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Commit a4b36d77 authored by Subhash Jadavani's avatar Subhash Jadavani
Browse files

mmc: sdhci-msm: add SDR104 CRC workaround enablement control 



On Certain chipsets, SDR104 mode might be unstable causing CRC error on
the interface. So we need a workaround which would skip printing register
dumps on CRC errors and also downgrade bus speed mode to SDR50/DDR50 in
case of continuous CRC errors. This patch adds "qcom,sdr104-wa" property
to enable this workaround if required.

Change-Id: I626d8ef45a97e8e6558e7f20be496de1f5a2a438
Signed-off-by: default avatarSubhash Jadavani <subhashj@codeaurora.org>
parent 0820ed55

Documentation/devicetree/bindings/mmc/sdhci-msm.txt

+5 −0
Original line number Diff line number Diff line
@@ -75,6 +75,11 @@ Optional Properties: 
						during clock scaling. If this property is not

						defined, then it falls back to the default HS

						bus speed mode to maintain backward compatibility.

	- qcom,sdr104-wa: On Certain chipsets, SDR104 mode might be unstable causing CRC errors

			  on the interface. So there is a workaround implemented to skip printing

			  register dumps on CRC errors and also downgrade bus speed mode to

			  SDR50/DDR50 in case of continuous CRC errors. Set this flag to enable

			  this workaround.



In the following, <supply> can be vdd (flash core voltage) or vdd-io (I/O voltage).

	- qcom,<supply>-always-on - specifies whether supply should be kept "on" always.

drivers/mmc/host/sdhci-msm.c

+3 −0
Original line number Diff line number Diff line
@@ -1960,6 +1960,8 @@ struct sdhci_msm_pltfm_data *sdhci_msm_populate_pdata(struct device *dev, 
	if (of_get_property(np, "qcom,core_3_0v_support", NULL))

		pdata->core_3_0v_support = true;



	pdata->sdr104_wa = of_property_read_bool(np, "qcom,sdr104-wa");



	return pdata;

out:

	return NULL;
@@ -4579,6 +4581,7 @@ static int sdhci_msm_probe(struct platform_device *pdev) 
	if (msm_host->pdata->nonhotplug)

		msm_host->mmc->caps2 |= MMC_CAP2_NONHOTPLUG;



	msm_host->mmc->sdr104_wa = msm_host->pdata->sdr104_wa;



	/* Initialize ICE if present */

	if (msm_host->ice.pdev) {

drivers/mmc/host/sdhci-msm.h

+1 −0
Original line number Diff line number Diff line
@@ -153,6 +153,7 @@ struct sdhci_msm_pltfm_data { 
	u32 ice_clk_min;

	struct sdhci_msm_pm_qos_data pm_qos_data;

	bool core_3_0v_support;

	bool sdr104_wa;

};



struct sdhci_msm_bus_vote {

include/linux/mmc/host.h

+1 −0
Original line number Diff line number Diff line
@@ -595,6 +595,7 @@ struct mmc_host { 
	struct io_latency_state io_lat_s;

#endif



	bool sdr104_wa;

	unsigned long		private[0] ____cacheline_aligned;

};