When sd/mmc work at DDR mode, like HS400/HS400ES/DDR52/DDR50 mode, the output clock rate is half of the internal clock rate.
This patch set the DDR_EN bit first for DDR mode, hardware divide the usdhc clock automatically, then follow the original sdr clock setting method.
Signed-off-by: Haibo Chen haibo.chen@nxp.com Signed-off-by: Ye Li ye.li@nxp.com --- drivers/mmc/fsl_esdhc.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c index 74007e2..87273c8 100644 --- a/drivers/mmc/fsl_esdhc.c +++ b/drivers/mmc/fsl_esdhc.c @@ -585,18 +585,31 @@ static void set_sysctl(struct fsl_esdhc_priv *priv, struct mmc *mmc, uint clock) #else int pre_div = 2; #endif - int ddr_pre_div = mmc->ddr_mode ? 2 : 1; int sdhc_clk = priv->sdhc_clk; uint clk;
+ /* + * For ddr mode, usdhc need to enable DDR mode first, after select + * this DDR mode, usdhc will automatically divide the usdhc clock + */ + if (mmc->ddr_mode) { + writel(readl(®s->mixctrl) | MIX_CTRL_DDREN, ®s->mixctrl); + sdhc_clk >>= 1; + } + if (clock < mmc->cfg->f_min) clock = mmc->cfg->f_min;
- while (sdhc_clk / (16 * pre_div * ddr_pre_div) > clock && pre_div < 256) - pre_div *= 2; + if (sdhc_clk / 16 > clock) { + for (; pre_div < 256; pre_div *= 2) + if ((sdhc_clk / pre_div) <= (clock * 16)) + break; + } else + pre_div = 1;
- while (sdhc_clk / (div * pre_div * ddr_pre_div) > clock && div < 16) - div++; + for (div = 1; div <= 16; div++) + if ((sdhc_clk / (div * pre_div)) <= clock) + break;
pre_div >>= 1; div -= 1;