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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 <khilman@deeprootsystems.com>
hifive-unleashed-5.1
Kevin Hilman 2008-12-10 17:37:17 -08:00 committed by Tony Lindgren
parent 90c62bf08f
commit 917fa280e5
1 changed files with 85 additions and 0 deletions
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85
arch/arm/mach-omap2/devices.c
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@ -14,6 +14,7 @@
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <mach/hardware.h>
#include <asm/mach-types.h>
@ -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();