[PATCH v3 5/6] mmc: sdhci-esdhc-imx: config watermark level and burst length
From: Haibo Chen <hidden>
Date: 2015-07-29 09:02:24
Also in:
linux-devicetree, linux-mmc, lkml
Subsystem:
multimedia card (mmc), secure digital (sd) and sdio subsystem, secure digital host controller interface (sdhci) driver, secure digital host controller interface (sdhci) nxp i.mx driver, the rest · Maintainers:
Ulf Hansson, Adrian Hunter, Haibo Chen, Linus Torvalds
i.MX7D support eMMC HS400 mode, this mode can run in 8 bit,200MHZ DDR mode. So the I/O speed improve a lot compare to SD3.0 The default burst length is 8, if we don't change this value, in HS400 mode, when we do eMMC read operation, we can find that the clock signal will stop for a period of time. This means the speed of data moving on AHB bus is slower than I/O speed. So we should improve the speed of data moving on AHB bus. For imx7d usdhc, this patch set the burst length as 16, and set watermark level as 64. The test result is the clock signal has no stop during the eMMC HS400 operation. For other imx usdhc, remain the default value: burst length as 8, watermark level as 16. Signed-off-by: Haibo Chen <redacted> --- drivers/mmc/host/sdhci-esdhc-imx.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index 158f93b..37d0095 100644
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c@@ -239,6 +239,11 @@ static inline int is_imx6q_usdhc(struct pltfm_imx_data *data) return data->socdata == &usdhc_imx6q_data; } +static inline int is_imx7d_usdhc(struct pltfm_imx_data *data) +{ + return data->socdata == &usdhc_imx7d_data; +} + static inline int esdhc_is_usdhc(struct pltfm_imx_data *data) { return !!(data->socdata->flags & ESDHC_FLAG_USDHC);
@@ -1145,7 +1150,11 @@ static int sdhci_esdhc_imx_probe(struct platform_device *pdev) * to something insane. Change it back here. */ if (esdhc_is_usdhc(imx_data)) { - writel(0x08100810, host->ioaddr + ESDHC_WTMK_LVL); + if (is_imx7d_usdhc(imx_data)) + writel(0x10401040, host->ioaddr + ESDHC_WTMK_LVL); + else + writel(0x08100810, host->ioaddr + ESDHC_WTMK_LVL); + host->quirks2 |= SDHCI_QUIRK2_PRESET_VALUE_BROKEN; host->mmc->caps |= MMC_CAP_1_8V_DDR;
--
1.9.1