[PATCH v1] mmc: sdhci-of-esdhc: add erratum A011334 support

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From: Yangbo Lu <yangbo.lu@xxxxxxx>

There are timing violations in case of few division ratio options
are selected for card clock frequency. prescaler*divisor options
/3,/5,/6,/7,/9,/10,/11,/13,/14 and /15 are not available in LX2
Rev1.0. prescaler*divisor options /4,/8 and /12 only available in
LX2 Rev1.0. Applicable only for HS400 mode. so by add the erratum
A011334 support to limit the prescaler*divisor in LX2 REV1.0

Signed-off-by: Yinbo Zhu <yinbo.zhu@xxxxxxx>
---
 drivers/mmc/host/sdhci-of-esdhc.c |   39 +++++++++++++++++++++++++++++++++++++
 1 files changed, 39 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/host/sdhci-of-esdhc.c b/drivers/mmc/host/sdhci-of-esdhc.c
index 9d5d145..8fdd970 100644
--- a/drivers/mmc/host/sdhci-of-esdhc.c
+++ b/drivers/mmc/host/sdhci-of-esdhc.c
@@ -33,6 +33,7 @@ struct sdhci_esdhc {
 	u8 vendor_ver;
 	u8 spec_ver;
 	bool quirk_incorrect_hostver;
+	bool quirk_limited_clk_division;
 	unsigned int peripheral_clock;
 };
 
@@ -466,6 +467,7 @@ static void esdhc_of_set_clock(struct sdhci_host *host, unsigned int clock)
 	struct sdhci_esdhc *esdhc = sdhci_pltfm_priv(pltfm_host);
 	int pre_div = 1;
 	int div = 1;
+	int division;
 	ktime_t timeout;
 	u32 temp;
 
@@ -519,6 +521,26 @@ static void esdhc_of_set_clock(struct sdhci_host *host, unsigned int clock)
 	while (host->max_clk / pre_div / div > clock && div < 16)
 		div++;
 
+	if (esdhc->quirk_limited_clk_division &&
+	    clock == MMC_HS200_MAX_DTR &&
+	    (host->mmc->ios.timing == MMC_TIMING_MMC_HS400 ||
+	     host->flags & SDHCI_HS400_TUNING)) {
+		division = pre_div * div;
+		if (division <= 4) {
+			pre_div = 4;
+			div = 1;
+		} else if (division <= 8) {
+			pre_div = 4;
+			div = 2;
+		} else if (division <= 12) {
+			pre_div = 4;
+			div = 3;
+		} else {
+			pr_warn("%s: using upsupported clock division.\n",
+				mmc_hostname(host->mmc));
+		}
+	}
+
 	dev_dbg(mmc_dev(host->mmc), "desired SD clock: %d, actual: %d\n",
 		clock, host->max_clk / pre_div / div);
 	host->mmc->actual_clock = host->max_clk / pre_div / div;
@@ -723,6 +745,12 @@ static void esdhc_tuning_block_enable(struct sdhci_host *host, bool enable)
 static int esdhc_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_esdhc *esdhc = sdhci_pltfm_priv(pltfm_host);
+
+	if (esdhc->quirk_limited_clk_division &&
+	    host->flags & SDHCI_HS400_TUNING)
+		esdhc_of_set_clock(host, host->clock);
 
 	esdhc_tuning_block_enable(host, true);
 	return sdhci_execute_tuning(mmc, opcode);
@@ -858,6 +886,11 @@ static SIMPLE_DEV_PM_OPS(esdhc_of_dev_pm_ops,
 	{ },
 };
 
+static struct soc_device_attribute soc_fixup_sdhc_clkdivs[] = {
+	{ .family = "QorIQ LX2160A", .revision = "1.0", },
+	{ },
+};
+
 static void esdhc_init(struct platform_device *pdev, struct sdhci_host *host)
 {
 	struct sdhci_pltfm_host *pltfm_host;
@@ -879,6 +912,11 @@ static void esdhc_init(struct platform_device *pdev, struct sdhci_host *host)
 	else
 		esdhc->quirk_incorrect_hostver = false;
 
+	if (soc_device_match(soc_fixup_sdhc_clkdivs))
+		esdhc->quirk_limited_clk_division = true;
+	else
+		esdhc->quirk_limited_clk_division = false;
+
 	np = pdev->dev.of_node;
 	clk = of_clk_get(np, 0);
 	if (!IS_ERR(clk)) {
@@ -937,6 +975,7 @@ static int sdhci_esdhc_probe(struct platform_device *pdev)
 
 	pltfm_host = sdhci_priv(host);
 	esdhc = sdhci_pltfm_priv(pltfm_host);
+
 	if (esdhc->vendor_ver == VENDOR_V_22)
 		host->quirks2 |= SDHCI_QUIRK2_HOST_NO_CMD23;
 
-- 
1.7.1




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