*
+ * Domain access control register, data fault status register,
+ * and instruction fault status register
+ */
+ mrc p15, 0, r4, c3, c0, 0
+ mrc p15, 0, r5, c5, c0, 0
+ mrc p15, 0, r6, c5, c0, 1
+ stmia r8!, {r4-r6}
+ /*
+ * Data aux fault status register, instruction aux fault status,
+ * data fault address register and instruction fault address register
+ */
+ mrc p15, 0, r4, c5, c1, 0
+ mrc p15, 0, r5, c5, c1, 1
+ mrc p15, 0, r6, c6, c0, 0
+ mrc p15, 0, r7, c6, c0, 2
+ stmia r8!, {r4-r7}
+ /*
+ * user r/w thread and process ID, user r/o thread and process ID,
+ * priv only thread and process ID, cache size selection
+ */
+ mrc p15, 0, r4, c13, c0, 2
+ mrc p15, 0, r5, c13, c0, 3
+ mrc p15, 0, r6, c13, c0, 4
+ mrc p15, 2, r7, c0, c0, 0
+ stmia r8!, {r4-r7}
+ /* Data TLB lockdown, instruction TLB lockdown registers */
+ mrc p15, 0, r5, c10, c0, 0
+ mrc p15, 0, r6, c10, c0, 1
+ stmia r8!, {r5-r6}
+ /* Secure or non secure vector base address, FCSE PID, Context PID*/
+ mrc p15, 0, r4, c12, c0, 0
+ mrc p15, 0, r5, c13, c0, 0
+ mrc p15, 0, r6, c13, c0, 1
+ stmia r8!, {r4-r6}
+ /* Primary remap, normal remap registers */
+ mrc p15, 0, r4, c10, c2, 0
+ mrc p15, 0, r5, c10, c2, 1
+ stmia r8!,{r4-r5}
+
+ /* Store current cpsr*/
+ mrs r2, cpsr
+ stmia r8!, {r2}
+
+ mrc p15, 0, r4, c1, c0, 0
+ /* save control register */
+ stmia r8!, {r4}
+
+clean_caches:
+ /* Clean Data or unified cache to POU*/
+ /* How to invalidate only L1 cache???? - #FIX_ME# */
+ /* mcr p15, 0, r11, c7, c11, 1 */
+ cmp r1, #0x1 @ Check whether L2 inval is required
+ beq omap3_do_wfi
+
+clean_l2:
+ /*
+ * jump out to kernel flush routine
+ * - reuse that code is better
+ * - it executes in a cached space so is faster than refetch per-block
+ * - should be faster and will change with kernel
+ * - 'might' have to copy address, load and jump to it
+ */
+ ldr r1, kernel_flush
+ mov lr, pc
+ bx r1
+
+omap3_do_wfi:
+ ldr r4, sdrc_power @ read the SDRC_POWER register
+ ldr r5, [r4] @ read the contents of SDRC_POWER
+ orr r5, r5, #0x40 @ enable self refresh on idle req
+ str r5, [r4] @ write back to SDRC_POWER register
+
/* Data memory barrier and Data sync barrier */
mov r1, #0
mcr p15, 0, r1, c7, c10, 4
mcr p15, 0, r1, c7, c10, 5
+/*
+ * ===================================
+ * == WFI instruction => Enter idle ==
+ * ===================================
+ */
wfi @ wait for interrupt
+/*
+ * ===================================
+ * == Resume path for non-OFF modes ==
+ * ===================================
+ */
nop
nop
nop
@@ -183,7 +310,29 @@ ENTRY(omap34xx_cpu_suspend)
nop
bl wait_sdrc_ok
- ldmfd sp!, {r0-r12, pc} @ restore regs and return
+/*
+ * ===================================
+ * == Exit point from non-OFF modes ==
+ * ===================================
+ */
+ ldmfd sp!, {r0-r12, pc} @ restore regs and return
+
+
+/*
+ * ==============================
+ * == Resume path for OFF mode ==
+ * ==============================
+ */
+
+/*
+ * The restore_* functions are called by the ROM code
+ * when back from WFI in OFF mode.
+ * Cf. the get_*restore_pointer functions.
+ *
+ * restore_es3: applies to 34xx >= ES3.0
+ * restore_3630: applies to 36xx
+ * restore: common code for 3xxx
+ */
restore_es3:
ldr r5, pm_prepwstst_core_p
ldr r4, [r5]
@@ -213,12 +362,17 @@ restore_3630:
ldr r1, control_mem_rta
mov r2, #OMAP36XX_RTA_DISABLE
str r2, [r1]
- /* Fall thru for the remaining logic */
+
+ /* Fall thru to common code for the remaining logic */
+
restore:
- /* Check what was the reason for mpu reset and store the reason in r9*/
- /* 1 - Only L1 and logic lost */
- /* 2 - Only L2 lost - In this case, we wont be here */
- /* 3 - Both L1 and L2 lost */
+ /*
+ * Check what was the reason for mpu reset and store the reason in r9:
+ * 0 - No context lost
+ * 1 - Only L1 and logic lost
+ * 2 - Only L2 lost - In this case, we wont be here
+ * 3 - Both L1 and L2 lost
+ */
ldr r1, pm_pwstctrl_mpu
ldr r2, [r1]
and r2, r2, #0x3
@@ -421,118 +575,12 @@ usettbr0:
and r4, r2
mcr p15, 0, r4, c1, c0, 0
+/*
+ * ==============================
+ * == Exit point from OFF mode ==
+ * ==============================
+ */
ldmfd sp!, {r0-r12, pc} @ restore regs and return
-save_context_wfi:
- mov r8, r0 /* Store SDRAM address in r8 */
- mrc p15, 0, r5, c1, c0, 1 @ Read Auxiliary Control Register
- mov r4, #0x1 @ Number of parameters for restore call
- stmia r8!, {r4-r5} @ Push parameters for restore call
- mrc p15, 1, r5, c9, c0, 2 @ Read L2 AUX ctrl register
- stmia r8!, {r4-r5} @ Push parameters for restore call
- /* Check what that target sleep state is:stored in r1*/
- /* 1 - Only L1 and logic lost */
- /* 2 - Only L2 lost */
- /* 3 - Both L1 and L2 lost */
- cmp r1, #0x2 /* Only L2 lost */
- beq clean_l2
- cmp r1, #0x1 /* L2 retained */
- /* r9 stores whether to clean L2 or not*/
- moveq r9, #0x0 /* Dont Clean L2 */
- movne r9, #0x1 /* Clean L2 */
-l1_logic_lost:
- /* Store sp and spsr to SDRAM */
- mov r4, sp
- mrs r5, spsr
- mov r6, lr
- stmia r8!, {r4-r6}
- /* Save all ARM registers */
- /* Coprocessor access control register */
- mrc p15, 0, r6, c1, c0, 2
- stmia r8!, {r6}
- /* TTBR0, TTBR1 and Translation table base control */
- mrc p15, 0, r4, c2, c0, 0
- mrc p15, 0, r5, c2, c0, 1
- mrc p15, 0, r6, c2, c0, 2
- stmia r8!, {r4-r6}
- /* Domain access control register, data fault status register,
- and instruction fault status register */
- mrc p15, 0, r4, c3, c0, 0
- mrc p15, 0, r5, c5, c0, 0
- mrc p15, 0, r6, c5, c0, 1
- stmia r8!, {r4-r6}
- /* Data aux fault status register, instruction aux fault status,
- datat fault address register and instruction fault address register*/
- mrc p15, 0, r4, c5, c1, 0
- mrc p15, 0, r5, c5, c1, 1
- mrc p15, 0, r6, c6, c0, 0
- mrc p15, 0, r7, c6, c0, 2
- stmia r8!, {r4-r7}
- /* user r/w thread and process ID, user r/o thread and process ID,
- priv only thread and process ID, cache size selection */
- mrc p15, 0, r4, c13, c0, 2
- mrc p15, 0, r5, c13, c0, 3
- mrc p15, 0, r6, c13, c0, 4
- mrc p15, 2, r7, c0, c0, 0
- stmia r8!, {r4-r7}
- /* Data TLB lockdown, instruction TLB lockdown registers */
- mrc p15, 0, r5, c10, c0, 0
- mrc p15, 0, r6, c10, c0, 1
- stmia r8!, {r5-r6}
- /* Secure or non secure vector base address, FCSE PID, Context PID*/
- mrc p15, 0, r4, c12, c0, 0
- mrc p15, 0, r5, c13, c0, 0
- mrc p15, 0, r6, c13, c0, 1
- stmia r8!, {r4-r6}
- /* Primary remap, normal remap registers */
- mrc p15, 0, r4, c10, c2, 0
- mrc p15, 0, r5, c10, c2, 1
- stmia r8!,{r4-r5}
-
- /* Store current cpsr*/
- mrs r2, cpsr
- stmia r8!, {r2}
-
- mrc p15, 0, r4, c1, c0, 0
- /* save control register */
- stmia r8!, {r4}
-clean_caches:
- /* Clean Data or unified cache to POU*/
- /* How to invalidate only L1 cache???? - #FIX_ME# */
- /* mcr p15, 0, r11, c7, c11, 1 */
- cmp r9, #1 /* Check whether L2 inval is required or not*/
- bne skip_l2_inval
-clean_l2:
- /*
- * Jump out to kernel flush routine
- * - reuse that code is better
- * - it executes in a cached space so is faster than refetch per-block
- * - should be faster and will change with kernel
- * - 'might' have to copy address, load and jump to it
- */
- ldr r1, kernel_flush
- mov lr, pc
- bx r1
-
-skip_l2_inval:
- /* Data memory barrier and Data sync barrier */
- mov r1, #0
- mcr p15, 0, r1, c7, c10, 4
- mcr p15, 0, r1, c7, c10, 5
-
- wfi @ wait for interrupt
- nop
- nop
- nop
- nop
- nop
- nop
- nop
- nop
- nop
- nop
- bl wait_sdrc_ok
- /* restore regs and return */
- ldmfd sp!, {r0-r12, pc}
/*
@@ -682,5 +730,6 @@ kick_counter:
.word 0
wait_dll_lock_counter:
.word 0
+
ENTRY(omap34xx_cpu_suspend_sz)
.word . - omap34xx_cpu_suspend
--
1.7.1
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