From: Rajendra Nayak <[email protected]> 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 <[email protected]> Signed-off-by: Kevin Hilman <[email protected]> --- 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 [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
