ARM: 6649/1: omap: use fncpy to copy the PM code functions to SRAM

The new fncpy API is better suited* for copying some
code to SRAM at runtime. This patch changes the ad-hoc
code to the more generic fncpy API.

*: 1. fncpy ensures that the thumb mode bit is propagated,
   2. fncpy provides the security of type safety between the
     original function and the sram function pointer.

Tested OK on OMAP3 in low power modes (RET/OFF)
using omap2plus_defconfig with !CONFIG_THUMB2_KERNEL.
Compile tested on OMAP1/2 using omap1_defconfig.

Boot tested on OMAP1 & OMAP2
Tested OK with suspend/resume on OMAP2420/n810

Boots fine on osk5912 and n800

Signed-off-by: Jean Pihet <j-pihet@ti.com>
Acked-by: Kevin Hilman <khilman@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Dave Martin <dave.martin@linaro.org>
Tested-by: Kevin Hilman <khilman@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 22 insertions, 6 deletions

diff --git a/arch/arm/plat-omap/include/plat/sram.h b/arch/arm/plat-omap/include/plat/sram.h
index 9967d5e855c..f500fc34d06 100644
--- a/arch/arm/plat-omap/include/plat/sram.h
+++ b/arch/arm/plat-omap/include/plat/sram.h
@@ -12,7 +12,19 @@
 #define __ARCH_ARM_OMAP_SRAM_H
 
 #ifndef __ASSEMBLY__
-extern void * omap_sram_push(void * start, unsigned long size);
+#include <asm/fncpy.h>
+
+extern void *omap_sram_push_address(unsigned long size);
+
+/* Macro to push a function to the internal SRAM, using the fncpy API */
+#define omap_sram_push(funcp, size) ({				\
+	typeof(&(funcp)) _res = NULL;				\
+	void *_sram_address = omap_sram_push_address(size);	\
+	if (_sram_address)					\
+		_res = fncpy(_sram_address, &(funcp), size);	\
+	_res;							\
+})
+
 extern void omap_sram_reprogram_clock(u32 dpllctl, u32 ckctl);
 
 extern void omap2_sram_ddr_init(u32 *slow_dll_ctrl, u32 fast_dll_ctrl,
diff --git a/arch/arm/plat-omap/sram.c b/arch/arm/plat-omap/sram.c
index e26e50487d6..68fcc7dc56e 100644
--- a/arch/arm/plat-omap/sram.c
+++ b/arch/arm/plat-omap/sram.c
@@ -242,7 +242,14 @@ static void __init omap_map_sram(void)
 	       omap_sram_size - SRAM_BOOTLOADER_SZ);
 }
 
-void * omap_sram_push(void * start, unsigned long size)
+/*
+ * Memory allocator for SRAM: calculates the new ceiling address
+ * for pushing a function using the fncpy API.
+ *
+ * Note that fncpy requires the returned address to be aligned
+ * to an 8-byte boundary.
+ */
+void *omap_sram_push_address(unsigned long size)
 {
 	if (size > (omap_sram_ceil - (omap_sram_base + SRAM_BOOTLOADER_SZ))) {
 		printk(KERN_ERR "Not enough space in SRAM\n");
@@ -250,10 +257,7 @@ void * omap_sram_push(void * start, unsigned long size)
 	}
 
 	omap_sram_ceil -= size;
-	omap_sram_ceil = ROUND_DOWN(omap_sram_ceil, sizeof(void *));
-	memcpy((void *)omap_sram_ceil, start, size);
-	flush_icache_range((unsigned long)omap_sram_ceil,
-		(unsigned long)(omap_sram_ceil + size));
+	omap_sram_ceil = ROUND_DOWN(omap_sram_ceil, FNCPY_ALIGN);
 
 	return (void *)omap_sram_ceil;
 }