[PATCH v3 6/6] mmc: dw_mmc: add samsung exynos5250 specific extentions

Thomas Abraham
2012-07-12T12:40:56Z

The instantiation of the Synopsis Designware controller on Exynos5250
include extension for SDR and DDR specific tx/rx phase shift timing
and CIU internal divider. In addition to that, the option to skip the
command hold stage is also introduced. Add support for these Exynos5250
specfic extenstions.

Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
---
.../devicetree/bindings/mmc/synposis-dw-mshc.txt | 38 ++++++++++++++++++-
drivers/mmc/host/dw_mmc-pltfm.c | 15 +++++++
drivers/mmc/host/dw_mmc.c | 40 +++++++++++++++++++-
drivers/mmc/host/dw_mmc.h | 14 +++++++
include/linux/mmc/dw_mmc.h | 6 +++
5 files changed, 110 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/mmc/synposis-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/synposis-dw-mshc.txt
index 3acd6c9..69d78c1 100644
--- a/Documentation/devicetree/bindings/mmc/synposis-dw-mshc.txt
+++ b/Documentation/devicetree/bindings/mmc/synposis-dw-mshc.txt
@@ -7,6 +7,8 @@ Required Properties:

* compatible: should be one of the following
- snps,dw-mshc: for controllers compliant with synopsis dw-mshc.
+ - samsung,exynos5250-dw-mshc: for controllers with Samsung
+ Exynos5250 specific extentions.

* reg: physical base address of the dw-mshc controller and size of its memory
region.
@@ -74,13 +76,45 @@ Aliases:
the following format 'mshc{n}' where n is a unique number for the alias.

+Samsung Exynos4/5 specific properties:
+
+Some of the variants of Exynos4 (such as Exynos4412) and Exynos5 SoC's
+includes few extensions to the Synopsis Designware Mobile Storage Host
+Controller. The following properties are used to describe those extensions.
+
+* samsung,dw-mshc-sdr-timing: Specifies the value of CUI clock divider, CIU
+ clock phase shift value in transmit mode and CIU clock phase shift value in
+ receive mode for single data rate mode operation. Refer notes of the valid
+ values below.
+
+* samsung,dw-mshc-ddr-timing: Specifies the value of CUI clock divider, CIU
+ clock phase shift value in transmit mode and CIU clock phase shift value in
+ receive mode for double data rate mode operation. Refer notes of the valid
+ values below. The order of the cells should be
+
+ - First Cell: CIU clock divider value (applicable only for Exynos5
+ SoC's, should be zero for Exynos4 SoC's)
+ - Second Cell: CIU clock phase shift value for tx mode.
+ - Third Cell: CIU clock phase shift value for rx mode.
+
+ Valid values for SDR and DDR CIU clock timing for Exynos5250:
+
+ - valid values for CIU clock divider, tx phase shift and rx phase shift
+ is 0 to 7.
+
+ - When CIU clock divider value is set to 3, all possible 8 phase shift
+ values can be used.
+
+ - If CIU clock divider value is 0 (that is divide by 1), both tx and rx
+ phase shift clocks should be 0.
+
Example:

The MSHC controller node can be split into two portions, SoC specific and
board specific portions as listed below.

dwmmc0@12200000 {
- compatible = "snps,dw-mshc";
+ compatible = "samsung,exynos5250-dw-mshc";
reg = <0x12200000 0x1000>;
interrupts = <0 75 0>;
#address-cells = <1>;
@@ -94,6 +128,8 @@ Example:
no-write-protect;
fifo-depth = <0x80>;
card-detect-delay = <200>;
+ samsung,dw-mshc-sdr-timing = <2 3 3>;
+ samsung,dw-mshc-ddr-timing = <1 2 3>;

slot@0 {
reg = <0>;
diff --git a/drivers/mmc/host/dw_mmc-pltfm.c b/drivers/mmc/host/dw_mmc-pltfm.c
index 8d24f6d..900f412 100644
--- a/drivers/mmc/host/dw_mmc-pltfm.c
+++ b/drivers/mmc/host/dw_mmc-pltfm.c
@@ -27,9 +27,24 @@ static struct dw_mci_drv_data synopsis_drv_data = {
.ctrl_type = DW_MCI_TYPE_SYNOPSIS,
};

+static unsigned long exynos5250_dwmmc_caps[4] = {
+ MMC_CAP_UHS_DDR50 | MMC_CAP_1_8V_DDR |
+ MMC_CAP_8_BIT_DATA | MMC_CAP_CMD23,
+ MMC_CAP_CMD23,
+ MMC_CAP_CMD23,
+ MMC_CAP_CMD23,
+};
+
+static struct dw_mci_drv_data exynos5250_drv_data = {
+ .ctrl_type = DW_MCI_TYPE_EXYNOS5250,
+ .caps = exynos5250_dwmmc_caps,
+};
+
static const struct of_device_id dw_mci_pltfm_match[] = {
{ .compatible = "snps,dw-mshc",
.data = (void *)&synopsis_drv_data, },
+ { .compatible = "samsung,exynos5250-dw-mshc",
+ .data = (void *)&exynos5250_drv_data, },
{},
};
MODULE_DEVICE_TABLE(of, dw_mci_pltfm_match);
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 3bc276d..bbf1209 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -236,6 +236,7 @@ static void dw_mci_set_timeout(struct dw_mci *host)
static u32 dw_mci_prepare_command(struct mmc_host *mmc, struct mmc_command *cmd)
{
struct mmc_data *data;
+ struct dw_mci_slot *slot = mmc_priv(mmc);
u32 cmdr;
cmd->error = -EINPROGRESS;

@@ -265,6 +266,17 @@ static u32 dw_mci_prepare_command(struct mmc_host *mmc, struct mmc_command *cmd)
cmdr |= SDMMC_CMD_DAT_WR;
}

+ /*
+ * Samsung Exynos5250 extends the use of CMD register with the use of
+ * bit 29 (which is reserved on standard MSHC controllers) for
+ * optionally bypassing the HOLD register for command and data. The
+ * HOLD register should be bypassed in case there is no phase shift
+ * applied on CMD/DATA that is sent to the card.
+ */
+ if (slot->host->drv_data->ctrl_type == DW_MCI_TYPE_EXYNOS5250)
+ if (SDMMC_CLKSEL_GET_SELCLK_DRV(mci_readl(slot->host, CLKSEL)))
+ cmdr |= SDMMC_CMD_USE_HOLD_REG;
+
return cmdr;
}

@@ -802,10 +814,19 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
regs = mci_readl(slot->host, UHS_REG);

/* DDR mode set */
- if (ios->timing == MMC_TIMING_UHS_DDR50)
+ if (ios->timing == MMC_TIMING_UHS_DDR50) {
regs |= (0x1 << slot->id) << 16;
- else
+ mci_writel(slot->host, CLKSEL, slot->host->ddr_timing);
+ } else {
regs &= ~(0x1 << slot->id) << 16;
+ mci_writel(slot->host, CLKSEL, slot->host->sdr_timing);
+ }
+
+ if (slot->host->drv_data->ctrl_type == DW_MCI_TYPE_EXYNOS5250) {
+ slot->host->bus_hz = clk_get_rate(slot->host->ciu_clk);
+ slot->host->bus_hz /= SDMMC_CLKSEL_GET_DIVRATIO(
+ mci_readl(slot->host, CLKSEL));
+ }

mci_writel(slot->host, UHS_REG, regs);

@@ -2086,6 +2107,7 @@ static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host)
struct dw_mci_board *pdata;
struct device *dev = host->dev;
struct device_node *np = dev->of_node;
+ u32 timing[3];
int idx, cnt;

pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
@@ -2108,6 +2130,20 @@ static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host)
if (of_get_property(np, of_quriks[idx].quirk, NULL))
pdata->quirks |= of_quriks[idx].id;

+ if (of_property_read_u32_array(dev->of_node,
+ "samsung,dw-mshc-sdr-timing", timing, 3))
+ host->sdr_timing = DW_MCI_DEF_SDR_TIMING;
+ else
+ host->sdr_timing = SDMMC_CLKSEL_TIMING(timing[0],
+ timing[1], timing[2]);
+
+ if (of_property_read_u32_array(dev->of_node,
+ "samsung,dw-mshc-ddr-timing", timing, 3))
+ host->ddr_timing = DW_MCI_DEF_DDR_TIMING;
+ else
+ host->ddr_timing = SDMMC_CLKSEL_TIMING(timing[0],
+ timing[1], timing[2]);
+
if (of_property_read_u32(np, "fifo-depth", &pdata->fifo_depth))
dev_info(dev, "fifo-depth property not found, using "
"value of FIFOTH register as default\n");
diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
index 1ecaa02..6c17282 100644
--- a/drivers/mmc/host/dw_mmc.h
+++ b/drivers/mmc/host/dw_mmc.h
@@ -53,6 +53,7 @@
#define SDMMC_IDINTEN 0x090
#define SDMMC_DSCADDR 0x094
#define SDMMC_BUFADDR 0x098
+#define SDMMC_CLKSEL 0x09C /* specific to Samsung Exynos5250 */
#define SDMMC_DATA(x) (x)

/*
@@ -111,6 +112,7 @@
#define SDMMC_INT_ERROR 0xbfc2
/* Command register defines */
#define SDMMC_CMD_START BIT(31)
+#define SDMMC_CMD_USE_HOLD_REG BIT(29)
#define SDMMC_CMD_CCS_EXP BIT(23)
#define SDMMC_CMD_CEATA_RD BIT(22)
#define SDMMC_CMD_UPD_CLK BIT(21)
@@ -142,6 +144,17 @@
/* Version ID register define */
#define SDMMC_GET_VERID(x) ((x) & 0xFFFF)

+#define DW_MCI_DEF_SDR_TIMING 0x03030002
+#define DW_MCI_DEF_DDR_TIMING 0x03020001
+#define SDMMC_CLKSEL_CCLK_SAMPLE(x) (((x) & 3) << 0)
+#define SDMMC_CLKSEL_CCLK_DRIVE(x) (((x) & 3) << 16)
+#define SDMMC_CLKSEL_CCLK_DIVIDER(x) (((x) & 3) << 24)
+#define SDMMC_CLKSEL_TIMING(x, y, z) (SDMMC_CLKSEL_CCLK_SAMPLE(x) | \
+ SDMMC_CLKSEL_CCLK_DRIVE(y) | \
+ SDMMC_CLKSEL_CCLK_DIVIDER(z))
+#define SDMMC_CLKSEL_GET_DIVRATIO(x) ((((x) >> 24) & 0x7) + 1)
+#define SDMMC_CLKSEL_GET_SELCLK_DRV(x) (((x) >> 16) & 0x7)
+
/* Register access macros */
#define mci_readl(dev, reg) \
__raw_readl((dev)->regs + SDMMC_##reg)
@@ -184,6 +197,7 @@ extern int dw_mci_resume(struct dw_mci *host);

/* Variations in the dw_mci controller */
#define DW_MCI_TYPE_SYNOPSIS 0
+#define DW_MCI_TYPE_EXYNOS5250 1 /* Samsung Exynos5250 Extensions */

/* dw_mci platform driver data */
struct dw_mci_drv_data {
diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
index ae45e4f..32c778f 100644
--- a/include/linux/mmc/dw_mmc.h
+++ b/include/linux/mmc/dw_mmc.h
@@ -82,6 +82,8 @@ struct mmc_data;
* @biu_clk: Pointer to bus interface unit clock instance.
* @ciu_clk: Pointer to card interface unit clock instance.
* @slot: Slots sharing this MMC controller.
+ * @sdr_timing: Clock phase shifting for driving and sampling in sdr mode
+ * @ddr_timing: Clock phase shifting for driving and sampling in ddr mode
* @fifo_depth: depth of FIFO.
* @data_shift: log2 of FIFO item size.
* @part_buf_start: Start index in part_buf.
@@ -166,6 +168,10 @@ struct dw_mci {
struct clk *ciu_clk;
struct dw_mci_slot *slot[MAX_MCI_SLOTS];

+ /* Phase Shift Value (for exynos5250 variant) */
+ u32 sdr_timing;
+ u32 ddr_timing;
+
/* FIFO push and pull */
int fifo_depth;
int data_shift;
--
1.6.6.rc2