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

Seungwon Jeon
2012-07-19T03:51:12Z

Hi,

This version does not seems to consider previous reviews fully.
Could you check the comments below?

July 12, 2012, Thomas Abraham <thomas.abraham@linaro.org> wrote:
> 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,
> +};
> +
Kyungmin Park has already pointed .
It's not still proper place for board specific caps.
If I'm incorrect, please let me know.
And why MMC_CAP_CMD23 is default caps for all channel of hosts?

> +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));
> + }
As you know, CLKSEL is specific for Samsung soc.
0x09C(CLKSEL) is reserved area in Synopsys memory map.
In case of non-samsung-soc, we cannot ensure this usage.
In previous version, I have suggested separating the variant into another file.

>
> 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;
Host of non-samsung will reach here.
host->sdr_timing is needed for this host? host->ddr_timing is the same.

> + 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
What is the basis for these timing?
These values is board-specific.

> +#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)
If it's for exynos5, it will be 7 not 3.

> +#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)
> +
Is this patch considered only for exynos5250?
In case of exynos4210, the number of bits is different.
If upper macros is backward-compatible, it would be better.

Best regards,
Seungwon Jeon

> /* 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
>
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