ARM: pm: omap3: run the ASM sleep code from DDR
Most of the ASM sleep code (in arch/arm/mach-omap2/sleep34xx.S)
is copied to internal SRAM at boot and after wake-up from CORE OFF
mode. 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 and the overhead in the code copy.
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),
. 852 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 564 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.
Kevin Hilman tested retention and off on 3430/n900, 3530/Overo and
3630/Zoom3
Signed-off-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-omap2/sleep34xx.S b/arch/arm/mach-omap2/sleep34xx.S
index d18f52e..17dbc5a 100644
--- a/arch/arm/mach-omap2/sleep34xx.S
+++ b/arch/arm/mach-omap2/sleep34xx.S
@@ -139,8 +139,10 @@
*
*
* 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.
@@ -158,9 +160,15 @@
* 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:
@@ -213,7 +221,32 @@
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
@@ -245,8 +278,86 @@
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
@@ -260,6 +371,31 @@
*/
ldmfd sp!, {r4 - r11, 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
+
/*
* ==============================
@@ -275,13 +411,17 @@
* 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.
*/
ENTRY(omap3_restore_es3)
ldr r5, pm_prepwstst_core_p
ldr r4, [r5]
and r4, r4, #0x3
cmp r4, #0x0 @ Check if previous power state of CORE is OFF
- bne omap3_restore
+ bne omap3_restore @ Fall through to OMAP3 common code
adr r0, es3_sdrc_fix
ldr r1, sram_base
ldr r2, es3_sdrc_fix_sz
@@ -293,7 +433,7 @@
bne copy_to_sram
ldr r1, sram_base
blx r1
- b omap3_restore
+ b omap3_restore @ Fall through to OMAP3 common code
ENDPROC(omap3_restore_es3)
ENTRY(omap3_restore_3630)
@@ -301,7 +441,7 @@
ldr r2, [r1]
and r2, r2, #0x3
cmp r2, #0x0 @ Check if previous power state of CORE is OFF
- bne omap3_restore
+ bne omap3_restore @ Fall through to OMAP3 common code
/* Disable RTA before giving control */
ldr r1, control_mem_rta
mov r2, #OMAP36XX_RTA_DISABLE
@@ -405,10 +545,31 @@
.ltorg
/*
+ * 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
+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 to and run from SRAM in order to reconfigure the SDRC parameters.
+ */
.text
.align 3
ENTRY(es3_sdrc_fix)
@@ -438,6 +599,9 @@
str r5, [r4] @ kick off refreshes
bx lr
+/*
+ * Local variables
+ */
.align
sdrc_syscfg:
.word SDRC_SYSCONFIG_P
@@ -456,120 +620,3 @@
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
-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