[PATCH v2 4/4] mmc: sdhci-esdhc-imx: set back the burst_length_enable bit to 1

From: Haibo Chen
Date: Tue Jun 23 2015 - 08:00:10 EST


Currently we find that if a usdhc is choosed to boot system, then ROM
code will set the burst length enable bit of this usdhc as 0.

This will make performance drop a lot if this usdhc's burst length is
16. So this patch set back the burst_length_enable bit as 1, which is
the default value, and means burst length is enabled for INCR.

Signed-off-by: Haibo Chen <haibo.chen@xxxxxxxxxxxxx>
---
drivers/mmc/host/sdhci-esdhc-imx.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index 1f0e0d9..e6a1995 100644
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -32,6 +32,7 @@
#include "sdhci-esdhc.h"

#define ESDHC_CTRL_D3CD 0x08
+#define ESDHC_BURST_LEN_EN_INCR (1 << 27)
/* VENDOR SPEC register */
#define ESDHC_VENDOR_SPEC 0xc0
#define ESDHC_VENDOR_SPEC_SDIO_QUIRK (1 << 1)
@@ -1088,6 +1089,16 @@ static int sdhci_esdhc_imx_probe(struct platform_device *pdev)
host->quirks2 |= SDHCI_QUIRK2_PRESET_VALUE_BROKEN;
host->mmc->caps |= MMC_CAP_1_8V_DDR;

+ /*
+ * ROM code will change the burst_length_enable setting to
+ * zero if this usdhc is choosed to boot system. Change it
+ * back here, otherwise it will impact the performance a
+ * lot if the burst length is 16.
+ */
+ writel(readl(host->ioaddr + SDHCI_HOST_CONTROL)
+ | ESDHC_BURST_LEN_EN_INCR,
+ host->ioaddr + SDHCI_HOST_CONTROL);
+
if (!(imx_data->socdata->flags & ESDHC_FLAG_HS200))
host->quirks2 |= SDHCI_QUIRK2_BROKEN_HS200;

--
1.9.1

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