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mmc: sdhci-omap: Add tuning support

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MMC tuning procedure is required to support SD card
UHS1-SDR104 mode and EMMC HS200 mode.

SDR104/HS200 DLL Tuning Procedure for AM572x platform is mentioned
in Figure 25-51. SDR104/HS200 DLL Tuning Procedure of
AM572x Sitara Processors Silicon Revision 2.0, 1.1 TRM
(SPRUHZ6I - October 2014–Revised April 2017 [1]).

The tuning function sdhci_omap_execute_tuning() will only be
called by the MMC/SD core if the corresponding speed modes
are supported by the OMAP silicon which is set in the mmc
host "caps" field.

[1] -> http://www.ti.com/lit/ug/spruhz6i/spruhz6i.pdf

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Kishon Vijay Abraham I 2018-02-05 18:20:17 +05:30 committed by Ulf Hansson
parent 27ceb7e0b0
commit 9fc2cd7612
1 changed files with 130 additions and 0 deletions
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130
drivers/mmc/host/sdhci-omap.c
View File

@ -37,6 +37,13 @@
#define CON_INIT BIT(1)
#define CON_OD BIT(0)
#define SDHCI_OMAP_DLL 0x0134
#define DLL_SWT BIT(20)
#define DLL_FORCE_SR_C_SHIFT 13
#define DLL_FORCE_SR_C_MASK (0x7f << DLL_FORCE_SR_C_SHIFT)
#define DLL_FORCE_VALUE BIT(12)
#define DLL_CALIB BIT(1)
#define SDHCI_OMAP_CMD 0x20c
#define SDHCI_OMAP_PSTATE 0x0224
@ -63,12 +70,16 @@
#define SDHCI_OMAP_AC12 0x23c
#define AC12_V1V8_SIGEN BIT(19)
#define AC12_SCLK_SEL BIT(23)
#define SDHCI_OMAP_CAPA 0x240
#define CAPA_VS33 BIT(24)
#define CAPA_VS30 BIT(25)
#define CAPA_VS18 BIT(26)
#define SDHCI_OMAP_CAPA2 0x0244
#define CAPA2_TSDR50 BIT(13)
#define SDHCI_OMAP_TIMEOUT 1 /* 1 msec */
#define SYSCTL_CLKD_MAX 0x3FF
@ -77,6 +88,8 @@
#define IOV_3V0 3000000 /* 300000 uV */
#define IOV_3V3 3300000 /* 330000 uV */
#define MAX_PHASE_DELAY 0x7C
struct sdhci_omap_data {
u32 offset;
};
@ -198,6 +211,120 @@ static void sdhci_omap_conf_bus_power(struct sdhci_omap_host *omap_host,
}
}
static inline void sdhci_omap_set_dll(struct sdhci_omap_host *omap_host,
int count)
{
int i;
u32 reg;
reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_DLL);
reg |= DLL_FORCE_VALUE;
reg &= ~DLL_FORCE_SR_C_MASK;
reg |= (count << DLL_FORCE_SR_C_SHIFT);
sdhci_omap_writel(omap_host, SDHCI_OMAP_DLL, reg);
reg |= DLL_CALIB;
sdhci_omap_writel(omap_host, SDHCI_OMAP_DLL, reg);
for (i = 0; i < 1000; i++) {
reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_DLL);
if (reg & DLL_CALIB)
break;
}
reg &= ~DLL_CALIB;
sdhci_omap_writel(omap_host, SDHCI_OMAP_DLL, reg);
}
static void sdhci_omap_disable_tuning(struct sdhci_omap_host *omap_host)
{
u32 reg;
reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_AC12);
reg &= ~AC12_SCLK_SEL;
sdhci_omap_writel(omap_host, SDHCI_OMAP_AC12, reg);
reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_DLL);
reg &= ~(DLL_FORCE_VALUE | DLL_SWT);
sdhci_omap_writel(omap_host, SDHCI_OMAP_DLL, reg);
}
static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode)
{
struct sdhci_host *host = mmc_priv(mmc);
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
struct sdhci_omap_host *omap_host = sdhci_pltfm_priv(pltfm_host);
struct device *dev = omap_host->dev;
struct mmc_ios *ios = &mmc->ios;
u32 start_window = 0, max_window = 0;
u8 cur_match, prev_match = 0;
u32 length = 0, max_len = 0;
u32 phase_delay = 0;
int ret = 0;
u32 reg;
pltfm_host = sdhci_priv(host);
omap_host = sdhci_pltfm_priv(pltfm_host);
dev = omap_host->dev;
/* clock tuning is not needed for upto 52MHz */
if (ios->clock <= 52000000)
return 0;
reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_CAPA2);
if (ios->timing == MMC_TIMING_UHS_SDR50 && !(reg & CAPA2_TSDR50))
return 0;
reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_DLL);
reg |= DLL_SWT;
sdhci_omap_writel(omap_host, SDHCI_OMAP_DLL, reg);
while (phase_delay <= MAX_PHASE_DELAY) {
sdhci_omap_set_dll(omap_host, phase_delay);
cur_match = !mmc_send_tuning(mmc, opcode, NULL);
if (cur_match) {
if (prev_match) {
length++;
} else {
start_window = phase_delay;
length = 1;
}
}
if (length > max_len) {
max_window = start_window;
max_len = length;
}
prev_match = cur_match;
phase_delay += 4;
}
if (!max_len) {
dev_err(dev, "Unable to find match\n");
ret = -EIO;
goto tuning_error;
}
reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_AC12);
if (!(reg & AC12_SCLK_SEL)) {
ret = -EIO;
goto tuning_error;
}
phase_delay = max_window + 4 * (max_len >> 1);
sdhci_omap_set_dll(omap_host, phase_delay);
goto ret;
tuning_error:
dev_err(dev, "Tuning failed\n");
sdhci_omap_disable_tuning(omap_host);
ret:
sdhci_reset(host, SDHCI_RESET_CMD | SDHCI_RESET_DATA);
return ret;
}
static int sdhci_omap_card_busy(struct mmc_host *mmc)
{
u32 reg, ac12;
@ -299,6 +426,8 @@ static int sdhci_omap_start_signal_voltage_switch(struct mmc_host *mmc,
static void sdhci_omap_set_power_mode(struct sdhci_omap_host *omap_host,
u8 power_mode)
{
if (omap_host->bus_mode == MMC_POWER_OFF)
sdhci_omap_disable_tuning(omap_host);
omap_host->power_mode = power_mode;
}
@ -635,6 +764,7 @@ static int sdhci_omap_probe(struct platform_device *pdev)
sdhci_omap_start_signal_voltage_switch;
host->mmc_host_ops.set_ios = sdhci_omap_set_ios;
host->mmc_host_ops.card_busy = sdhci_omap_card_busy;
host->mmc_host_ops.execute_tuning = sdhci_omap_execute_tuning;
sdhci_read_caps(host);
host->caps |= SDHCI_CAN_DO_ADMA2;