From: Marek Vasut marex@denx.de
Enable d-cache early in SPL right after DRAM is started up. This reduces U-Boot proper load time by 650ms when loaded from SPI NOR.
Signed-off-by: Marek Vasut marex@denx.de Signed-off-by: Philip Oberfichtner pro@denx.de
---
Changes in v6: - Once more improve the dcache_disable() comment
Changes in v5: - Clarify dcache_disable() comment
Changes in v4: - Elaborate on dcache_disable() comment
Changes in v3: - Use newly introduced Kconfig symbol for dh_imx6_defconfig
Changes in v2: - Add comment to explain the relevance of dcache_disable()
board/dhelectronics/dh_imx6/dh_imx6_spl.c | 41 +++++++++++++++++++++++ configs/dh_imx6_defconfig | 1 + 2 files changed, 42 insertions(+)
diff --git a/board/dhelectronics/dh_imx6/dh_imx6_spl.c b/board/dhelectronics/dh_imx6/dh_imx6_spl.c index e49e97724a..20a330cce6 100644 --- a/board/dhelectronics/dh_imx6/dh_imx6_spl.c +++ b/board/dhelectronics/dh_imx6/dh_imx6_spl.c @@ -6,6 +6,7 @@ */
#include <common.h> +#include <cpu_func.h> #include <init.h> #include <asm/arch/clock.h> #include <asm/arch/crm_regs.h> @@ -14,11 +15,13 @@ #include <asm/arch/mx6-ddr.h> #include <asm/arch/mx6-pins.h> #include <asm/arch/sys_proto.h> +#include <asm/cache.h> #include <asm/gpio.h> #include <asm/mach-imx/boot_mode.h> #include <asm/mach-imx/iomux-v3.h> #include <asm/mach-imx/mxc_i2c.h> #include <asm/io.h> +#include <asm/system.h> #include <errno.h> #include <fuse.h> #include <fsl_esdhc_imx.h> @@ -610,6 +613,20 @@ static void dhcom_spl_dram_init(void) } }
+void dram_bank_mmu_setup(int bank) +{ + int i; + + set_section_dcache(ROMCP_ARB_BASE_ADDR >> MMU_SECTION_SHIFT, DCACHE_DEFAULT_OPTION); + set_section_dcache(IRAM_BASE_ADDR >> MMU_SECTION_SHIFT, DCACHE_DEFAULT_OPTION); + + for (i = MMDC0_ARB_BASE_ADDR >> MMU_SECTION_SHIFT; + i < ((MMDC0_ARB_BASE_ADDR >> MMU_SECTION_SHIFT) + + (SZ_1G >> MMU_SECTION_SHIFT)); + i++) + set_section_dcache(i, DCACHE_DEFAULT_OPTION); +} + void board_init_f(ulong dummy) { /* setup AIPS and disable watchdog */ @@ -636,9 +653,33 @@ void board_init_f(ulong dummy) /* DDR3 initialization */ dhcom_spl_dram_init();
+ /* Set up early MMU tables at the beginning of DRAM and start d-cache */ + gd->arch.tlb_addr = MMDC0_ARB_BASE_ADDR + SZ_32M; + gd->arch.tlb_size = PGTABLE_SIZE; + enable_caches(); + /* Clear the BSS. */ memset(__bss_start, 0, __bss_end - __bss_start);
/* load/boot image from boot device */ board_init_r(NULL, 0); } + +void spl_board_prepare_for_boot(void) +{ + /* + * Flush and disable dcache. Without it, the following bootstage might fail randomly because + * dirty cache lines may not have been written back to DRAM. + * + * If dcache_disable() would be omitted, the following scenario may occur: + * + * The SPL enables dcache and cachelines get populated with data. Then dcache gets disabled + * in U-Boot proper, but still contains dirty data, i.e. the corresponding DRAM locations + * have not yet been updated. When U-Boot reads these locations, it sees an (incorrect) old + * state of the content. + * + * Furthermore, the DRAM contents have likely been modified by U-Boot while dcache was + * disabled. Thus, U-Boot flushing dcache would corrupt DRAM with stale data. + */ + dcache_disable(); /* implies flush_dcache_all() */ +} diff --git a/configs/dh_imx6_defconfig b/configs/dh_imx6_defconfig index 051816f719..1be6ae62ce 100644 --- a/configs/dh_imx6_defconfig +++ b/configs/dh_imx6_defconfig @@ -1,4 +1,5 @@ CONFIG_ARM=y +CONFIG_SPL_SYS_L2_PL310=y CONFIG_ARCH_MX6=y CONFIG_SYS_TEXT_BASE=0x17800000 CONFIG_SYS_MALLOC_F_LEN=0x1000