Re: [PATCH 2/2] mmc: host: sunxi: add support for A64 mmc controller

From: Hans de Goede
Date: Sat Jul 30 2016 - 06:33:29 EST

Hi,

On 30-07-16 11:36, Icenowy Zheng wrote:
A64 SoC features a MMC controller which need only the mod clock, and can
calibrate delay by itself. This patch adds support for the new MMC
controller IP core.

Signed-off-by: Icenowy Zheng <icenowy@xxxxxxxx>

Cool stuff, thanks for your work on this!

---
drivers/mmc/host/sunxi-mmc.c | 166 +++++++++++++++++++++++++++++++------------
1 file changed, 122 insertions(+), 44 deletions(-)

diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
index 2ee4c21..ac56bcf 100644
--- a/drivers/mmc/host/sunxi-mmc.c
+++ b/drivers/mmc/host/sunxi-mmc.c
@@ -72,6 +72,14 @@
#define SDXC_REG_CHDA (0x90)
#define SDXC_REG_CBDA (0x94)

+/* New registers introduced in A64 */
+#define SDXC_REG_A12A 0x058 /* SMC Auto Command 12 Register */
+#define SDXC_REG_SD_NTSR 0x05C /* SMC New Timing Set Register */
+#define SDXC_REG_DRV_DL 0x140 /* Drive Delay Control Register */
+#define SDXC_REG_SAMP_DL_REG 0x144 /* SMC sample delay control */
+#define SDXC_REG_DS_DL_REG 0x148 /* SMC data strobe delay control */
+
+
#define mmc_readl(host, reg) \
readl((host)->reg_base + SDXC_##reg)
#define mmc_writel(host, reg, value) \
@@ -217,6 +225,15 @@
#define SDXC_CLK_50M_DDR 3
#define SDXC_CLK_50M_DDR_8BIT 4

+#define SDXC_2X_TIMING_MODE BIT(31)
+
+#define SDXC_CAL_START BIT(15)
+#define SDXC_CAL_DONE BIT(14)
+#define SDXC_CAL_DL_SHIFT 8
+#define SDXC_CAL_DL_SW_EN BIT(7)
+#define SDXC_CAL_DL_SW_SHIFT 0
+#define SDXC_CAL_DL_MASK 0x3f
+
struct sunxi_mmc_clk_delay {
u32 output;
u32 sample;
@@ -261,6 +278,9 @@ struct sunxi_mmc_host {

/* vqmmc */
bool vqmmc_enabled;
+
+ /* does the IP block support autocalibration? */
+ bool can_calibrate;
};

static int sunxi_mmc_reset_host(struct sunxi_mmc_host *host)
@@ -653,10 +673,66 @@ static int sunxi_mmc_oclk_onoff(struct sunxi_mmc_host *host, u32 oclk_en)
return 0;
}

+static int sunxi_mmc_calibrate(struct sunxi_mmc_host *host,
+ struct mmc_ios *ios, int reg_off)
+{
+ u32 reg = readl(host->reg_base + reg_off);
+ u32 delay;
+
+ reg &= ~(SDXC_CAL_DL_MASK << SDXC_CAL_DL_SW_SHIFT);
+ reg &= ~SDXC_CAL_DL_SW_EN;
+
+ writel(reg | SDXC_CAL_START, host->reg_base + reg_off);
+
+ dev_dbg(mmc_dev(host->mmc), "calibration started\n");
+
+ while (!((reg = readl(host->reg_base + reg_off)) & SDXC_CAL_DONE))
+ cpu_relax();
+
+ delay = (reg >> SDXC_CAL_DL_SHIFT) & SDXC_CAL_DL_MASK;
+
+ reg &= ~SDXC_CAL_START;
+ reg |= (delay << SDXC_CAL_DL_SW_SHIFT) | SDXC_CAL_DL_SW_EN;
+
+ writel(reg, host->reg_base + reg_off);
+
+ dev_dbg(mmc_dev(host->mmc), "calibration ended, res is 0x%x\n", reg);
+
+ return 0;
+}
+
+static int sunxi_mmc_determine_delays(struct sunxi_mmc_host *host,
+ struct mmc_ios *ios, int rate)
+{
+ int index;
+
+ if (rate <= 400000) {
+ index = SDXC_CLK_400K;
+ } else if (rate <= 25000000) {
+ index = SDXC_CLK_25M;
+ } else if (rate <= 52000000) {
+ if (ios->timing != MMC_TIMING_UHS_DDR50 &&
+ ios->timing != MMC_TIMING_MMC_DDR52) {
+ index = SDXC_CLK_50M;
+ } else if (ios->bus_width == MMC_BUS_WIDTH_8) {
+ index = SDXC_CLK_50M_DDR_8BIT;
+ } else {
+ index = SDXC_CLK_50M_DDR;
+ }
+ } else {
+ return -EINVAL;
+ }
+
+ clk_set_phase(host->clk_sample, host->clk_delays[index].sample);
+ clk_set_phase(host->clk_output, host->clk_delays[index].output);
+
+ return 0;
+}
+

The factoring out of this into a function really should be done in
a separate preparation patch, that will also make the patch making
the actual functional changes much easier to read.

Regards,

Hans



static int sunxi_mmc_clk_set_rate(struct sunxi_mmc_host *host,
struct mmc_ios *ios)
{
- u32 rate, oclk_dly, rval, sclk_dly;
+ u32 rate, rval;
u32 clock = ios->clock;
int ret;

@@ -692,32 +768,18 @@ static int sunxi_mmc_clk_set_rate(struct sunxi_mmc_host *host,
}
mmc_writel(host, REG_CLKCR, rval);

- /* determine delays */
- if (rate <= 400000) {
- oclk_dly = host->clk_delays[SDXC_CLK_400K].output;
- sclk_dly = host->clk_delays[SDXC_CLK_400K].sample;
- } else if (rate <= 25000000) {
- oclk_dly = host->clk_delays[SDXC_CLK_25M].output;
- sclk_dly = host->clk_delays[SDXC_CLK_25M].sample;
- } else if (rate <= 52000000) {
- if (ios->timing != MMC_TIMING_UHS_DDR50 &&
- ios->timing != MMC_TIMING_MMC_DDR52) {
- oclk_dly = host->clk_delays[SDXC_CLK_50M].output;
- sclk_dly = host->clk_delays[SDXC_CLK_50M].sample;
- } else if (ios->bus_width == MMC_BUS_WIDTH_8) {
- oclk_dly = host->clk_delays[SDXC_CLK_50M_DDR_8BIT].output;
- sclk_dly = host->clk_delays[SDXC_CLK_50M_DDR_8BIT].sample;
- } else {
- oclk_dly = host->clk_delays[SDXC_CLK_50M_DDR].output;
- sclk_dly = host->clk_delays[SDXC_CLK_50M_DDR].sample;
- }
+ if (host->can_calibrate) {
+ ret = sunxi_mmc_calibrate(host, ios, SDXC_REG_SAMP_DL_REG);
+ if (ret)
+ return ret;
+
+ /* TODO: enable calibrate on sdc2 SDXC_REG_DS_DL_REG of A64 */
} else {
- return -EINVAL;
+ ret = sunxi_mmc_determine_delays(host, ios, rate);
+ if (ret)
+ return ret;
}

- clk_set_phase(host->clk_sample, sclk_dly);
- clk_set_phase(host->clk_output, oclk_dly);
-
return sunxi_mmc_oclk_onoff(host, 1);
}

@@ -942,6 +1004,7 @@ static const struct of_device_id sunxi_mmc_of_match[] = {
{ .compatible = "allwinner,sun4i-a10-mmc", },
{ .compatible = "allwinner,sun5i-a13-mmc", },
{ .compatible = "allwinner,sun9i-a80-mmc", },
+ { .compatible = "allwinner,sun50i-a64-mmc", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, sunxi_mmc_of_match);
@@ -990,6 +1053,11 @@ static int sunxi_mmc_resource_request(struct sunxi_mmc_host *host,
else
host->clk_delays = sunxi_mmc_clk_delays;

+ if (of_device_is_compatible(np, "allwinner,sun50i-a64-mmc"))
+ host->can_calibrate = true;
+ else
+ host->can_calibrate = false;
+
ret = mmc_regulator_get_supply(host->mmc);
if (ret) {
if (ret != -EPROBE_DEFER)
@@ -1014,16 +1082,22 @@ static int sunxi_mmc_resource_request(struct sunxi_mmc_host *host,
return PTR_ERR(host->clk_mmc);
}

- host->clk_output = devm_clk_get(&pdev->dev, "output");
- if (IS_ERR(host->clk_output)) {
- dev_err(&pdev->dev, "Could not get output clock\n");
- return PTR_ERR(host->clk_output);
- }
+ /* self-calibrate version of the IP block needs no output/sample */
+ if (!host->can_calibrate) {
+ host->clk_output = devm_clk_get(&pdev->dev, "output");
+ if (IS_ERR(host->clk_output)) {
+ dev_err(&pdev->dev, "Could not get output clock\n");
+ return PTR_ERR(host->clk_output);
+ }

- host->clk_sample = devm_clk_get(&pdev->dev, "sample");
- if (IS_ERR(host->clk_sample)) {
- dev_err(&pdev->dev, "Could not get sample clock\n");
- return PTR_ERR(host->clk_sample);
+ host->clk_sample = devm_clk_get(&pdev->dev, "sample");
+ if (IS_ERR(host->clk_sample)) {
+ dev_err(&pdev->dev, "Could not get sample clock\n");
+ return PTR_ERR(host->clk_sample);
+ }
+ } else {
+ host->clk_sample = NULL;
+ host->clk_output = NULL;
}

host->reset = devm_reset_control_get_optional(&pdev->dev, "ahb");
@@ -1042,16 +1116,18 @@ static int sunxi_mmc_resource_request(struct sunxi_mmc_host *host,
goto error_disable_clk_ahb;
}

- ret = clk_prepare_enable(host->clk_output);
- if (ret) {
- dev_err(&pdev->dev, "Enable output clk err %d\n", ret);
- goto error_disable_clk_mmc;
- }
+ if (!host->can_calibrate) {
+ ret = clk_prepare_enable(host->clk_output);
+ if (ret) {
+ dev_err(&pdev->dev, "Enable output clk err %d\n", ret);
+ goto error_disable_clk_mmc;
+ }

- ret = clk_prepare_enable(host->clk_sample);
- if (ret) {
- dev_err(&pdev->dev, "Enable sample clk err %d\n", ret);
- goto error_disable_clk_output;
+ ret = clk_prepare_enable(host->clk_sample);
+ if (ret) {
+ dev_err(&pdev->dev, "Enable sample clk err %d\n", ret);
+ goto error_disable_clk_output;
+ }
}

if (!IS_ERR(host->reset)) {
@@ -1078,9 +1154,11 @@ error_assert_reset:
if (!IS_ERR(host->reset))
reset_control_assert(host->reset);
error_disable_clk_sample:
- clk_disable_unprepare(host->clk_sample);
+ if (!host->can_calibrate)
+ clk_disable_unprepare(host->clk_sample);
error_disable_clk_output:
- clk_disable_unprepare(host->clk_output);
+ if (!host->can_calibrate)
+ clk_disable_unprepare(host->clk_output);
error_disable_clk_mmc:
clk_disable_unprepare(host->clk_mmc);
error_disable_clk_ahb: