From 917fa280e5e99edcae44a34feab295a59922d16c Mon Sep 17 00:00:00 2001 From: Kevin Hilman Date: Wed, 10 Dec 2008 17:37:17 -0800 Subject: [PATCH] omap mmc: force MMC module reset on boot The bootloader may leave the MMC in a state which prevents hitting retention. Even when MMC is not compiled in, each MMC module needs to be forced into reset. Signed-off-by: Kevin Hilman --- arch/arm/mach-omap2/devices.c | 85 +++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) diff --git a/arch/arm/mach-omap2/devices.c b/arch/arm/mach-omap2/devices.c index 6e03272b052..9d7216ff6c9 100644 --- a/arch/arm/mach-omap2/devices.c +++ b/arch/arm/mach-omap2/devices.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include @@ -299,6 +300,89 @@ static inline void omap_init_sha1_md5(void) { } /*-------------------------------------------------------------------------*/ +#ifdef CONFIG_ARCH_OMAP3 + +#define MMCHS_SYSCONFIG 0x0010 +#define MMCHS_SYSCONFIG_SWRESET (1 << 1) +#define MMCHS_SYSSTATUS 0x0014 +#define MMCHS_SYSSTATUS_RESETDONE (1 << 0) + +static struct platform_device dummy_pdev = { + .dev = { + .bus = &platform_bus_type, + }, +}; + +/** + * omap_hsmmc_reset() - Full reset of each HS-MMC controller + * + * Ensure that each MMC controller is fully reset. Controllers + * left in an unknown state (by bootloader) may prevent retention + * or OFF-mode. This is especially important in cases where the + * MMC driver is not enabled, _or_ built as a module. + * + * In order for reset to work, interface, functional and debounce + * clocks must be enabled. The debounce clock comes from func_32k_clk + * and is not under SW control, so we only enable i- and f-clocks. + **/ +static void __init omap_hsmmc_reset(void) +{ + u32 i, nr_controllers = cpu_is_omap34xx() ? OMAP34XX_NR_MMC : + OMAP24XX_NR_MMC; + + for (i = 0; i < nr_controllers; i++) { + u32 v, base = 0; + struct clk *iclk, *fclk; + struct device *dev = &dummy_pdev.dev; + + switch (i) { + case 0: + base = OMAP2_MMC1_BASE; + break; + case 1: + base = OMAP2_MMC2_BASE; + break; + case 2: + base = OMAP3_MMC3_BASE; + break; + } + + dummy_pdev.id = i; + iclk = clk_get(dev, "mmchs_ick"); + if (iclk && clk_enable(iclk)) + iclk = NULL; + + fclk = clk_get(dev, "mmchs_fck"); + if (fclk && clk_enable(fclk)) + fclk = NULL; + + if (!iclk || !fclk) { + printk(KERN_WARNING + "%s: Unable to enable clocks for MMC%d, " + "cannot reset.\n", __func__, i); + break; + } + + omap_writel(MMCHS_SYSCONFIG_SWRESET, base + MMCHS_SYSCONFIG); + v = omap_readl(base + MMCHS_SYSSTATUS); + while (!(omap_readl(base + MMCHS_SYSSTATUS) & + MMCHS_SYSSTATUS_RESETDONE)) + cpu_relax(); + + if (fclk) { + clk_disable(fclk); + clk_put(fclk); + } + if (iclk) { + clk_disable(iclk); + clk_put(iclk); + } + } +} +#else +static inline void omap_hsmmc_reset(void) {} +#endif + #if defined(CONFIG_MMC_OMAP) || defined(CONFIG_MMC_OMAP_MODULE) || \ defined(CONFIG_MMC_OMAP_HS) || defined(CONFIG_MMC_OMAP_HS_MODULE) @@ -418,6 +502,7 @@ static int __init omap2_init_devices(void) /* please keep these calls, and their implementations above, * in alphabetical order so they're easier to sort through. */ + omap_hsmmc_reset(); omap_init_mbox(); omap_init_mcspi(); omap_hdq_init(); -- 2.41.1