From: Jean Pihet Date: Sat, 18 Dec 2010 15:44:45 +0000 (+0100) Subject: OMAP3: rework of the ASM sleep code execution paths X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=f7dfe3d8a98b7c4869c09826e3a65663cb9c71be;p=linux-beck.git OMAP3: rework of the ASM sleep code execution paths - 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 Acked-by: Santosh Shilimkar Tested-by: Nishanth Menon Signed-off-by: Kevin Hilman --- diff --git a/arch/arm/mach-omap2/control.c b/arch/arm/mach-omap2/control.c index 27ed558fdf54..0269bb055b69 100644 --- a/arch/arm/mach-omap2/control.c +++ b/arch/arm/mach-omap2/control.c @@ -239,7 +239,14 @@ 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 provide a + * physical restore address where the ROM code jumps while waking + * up from MPU OFF/OSWR state. + * The restore pointer is stored into the scratchpad. + */ 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 5b978b8401c4..06e47326e17c 100644 --- a/arch/arm/mach-omap2/sleep34xx.S +++ b/arch/arm/mach-omap2/sleep34xx.S @@ -69,6 +69,13 @@ /* * API functions + */ + +/* + * The "get_*restore_pointer" functions are used to provide a + * physical restore address where the ROM code jumps while waking + * up from MPU OFF/OSWR state. + * The restore pointer is stored into the scratchpad. */ .text @@ -102,7 +109,7 @@ 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 may not need this. */ ENTRY(enable_omap3630_toggle_l2_on_restore) stmfd sp!, {lr} @ save registers on stack @@ -143,35 +150,163 @@ api_params: 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_cpu_suspend() - This bit of code saves the CPU context if needed + * and executes the WFI instruction. Calling WFI effectively changes the + * power domains states to the desired target power states. + * * - * 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. The execution pointer + * in SRAM is _omap_sram_idle. + * - 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 + */ + /* Directly jump to WFI is the context save is not required */ cmp r1, #0x0 - /* If context save is required, do that and execute wfi */ - bne save_context_wfi + beq omap3_do_wfi + + /* Otherwise fall through to the save context code */ +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 @@ -184,7 +319,29 @@ 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] @@ -214,12 +371,17 @@ restore_3630: ldr r1, control_mem_rta mov r2, #OMAP36XX_RTA_DISABLE str r2, [r1] - /* Fall thru for the remaining logic */ + + /* Fall through 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 @@ -422,119 +584,12 @@ 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 - * - lr is used since we are running in SRAM currently. - */ - 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} /* @@ -687,5 +742,6 @@ kick_counter: .word 0 wait_dll_lock_counter: .word 0 + ENTRY(omap34xx_cpu_suspend_sz) .word . - omap34xx_cpu_suspend