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mmc: sdhci-cadence: do not use hardware tuning for SD mode

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As commit ef6b75671b ("mmc: sdhci-cadence: send tune request twice to
work around errata") stated, this IP has an errata. This commit applies
the second workaround for the SD mode.

Due to the errata, it is not possible to use the hardware tuning provided
by SDHCI_HOST_CONTROL2.

Use the software-controlled tuning like the eMMC mode.

Set sdhci_host_ops::platform_execute_tuning instead of overriding
mmc_host_ops::execute_tuning.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Link: https://lore.kernel.org/r/20200720061141.172944-1-yamada.masahiro@socionext.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Masahiro Yamada 2020-07-20 15:11:41 +09:00 committed by Ulf Hansson
parent 786d33c887
commit adc40a5179
1 changed files with 74 additions and 73 deletions
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147
drivers/mmc/host/sdhci-cadence.c
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@ -202,6 +202,79 @@ static u32 sdhci_cdns_get_emmc_mode(struct sdhci_cdns_priv *priv)
return FIELD_GET(SDHCI_CDNS_HRS06_MODE, tmp);
}
static int sdhci_cdns_set_tune_val(struct sdhci_host *host, unsigned int val)
{
struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
void __iomem *reg = priv->hrs_addr + SDHCI_CDNS_HRS06;
u32 tmp;
int i, ret;
if (WARN_ON(!FIELD_FIT(SDHCI_CDNS_HRS06_TUNE, val)))
return -EINVAL;
tmp = readl(reg);
tmp &= ~SDHCI_CDNS_HRS06_TUNE;
tmp |= FIELD_PREP(SDHCI_CDNS_HRS06_TUNE, val);
/*
* Workaround for IP errata:
* The IP6116 SD/eMMC PHY design has a timing issue on receive data
* path. Send tune request twice.
*/
for (i = 0; i < 2; i++) {
tmp |= SDHCI_CDNS_HRS06_TUNE_UP;
writel(tmp, reg);
ret = readl_poll_timeout(reg, tmp,
!(tmp & SDHCI_CDNS_HRS06_TUNE_UP),
0, 1);
if (ret)
return ret;
}
return 0;
}
/*
* In SD mode, software must not use the hardware tuning and instead perform
* an almost identical procedure to eMMC.
*/
static int sdhci_cdns_execute_tuning(struct sdhci_host *host, u32 opcode)
{
int cur_streak = 0;
int max_streak = 0;
int end_of_streak = 0;
int i;
/*
* Do not execute tuning for UHS_SDR50 or UHS_DDR50.
* The delay is set by probe, based on the DT properties.
*/
if (host->timing != MMC_TIMING_MMC_HS200 &&
host->timing != MMC_TIMING_UHS_SDR104)
return 0;
for (i = 0; i < SDHCI_CDNS_MAX_TUNING_LOOP; i++) {
if (sdhci_cdns_set_tune_val(host, i) ||
mmc_send_tuning(host->mmc, opcode, NULL)) { /* bad */
cur_streak = 0;
} else { /* good */
cur_streak++;
if (cur_streak > max_streak) {
max_streak = cur_streak;
end_of_streak = i;
}
}
}
if (!max_streak) {
dev_err(mmc_dev(host->mmc), "no tuning point found\n");
return -EIO;
}
return sdhci_cdns_set_tune_val(host, end_of_streak - max_streak / 2);
}
static void sdhci_cdns_set_uhs_signaling(struct sdhci_host *host,
unsigned int timing)
{
@ -241,6 +314,7 @@ static const struct sdhci_ops sdhci_cdns_ops = {
.get_timeout_clock = sdhci_cdns_get_timeout_clock,
.set_bus_width = sdhci_set_bus_width,
.reset = sdhci_reset,
.platform_execute_tuning = sdhci_cdns_execute_tuning,
.set_uhs_signaling = sdhci_cdns_set_uhs_signaling,
};
@ -253,78 +327,6 @@ static const struct sdhci_pltfm_data sdhci_cdns_pltfm_data = {
.ops = &sdhci_cdns_ops,
};
static int sdhci_cdns_set_tune_val(struct sdhci_host *host, unsigned int val)
{
struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
void __iomem *reg = priv->hrs_addr + SDHCI_CDNS_HRS06;
u32 tmp;
int i, ret;
if (WARN_ON(!FIELD_FIT(SDHCI_CDNS_HRS06_TUNE, val)))
return -EINVAL;
tmp = readl(reg);
tmp &= ~SDHCI_CDNS_HRS06_TUNE;
tmp |= FIELD_PREP(SDHCI_CDNS_HRS06_TUNE, val);
/*
* Workaround for IP errata:
* The IP6116 SD/eMMC PHY design has a timing issue on receive data
* path. Send tune request twice.
*/
for (i = 0; i < 2; i++) {
tmp |= SDHCI_CDNS_HRS06_TUNE_UP;
writel(tmp, reg);
ret = readl_poll_timeout(reg, tmp,
!(tmp & SDHCI_CDNS_HRS06_TUNE_UP),
0, 1);
if (ret)
return ret;
}
return 0;
}
static int sdhci_cdns_execute_tuning(struct mmc_host *mmc, u32 opcode)
{
struct sdhci_host *host = mmc_priv(mmc);
int cur_streak = 0;
int max_streak = 0;
int end_of_streak = 0;
int i;
/*
* This handler only implements the eMMC tuning that is specific to
* this controller. Fall back to the standard method for SD timing.
*/
if (host->timing != MMC_TIMING_MMC_HS200)
return sdhci_execute_tuning(mmc, opcode);
if (WARN_ON(opcode != MMC_SEND_TUNING_BLOCK_HS200))
return -EINVAL;
for (i = 0; i < SDHCI_CDNS_MAX_TUNING_LOOP; i++) {
if (sdhci_cdns_set_tune_val(host, i) ||
mmc_send_tuning(host->mmc, opcode, NULL)) { /* bad */
cur_streak = 0;
} else { /* good */
cur_streak++;
if (cur_streak > max_streak) {
max_streak = cur_streak;
end_of_streak = i;
}
}
}
if (!max_streak) {
dev_err(mmc_dev(host->mmc), "no tuning point found\n");
return -EIO;
}
return sdhci_cdns_set_tune_val(host, end_of_streak - max_streak / 2);
}
static void sdhci_cdns_hs400_enhanced_strobe(struct mmc_host *mmc,
struct mmc_ios *ios)
{
@ -385,7 +387,6 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
priv->hrs_addr = host->ioaddr;
priv->enhanced_strobe = false;
host->ioaddr += SDHCI_CDNS_SRS_BASE;
host->mmc_host_ops.execute_tuning = sdhci_cdns_execute_tuning;
host->mmc_host_ops.hs400_enhanced_strobe =
sdhci_cdns_hs400_enhanced_strobe;
sdhci_enable_v4_mode(host);