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mmc: sdhci-msm: Re-initialize DLL if MCLK is gated dynamically

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On few SDHCI-MSM controllers, the host controller's clock tuning
circuit may go out of sync if controller clocks are gated which
eventually will result in data CRC, command CRC/timeout errors.
To overcome this h/w limitation, the DLL needs to be re-initialized
and restored with its old settings once clocks are ungated.

Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
Reviewed-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Veerabhadrarao Badiganti 2018-11-12 12:22:17 +05:30 committed by Ulf Hansson
parent 247cb8b7a7
commit 21f1e2d457
1 changed files with 67 additions and 11 deletions
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78
drivers/mmc/host/sdhci-msm.c
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@ -232,6 +232,7 @@ struct sdhci_msm_variant_ops {
*/
struct sdhci_msm_variant_info {
bool mci_removed;
bool restore_dll_config;
const struct sdhci_msm_variant_ops *var_ops;
const struct sdhci_msm_offset *offset;
};
@ -256,6 +257,7 @@ struct sdhci_msm_host {
bool pwr_irq_flag;
u32 caps_0;
bool mci_removed;
bool restore_dll_config;
const struct sdhci_msm_variant_ops *var_ops;
const struct sdhci_msm_offset *offset;
};
@ -1025,6 +1027,48 @@ out:
return ret;
}
static bool sdhci_msm_is_tuning_needed(struct sdhci_host *host)
{
struct mmc_ios *ios = &host->mmc->ios;
/*
* Tuning is required for SDR104, HS200 and HS400 cards and
* if clock frequency is greater than 100MHz in these modes.
*/
if (host->clock <= CORE_FREQ_100MHZ ||
!(ios->timing == MMC_TIMING_MMC_HS400 ||
ios->timing == MMC_TIMING_MMC_HS200 ||
ios->timing == MMC_TIMING_UHS_SDR104) ||
ios->enhanced_strobe)
return false;
return true;
}
static int sdhci_msm_restore_sdr_dll_config(struct sdhci_host *host)
{
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
int ret;
/*
* SDR DLL comes into picture only for timing modes which needs
* tuning.
*/
if (!sdhci_msm_is_tuning_needed(host))
return 0;
/* Reset the tuning block */
ret = msm_init_cm_dll(host);
if (ret)
return ret;
/* Restore the tuning block */
ret = msm_config_cm_dll_phase(host, msm_host->saved_tuning_phase);
return ret;
}
static int sdhci_msm_execute_tuning(struct mmc_host *mmc, u32 opcode)
{
struct sdhci_host *host = mmc_priv(mmc);
@ -1035,14 +1079,7 @@ static int sdhci_msm_execute_tuning(struct mmc_host *mmc, u32 opcode)
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
/*
* Tuning is required for SDR104, HS200 and HS400 cards and
* if clock frequency is greater than 100MHz in these modes.
*/
if (host->clock <= CORE_FREQ_100MHZ ||
!(ios.timing == MMC_TIMING_MMC_HS400 ||
ios.timing == MMC_TIMING_MMC_HS200 ||
ios.timing == MMC_TIMING_UHS_SDR104))
if (!sdhci_msm_is_tuning_needed(host))
return 0;
/*
@ -1069,7 +1106,6 @@ retry:
if (rc)
return rc;
msm_host->saved_tuning_phase = phase;
rc = mmc_send_tuning(mmc, opcode, NULL);
if (!rc) {
/* Tuning is successful at this tuning point */
@ -1094,6 +1130,7 @@ retry:
rc = msm_config_cm_dll_phase(host, phase);
if (rc)
return rc;
msm_host->saved_tuning_phase = phase;
dev_dbg(mmc_dev(mmc), "%s: Setting the tuning phase to %d\n",
mmc_hostname(mmc), phase);
} else {
@ -1616,7 +1653,6 @@ static const struct sdhci_msm_variant_ops v5_var_ops = {
};
static const struct sdhci_msm_variant_info sdhci_msm_mci_var = {
.mci_removed = false,
.var_ops = &mci_var_ops,
.offset = &sdhci_msm_mci_offset,
};
@ -1627,9 +1663,17 @@ static const struct sdhci_msm_variant_info sdhci_msm_v5_var = {
.offset = &sdhci_msm_v5_offset,
};
static const struct sdhci_msm_variant_info sdm845_sdhci_var = {
.mci_removed = true,
.restore_dll_config = true,
.var_ops = &v5_var_ops,
.offset = &sdhci_msm_v5_offset,
};
static const struct of_device_id sdhci_msm_dt_match[] = {
{.compatible = "qcom,sdhci-msm-v4", .data = &sdhci_msm_mci_var},
{.compatible = "qcom,sdhci-msm-v5", .data = &sdhci_msm_v5_var},
{.compatible = "qcom,sdm845-sdhci", .data = &sdm845_sdhci_var},
{},
};
@ -1689,6 +1733,7 @@ static int sdhci_msm_probe(struct platform_device *pdev)
var_info = of_device_get_match_data(&pdev->dev);
msm_host->mci_removed = var_info->mci_removed;
msm_host->restore_dll_config = var_info->restore_dll_config;
msm_host->var_ops = var_info->var_ops;
msm_host->offset = var_info->offset;
@ -1928,9 +1973,20 @@ static int sdhci_msm_runtime_resume(struct device *dev)
struct sdhci_host *host = dev_get_drvdata(dev);
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
int ret;
return clk_bulk_prepare_enable(ARRAY_SIZE(msm_host->bulk_clks),
ret = clk_bulk_prepare_enable(ARRAY_SIZE(msm_host->bulk_clks),
msm_host->bulk_clks);
if (ret)
return ret;
/*
* Whenever core-clock is gated dynamically, it's needed to
* restore the SDR DLL settings when the clock is ungated.
*/
if (msm_host->restore_dll_config && msm_host->clk_rate)
return sdhci_msm_restore_sdr_dll_config(host);
return 0;
}
#endif