From: Rajendra Nayak <rnayak@xxxxxx>
This patch implements locking using the semaphore in scratchpad
memory preventing any concurrent access to scratchpad from OMAP
and Baseband/Modem processor.
Signed-off-by: Rajendra Nayak <rnayak@xxxxxx>
Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/mach-omap2/sleep34xx.S | 33 +++++++++++++++++++++++++++++++++
1 files changed, 33 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mach-omap2/sleep34xx.S b/arch/arm/mach-omap2/sleep34xx.S
index 22fcc14..12a8ba0 100644
--- a/arch/arm/mach-omap2/sleep34xx.S
+++ b/arch/arm/mach-omap2/sleep34xx.S
@@ -33,6 +33,8 @@
#include "prm.h"
#include "sdrc.h"
+#define SDRC_SCRATCHPAD_SEM_V 0xfa00291c
+
#define PM_PREPWSTST_CORE_V OMAP34XX_PRM_REGADDR(CORE_MOD, \
OMAP3430_PM_PREPWSTST)
#define PM_PREPWSTST_CORE_P 0x48306AE8
@@ -57,6 +59,37 @@
#define SDRC_DLLA_STATUS_V OMAP34XX_SDRC_REGADDR(SDRC_DLLA_STATUS)
#define SDRC_DLLA_CTRL_V OMAP34XX_SDRC_REGADDR(SDRC_DLLA_CTRL)
+ .text
+/* Function to aquire the semaphore in scratchpad */
+ENTRY(lock_scratchpad_sem)
+ stmfd sp!, {lr} @ save registers on stack
+wait_sem:
+ mov r0,#1
+ ldr r1, sdrc_scratchpad_sem
+wait_loop:
+ ldr r2, [r1] @ load the lock value
+ cmp r2, r0 @ is the lock free ?
+ beq wait_loop @ not free...
+ swp r2, r0, [r1] @ semaphore free so lock it and proceed
+ cmp r2, r0 @ did we succeed ?
+ beq wait_sem @ no - try again
+ ldmfd sp!, {pc} @ restore regs and return
+sdrc_scratchpad_sem:
+ .word SDRC_SCRATCHPAD_SEM_V
+ENTRY(lock_scratchpad_sem_sz)
+ .word . - lock_scratchpad_sem
+
+ .text
+/* Function to release the scratchpad semaphore */
+ENTRY(unlock_scratchpad_sem)
+ stmfd sp!, {lr} @ save registers on stack
+ ldr r3, sdrc_scratchpad_sem
+ mov r2,#0
+ str r2,[r3]
+ ldmfd sp!, {pc} @ restore regs and return
+ENTRY(unlock_scratchpad_sem_sz)
+ .word . - unlock_scratchpad_sem
+
.text
/* Function call to get the restore pointer for resume from OFF */
ENTRY(get_restore_pointer)
--
1.6.6
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
