From 4519c2bf433b97d091635eb51e4ba8ffa1c84d62 Mon Sep 17 00:00:00 2001 From: Paul Walmsley Date: Tue, 12 May 2009 17:26:32 -0600 Subject: OMAP3 clock: only unlock SDRC DLL if SDRC clk < 83MHz According to the 34xx TRM Rev. K section 11.2.4.4.11.1 "Purpose of the DLL/CDL Module," the SDRC delay-locked-loop can be locked at any SDRC clock frequency from 83MHz to 166MHz. CDP code unconditionally unlocked the DLL whenever shifting to a lower SDRC speed, but this seems unnecessary and error-prone, as the DLL is no longer able to compensate for process, voltage, and temperature variations. Instead, only unlock the DLL when the SDRC clock rate would be less than 83MHz. Signed-off-by: Paul Walmsley --- arch/arm/plat-omap/include/mach/sram.h | 6 ++++-- arch/arm/plat-omap/sram.c | 7 ++++--- 2 files changed, 8 insertions(+), 5 deletions(-) (limited to 'arch/arm/plat-omap') diff --git a/arch/arm/plat-omap/include/mach/sram.h b/arch/arm/plat-omap/include/mach/sram.h index ab35d622dcf..dca7c16ae90 100644 --- a/arch/arm/plat-omap/include/mach/sram.h +++ b/arch/arm/plat-omap/include/mach/sram.h @@ -23,7 +23,8 @@ 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 sdrc_actim_ctrlb, u32 m2, + u32 unlock_dll); /* Do not use these */ extern void omap1_sram_reprogram_clock(u32 ckctl, u32 dpllctl); @@ -60,7 +61,8 @@ 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 sdrc_actim_ctrlb, u32 m2, + u32 unlock_dll); extern unsigned long omap3_sram_configure_core_dpll_sz; #endif diff --git a/arch/arm/plat-omap/sram.c b/arch/arm/plat-omap/sram.c index 38353386e91..876f5a7ecaf 100644 --- a/arch/arm/plat-omap/sram.c +++ b/arch/arm/plat-omap/sram.c @@ -365,16 +365,17 @@ static inline int omap243x_sram_init(void) static u32 (*_omap3_sram_configure_core_dpll)(u32 sdrc_rfr_ctrl, u32 sdrc_actim_ctrla, u32 sdrc_actim_ctrlb, - u32 m2); + u32 m2, u32 unlock_dll); u32 omap3_configure_core_dpll(u32 sdrc_rfr_ctrl, u32 sdrc_actim_ctrla, - u32 sdrc_actim_ctrlb, u32 m2) + u32 sdrc_actim_ctrlb, u32 m2, u32 unlock_dll) { if (!_omap3_sram_configure_core_dpll) omap_sram_error(); return _omap3_sram_configure_core_dpll(sdrc_rfr_ctrl, sdrc_actim_ctrla, - sdrc_actim_ctrlb, m2); + sdrc_actim_ctrlb, m2, + unlock_dll); } /* REVISIT: Should this be same as omap34xx_sram_init() after off-idle? */ -- cgit v1.2.3