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From: Sylvain Rochet <sylvain.rochet@finsecur.com>
To: Wenyou Yang <wenyou.yang@atmel.com>,
	nicolas.ferre@atmel.com, linux@arm.linux.org.uk,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	alexandre.belloni@free-electrons.com, peda@axentia.se
Cc: Sylvain Rochet <sylvain.rochet@finsecur.com>
Subject: [PATCH v2 1/2] pm: at91: pm_slowclock: fix suspend/resume hang up in timeouts
Date: Mon, 26 Jan 2015 15:54:39 +0100	[thread overview]
Message-ID: <1422284080-32446-2-git-send-email-sylvain.rochet@finsecur.com> (raw)
In-Reply-To: <1422284080-32446-1-git-send-email-sylvain.rochet@finsecur.com>

Removed timeout on XTAL, PLL lock and Master Clock Ready, hang if
something went wrong instead of continuing in unknown condition. There
is not much we can do if a PLL lock never ends, we are running in SRAM
and we will not be able to connect back the sdram or ddram in order to
be able to fire up a message or just panic.

As a bonus, not decounting the timeout register in slow clock mode
reduce cumulated suspend time and resume time from ~17ms to ~15ms.

Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
---
 arch/arm/mach-at91/pm_slowclock.S | 33 ++++-----------------------------
 1 file changed, 4 insertions(+), 29 deletions(-)

diff --git a/arch/arm/mach-at91/pm_slowclock.S b/arch/arm/mach-at91/pm_slowclock.S
index 2001877..79dfdbe 100644
--- a/arch/arm/mach-at91/pm_slowclock.S
+++ b/arch/arm/mach-at91/pm_slowclock.S
@@ -34,11 +34,6 @@
  */
 #undef SLOWDOWN_MASTER_CLOCK
 
-#define MCKRDY_TIMEOUT		1000
-#define MOSCRDY_TIMEOUT 	1000
-#define PLLALOCK_TIMEOUT	1000
-#define PLLBLOCK_TIMEOUT	1000
-
 pmc	.req	r0
 sdramc	.req	r1
 ramc1	.req	r2
@@ -50,56 +45,36 @@ tmp2	.req	r5
  * Wait until master clock is ready (after switching master clock source)
  */
 	.macro wait_mckrdy
-	mov	tmp2, #MCKRDY_TIMEOUT
-1:	sub	tmp2, tmp2, #1
-	cmp	tmp2, #0
-	beq	2f
-	ldr	tmp1, [pmc, #AT91_PMC_SR]
+1:	ldr	tmp1, [pmc, #AT91_PMC_SR]
 	tst	tmp1, #AT91_PMC_MCKRDY
 	beq	1b
-2:
 	.endm
 
 /*
  * Wait until master oscillator has stabilized.
  */
 	.macro wait_moscrdy
-	mov	tmp2, #MOSCRDY_TIMEOUT
-1:	sub	tmp2, tmp2, #1
-	cmp	tmp2, #0
-	beq	2f
-	ldr	tmp1, [pmc, #AT91_PMC_SR]
+1:	ldr	tmp1, [pmc, #AT91_PMC_SR]
 	tst	tmp1, #AT91_PMC_MOSCS
 	beq	1b
-2:
 	.endm
 
 /*
  * Wait until PLLA has locked.
  */
 	.macro wait_pllalock
-	mov	tmp2, #PLLALOCK_TIMEOUT
-1:	sub	tmp2, tmp2, #1
-	cmp	tmp2, #0
-	beq	2f
-	ldr	tmp1, [pmc, #AT91_PMC_SR]
+1:	ldr	tmp1, [pmc, #AT91_PMC_SR]
 	tst	tmp1, #AT91_PMC_LOCKA
 	beq	1b
-2:
 	.endm
 
 /*
  * Wait until PLLB has locked.
  */
 	.macro wait_pllblock
-	mov	tmp2, #PLLBLOCK_TIMEOUT
-1:	sub	tmp2, tmp2, #1
-	cmp	tmp2, #0
-	beq	2f
-	ldr	tmp1, [pmc, #AT91_PMC_SR]
+1:	ldr	tmp1, [pmc, #AT91_PMC_SR]
 	tst	tmp1, #AT91_PMC_LOCKB
 	beq	1b
-2:
 	.endm
 
 	.text
-- 
2.1.4


  reply	other threads:[~2015-01-26 14:54 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-26  9:36 [PATCH v2 00/12] AT91 pm cleanup for 3.20 Wenyou Yang
2015-01-26  9:37 ` [PATCH v2 01/12] pm: at91: pm_slowclock: improve reliability of suspend/resume Wenyou Yang
2015-01-26 14:54   ` [PATCH v2 0/2] " Sylvain Rochet
2015-01-26 14:54     ` Sylvain Rochet [this message]
2015-01-26 14:54     ` [PATCH v2 2/2] pm: at91: pm_slowclock: remove clocks which are already stopped when entering slow clock mode Sylvain Rochet
2015-01-26  9:38 ` [PATCH v2 02/12] pm: at91: Workaround DDRSDRC self-refresh bug with LPDDR1 memories Wenyou Yang
2015-01-26 10:36   ` Sylvain Rochet
2015-01-26 13:34     ` Nicolas Ferre
2015-01-26 13:44       ` Sylvain Rochet
2015-01-26 15:58         ` Peter Rosin
2015-01-26 16:04           ` Nicolas Ferre
2015-01-26 16:11             ` Sylvain Rochet
2015-01-26  9:39 ` [PATCH v2 03/12] pm: at91: pm_slowclock: remove the unused code related with SLOWDOWN_MASTER_CLOCK Wenyou Yang
2015-01-26  9:40 ` [PATCH v2 04/12] pm: at91: move the copying the sram function to the sram initializationi phase Wenyou Yang
2015-01-26 12:57   ` Sergei Shtylyov
2015-01-27  3:27     ` Yang, Wenyou
2015-01-26  9:40 ` [PATCH v2 05/12] ARM: at91: move select SRAM to ARCH_AT91 Wenyou Yang
2015-01-26  9:41 ` [PATCH v2 06/12] pm: at91: remove the config item CONFIG_AT91_SLOW_CLOCK Wenyou Yang
2015-01-26  9:42 ` [PATCH v2 07/12] pm: at91: the standby mode uses the same sram function as the suspend to memory mode Wenyou Yang
2015-01-26 10:09   ` Sylvain Rochet
2015-01-27  4:44     ` Yang, Wenyou
2015-01-26  9:42 ` [PATCH v2 08/12] pm: at91: rename file name: pm_slowclock.S -->pm_suspend.S Wenyou Yang
2015-01-26  9:43 ` [PATCH v2 09/12] pm: at91: rename function name: at91_slow_clock()-->at91_pm_suspend_sram_fn Wenyou Yang
2015-01-26  9:44 ` [PATCH v2 10/12] pm: at91: remove the at91_xxx_standby() function definitions in the pm.h Wenyou Yang
2015-01-26  9:45 ` [PATCH v2 11/12] pm: at91: setup: remove the struct ramc_ids .data at91_xxx_standby members Wenyou Yang
2015-01-26  9:45 ` [PATCH v2 12/12] pm: at91: amend the pm_suspend entry for at91_cpuidle_device Wenyou Yang
2015-01-26  9:55 ` [PATCH v2 00/12] AT91 pm cleanup for 3.20 Sylvain Rochet
2015-01-27  2:58   ` Yang, Wenyou

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