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]> --- arch/arm/mach-omap2/resource34xx.c | 6 +++++- arch/arm/mach-omap2/resource34xx.h | 2 ++ arch/arm/mach-omap2/sleep34xx.S | 32 ++++++++++++++++++++++++++++++++ 3 files changed, 39 insertions(+), 1 deletions(-) diff --git a/arch/arm/mach-omap2/resource34xx.c b/arch/arm/mach-omap2/resource34xx.c index 82405b6..408d3ab 100644 --- a/arch/arm/mach-omap2/resource34xx.c +++ b/arch/arm/mach-omap2/resource34xx.c @@ -236,6 +236,7 @@ static int program_opp_freq(int res, int target_level, int current_level) int ret = 0, l3_div; int *curr_opp; + lock_scratchpad_sem(); if (res == VDD1_OPP) { curr_opp = &curr_vdd1_opp; clk_set_rate(dpll1_clk, mpu_opps[target_level].rate); @@ -253,11 +254,14 @@ static int program_opp_freq(int res, int target_level, int current_level) ret = clk_set_rate(dpll3_clk, l3_opps[target_level].rate * l3_div); } - if (ret) + if (ret) { + unlock_scratchpad_sem(); return current_level; + } #ifdef CONFIG_PM omap3_save_scratchpad_contents(); #endif + unlock_scratchpad_sem(); *curr_opp = target_level; return target_level; diff --git a/arch/arm/mach-omap2/resource34xx.h b/arch/arm/mach-omap2/resource34xx.h index a160665..5b5618a 100644 --- a/arch/arm/mach-omap2/resource34xx.h +++ b/arch/arm/mach-omap2/resource34xx.h @@ -29,6 +29,8 @@ #include <mach/omap34xx.h> extern int sr_voltagescale_vcbypass(u32 t_opp, u32 c_opp, u8 t_vsel, u8 c_vsel); +extern void lock_scratchpad_sem(); +extern void unlock_scratchpad_sem(); /* * mpu_latency/core_latency are used to control the cpuidle C state. diff --git a/arch/arm/mach-omap2/sleep34xx.S b/arch/arm/mach-omap2/sleep34xx.S index 38aa3fd..aedcf94 100644 --- a/arch/arm/mach-omap2/sleep34xx.S +++ b/arch/arm/mach-omap2/sleep34xx.S @@ -39,6 +39,7 @@ #define PM_PREPWSTST_MPU_V OMAP34XX_PRM_REGADDR(MPU_MOD, \ OMAP3430_PM_PREPWSTST) #define CM_IDLEST1_CORE_V OMAP34XX_CM_REGADDR(CORE_MOD, CM_IDLEST1) +#define SDRC_SCRATCHPAD_SEM_V 0xd800291C /* * This is the physical address of the register as specified @@ -62,6 +63,37 @@ #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) -- 1.5.4.7 -- 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
