[PATCH v4 2/7] OMAP3: PM: Erratum i581 support: dll kick strategy

From: Peter 'p2' De Schrijver <redacted>

Erratum i581 impacts OMAP3 platforms.
PRCM DPLL control FSM removes SDRC_IDLEREQ before DPLL3 locks causing
the DPLL not to be locked at times.

IMPORTANT:
*) This is not a complete workaround implementation as recommended
by the silicon erratum. this is a support logic for detecting lockups and
attempting to recover where possible and is known to provide stability
in multiple platforms.
*) This code is mostly important for inactive and retention. The ROM code
waits for the maximum dll lock time when resuming from off mode. So for
off mode this code isn't really needed.

This should eventually get refactored as part of cleanups to sleep34xx.S

Cc: Kevin Hilman <redacted>
Cc: Tony Lindgren <tony@atomide.com>

Signed-off-by: Peter 'p2' De Schrijver <redacted>
---
(no change done, posting for completeness of the series)
v2: https://patchwork.kernel.org/patch/365252/
? ? ? ?typo correction- erratum, support, added comment from Peter from the
? ? ? ?thread to commit message
v1: http://marc.info/?l=linux-omap&m=129013172525234&w=2
?arch/arm/mach-omap2/sleep34xx.S | ? 52 +++++++++++++++++++++++++++++++++++---
?1 files changed, 47 insertions(+), 5 deletions(-)

diff --git a/arch/arm/mach-omap2/sleep34xx.S b/arch/arm/mach-omap2/sleep34xx.S
index 2c20fcf..3fbd1e5 100644
--- a/arch/arm/mach-omap2/sleep34xx.S
+++ b/arch/arm/mach-omap2/sleep34xx.S

@@ -42,6 +42,7 @@

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?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 CM_IDLEST_CKGEN_V ? ? ?OMAP34XX_CM_REGADDR(PLL_MOD, CM_IDLEST)
?#define SRAM_BASE_P ? ? ? ? ? ?0x40200000
?#define CONTROL_STAT ? ? ? ? ? 0x480022F0
?#define SCRATCHPAD_MEM_OFFS ? ?0x310 /* Move this as correct place is

@@ -554,31 +555,67 @@ skip_l2_inval:

?/* 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]
- ? ? ? ?and ? ? r5, r5, #0x2
- ? ? ? ?cmp ? ? r5, #0
- ? ? ? ?bne ? ? wait_sdrc_ok
+ ? ? ? ?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]
-wait_dll_lock:
+is_dll_in_lock_mode:
+
? ? ? ? /* Is dll in lock mode? */
? ? ? ? ldr ? ? r4, sdrc_dlla_ctrl
? ? ? ? ldr ? ? r5, [r4]
? ? ? ? tst ? ? r5, #0x4
? ? ? ? bxne ? ?lr
? ? ? ? /* wait till dll locks */
- ? ? ? ?ldr ? ? r4, sdrc_dlla_status
+wait_dll_lock_timed:
+ ? ? ? ldr ? ? r4, wait_dll_lock_counter
+ ? ? ? add ? ? r4, r4, #1
+ ? ? ? str ? ? r4, wait_dll_lock_counter
+ ? ? ? ldr ? ? r4, sdrc_dlla_status
+ ? ? ? ?mov ? ?r6, #8 ? ? ? ? ?/* Wait 20uS for lock */
+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

+ ? ? ? /* 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, kick_counter
+ ? ? ? b ? ? ? wait_dll_lock_timed
+
?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:

@@ -615,5 +652,10 @@ control_stat:

? ? ? ?.word ? CONTROL_STAT
?kernel_flush:
? ? ? ?.word v7_flush_dcache_all
+ ? ? ? /* these 2 words need to be at the end !!! */
+kick_counter:
+ ? ? ? .word ? 0
+wait_dll_lock_counter:
+ ? ? ? .word ? 0