RE: [PATCH 2/2] OMAP3 PM: sleep code clean up

Kevin,

-----Original Message----- From: Kevin Hilman [mailto:khilman@deeprootsystems.com] Sent: Saturday, September 25, 2010 1:35 AM To: Sripathy, Vishwanath Cc: linux-omap@vger.kernel.org; linaro-dev@lists.linaro.org Subject: Re: [PATCH 2/2] OMAP3 PM: sleep code clean up

Vishwanath BS vishwanath.bs@ti.com writes:

...

This patch has done some clean up of omap3 sleep code. Basically all possible hardcodings are removed and code is Reorganized into more logical buckets for better readability and instrumentation.

Tested on ZOOM3.

Again, please describe more about how it was tested. idle? suspend? retention? off?

This has been tested for both RET and OFF mode in Idle and suspend path. Will update the change log for the same.

Also please fix long-line checkpatch warnings.

OK.

While breaking this up in to subroutines, why not just call them all from the C-code instead of assembly?

I thought about that. But unfortunately, while saving CPU registers (in save_context_wfi), LR also gets saved. So if I call wfi routine (omap34xx_do_wfi ) from C code itself, then LR would have pointed to omap34xx_do_wfi while saving the registers which is not correct.

But this also makes me wonder, if we're going to clean this up, the bulk of it could be re-written in C, with some inline asm helpers as needed.

Probably yes. But as this code is specific to OMAP3, do you think it's worth spending time on rewriting the entire code in C? It might be a significant effort and it will not be reusable for other ARM SOCs.

Vishwa

Kevin

...

Signed-off-by: Vishwanath BS vishwanath.bs@ti.com Cc: Kevin Hillman khilman@deeprootsystems.com Cc: <Linaro> linaro-dev@lists.linaro.org

---

arch/arm/mach-omap2/sleep34xx.S | 377 ++++++++++++++-----------

---

...

arch/arm/plat-omap/include/plat/control.h | 2 + 2 files changed, 189 insertions(+), 190 deletions(-)

diff --git a/arch/arm/mach-omap2/sleep34xx.S b/arch/arm/mach-

omap2/sleep34xx.S

...

index ba53191..734f82a --- a/arch/arm/mach-omap2/sleep34xx.S +++ b/arch/arm/mach-omap2/sleep34xx.S @@ -33,17 +33,20 @@ #include "prm.h" #include "sdrc.h"

-#define SDRC_SCRATCHPAD_SEM_V 0xfa00291c +#define SDRC_SCRATCHPAD_SEM_OFFS 0xc +#define SDRC_SCRATCHPAD_SEM_V OMAP343X_SCRATCHPAD_REGADDR \

•                                               (SDRC_SCRATCHPAD_SEM_OFFS)
  
  

#define PM_PREPWSTST_CORE_V OMAP34XX_PRM_REGADDR(CORE_MOD, \

•                       OMAP3430_PM_PREPWSTST)
  

-#define PM_PREPWSTST_CORE_P 0x48306AE8

•                                               OMAP3430_PM_PREPWSTST)
  

+#define PM_PREPWSTST_CORE_P OMAP3430_PRM_BASE + CORE_MOD + \

•                                                       OMAP3430_PM_PREPWSTST
  

#define PM_PREPWSTST_MPU_V OMAP34XX_PRM_REGADDR(MPU_MOD, \ OMAP3430_PM_PREPWSTST) #define PM_PWSTCTRL_MPU_P OMAP3430_PRM_BASE + MPU_MOD +

OMAP2_PM_PWSTCTRL

...

#define CM_IDLEST1_CORE_V OMAP34XX_CM_REGADDR(CORE_MOD,

CM_IDLEST1)

...

-#define SRAM_BASE_P 0x40200000 -#define CONTROL_STAT 0x480022F0 +#define SRAM_BASE_P 0x40200000 +#define CONTROL_STAT OMAP343X_CTRL_BASE +

OMAP343X_CONTROL_STATUS

...

#define SCRATCHPAD_MEM_OFFS 0x310 /* Move this as correct place is * available */ #define SCRATCHPAD_BASE_P (OMAP343X_CTRL_BASE +

OMAP343X_CONTROL_MEM_WKUP\

...

@@ -184,29 +187,16 @@ api_params: ENTRY(save_secure_ram_context_sz) .word . - save_secure_ram_context

-/*

• • Forces OMAP into idle state
• • omap34xx_suspend() - This bit of code just executes the WFI
• • for normal idles.
• • 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.
• */

-ENTRY(omap34xx_cpu_suspend) +/* Function to execute WFI. When the MPU wakes up from retention

• • or inactive mode, it continues execution just after wfi */

fix multi-line comment style

...

+ENTRY(omap34xx_do_wfi) stmfd sp!, {r0-r12, lr} @ save registers on stack -loop:

• /*b loop*/ @Enable to debug by stepping through code
• /* 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

• cmp r1, #0x0
• /* If context save is required, do that and execute wfi */
• bne save_context_wfi /* Data memory barrier and Data sync barrier */ mov r1, #0 mcr p15, 0, r1, c7, c10, 4

@@ -225,8 +215,182 @@ loop: nop nop bl wait_sdrc_ok

• ldmfd sp!, {r0-r12, pc} @ restore regs and return

+/*

• • Forces OMAP into idle state
• • omap34xx_cpu_suspend() - This bit of code just executes the WFI
• • for normal idles and saves the context before WFI on off modes.
• */

+ENTRY(omap34xx_cpu_suspend)

• stmfd sp!, {r0-r12, lr} @ save registers on stack

+loop:

• /*b loop*/ @Enable to debug by stepping through code

• /* r0 contains restore pointer in sdram */

• /* r1 contains information about saving context */

• cmp r1, #0x0

• /* If context save is required, do that and execute wfi */

• bne save_context_wfi

• bl omap34xx_do_wfi

  ldmfd sp!, {r0-r12, pc} @ restore regs and return

+save_context_wfi:

• /*b save_context_wfi*/ @ enable to debug save code
• 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:

• /* read clidr */
• mrc p15, 1, r0, c0, c0, 1
• /* extract loc from clidr */
• ands r3, r0, #0x7000000
• /* left align loc bit field */
• mov r3, r3, lsr #23
• /* if loc is 0, then no need to clean */
• beq finished
• /* start clean at cache level 0 */
• mov r10, #0

+loop1:

• /* work out 3x current cache level */
• add r2, r10, r10, lsr #1
• /* extract cache type bits from clidr*/
• mov r1, r0, lsr r2
• /* mask of the bits for current cache only */
• and r1, r1, #7
• /* see what cache we have at this level */
• cmp r1, #2
• /* skip if no cache, or just i-cache */
• blt skip
• /* select current cache level in cssr */
• mcr p15, 2, r10, c0, c0, 0
• /* isb to sych the new cssr&csidr */
• isb
• /* read the new csidr */
• mrc p15, 1, r1, c0, c0, 0
• /* extract the length of the cache lines */
• and r2, r1, #7
• /* add 4 (line length offset) */
• add r2, r2, #4
• ldr r4, assoc_mask
• /* find maximum number on the way size */
• ands r4, r4, r1, lsr #3
• /* find bit position of way size increment */
• clz r5, r4
• ldr r7, numset_mask
• /* extract max number of the index size*/
• ands r7, r7, r1, lsr #13

+loop2:

• mov r9, r4
• /* create working copy of max way size*/

+loop3:

• /* factor way and cache number into r11 */
• orr r11, r10, r9, lsl r5
• /* factor index number into r11 */
• orr r11, r11, r7, lsl r2
• /*clean & invalidate by set/way */
• mcr p15, 0, r11, c7, c10, 2
• /* decrement the way*/
• subs r9, r9, #1
• bge loop3
• /*decrement the index */
• subs r7, r7, #1
• bge loop2

+skip:

• add r10, r10, #2
• /* increment cache number */
• cmp r3, r10
• bgt loop1

+finished:

• /*swith back to cache level 0 */
• mov r10, #0
• /* select current cache level in cssr */
• mcr p15, 2, r10, c0, c0, 0
• isb

+skip_l2_inval:

• bl omap34xx_do_wfi
• ldmfd sp!, {r0-r12, pc}

+/* This is where ROM code jumps when MPU comes out of off mode */ restore_es3: /*b restore_es3*/ @ Enable to debug restore code ldr r5, pm_prepwstst_core_p @@ -437,175 +601,8 @@ usettbr0: ldr r2, cache_pred_disable_mask and r4, r2 mcr p15, 0, r4, c1, c0, 0

• ldmfd sp!, {r0-r12, pc} @ restore regs and return

-save_context_wfi:

• /*b save_context_wfi*/ @ enable to debug save code
• 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:

• /* read clidr */
• mrc p15, 1, r0, c0, c0, 1
• /* extract loc from clidr */
• ands r3, r0, #0x7000000
• /* left align loc bit field */
• mov r3, r3, lsr #23
• /* if loc is 0, then no need to clean */
• beq finished
• /* start clean at cache level 0 */
• mov r10, #0

-loop1:

• /* work out 3x current cache level */
• add r2, r10, r10, lsr #1
• /* extract cache type bits from clidr*/
• mov r1, r0, lsr r2
• /* mask of the bits for current cache only */
• and r1, r1, #7
• /* see what cache we have at this level */
• cmp r1, #2
• /* skip if no cache, or just i-cache */
• blt skip
• /* select current cache level in cssr */
• mcr p15, 2, r10, c0, c0, 0
• /* isb to sych the new cssr&csidr */
• isb
• /* read the new csidr */
• mrc p15, 1, r1, c0, c0, 0
• /* extract the length of the cache lines */
• and r2, r1, #7
• /* add 4 (line length offset) */
• add r2, r2, #4
• ldr r4, assoc_mask
• /* find maximum number on the way size */
• ands r4, r4, r1, lsr #3
• /* find bit position of way size increment */
• clz r5, r4
• ldr r7, numset_mask
• /* extract max number of the index size*/
• ands r7, r7, r1, lsr #13

-loop2:

• mov r9, r4
• /* create working copy of max way size*/

-loop3:

• /* factor way and cache number into r11 */
• orr r11, r10, r9, lsl r5
• /* factor index number into r11 */
• orr r11, r11, r7, lsl r2
• /*clean & invalidate by set/way */
• mcr p15, 0, r11, c7, c10, 2
• /* decrement the way*/
• subs r9, r9, #1
• bge loop3
• /*decrement the index */
• subs r7, r7, #1
• bge loop2

-skip:

• add r10, r10, #2
• /* increment cache number */
• cmp r3, r10
• bgt loop1

-finished:

• /*swith back to cache level 0 */
• mov r10, #0
• /* select current cache level in cssr */
• mcr p15, 2, r10, c0, c0, 0
• isb

-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}

/* Make sure SDRC accesses are ok */ wait_sdrc_ok: @@ -669,4 +666,4 @@ cache_pred_disable_mask: control_stat: .word CONTROL_STAT ENTRY(omap34xx_cpu_suspend_sz)

• .word . - omap34xx_cpu_suspend

• .word . - omap34xx_cpu_suspend

diff --git a/arch/arm/plat-omap/include/plat/control.h b/arch/arm/plat-

omap/include/plat/control.h

...

index 46e166d..306259e 100644 --- a/arch/arm/plat-omap/include/plat/control.h +++ b/arch/arm/plat-omap/include/plat/control.h @@ -314,6 +314,8 @@ #define OMAP343X_SCRATCHPAD_ROM (OMAP343X_CTRL_BASE +

0x860)

...

#define OMAP343X_SCRATCHPAD (OMAP343X_CTRL_BASE + 0x910) #define OMAP343X_SCRATCHPAD_ROM_OFFSET 0x19C +#define OMAP343X_SCRATCHPAD_REGADDR(reg) \

•               OMAP2_L4_IO_ADDRESS(OMAP343X_SCRATCHPAD + reg)
  
  

/* AM35XX_CONTROL_IPSS_CLK_CTRL bits */ #define AM35XX_USBOTG_VBUSP_CLK_SHIFT 0