[PATCH] ARM: 2781/2: PXA27x Standby mode take 2

Patch from Todd Poynor

Add support for PXA27x Standby mode, a low-power mode that retains CPU
and some peripheral state (the existing "sleep" mode is a power-power
mode that retains less state). Activated via:
echo -n standby > /sys/power/state
From: David Burrage and Todd Poynor

Signed-off-by: Todd Poynor <tpoynor@mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

4 files changed, 45 insertions, 1 deletions

diff --git a/arch/arm/mach-pxa/Makefile b/arch/arm/mach-pxa/Makefile
index c4e6d2523585..efc2f657184e 100644
--- a/arch/arm/mach-pxa/Makefile
+++ b/arch/arm/mach-pxa/Makefile
@@ -24,3 +24,7 @@ obj-$(CONFIG_LEDS) += $(led-y)
 
 # Misc features
 obj-$(CONFIG_PM) += pm.o sleep.o
+
+ifeq ($(CONFIG_PXA27x),y)
+obj-$(CONFIG_PM) += standby.o
+endif
diff --git a/arch/arm/mach-pxa/pxa27x.c b/arch/arm/mach-pxa/pxa27x.c
index 893964fb9659..9a791b07118d 100644
--- a/arch/arm/mach-pxa/pxa27x.c
+++ b/arch/arm/mach-pxa/pxa27x.c
@@ -126,6 +126,7 @@ int pxa_cpu_pm_prepare(suspend_state_t state)
 {
         switch (state) {
         case PM_SUSPEND_MEM:
+        case PM_SUSPEND_STANDBY:
                 return 0;
         default:
                 return -EINVAL;
@@ -138,7 +139,10 @@ void pxa_cpu_pm_enter(suspend_state_t state)
         extern void pxa_cpu_suspend(unsigned int);
         extern void pxa_cpu_resume(void);
 
-        CKEN = CKEN22_MEMC | CKEN9_OSTIMER;
+        if (state == PM_SUSPEND_STANDBY)
+                CKEN = CKEN22_MEMC | CKEN9_OSTIMER | CKEN16_LCD |CKEN0_PWM0;
+        else
+                CKEN = CKEN22_MEMC | CKEN9_OSTIMER;
 
         /* ensure voltage-change sequencer not initiated, which hangs */
         PCFR &= ~PCFR_FVC;
@@ -147,6 +151,9 @@ void pxa_cpu_pm_enter(suspend_state_t state)
         PEDR = 0xDF12FE1B;
 
         switch (state) {
+        case PM_SUSPEND_STANDBY:
+                pxa_cpu_standby();
+                break;
         case PM_SUSPEND_MEM:
                 /* set resume return address */
                 PSPR = virt_to_phys(pxa_cpu_resume);
diff --git a/arch/arm/mach-pxa/standby.S b/arch/arm/mach-pxa/standby.S
new file mode 100644
index 000000000000..8a3f27b76784
--- /dev/null
+++ b/arch/arm/mach-pxa/standby.S
@@ -0,0 +1,32 @@
+/*
+ * PXA27x standby mode
+ *
+ * Author: David Burrage
+ *
+ * 2005 (c) MontaVista Software, Inc. This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+
+#include <linux/config.h>
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/hardware.h>
+
+#include <asm/arch/pxa-regs.h>
+
+                .text
+
+ENTRY(pxa_cpu_standby)
+        ldr     r0, =PSSR
+        mov     r1, #(PSSR_PH | PSSR_STS)
+        mov     r2, #2
+        mov     r3, #UNCACHED_PHYS_0    @ Read mem context in.
+        ldr     ip, [r3]
+        b       1f
+
+        .align  5
+1:      mcr     p14, 0, r2, c7, c0, 0   @ put the system into Standby
+        str     r1, [r0]                @ make sure PSSR_PH/STS are clear
+        mov     pc, lr
diff --git a/include/asm-arm/arch-pxa/pxa-regs.h b/include/asm-arm/arch-pxa/pxa-regs.h
index b5e54a9e9fa7..803dc92c9038 100644
--- a/include/asm-arm/arch-pxa/pxa-regs.h
+++ b/include/asm-arm/arch-pxa/pxa-regs.h
@@ -1505,6 +1505,7 @@
 #define PSSR_OTGPH      (1 << 6)        /* OTG Peripheral control Hold */
 #define PSSR_RDH        (1 << 5)        /* Read Disable Hold */
 #define PSSR_PH         (1 << 4)        /* Peripheral Control Hold */
+#define PSSR_STS        (1 << 3)        /* Standby Mode Status */
 #define PSSR_VFS        (1 << 2)        /* VDD Fault Status */
 #define PSSR_BFS        (1 << 1)        /* Battery Fault Status */
 #define PSSR_SSS        (1 << 0)        /* Software Sleep Status */