From f3bb3d7422b4161df31e2fd2e503897926d8ffe7 Mon Sep 17 00:00:00 2001 From: Russell King Date: Mon, 23 Jan 2012 18:39:21 +0000 Subject: ARM: sa11x0: fix sleep entry Sometimes, we get stuck while trying to enter sleep. This seems to occur if we do not have udelay() in the instruction cache. Avoid this by requesting a short delay prior to modifying the SDRAM timings. Signed-off-by: Russell King --- arch/arm/mach-sa1100/sleep.S | 37 ++++++++++++++++++++++--------------- 1 file changed, 22 insertions(+), 15 deletions(-) (limited to 'arch/arm/mach-sa1100') diff --git a/arch/arm/mach-sa1100/sleep.S b/arch/arm/mach-sa1100/sleep.S index e8223315b442..30cc6721665b 100644 --- a/arch/arm/mach-sa1100/sleep.S +++ b/arch/arm/mach-sa1100/sleep.S @@ -26,27 +26,36 @@ * * Causes sa11x0 to enter sleep state * + * Must be aligned to a cacheline. */ - + .balign 32 ENTRY(sa1100_finish_suspend) @ disable clock switching mcr p15, 0, r1, c15, c2, 2 - @ Adjust memory timing before lowering CPU clock - @ Clock speed adjustment without changing memory timing makes - @ CPU hang in some cases - ldr r0, =MDREFR - ldr r1, [r0] - orr r1, r1, #MDREFR_K1DB2 - str r1, [r0] + ldr r6, =MDREFR + ldr r4, [r6] + orr r4, r4, #MDREFR_K1DB2 + ldr r5, =PPCR + + @ Pre-load __udelay into the I-cache + mov r0, #1 + bl __udelay + mov r0, r0 + + @ The following must all exist in a single cache line to + @ avoid accessing memory until this sequence is complete, + @ otherwise we occasionally hang. + + @ Adjust memory timing before lowering CPU clock + str r4, [r6] @ delay 90us and set CPU PLL to lowest speed @ fixes resume problem on high speed SA1110 mov r0, #90 bl __udelay - ldr r0, =PPCR mov r1, #0 - str r1, [r0] + str r1, [r5] mov r0, #90 bl __udelay @@ -85,12 +94,10 @@ ENTRY(sa1100_finish_suspend) bic r5, r5, #FMsk(MSC_RT) bic r5, r5, #FMsk(MSC_RT)<<16 - ldr r6, =MDREFR - ldr r7, [r6] -bic r7, r7, #0x0000FF00 -bic r7, r7, #0x000000F0 -orr r8, r7, #MDREFR_SLFRSH + bic r7, r7, #0x0000FF00 + bic r7, r7, #0x000000F0 + orr r8, r7, #MDREFR_SLFRSH ldr r9, =MDCNFG ldr r10, [r9] -- cgit v1.2.3