From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752098Ab2ILJVi (ORCPT ); Wed, 12 Sep 2012 05:21:38 -0400 Received: from na3sys009aog117.obsmtp.com ([74.125.149.242]:46552 "EHLO na3sys009aog117.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751830Ab2ILJVg (ORCPT ); Wed, 12 Sep 2012 05:21:36 -0400 MIME-Version: 1.0 In-Reply-To: <1346764151-21323-1-git-send-email-gururaja.hebbar@ti.com> References: <1346764151-21323-1-git-send-email-gururaja.hebbar@ti.com> Date: Wed, 12 Sep 2012 14:51:34 +0530 Message-ID: Subject: Re: [PATCH] mmc: omap_hsmmc: Enable HSPE bit for high speed cards From: "T Krishnamoorthy, Balaji" To: "Hebbar, Gururaja" Cc: linux-omap@vger.kernel.org, linux-mmc@vger.kernel.org, svenkatr@ti.com, rob.herring@calxeda.com, linux-kernel@vger.kernel.org, grant.likely@secretlab.ca, cjb@laptop.org, nsekhar@ti.com, sudhakar.raj@ti.com Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 4, 2012 at 6:39 PM, 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. Is this specific to some boards or all board with TI81xx ? What is the side-effect if not done ? > > 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 > --- > :100644 100644 be76a23... ed271fc... M Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt > :100644 100644 eb3e4d5... 00c658b... M arch/arm/plat-omap/include/plat/mmc.h > :100644 100644 c3e96a2... 0e14834... 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 | 30 +++++++++++++++++++- > 3 files changed, 31 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@0x4809c000 { > diff --git a/arch/arm/plat-omap/include/plat/mmc.h b/arch/arm/plat-omap/include/plat/mmc.h > index eb3e4d5..00c658b 100644 > --- a/arch/arm/plat-omap/include/plat/mmc.h > +++ b/arch/arm/plat-omap/include/plat/mmc.h > @@ -127,6 +127,7 @@ 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 c3e96a2..0e14834 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 > @@ -490,6 +492,7 @@ 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); > > @@ -497,7 +500,8 @@ 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); > @@ -508,6 +512,27 @@ 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) I think clkdiv is not needed clk_get_rate(host->fclk)/clkdiv is same as ios->clock > + regval |= HSPE; > + else > + regval &= ~HSPE; > + > + OMAP_HSMMC_WRITE(host->base, HCTL, regval); > + } > + > omap_hsmmc_start_clock(host); > } > > @@ -1701,6 +1726,9 @@ static struct omap_mmc_platform_data *of_get_hsmmc_pdata(struct device *dev) > if (of_find_property(np, "ti,needs-special-reset", NULL)) > pdata->slots[0].features |= HSMMC_HAS_UPDATED_RESET; > > + if (of_find_property(np, "ti,needs-special-hs-handling", NULL)) > + pdata->slots[0].features |= HSMMC_HAS_HSPE_SUPPORT; > + > return pdata; > } > #else > -- > 1.7.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html