From 93b15783232cb3a866ec9253cb4284a812cc5fe8 Mon Sep 17 00:00:00 2001 From: Sascha Hauer Date: Wed, 22 May 2013 09:51:54 +0200 Subject: mci i.MX esdhc: Fix clock divider calculation This updates the i.MX esdhc divider settings to FSLs U-Boot. Current timings work fine for SD cards, but not for eMMC. Although the calculation is fine according to the datasheet and reading from eMMC works, writing is broken. Atleast on i.MX53/tqma53. With this patch the result is the same, but uses different divider values to achieve it. While at it, replace the udelay with a busy-loop. Signed-off-by: Sascha Hauer Signed-off-by: Steffen Trumtrar Signed-off-by: Sascha Hauer --- drivers/mci/imx-esdhc.c | 46 +++++++++++++++++++++++++++------------------- 1 file changed, 27 insertions(+), 19 deletions(-) (limited to 'drivers/mci/imx-esdhc.c') diff --git a/drivers/mci/imx-esdhc.c b/drivers/mci/imx-esdhc.c index ae934f487a..46bd6d2953 100644 --- a/drivers/mci/imx-esdhc.c +++ b/drivers/mci/imx-esdhc.c @@ -44,7 +44,6 @@ struct fsl_esdhc_host { struct mci_host mci; void __iomem *regs; - unsigned long cur_clock; struct device_d *dev; struct clk *clk; }; @@ -333,30 +332,38 @@ static void set_sysctl(struct mci_host *mci, u32 clock) void __iomem *regs = host->regs; int sdhc_clk = clk_get_rate(host->clk); u32 clk; - - if (clock < mci->f_min) - clock = mci->f_min; - - pre_div = 0; - - for (pre_div = 1; pre_div < 256; pre_div <<= 1) { - if (sdhc_clk / pre_div < clock * 16) + unsigned long cur_clock; + + /* + * With eMMC and imx53 (sdhc_clk=200MHz) a pre_div of 1 results in + * pre_div=1,div=4 (=50MHz) + * which is valid and should work, but somehow doesn't. + * Starting with pre_div=2 gives + * pre_div=2, div=2 (=50MHz) + * and works fine. + */ + pre_div = 2; + + if (sdhc_clk == clock) + pre_div = 1; + else if (sdhc_clk / 16 > clock) + for (; pre_div < 256; pre_div *= 2) + if ((sdhc_clk / pre_div) <= (clock * 16)) + break; + + for (div = 1; div <= 16; div++) + if ((sdhc_clk / (div * pre_div)) <= clock) break; - }; - - div = sdhc_clk / pre_div / clock; - if (sdhc_clk / pre_div / div > clock) - div++; + cur_clock = sdhc_clk / pre_div / div; - host->cur_clock = sdhc_clk / pre_div / div; + dev_dbg(host->dev, "set clock: wanted: %d got: %ld\n", clock, cur_clock); + dev_dbg(host->dev, "pre_div: %d div: %d\n", pre_div, div); + /* the register values start with 0 */ div -= 1; pre_div >>= 1; - dev_dbg(host->dev, "set clock: wanted: %d got: %ld\n", clock, host->cur_clock); - dev_dbg(host->dev, "pre_div: %d div: %d\n", pre_div, div); - clk = (pre_div << 8) | (div << 4); esdhc_clrbits32(regs + SDHCI_CLOCK_CONTROL__TIMEOUT_CONTROL__SOFTWARE_RESET, @@ -365,7 +372,8 @@ static void set_sysctl(struct mci_host *mci, u32 clock) esdhc_clrsetbits32(regs + SDHCI_CLOCK_CONTROL__TIMEOUT_CONTROL__SOFTWARE_RESET, SYSCTL_CLOCK_MASK, clk); - udelay(10000); + wait_on_timeout(10 * MSECOND, + !(esdhc_read32(regs + SDHCI_PRESENT_STATE) & PRSSTAT_SDSTB)); clk = SYSCTL_PEREN | SYSCTL_CKEN; -- cgit v1.2.3