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authorHebbar, Gururaja <gururaja.hebbar@ti.com>2012-11-19 21:59:58 +0530
committerChris Ball <cjb@laptop.org>2012-12-06 13:54:56 -0500
commitcd587096c0e2b85a67e77721a753679bac89b394 (patch)
tree22ae2292f85cb8d36530535bc087bacdb8889158 /drivers/mmc
parentdc7745bd32272a614a6598c05db4510548ef18f2 (diff)
mmc: omap_hsmmc: Enable HSPE bit for high speed cards
HSMMC IP on AM33xx need a special setting to handle High-speed cards. Other platforms like TI81xx, OMAP4 may need this as-well. This depends on the HSMMC IP timing closure done for the high speed cards. From AM335x TRM (SPRUH73F - 18.3.12 Output Signals Generation): The MMC/SD/SDIO output signals can be driven on either falling edge or rising edge depending on the SD_HCTL[2] HSPE bit. This feature allows to reach better timing performance, and thus to increase data transfer frequency. There are few pre-requisites for enabling the HSPE bit - Controller should support High-Speed-Enable Bit and - Controller should not be using DDR Mode and - Controller should advertise that it supports High Speed in capabilities register and - MMC/SD clock coming out of controller > 25MHz Signed-off-by: Hebbar, Gururaja <gururaja.hebbar@ti.com> Signed-off-by: Venkatraman S <svenkatr@ti.com> Signed-off-by: Chris Ball <cjb@laptop.org>
Diffstat (limited to 'drivers/mmc')
-rw-r--r--drivers/mmc/host/omap_hsmmc.c30
1 files changed, 29 insertions, 1 deletions
diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index 571cd80521c7..18d3f19ef4e5 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -63,6 +63,7 @@
#define VS18 (1 << 26)
#define VS30 (1 << 25)
+#define HSS (1 << 21)
#define SDVS18 (0x5 << 9)
#define SDVS30 (0x6 << 9)
#define SDVS33 (0x7 << 9)
@@ -90,6 +91,7 @@
#define MSBS (1 << 5)
#define BCE (1 << 1)
#define FOUR_BIT (1 << 1)
+#define HSPE (1 << 2)
#define DDR (1 << 19)
#define DW8 (1 << 5)
#define CC 0x1
@@ -495,6 +497,7 @@ static void omap_hsmmc_set_clock(struct omap_hsmmc_host *host)
struct mmc_ios *ios = &host->mmc->ios;
unsigned long regval;
unsigned long timeout;
+ unsigned long clkdiv;
dev_vdbg(mmc_dev(host->mmc), "Set clock to %uHz\n", ios->clock);
@@ -502,7 +505,8 @@ static void omap_hsmmc_set_clock(struct omap_hsmmc_host *host)
regval = OMAP_HSMMC_READ(host->base, SYSCTL);
regval = regval & ~(CLKD_MASK | DTO_MASK);
- regval = regval | (calc_divisor(host, ios) << 6) | (DTO << 16);
+ clkdiv = calc_divisor(host, ios);
+ regval = regval | (clkdiv << 6) | (DTO << 16);
OMAP_HSMMC_WRITE(host->base, SYSCTL, regval);
OMAP_HSMMC_WRITE(host->base, SYSCTL,
OMAP_HSMMC_READ(host->base, SYSCTL) | ICE);
@@ -513,6 +517,27 @@ static void omap_hsmmc_set_clock(struct omap_hsmmc_host *host)
&& time_before(jiffies, timeout))
cpu_relax();
+ /*
+ * Enable High-Speed Support
+ * Pre-Requisites
+ * - Controller should support High-Speed-Enable Bit
+ * - Controller should not be using DDR Mode
+ * - Controller should advertise that it supports High Speed
+ * in capabilities register
+ * - MMC/SD clock coming out of controller > 25MHz
+ */
+ if ((mmc_slot(host).features & HSMMC_HAS_HSPE_SUPPORT) &&
+ (ios->timing != MMC_TIMING_UHS_DDR50) &&
+ ((OMAP_HSMMC_READ(host->base, CAPA) & HSS) == HSS)) {
+ regval = OMAP_HSMMC_READ(host->base, HCTL);
+ if (clkdiv && (clk_get_rate(host->fclk)/clkdiv) > 25000000)
+ regval |= HSPE;
+ else
+ regval &= ~HSPE;
+
+ OMAP_HSMMC_WRITE(host->base, HCTL, regval);
+ }
+
omap_hsmmc_start_clock(host);
}
@@ -1715,6 +1740,9 @@ static struct omap_mmc_platform_data *of_get_hsmmc_pdata(struct device *dev)
if (!of_property_read_u32(np, "max-frequency", &max_freq))
pdata->max_freq = max_freq;
+ if (of_find_property(np, "ti,needs-special-hs-handling", NULL))
+ pdata->slots[0].features |= HSMMC_HAS_HSPE_SUPPORT;
+
return pdata;
}
#else