diff options
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/mach-omap2/Kconfig | 12 | ||||
| -rw-r--r-- | arch/arm/mach-omap2/sram34xx.S | 19 |
2 files changed, 29 insertions, 2 deletions
diff --git a/arch/arm/mach-omap2/Kconfig b/arch/arm/mach-omap2/Kconfig index 7309aab305a..0cd25ceadb4 100644 --- a/arch/arm/mach-omap2/Kconfig +++ b/arch/arm/mach-omap2/Kconfig @@ -128,3 +128,15 @@ config OMAP3_EMU help Say Y here to enable debugging hardware of omap3 +config OMAP3_SDRC_AC_TIMING + bool "Enable SDRC AC timing register changes" + depends on ARCH_OMAP3 && ARCH_OMAP34XX + default n + help + If you know that none of your system initiators will attempt to + access SDRAM during CORE DVFS, select Y here. This should boost + SDRAM performance at lower CORE OPPs. There are relatively few + users who will wish to say yes at this point - almost everyone will + wish to say no. Selecting yes without understanding what is + going on could result in system crashes; + diff --git a/arch/arm/mach-omap2/sram34xx.S b/arch/arm/mach-omap2/sram34xx.S index 82aa4a3d160..de99ba2a57a 100644 --- a/arch/arm/mach-omap2/sram34xx.S +++ b/arch/arm/mach-omap2/sram34xx.S @@ -91,8 +91,19 @@ * new SDRC_ACTIM_CTRL_B_1 register contents * new SDRC_MR_1 register value * - * If the param SDRC_RFR_CTRL_1 is 0, the parameters - * are not programmed into the SDRC CS1 registers + * If the param SDRC_RFR_CTRL_1 is 0, the parameters are not programmed into + * the SDRC CS1 registers + * + * NOTE: This code no longer attempts to program the SDRC AC timing and MR + * registers. This is because the code currently cannot ensure that all + * L3 initiators (e.g., sDMA, IVA, DSS DISPC, etc.) are not accessing the + * SDRAM when the registers are written. If the registers are changed while + * an initiator is accessing SDRAM, memory can be corrupted and/or the SDRC + * may enter an unpredictable state. In the future, the intent is to + * re-enable this code in cases where we can ensure that no initiators are + * touching the SDRAM. Until that time, users who know that their use case + * can satisfy the above requirement can enable the CONFIG_OMAP3_SDRC_AC_TIMING + * option. */ ENTRY(omap3_sram_configure_core_dpll) stmfd sp!, {r1-r12, lr} @ store regs to stack @@ -219,6 +230,7 @@ configure_sdrc: ldr r12, omap_sdrc_rfr_ctrl_0_val @ fetch value from SRAM ldr r11, omap3_sdrc_rfr_ctrl_0 @ fetch addr from SRAM str r12, [r11] @ store +#ifdef CONFIG_OMAP3_SDRC_AC_TIMING ldr r12, omap_sdrc_actim_ctrl_a_0_val ldr r11, omap3_sdrc_actim_ctrl_a_0 str r12, [r11] @@ -228,11 +240,13 @@ configure_sdrc: ldr r12, omap_sdrc_mr_0_val ldr r11, omap3_sdrc_mr_0 str r12, [r11] +#endif ldr r12, omap_sdrc_rfr_ctrl_1_val cmp r12, #0 @ if SDRC_RFR_CTRL_1 is 0, beq skip_cs1_prog @ do not program cs1 params ldr r11, omap3_sdrc_rfr_ctrl_1 str r12, [r11] +#ifdef CONFIG_OMAP3_SDRC_AC_TIMING ldr r12, omap_sdrc_actim_ctrl_a_1_val ldr r11, omap3_sdrc_actim_ctrl_a_1 str r12, [r11] @@ -242,6 +256,7 @@ configure_sdrc: ldr r12, omap_sdrc_mr_1_val ldr r11, omap3_sdrc_mr_1 str r12, [r11] +#endif skip_cs1_prog: ldr r12, [r11] @ posted-write barrier for SDRC bx lr |