From mboxrd@z Thu Jan 1 00:00:00 1970 From: Santosh Shilimkar Subject: Re: [PATCH] OMAP3: run the ASM sleep code from DDR Date: Fri, 17 Jun 2011 15:21:36 +0530 Message-ID: <4DFB23A8.2020408@ti.com> References: <1308300725-12150-1-git-send-email-j-pihet@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from na3sys009aog105.obsmtp.com ([74.125.149.75]:34709 "EHLO na3sys009aog105.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753095Ab1FQJvn (ORCPT ); Fri, 17 Jun 2011 05:51:43 -0400 Received: by mail-yw0-f47.google.com with SMTP id 12so775557ywa.20 for ; Fri, 17 Jun 2011 02:51:42 -0700 (PDT) In-Reply-To: <1308300725-12150-1-git-send-email-j-pihet@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: jean.pihet@newoldbits.com Cc: linux-omap@vger.kernel.org, Jean Pihet On 6/17/2011 2:22 PM, jean.pihet@newoldbits.com wrote: > From: Jean Pihet > > Most of the ASM sleep code (in arch/arm/mach-omap2/sleep34xx.S) > is copied to internal SRAM and run from there. > However only a small part of the code really needs to run from internal SRAM. > > This fix lets most of the ASM idle code run from the DDR > in order to minimize the SRAM usage. No performance > loss or gain can be measured with a 32KHz clock period. > > The only pieces of code that are mandatory in SRAM > are: > - the i443 erratum WA, > - the i581 erratum WA, > - the security extension code. > > SRAM usage: > - original code: > . 560 bytes for omap3_sram_configure_core_dpll (used by DVFS), > . 1196 bytes for omap_sram_idle (used by suspend/resume in RETention), > . 124 bytes for es3_sdrc_fix (used by suspend/resume in OFF mode on ES3.x), > . 108 bytes for save_secure_ram_context (used on HS parts only). > > With this fix the usage for suspend/resume in RETention goes down 288 bytes, > so the gain in SRAM usage for suspend/resume is 908 bytes. > > Also fixed the SRAM initialization sequence to avoid an unnecessary > copy to SRAM at boot time and for readability. > > Tested on Beagleboard (ES2.x) in idle with full RET and OFF modes. > > Signed-off-by: Jean Pihet As mentioned in the other thread, with auto-deps set always which is the case on OMAP3, this patch is safe. FWIW: Acked-by: Santosh Shilimkar c > --- > arch/arm/mach-omap2/pm.h | 20 ++- > arch/arm/mach-omap2/pm34xx.c | 20 ++- > arch/arm/mach-omap2/sleep34xx.S | 316 ++++++++++++++++++++++----------------- > arch/arm/plat-omap/sram.c | 15 +-- > 4 files changed, 213 insertions(+), 158 deletions(-) > > diff --git a/arch/arm/mach-omap2/pm.h b/arch/arm/mach-omap2/pm.h > index 45bcfce..a4ec213 100644 > --- a/arch/arm/mach-omap2/pm.h > +++ b/arch/arm/mach-omap2/pm.h > @@ -88,18 +88,28 @@ extern int pm_dbg_regset_init(int reg_set); > #define pm_dbg_regset_init(reg_set) do {} while (0); > #endif /* CONFIG_PM_DEBUG */ > > +/* 24xx */ > extern void omap24xx_idle_loop_suspend(void); > +extern unsigned int omap24xx_idle_loop_suspend_sz; > > extern void omap24xx_cpu_suspend(u32 dll_ctrl, void __iomem *sdrc_dlla_ctrl, > void __iomem *sdrc_power); > +extern unsigned int omap24xx_cpu_suspend_sz; > + > +/* 3xxx */ > extern void omap34xx_cpu_suspend(u32 *addr, int save_state); > -extern int save_secure_ram_context(u32 *addr); > -extern void omap3_save_scratchpad_contents(void); > > -extern unsigned int omap24xx_idle_loop_suspend_sz; > +/* omap3_do_wfi function pointer and size, for copy to SRAM */ > +extern void omap3_do_wfi(void); > +extern unsigned int omap3_do_wfi_sz; > +/* ... and its pointer from SRAM after copy */ > +extern void (*omap3_do_wfi_sram)(void); > + > +/* save_secure_ram_context function pointer and size, for copy to SRAM */ > +extern int save_secure_ram_context(u32 *addr); > extern unsigned int save_secure_ram_context_sz; > -extern unsigned int omap24xx_cpu_suspend_sz; > -extern unsigned int omap34xx_cpu_suspend_sz; > + > +extern void omap3_save_scratchpad_contents(void); > > #define PM_RTA_ERRATUM_i608 (1<< 0) > #define PM_SDRC_WAKEUP_ERRATUM_i583 (1<< 1) > diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c > index c155c9d..f056732 100644 > --- a/arch/arm/mach-omap2/pm34xx.c > +++ b/arch/arm/mach-omap2/pm34xx.c > @@ -83,9 +83,8 @@ struct power_state { > > static LIST_HEAD(pwrst_list); > > -static void (*_omap_sram_idle)(u32 *addr, int save_state); > - > static int (*_omap_save_secure_sram)(u32 *addr); > +void (*omap3_do_wfi_sram)(void); > > static struct powerdomain *mpu_pwrdm, *neon_pwrdm; > static struct powerdomain *core_pwrdm, *per_pwrdm; > @@ -352,9 +351,6 @@ void omap_sram_idle(void) > int core_prev_state, per_prev_state; > u32 sdrc_pwr = 0; > > - if (!_omap_sram_idle) > - return; > - > pwrdm_clear_all_prev_pwrst(mpu_pwrdm); > pwrdm_clear_all_prev_pwrst(neon_pwrdm); > pwrdm_clear_all_prev_pwrst(core_pwrdm); > @@ -436,7 +432,7 @@ void omap_sram_idle(void) > * get saved. The restore path then reads from this > * location and restores them back. > */ > - _omap_sram_idle(omap3_arm_context, save_state); > + omap34xx_cpu_suspend(omap3_arm_context, save_state); > cpu_init(); > > /* Restore normal SDRC POWER settings */ > @@ -852,10 +848,17 @@ static int __init clkdms_setup(struct clockdomain *clkdm, void *unused) > return 0; > } > > +/* > + * Push functions to SRAM > + * > + * The minimum set of functions is pushed to SRAM for execution: > + * - omap3_do_wfi for erratum i581 WA, > + * - save_secure_ram_context for security extensions. > + */ > void omap_push_sram_idle(void) > { > - _omap_sram_idle = omap_sram_push(omap34xx_cpu_suspend, > - omap34xx_cpu_suspend_sz); > + omap3_do_wfi_sram = omap_sram_push(omap3_do_wfi, omap3_do_wfi_sz); > + > if (omap_type() != OMAP2_DEVICE_TYPE_GP) > _omap_save_secure_sram = omap_sram_push(save_secure_ram_context, > save_secure_ram_context_sz); > @@ -920,7 +923,6 @@ static int __init omap3_pm_init(void) > per_clkdm = clkdm_lookup("per_clkdm"); > core_clkdm = clkdm_lookup("core_clkdm"); > > - omap_push_sram_idle(); > #ifdef CONFIG_SUSPEND > suspend_set_ops(&omap_pm_ops); > #endif /* CONFIG_SUSPEND */ > diff --git a/arch/arm/mach-omap2/sleep34xx.S b/arch/arm/mach-omap2/sleep34xx.S > index 63f1066..2ef0c0d 100644 > --- a/arch/arm/mach-omap2/sleep34xx.S > +++ b/arch/arm/mach-omap2/sleep34xx.S > @@ -179,8 +179,10 @@ ENTRY(save_secure_ram_context_sz) > * > * > * Notes: > - * - this code gets copied to internal SRAM at boot and after wake-up > - * from OFF mode. The execution pointer in SRAM is _omap_sram_idle. > + * - only the minimum set of functions gets copied to internal SRAM at boot > + * and after wake-up from OFF mode, cf. omap_push_sram_idle. The function > + * pointers in SDRAM or SRAM are called depending on the desired low power > + * target state. > * - 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. > @@ -198,9 +200,15 @@ ENTRY(omap34xx_cpu_suspend) > * 3 - Both L1 and L2 lost and logic lost > */ > > - /* Directly jump to WFI is the context save is not required */ > - cmp r1, #0x0 > - beq omap3_do_wfi > + /* > + * For OFF mode: save context and jump to WFI in SDRAM (omap3_do_wfi) > + * For non-OFF modes: jump to the WFI code in SRAM (omap3_do_wfi_sram) > + */ > + ldr r4, omap3_do_wfi_sram_addr > + ldr r5, [r4] > + cmp r1, #0x0 @ If no context save required, > + bxeq r5 @ jump to the WFI code in SRAM > + > > /* Otherwise fall through to the save context code */ > save_context_wfi: > @@ -284,7 +292,32 @@ clean_caches: > THUMB( nop ) > .arm > > -omap3_do_wfi: > + b omap3_do_wfi > + > +/* > + * Local variables > + */ > +omap3_do_wfi_sram_addr: > + .word omap3_do_wfi_sram > +kernel_flush: > + .word v7_flush_dcache_all > + > +/* =================================== > + * == WFI instruction => Enter idle == > + * =================================== > + */ > + > +/* > + * Do WFI instruction > + * Includes the resume path for non-OFF modes > + * > + * This code gets copied to internal SRAM and is accessible > + * from both SDRAM and SRAM: > + * - executed from SRAM for non-off modes (omap3_do_wfi_sram), > + * - executed from SDRAM for OFF mode (omap3_do_wfi). > + */ > + .align 3 > +ENTRY(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 > @@ -316,8 +349,86 @@ omap3_do_wfi: > nop > nop > nop > - bl wait_sdrc_ok > > +/* > + * This function implements the erratum ID i581 WA: > + * SDRC state restore before accessing the SDRAM > + * > + * Only used at return from non-OFF mode. For OFF > + * mode the ROM code configures the SDRC and > + * the DPLL before calling the restore code directly > + * from DDR. > + */ > + > +/* Make sure SDRC accesses are ok */ > +wait_sdrc_ok: > + > +/* DPLL3 must be locked before accessing the SDRC. Maybe the HW ensures this */ > + ldr r4, cm_idlest_ckgen > +wait_dpll3_lock: > + ldr r5, [r4] > + tst r5, #1 > + beq wait_dpll3_lock > + > + ldr r4, cm_idlest1_core > +wait_sdrc_ready: > + ldr r5, [r4] > + tst r5, #0x2 > + bne wait_sdrc_ready > + /* allow DLL powerdown upon hw idle req */ > + ldr r4, sdrc_power > + ldr r5, [r4] > + bic r5, r5, #0x40 > + str r5, [r4] > + > +/* > + * PC-relative stores lead to undefined behaviour in Thumb-2: use a r7 as a > + * base instead. > + * Be careful not to clobber r7 when maintaing this code. > + */ > + > +is_dll_in_lock_mode: > + /* Is dll in lock mode? */ > + ldr r4, sdrc_dlla_ctrl > + ldr r5, [r4] > + tst r5, #0x4 > + bne exit_nonoff_modes @ Return if locked > + /* wait till dll locks */ > + adr r7, kick_counter > +wait_dll_lock_timed: > + ldr r4, wait_dll_lock_counter > + add r4, r4, #1 > + str r4, [r7, #wait_dll_lock_counter - kick_counter] > + ldr r4, sdrc_dlla_status > + /* Wait 20uS for lock */ > + mov r6, #8 > +wait_dll_lock: > + subs r6, r6, #0x1 > + beq kick_dll > + ldr r5, [r4] > + and r5, r5, #0x4 > + cmp r5, #0x4 > + bne wait_dll_lock > + b exit_nonoff_modes @ Return when locked > + > + /* disable/reenable DLL if not locked */ > +kick_dll: > + ldr r4, sdrc_dlla_ctrl > + ldr r5, [r4] > + mov r6, r5 > + bic r6, #(1<<3) @ disable dll > + str r6, [r4] > + dsb > + orr r6, r6, #(1<<3) @ enable dll > + str r6, [r4] > + dsb > + ldr r4, kick_counter > + add r4, r4, #1 > + str r4, [r7] @ kick_counter > + b wait_dll_lock_timed > + > +exit_nonoff_modes: > + /* Re-enable C-bit if needed */ > mrc p15, 0, r0, c1, c0, 0 > tst r0, #(1<< 2) @ Check C bit enabled? > orreq r0, r0, #(1<< 2) @ Enable the C bit if cleared > @@ -331,6 +442,31 @@ omap3_do_wfi: > */ > ldmfd sp!, {r0-r12, pc} @ restore regs and return > > +/* > + * Local variables > + */ > +sdrc_power: > + .word SDRC_POWER_V > +cm_idlest1_core: > + .word CM_IDLEST1_CORE_V > +cm_idlest_ckgen: > + .word CM_IDLEST_CKGEN_V > +sdrc_dlla_status: > + .word SDRC_DLLA_STATUS_V > +sdrc_dlla_ctrl: > + .word SDRC_DLLA_CTRL_V > + /* > + * When exporting to userspace while the counters are in SRAM, > + * these 2 words need to be at the end to facilitate retrival! > + */ > +kick_counter: > + .word 0 > +wait_dll_lock_counter: > + .word 0 > + > +ENTRY(omap3_do_wfi_sz) > + .word . - omap3_do_wfi > + > > /* > * ============================== > @@ -346,6 +482,10 @@ omap3_do_wfi: > * restore_es3: applies to 34xx>= ES3.0 > * restore_3630: applies to 36xx > * restore: common code for 3xxx > + * > + * Note: when back from CORE and MPU OFF mode we are running > + * from SDRAM, without MMU, without the caches and prediction. > + * Also the SRAM content has been cleared. > */ > restore_es3: > ldr r5, pm_prepwstst_core_p > @@ -364,7 +504,8 @@ copy_to_sram: > bne copy_to_sram > ldr r1, sram_base > blx r1 > - b restore > + > + b restore @ Fall through to common code > > restore_3630: > ldr r1, pm_prepwstst_core_p > @@ -574,12 +715,41 @@ usettbr0: > restoremmu_on: > ldmfd sp!, {r0-r12, pc} @ restore regs and return > > +/* > + * Local variables > + */ > +pm_prepwstst_core_p: > + .word PM_PREPWSTST_CORE_P > +pm_pwstctrl_mpu: > + .word PM_PWSTCTRL_MPU_P > +scratchpad_base: > + .word SCRATCHPAD_BASE_P > +sram_base: > + .word SRAM_BASE_P + 0x8000 > +ttbrbit_mask: > + .word 0xFFFFC000 > +table_index_mask: > + .word 0xFFF00000 > +table_entry: > + .word 0x00000C02 > +cache_pred_disable_mask: > + .word 0xFFFFE7FB > +control_stat: > + .word CONTROL_STAT > +control_mem_rta: > + .word CONTROL_MEM_RTA_CTRL > +l2dis_3630: > + .word 0 > + > > /* > * Internal functions > */ > > -/* This function implements the erratum ID i443 WA, applies to 34xx>= ES3.0 */ > +/* This function implements the erratum ID i443 WA, applies to 34xx>= ES3.0 > + * > + * Copied and run from SRAM in order to reconfigure the SDRC parameters. > + */ > .text > .align 3 > ENTRY(es3_sdrc_fix) > @@ -609,6 +779,9 @@ ENTRY(es3_sdrc_fix) > str r5, [r4] @ kick off refreshes > bx lr > > +/* > + * Local variables > + */ > .align > sdrc_syscfg: > .word SDRC_SYSCONFIG_P > @@ -627,128 +800,3 @@ sdrc_manual_1: > ENDPROC(es3_sdrc_fix) > ENTRY(es3_sdrc_fix_sz) > .word . - es3_sdrc_fix > - > -/* > - * This function implements the erratum ID i581 WA: > - * SDRC state restore before accessing the SDRAM > - * > - * Only used at return from non-OFF mode. For OFF > - * mode the ROM code configures the SDRC and > - * the DPLL before calling the restore code directly > - * from DDR. > - */ > - > -/* Make sure SDRC accesses are ok */ > -wait_sdrc_ok: > - > -/* DPLL3 must be locked before accessing the SDRC. Maybe the HW ensures this */ > - ldr r4, cm_idlest_ckgen > -wait_dpll3_lock: > - ldr r5, [r4] > - tst r5, #1 > - beq wait_dpll3_lock > - > - ldr r4, cm_idlest1_core > -wait_sdrc_ready: > - ldr r5, [r4] > - tst r5, #0x2 > - bne wait_sdrc_ready > - /* allow DLL powerdown upon hw idle req */ > - ldr r4, sdrc_power > - ldr r5, [r4] > - bic r5, r5, #0x40 > - str r5, [r4] > - > -/* > - * PC-relative stores lead to undefined behaviour in Thumb-2: use a r7 as a > - * base instead. > - * Be careful not to clobber r7 when maintaing this code. > - */ > - > -is_dll_in_lock_mode: > - /* Is dll in lock mode? */ > - ldr r4, sdrc_dlla_ctrl > - ldr r5, [r4] > - tst r5, #0x4 > - bxne lr @ Return if locked > - /* wait till dll locks */ > - adr r7, kick_counter > -wait_dll_lock_timed: > - ldr r4, wait_dll_lock_counter > - add r4, r4, #1 > - str r4, [r7, #wait_dll_lock_counter - kick_counter] > - ldr r4, sdrc_dlla_status > - /* Wait 20uS for lock */ > - mov r6, #8 > -wait_dll_lock: > - subs r6, r6, #0x1 > - beq kick_dll > - ldr r5, [r4] > - and r5, r5, #0x4 > - cmp r5, #0x4 > - bne wait_dll_lock > - bx lr @ Return when locked > - > - /* disable/reenable DLL if not locked */ > -kick_dll: > - ldr r4, sdrc_dlla_ctrl > - ldr r5, [r4] > - mov r6, r5 > - bic r6, #(1<<3) @ disable dll > - str r6, [r4] > - dsb > - orr r6, r6, #(1<<3) @ enable dll > - str r6, [r4] > - dsb > - ldr r4, kick_counter > - add r4, r4, #1 > - str r4, [r7] @ kick_counter > - b wait_dll_lock_timed > - > - .align > -cm_idlest1_core: > - .word CM_IDLEST1_CORE_V > -cm_idlest_ckgen: > - .word CM_IDLEST_CKGEN_V > -sdrc_dlla_status: > - .word SDRC_DLLA_STATUS_V > -sdrc_dlla_ctrl: > - .word SDRC_DLLA_CTRL_V > -pm_prepwstst_core_p: > - .word PM_PREPWSTST_CORE_P > -pm_pwstctrl_mpu: > - .word PM_PWSTCTRL_MPU_P > -scratchpad_base: > - .word SCRATCHPAD_BASE_P > -sram_base: > - .word SRAM_BASE_P + 0x8000 > -sdrc_power: > - .word SDRC_POWER_V > -ttbrbit_mask: > - .word 0xFFFFC000 > -table_index_mask: > - .word 0xFFF00000 > -table_entry: > - .word 0x00000C02 > -cache_pred_disable_mask: > - .word 0xFFFFE7FB > -control_stat: > - .word CONTROL_STAT > -control_mem_rta: > - .word CONTROL_MEM_RTA_CTRL > -kernel_flush: > - .word v7_flush_dcache_all > -l2dis_3630: > - .word 0 > - /* > - * When exporting to userspace while the counters are in SRAM, > - * these 2 words need to be at the end to facilitate retrival! > - */ > -kick_counter: > - .word 0 > -wait_dll_lock_counter: > - .word 0 > -ENDPROC(omap34xx_cpu_suspend) > - > -ENTRY(omap34xx_cpu_suspend_sz) > - .word . - omap34xx_cpu_suspend > diff --git a/arch/arm/plat-omap/sram.c b/arch/arm/plat-omap/sram.c > index 6af3d0b..363c91e 100644 > --- a/arch/arm/plat-omap/sram.c > +++ b/arch/arm/plat-omap/sram.c > @@ -394,20 +394,15 @@ void omap3_sram_restore_context(void) > } > #endif /* CONFIG_PM */ > > -static int __init omap34xx_sram_init(void) > -{ > - _omap3_sram_configure_core_dpll = > - omap_sram_push(omap3_sram_configure_core_dpll, > - omap3_sram_configure_core_dpll_sz); > - omap_push_sram_idle(); > - return 0; > -} > -#else > +#endif /* CONFIG_ARCH_OMAP3 */ > + > static inline int omap34xx_sram_init(void) > { > +#if defined(CONFIG_ARCH_OMAP3)&& defined(CONFIG_PM) > + omap3_sram_restore_context(); > +#endif > return 0; > } > -#endif > > int __init omap_sram_init(void) > {