diff options
Diffstat (limited to 'arch/arm/mach-omap2')
| -rw-r--r-- | arch/arm/mach-omap2/clock34xx.c | 30 | ||||
| -rw-r--r-- | arch/arm/mach-omap2/sram34xx.S | 20 |
2 files changed, 37 insertions, 13 deletions
diff --git a/arch/arm/mach-omap2/clock34xx.c b/arch/arm/mach-omap2/clock34xx.c index 5458ab3bf65..4bfa650bb34 100644 --- a/arch/arm/mach-omap2/clock34xx.c +++ b/arch/arm/mach-omap2/clock34xx.c @@ -286,6 +286,20 @@ static struct omap_clk omap34xx_clks[] = { #define MIN_SDRC_DLL_LOCK_FREQ 83000000 +#define CYCLES_PER_MHZ 1000000 + +/* Scale factor for fixed-point arith in omap3_core_dpll_m2_set_rate() */ +#define SDRC_MPURATE_SCALE 8 + +/* 2^SDRC_MPURATE_BASE_SHIFT: MPU MHz that SDRC_MPURATE_LOOPS is defined for */ +#define SDRC_MPURATE_BASE_SHIFT 9 + +/* + * SDRC_MPURATE_LOOPS: Number of MPU loops to execute at + * 2^MPURATE_BASE_SHIFT MHz for SDRC to stabilize + */ +#define SDRC_MPURATE_LOOPS 96 + /** * omap3_dpll_recalc - recalculate DPLL rate * @clk: DPLL struct clk @@ -709,7 +723,8 @@ static int omap3_core_dpll_m2_set_rate(struct clk *clk, unsigned long rate) { u32 new_div = 0; u32 unlock_dll = 0; - unsigned long validrate, sdrcrate; + u32 c; + unsigned long validrate, sdrcrate, mpurate; struct omap_sdrc_params *sp; if (!clk || !rate) @@ -737,6 +752,17 @@ static int omap3_core_dpll_m2_set_rate(struct clk *clk, unsigned long rate) unlock_dll = 1; } + /* + * XXX This only needs to be done when the CPU frequency changes + */ + mpurate = arm_fck.rate / CYCLES_PER_MHZ; + c = (mpurate << SDRC_MPURATE_SCALE) >> SDRC_MPURATE_BASE_SHIFT; + c += 1; /* for safety */ + c *= SDRC_MPURATE_LOOPS; + c >>= SDRC_MPURATE_SCALE; + if (c == 0) + c = 1; + pr_debug("clock: changing CORE DPLL rate from %lu to %lu\n", clk->rate, validrate); pr_debug("clock: SDRC timing params used: %08x %08x %08x\n", @@ -747,7 +773,7 @@ static int omap3_core_dpll_m2_set_rate(struct clk *clk, unsigned long rate) /* REVISIT: Add SDRC_MR changing to this code also */ omap3_configure_core_dpll(sp->rfr_ctrl, sp->actim_ctrla, - sp->actim_ctrlb, new_div, unlock_dll); + sp->actim_ctrlb, new_div, unlock_dll, c); return 0; } diff --git a/arch/arm/mach-omap2/sram34xx.S b/arch/arm/mach-omap2/sram34xx.S index 84781a6cd26..8d4a88c3071 100644 --- a/arch/arm/mach-omap2/sram34xx.S +++ b/arch/arm/mach-omap2/sram34xx.S @@ -42,10 +42,14 @@ * r0 = sdrc_rfr_ctrl r1 = sdrc_actim_ctrla r2 = sdrc_actim_ctrlb r3 = M2 * r4 = Unlock SDRC DLL? (1 = yes, 0 = no) -- only unlock DLL for * SDRC rates < 83MHz + * r5 = number of MPU cycles to wait for SDRC to stabilize after + * reprogramming the SDRC when switching to a slower MPU speed + * */ ENTRY(omap3_sram_configure_core_dpll) stmfd sp!, {r1-r12, lr} @ store regs to stack ldr r4, [sp, #52] @ pull extra args off the stack + ldr r5, [sp, #56] @ load extra args from the stack dsb @ flush buffered writes to interconnect cmp r3, #0x2 blne configure_sdrc @@ -59,7 +63,11 @@ ENTRY(omap3_sram_configure_core_dpll) bleq wait_dll_unlock blne wait_dll_lock cmp r3, #0x1 - blne configure_sdrc + beq return_to_sdram + bl configure_sdrc + mov r12, r5 @ if slowing, wait for SDRC to stabilize + bl wait_clk_stable +return_to_sdram: isb @ prevent speculative exec past here mov r0, #0 @ return value ldmfd sp!, {r1-r12, pc} @ restore regs and return @@ -106,16 +114,6 @@ configure_core_dpll: wait_clk_stable: subs r12, r12, #1 bne wait_clk_stable - nop - nop - nop - nop - nop - nop - nop - nop - nop - nop bx lr enable_sdrc: ldr r11, omap3_cm_iclken1_core |