diff options
| author | Hebbar, Gururaja <gururaja.hebbar@ti.com> | 2012-11-19 21:59:58 +0530 |
|---|---|---|
| committer | Chris Ball <cjb@laptop.org> | 2012-12-06 13:54:56 -0500 |
| commit | cd587096c0e2b85a67e77721a753679bac89b394 (patch) | |
| tree | 22ae2292f85cb8d36530535bc087bacdb8889158 /drivers | |
| parent | dc7745bd32272a614a6598c05db4510548ef18f2 (diff) | |
| download | linux-cd587096c0e2b85a67e77721a753679bac89b394.tar.bz2 | |
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')
| -rw-r--r-- | drivers/mmc/host/omap_hsmmc.c | 30 |
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 |