[PATCH V3] mmc: omap_hsmmc: Enable HSPE bit for high speed cards
Felipe Balbi
balbi at ti.com
Wed Oct 31 08:26:39 EDT 2012
Hi,
On Wed, Oct 31, 2012 at 05:27:36PM +0530, Hebbar, Gururaja wrote:
> 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
>
> Note:
> The implementation reuses the output of calc_divisor() so as to reduce
> code addition.
>
> Signed-off-by: Hebbar, Gururaja <gururaja.hebbar at ti.com>
this looks good to my eyes, hopefully I haven't missed anything:
Reviewed-by: Felipe Balbi <balbi at ti.com>
> ---
> Rebased on mmc-next (v3.7.0-rc1)
> Only Build tested since EDMA support for AM335x is not yet added
>
> Changes in V2
> - Added note in commit message about code re-use
> - replaced ((a & BIT(n) == BIT(n))) with (a & BIT(n)) since
> effectively both are same.
>
> Changes in V3
> - use symbolic define for hardcoded value (25000000)
> - use of_property_read_bool() instead of of_find_property()
>
> :100644 100644 be76a23... ed271fc... M Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt
> :100644 100644 8b4e4f2... 346af5b... M arch/arm/plat-omap/include/plat/mmc.h
> :100644 100644 5434fd8... 4f7fcee... M drivers/mmc/host/omap_hsmmc.c
> .../devicetree/bindings/mmc/ti-omap-hsmmc.txt | 1 +
> arch/arm/plat-omap/include/plat/mmc.h | 1 +
> drivers/mmc/host/omap_hsmmc.c | 31 +++++++++++++++++++-
> 3 files changed, 32 insertions(+), 1 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt
> index be76a23..ed271fc 100644
> --- a/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt
> +++ b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt
> @@ -19,6 +19,7 @@ ti,dual-volt: boolean, supports dual voltage cards
> "supply-name" examples are "vmmc", "vmmc_aux" etc
> ti,non-removable: non-removable slot (like eMMC)
> ti,needs-special-reset: Requires a special softreset sequence
> +ti,needs-special-hs-handling: HSMMC IP needs special setting for handling High Speed
>
> Example:
> mmc1: mmc at 0x4809c000 {
> diff --git a/arch/arm/plat-omap/include/plat/mmc.h b/arch/arm/plat-omap/include/plat/mmc.h
> index 8b4e4f2..346af5b 100644
> --- a/arch/arm/plat-omap/include/plat/mmc.h
> +++ b/arch/arm/plat-omap/include/plat/mmc.h
> @@ -126,6 +126,7 @@ struct omap_mmc_platform_data {
> /* we can put the features above into this variable */
> #define HSMMC_HAS_PBIAS (1 << 0)
> #define HSMMC_HAS_UPDATED_RESET (1 << 1)
> +#define HSMMC_HAS_HSPE_SUPPORT (1 << 2)
> unsigned features;
>
> int switch_pin; /* gpio (card detect) */
> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
> index 5434fd8..4f7fcee 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
> @@ -113,6 +115,7 @@
> #define MMC_TIMEOUT_MS 20
> #define OMAP_MMC_MIN_CLOCK 400000
> #define OMAP_MMC_MAX_CLOCK 52000000
> +#define HSMMC_CLKOUT 25000000
> #define DRIVER_NAME "omap_hsmmc"
>
> /*
> @@ -495,6 +498,7 @@ 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 +506,8 @@ 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 +518,27 @@ 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)) {
> + regval = OMAP_HSMMC_READ(host->base, HCTL);
> + if (clkdiv && (clk_get_rate(host->fclk)/clkdiv) > HSMMC_CLKOUT)
> + regval |= HSPE;
> + else
> + regval &= ~HSPE;
> +
> + OMAP_HSMMC_WRITE(host->base, HCTL, regval);
> + }
> +
> omap_hsmmc_start_clock(host);
> }
>
> @@ -1709,6 +1735,9 @@ 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_property_read_bool(np, "ti,needs-special-hs-handling"))
> + pdata->slots[0].features |= HSMMC_HAS_HSPE_SUPPORT;
> +
> return pdata;
> }
> #else
> --
> 1.7.0.4
>
--
balbi
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 836 bytes
Desc: Digital signature
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20121031/0e1f36c4/attachment.sig>
More information about the linux-arm-kernel
mailing list