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mmc: sdhci-esdhc-imx: add sd3.0 SDR clock tuning support
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Freescale i.MX6Q/DL uSDHC clock tuning progress is a little different from
the standard tuning process defined in host controller spec v3.0.
Thus we use platform_execute_tuning instead of standard sdhci tuning.

The main difference are:
1) not only generate Buffer Read Ready interrupt when tuning is performing.
   It generates all other DATA interrupts like the normal data command.
2) SDHCI_CTRL_EXEC_TUNING is not automatically cleared by HW,
   instead it's controlled by SW.
3) SDHCI_CTRL_TUNED_CLK is not automatically set by HW,
   it's controlled by SW.
4) the clock delay for every tuning is set by SW.

Signed-off-by: Dong Aisheng <b29396@freescale.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
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Dong Aisheng authored and Chris Ball committed Sep 26, 2013
1 parent fed2f6e commit 0322191
Showing 1 changed file with 195 additions and 1 deletion.
196 changes: 195 additions & 1 deletion drivers/mmc/host/sdhci-esdhc-imx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -34,13 +34,25 @@
/* VENDOR SPEC register */
#define ESDHC_VENDOR_SPEC 0xc0
#define ESDHC_VENDOR_SPEC_SDIO_QUIRK (1 << 1)
#define ESDHC_VENDOR_SPEC_VSELECT (1 << 1)
#define ESDHC_VENDOR_SPEC_FRC_SDCLK_ON (1 << 8)
#define ESDHC_WTMK_LVL 0x44
#define ESDHC_MIX_CTRL 0x48
#define ESDHC_MIX_CTRL_AC23EN (1 << 7)
#define ESDHC_MIX_CTRL_EXE_TUNE (1 << 22)
#define ESDHC_MIX_CTRL_SMPCLK_SEL (1 << 23)
#define ESDHC_MIX_CTRL_FBCLK_SEL (1 << 25)
/* Bits 3 and 6 are not SDHCI standard definitions */
#define ESDHC_MIX_CTRL_SDHCI_MASK 0xb7

/* tune control register */
#define ESDHC_TUNE_CTRL_STATUS 0x68
#define ESDHC_TUNE_CTRL_STEP 1
#define ESDHC_TUNE_CTRL_MIN 0
#define ESDHC_TUNE_CTRL_MAX ((1 << 7) - 1)

#define ESDHC_TUNING_BLOCK_PATTERN_LEN 64

/*
* Our interpretation of the SDHCI_HOST_CONTROL register
*/
Expand Down Expand Up @@ -91,7 +103,7 @@ struct pltfm_imx_data {
MULTIBLK_IN_PROCESS, /* exact multiblock cmd in process */
WAIT_FOR_INT, /* sent CMD12, waiting for response INT */
} multiblock_status;

u32 uhs_mode;
};

static struct platform_device_id imx_esdhc_devtype[] = {
Expand Down Expand Up @@ -165,6 +177,16 @@ static u32 esdhc_readl_le(struct sdhci_host *host, int reg)
struct pltfm_imx_data *imx_data = pltfm_host->priv;
u32 val = readl(host->ioaddr + reg);

if (unlikely(reg == SDHCI_PRESENT_STATE)) {
u32 fsl_prss = val;
/* save the least 20 bits */
val = fsl_prss & 0x000FFFFF;
/* move dat[0-3] bits */
val |= (fsl_prss & 0x0F000000) >> 4;
/* move cmd line bit */
val |= (fsl_prss & 0x00800000) << 1;
}

if (unlikely(reg == SDHCI_CAPABILITIES)) {
/* In FSL esdhc IC module, only bit20 is used to indicate the
* ADMA2 capability of esdhc, but this bit is messed up on
Expand All @@ -179,6 +201,17 @@ static u32 esdhc_readl_le(struct sdhci_host *host, int reg)
}
}

if (unlikely(reg == SDHCI_CAPABILITIES_1) && is_imx6q_usdhc(imx_data))
val = SDHCI_SUPPORT_DDR50 | SDHCI_SUPPORT_SDR104
| SDHCI_SUPPORT_SDR50;

if (unlikely(reg == SDHCI_MAX_CURRENT) && is_imx6q_usdhc(imx_data)) {
val = 0;
val |= 0xFF << SDHCI_MAX_CURRENT_330_SHIFT;
val |= 0xFF << SDHCI_MAX_CURRENT_300_SHIFT;
val |= 0xFF << SDHCI_MAX_CURRENT_180_SHIFT;
}

if (unlikely(reg == SDHCI_INT_STATUS)) {
if (val & ESDHC_INT_VENDOR_SPEC_DMA_ERR) {
val &= ~ESDHC_INT_VENDOR_SPEC_DMA_ERR;
Expand Down Expand Up @@ -257,6 +290,8 @@ static u16 esdhc_readw_le(struct sdhci_host *host, int reg)
{
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
struct pltfm_imx_data *imx_data = pltfm_host->priv;
u16 ret = 0;
u32 val;

if (unlikely(reg == SDHCI_HOST_VERSION)) {
reg ^= 2;
Expand All @@ -269,15 +304,58 @@ static u16 esdhc_readw_le(struct sdhci_host *host, int reg)
}
}

if (unlikely(reg == SDHCI_HOST_CONTROL2)) {
val = readl(host->ioaddr + ESDHC_VENDOR_SPEC);
if (val & ESDHC_VENDOR_SPEC_VSELECT)
ret |= SDHCI_CTRL_VDD_180;

if (is_imx6q_usdhc(imx_data)) {
val = readl(host->ioaddr + ESDHC_MIX_CTRL);
if (val & ESDHC_MIX_CTRL_EXE_TUNE)
ret |= SDHCI_CTRL_EXEC_TUNING;
if (val & ESDHC_MIX_CTRL_SMPCLK_SEL)
ret |= SDHCI_CTRL_TUNED_CLK;
}

ret |= (imx_data->uhs_mode & SDHCI_CTRL_UHS_MASK);
ret &= ~SDHCI_CTRL_PRESET_VAL_ENABLE;

return ret;
}

return readw(host->ioaddr + reg);
}

static void esdhc_writew_le(struct sdhci_host *host, u16 val, int reg)
{
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
struct pltfm_imx_data *imx_data = pltfm_host->priv;
u32 new_val = 0;

switch (reg) {
case SDHCI_CLOCK_CONTROL:
new_val = readl(host->ioaddr + ESDHC_VENDOR_SPEC);
if (val & SDHCI_CLOCK_CARD_EN)
new_val |= ESDHC_VENDOR_SPEC_FRC_SDCLK_ON;
else
new_val &= ~ESDHC_VENDOR_SPEC_FRC_SDCLK_ON;
writel(new_val, host->ioaddr + ESDHC_VENDOR_SPEC);
return;
case SDHCI_HOST_CONTROL2:
new_val = readl(host->ioaddr + ESDHC_VENDOR_SPEC);
if (val & SDHCI_CTRL_VDD_180)
new_val |= ESDHC_VENDOR_SPEC_VSELECT;
else
new_val &= ~ESDHC_VENDOR_SPEC_VSELECT;
writel(new_val, host->ioaddr + ESDHC_VENDOR_SPEC);
imx_data->uhs_mode = val & SDHCI_CTRL_UHS_MASK;
new_val = readl(host->ioaddr + ESDHC_MIX_CTRL);
if (val & SDHCI_CTRL_TUNED_CLK)
new_val |= ESDHC_MIX_CTRL_SMPCLK_SEL;
else
new_val &= ~ESDHC_MIX_CTRL_SMPCLK_SEL;
writel(new_val , host->ioaddr + ESDHC_MIX_CTRL);
return;
case SDHCI_TRANSFER_MODE:
if ((imx_data->flags & ESDHC_FLAG_MULTIBLK_NO_INT)
&& (host->cmd->opcode == SD_IO_RW_EXTENDED)
Expand Down Expand Up @@ -500,6 +578,121 @@ static int esdhc_pltfm_bus_width(struct sdhci_host *host, int width)
return 0;
}

static void esdhc_prepare_tuning(struct sdhci_host *host, u32 val)
{
u32 reg;

/* FIXME: delay a bit for card to be ready for next tuning due to errors */
mdelay(1);

reg = readl(host->ioaddr + ESDHC_MIX_CTRL);
reg |= ESDHC_MIX_CTRL_EXE_TUNE | ESDHC_MIX_CTRL_SMPCLK_SEL |
ESDHC_MIX_CTRL_FBCLK_SEL;
writel(reg, host->ioaddr + ESDHC_MIX_CTRL);
writel(val << 8, host->ioaddr + ESDHC_TUNE_CTRL_STATUS);
dev_dbg(mmc_dev(host->mmc),
"tunning with delay 0x%x ESDHC_TUNE_CTRL_STATUS 0x%x\n",
val, readl(host->ioaddr + ESDHC_TUNE_CTRL_STATUS));
}

static void esdhc_request_done(struct mmc_request *mrq)
{
complete(&mrq->completion);
}

static int esdhc_send_tuning_cmd(struct sdhci_host *host, u32 opcode)
{
struct mmc_command cmd = {0};
struct mmc_request mrq = {0};
struct mmc_data data = {0};
struct scatterlist sg;
char tuning_pattern[ESDHC_TUNING_BLOCK_PATTERN_LEN];

cmd.opcode = opcode;
cmd.arg = 0;
cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;

data.blksz = ESDHC_TUNING_BLOCK_PATTERN_LEN;
data.blocks = 1;
data.flags = MMC_DATA_READ;
data.sg = &sg;
data.sg_len = 1;

sg_init_one(&sg, tuning_pattern, sizeof(tuning_pattern));

mrq.cmd = &cmd;
mrq.cmd->mrq = &mrq;
mrq.data = &data;
mrq.data->mrq = &mrq;
mrq.cmd->data = mrq.data;

mrq.done = esdhc_request_done;
init_completion(&(mrq.completion));

disable_irq(host->irq);
spin_lock(&host->lock);
host->mrq = &mrq;

sdhci_send_command(host, mrq.cmd);

spin_unlock(&host->lock);
enable_irq(host->irq);

wait_for_completion(&mrq.completion);

if (cmd.error)
return cmd.error;
if (data.error)
return data.error;

return 0;
}

static void esdhc_post_tuning(struct sdhci_host *host)
{
u32 reg;

reg = readl(host->ioaddr + ESDHC_MIX_CTRL);
reg &= ~ESDHC_MIX_CTRL_EXE_TUNE;
writel(reg, host->ioaddr + ESDHC_MIX_CTRL);
}

static int esdhc_executing_tuning(struct sdhci_host *host, u32 opcode)
{
int min, max, avg, ret;

/* find the mininum delay first which can pass tuning */
min = ESDHC_TUNE_CTRL_MIN;
while (min < ESDHC_TUNE_CTRL_MAX) {
esdhc_prepare_tuning(host, min);
if (!esdhc_send_tuning_cmd(host, opcode))
break;
min += ESDHC_TUNE_CTRL_STEP;
}

/* find the maxinum delay which can not pass tuning */
max = min + ESDHC_TUNE_CTRL_STEP;
while (max < ESDHC_TUNE_CTRL_MAX) {
esdhc_prepare_tuning(host, max);
if (esdhc_send_tuning_cmd(host, opcode)) {
max -= ESDHC_TUNE_CTRL_STEP;
break;
}
max += ESDHC_TUNE_CTRL_STEP;
}

/* use average delay to get the best timing */
avg = (min + max) / 2;
esdhc_prepare_tuning(host, avg);
ret = esdhc_send_tuning_cmd(host, opcode);
esdhc_post_tuning(host);

dev_dbg(mmc_dev(host->mmc), "tunning %s at 0x%x ret %d\n",
ret ? "failed" : "passed", avg, ret);

return ret;
}

static const struct sdhci_ops sdhci_esdhc_ops = {
.read_l = esdhc_readl_le,
.read_w = esdhc_readw_le,
Expand All @@ -511,6 +704,7 @@ static const struct sdhci_ops sdhci_esdhc_ops = {
.get_min_clock = esdhc_pltfm_get_min_clock,
.get_ro = esdhc_pltfm_get_ro,
.platform_bus_width = esdhc_pltfm_bus_width,
.platform_execute_tuning = esdhc_executing_tuning,
};

static const struct sdhci_pltfm_data sdhci_esdhc_imx_pdata = {
Expand Down

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