linux-kernel - [PATCH v3] mmc: sdhci_am654: Disable HS400 for AM62P SR1.0 and SR1.1

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Message-ID: <20250818203310.3066985-1-jm@ti.com>
Date: Mon, 18 Aug 2025 15:33:10 -0500
From: Judith Mendez <jm@...com>
To: Judith Mendez <jm@...com>, Adrian Hunter <adrian.hunter@...el.com>,
        Ulf
 Hansson <ulf.hansson@...aro.org>
CC: <linux-mmc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Andrew Davis
	<afd@...com>
Subject: [PATCH v3] mmc: sdhci_am654: Disable HS400 for AM62P SR1.0 and SR1.1

This adds SDHCI_AM654_QUIRK_DISABLE_HS400 quirk which shall be used
to disable HS400 support. AM62P SR1.0 and SR1.1 do not support HS400
due to errata i2458 [0] so disable HS400 for these SoC revisions.

[0] https://www.ti.com/lit/er/sprz574a/sprz574a.pdf
Signed-off-by: Judith Mendez <jm@...com>
---
This patch was separated from [0] since it will be merged to
different trees anyways.

Link to v2:
[0] https://lore.kernel.org/linux-mmc/20250807225138.1228333-1-jm@ti.com
---
 drivers/mmc/host/sdhci_am654.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/mmc/host/sdhci_am654.c b/drivers/mmc/host/sdhci_am654.c
index 8a099508b939..cc8c4145bf2b 100644
--- a/drivers/mmc/host/sdhci_am654.c
+++ b/drivers/mmc/host/sdhci_am654.c
@@ -155,6 +155,7 @@ struct sdhci_am654_data {
 
 #define SDHCI_AM654_QUIRK_FORCE_CDTEST BIT(0)
 #define SDHCI_AM654_QUIRK_SUPPRESS_V1P8_ENA BIT(1)
+#define SDHCI_AM654_QUIRK_DISABLE_HS400 BIT(2)
 };
 
 struct window {
@@ -764,6 +765,7 @@ static int sdhci_am654_init(struct sdhci_host *host)
 {
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct sdhci_am654_data *sdhci_am654 = sdhci_pltfm_priv(pltfm_host);
+	struct device *dev = mmc_dev(host->mmc);
 	u32 ctl_cfg_2 = 0;
 	u32 mask;
 	u32 val;
@@ -819,6 +821,12 @@ static int sdhci_am654_init(struct sdhci_host *host)
 	if (ret)
 		goto err_cleanup_host;
 
+	if (sdhci_am654->quirks & SDHCI_AM654_QUIRK_DISABLE_HS400 &&
+	    host->mmc->caps2 & (MMC_CAP2_HS400 | MMC_CAP2_HS400_ES)) {
+		dev_info(dev, "Disable descoped HS400 mode for this silicon revision\n");
+		host->mmc->caps2 &= ~(MMC_CAP2_HS400 | MMC_CAP2_HS400_ES);
+	}
+
 	ret = __sdhci_add_host(host);
 	if (ret)
 		goto err_cleanup_host;
@@ -882,6 +890,12 @@ static int sdhci_am654_get_of_property(struct platform_device *pdev,
 	return 0;
 }
 
+static const struct soc_device_attribute sdhci_am654_descope_hs400[] = {
+	{ .family = "AM62PX", .revision = "SR1.0" },
+	{ .family = "AM62PX", .revision = "SR1.1" },
+	{ /* sentinel */ }
+};
+
 static const struct of_device_id sdhci_am654_of_match[] = {
 	{
 		.compatible = "ti,am654-sdhci-5.1",
@@ -969,6 +983,10 @@ static int sdhci_am654_probe(struct platform_device *pdev)
 	if (ret)
 		return dev_err_probe(dev, ret, "parsing dt failed\n");
 
+	soc = soc_device_match(sdhci_am654_descope_hs400);
+	if (soc)
+		sdhci_am654->quirks |= SDHCI_AM654_QUIRK_DISABLE_HS400;
+
 	host->mmc_host_ops.start_signal_voltage_switch = sdhci_am654_start_signal_voltage_switch;
 	host->mmc_host_ops.execute_tuning = sdhci_am654_execute_tuning;
 
-- 
2.49.0