From c9812d042a21eb492a36cfabf9f41107f5ecee3d Mon Sep 17 00:00:00 2001 From: Paul Walmsley Date: Fri, 19 Jun 2009 19:08:26 -0600 Subject: OMAP3 clock: add a short delay when lowering CORE clk rate When changing the SDRAM clock from 166MHz to 83MHz via the CORE DPLL M2 divider, add a short delay before returning to SDRAM to allow the SDRC time to stabilize. Without this delay, the system is prone to random panics upon re-entering SDRAM. This time delay varies based on MPU frequency. At 500MHz MPU frequency at room temperature, 64 loops seems to work okay; so add another 32 loops for environmental and process variation. Signed-off-by: Paul Walmsley --- arch/arm/plat-omap/include/mach/sram.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/arm/plat-omap/include/mach/sram.h') diff --git a/arch/arm/plat-omap/include/mach/sram.h b/arch/arm/plat-omap/include/mach/sram.h index dca7c16ae903..c32fa0a220dc 100644 --- a/arch/arm/plat-omap/include/mach/sram.h +++ b/arch/arm/plat-omap/include/mach/sram.h @@ -24,7 +24,7 @@ extern u32 omap2_set_prcm(u32 dpll_ctrl_val, u32 sdrc_rfr_val, int bypass); extern u32 omap3_configure_core_dpll(u32 sdrc_rfr_ctrl, u32 sdrc_actim_ctrla, u32 sdrc_actim_ctrlb, u32 m2, - u32 unlock_dll); + u32 unlock_dll, u32 f); /* Do not use these */ extern void omap1_sram_reprogram_clock(u32 ckctl, u32 dpllctl); @@ -62,7 +62,7 @@ extern unsigned long omap243x_sram_reprogram_sdrc_sz; extern u32 omap3_sram_configure_core_dpll(u32 sdrc_rfr_ctrl, u32 sdrc_actim_ctrla, u32 sdrc_actim_ctrlb, u32 m2, - u32 unlock_dll); + u32 unlock_dll, u32 f); extern unsigned long omap3_sram_configure_core_dpll_sz; #endif -- cgit v1.2.3