Re: [PATCH V2 2/2] mmc: sdhci-msm: Re-initialize DLL if MCLK is gated dynamically

Veerabhadrarao Badiganti
2018-11-12T06:57:52Z

Please ignore this patch set. Right patch-set is V5.
https://patchwork.kernel.org/project/linux-mmc/list/?series=41661

Sorry for the inconvenience.

Thanks

Veera

On 11/12/2018 12:08 PM, Veerabhadrarao Badiganti wrote:
> 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>
> ---
> drivers/mmc/host/sdhci-msm.c | 78 +++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 67 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> index 3cc8bfe..4cac593 100644
> --- a/drivers/mmc/host/sdhci-msm.c
> +++ b/drivers/mmc/host/sdhci-msm.c
> @@ -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 @@ static int sdhci_msm_hs400_dll_calibration(struct sdhci_host *host)
> 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 @@ static int sdhci_msm_execute_tuning(struct mmc_host *mmc, u32 opcode)
> 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 @@ static int sdhci_msm_execute_tuning(struct mmc_host *mmc, u32 opcode)
> 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 void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
> };
>
> 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 void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
> .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
>