[ARM] 4731/1: S3C2412: Check for incomplete sleep

Check if the sleep command returns due to a pending interrupt
in the standby unit. If this happens, try and ack the IRQ
before re-trying the resume.

It is currently unclear whether the resume can be backed out
of at this stage as this could cause a problem with level
based interrupts.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 72 insertions, 15 deletions

diff --git a/arch/arm/mach-s3c2412/Makefile b/arch/arm/mach-s3c2412/Makefile
index f8e011691b31..7b782c7df7b4 100644
--- a/arch/arm/mach-s3c2412/Makefile
+++ b/arch/arm/mach-s3c2412/Makefile
@@ -13,7 +13,7 @@ obj-$(CONFIG_CPU_S3C2412)	+= s3c2412.o
 obj-$(CONFIG_CPU_S3C2412)       += irq.o
 obj-$(CONFIG_CPU_S3C2412)       += clock.o
 obj-$(CONFIG_S3C2412_DMA)       += dma.o
-obj-$(CONFIG_S3C2412_PM)        += pm.o
+obj-$(CONFIG_S3C2412_PM)        += pm.o sleep.o
 
 # Machine support
 
diff --git a/arch/arm/mach-s3c2412/pm.c b/arch/arm/mach-s3c2412/pm.c
index 974ffb130479..d4ffb2d98076 100644
--- a/arch/arm/mach-s3c2412/pm.c
+++ b/arch/arm/mach-s3c2412/pm.c
@@ -33,6 +33,8 @@
 
 #include <asm/plat-s3c24xx/s3c2412.h>
 
+extern void s3c2412_sleep_enter(void);
+
 static void s3c2412_cpu_suspend(void)
 {
         unsigned long tmp;
@@ -43,20 +45,7 @@ static void s3c2412_cpu_suspend(void)
         tmp |= S3C2412_PWRCFG_STANDBYWFI_SLEEP;
         __raw_writel(tmp, S3C2412_PWRCFG);
 
-        /* issue the standby signal into the pm unit. Note, we
-         * issue a write-buffer drain just in case */
-
-        tmp = 0;
-
-        asm("b 1f\n\t"
-            ".align 5\n\t"
-            "1:\n\t"
-            "mcr p15, 0, %0, c7, c10, 4\n\t"
-            "mcr p15, 0, %0, c7, c0, 4" :: "r" (tmp));
-
-        /* we should never get past here */
-
-        panic("sleep resumed to originator?");
+        s3c2412_sleep_enter();
 }
 
 static void s3c2412_pm_prepare(void)
diff --git a/arch/arm/mach-s3c2412/sleep.S b/arch/arm/mach-s3c2412/sleep.S
new file mode 100644
index 000000000000..db32cac4199a
--- /dev/null
+++ b/arch/arm/mach-s3c2412/sleep.S
@@ -0,0 +1,68 @@
+/* linux/arch/arm/mach-s3c2412/sleep.S
+ *
+ * Copyright (c) 2007 Simtec Electronics
+ *      Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C2412 Power Manager low-level sleep support
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/hardware.h>
+#include <asm/arch/map.h>
+
+#include <asm/arch/regs-irq.h>
+
+        .text
+
+        .global s3c2412_sleep_enter
+
+s3c2412_sleep_enter:
+        mov     r0, #0                  /* argument for coprocessors */
+        ldr     r1, =S3C2410_INTPND
+        ldr     r2, =S3C2410_SRCPND
+        ldr     r3, =S3C2410_EINTPEND
+
+        teq     r0, r0
+        bl      s3c2412_sleep_enter1
+        teq     pc, r0
+        bl      s3c2412_sleep_enter1
+
+        .align  5
+
+        /* this is called twice, first with the Z flag to ensure that the
+         * instructions have been loaded into the cache, and the second
+         * time to try and suspend the system.
+        */
+s3c2412_sleep_enter1:
+        mcr     p15, 0, r0, c7, c10, 4
+        mcrne   p15, 0, r0, c7, c0, 4
+
+        /* if we return from here, it is because an interrupt was
+         * active when we tried to shutdown. Try and ack the IRQ and
+         * retry, as simply returning causes the system to lock.
+        */
+
+        ldrne   r9, [ r1 ]
+        strne   r9, [ r1 ]
+        ldrne   r9, [ r2 ]
+        strne   r9, [ r2 ]
+        ldrne   r9, [ r3 ]
+        strne   r9, [ r3 ]
+        bne     s3c2412_sleep_enter1
+
+        mov     pc, r14