linux-kernel - [PATCH v7 2/2] mmc: add new sdhci reset sequence for brcm 74165b0

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Date: Tue,  2 Jan 2024 11:09:10 -0500
From: Kamal Dasu <kamal.dasu@...adcom.com>
To: ulf.hansson@...aro.org,
	linux-kernel@...r.kernel.org,
	alcooperx@...il.com,
	linux-arm-kernel@...ts.infradead.org,
	adrian.hunter@...el.com,
	linux-mmc@...r.kernel.org,
	robh+dt@...nel.org,
	krzysztof.kozlowski+dt@...aro.org,
	conor+dt@...nel.org,
	devicetree@...r.kernel.org
Cc: f.fainelli@...il.com,
	bcm-kernel-feedback-list@...adcom.com,
	Kamal Dasu <kdasu@...adcom.com>
Subject: [PATCH v7 2/2] mmc: add new sdhci reset sequence for brcm 74165b0

From: Kamal Dasu <kdasu@...adcom.com>

74165b0 shall use a new sdio controller core version which
requires a different reset sequence. For core reset we use
sdhci_reset. For CMD and/or DATA reset added a new function
to also enable SDHCI clocks SDHCI_CLOCK_CARD_EN
SDHCI_CLOCK_INT_EN along with the SDHCI_RESET_CMD and/or
SDHCI_RESET_DATA fields.

Signed-off-by: Kamal Dasu <kdasu@...adcom.com>
---
 drivers/mmc/host/sdhci-brcmstb.c | 69 +++++++++++++++++++++++++++++---
 1 file changed, 64 insertions(+), 5 deletions(-)

diff --git a/drivers/mmc/host/sdhci-brcmstb.c b/drivers/mmc/host/sdhci-brcmstb.c
index c23251bb95f3..9053526fa212 100644
--- a/drivers/mmc/host/sdhci-brcmstb.c
+++ b/drivers/mmc/host/sdhci-brcmstb.c
@@ -6,6 +6,7 @@
  */
 
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/mmc/host.h>
 #include <linux/module.h>
 #include <linux/of.h>
@@ -44,8 +45,13 @@ struct brcmstb_match_priv {
 
 static inline void enable_clock_gating(struct sdhci_host *host)
 {
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_brcmstb_priv *priv = sdhci_pltfm_priv(pltfm_host);
 	u32 reg;
 
+	if (!(priv->flags & BRCMSTB_PRIV_FLAGS_GATE_CLOCK))
+		return;
+
 	reg = sdhci_readl(host, SDHCI_VENDOR);
 	reg |= SDHCI_VENDOR_GATE_SDCLK_EN;
 	sdhci_writel(host, reg, SDHCI_VENDOR);
@@ -53,14 +59,53 @@ static inline void enable_clock_gating(struct sdhci_host *host)
 
 static void brcmstb_reset(struct sdhci_host *host, u8 mask)
 {
-	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
-	struct sdhci_brcmstb_priv *priv = sdhci_pltfm_priv(pltfm_host);
-
 	sdhci_and_cqhci_reset(host, mask);
 
 	/* Reset will clear this, so re-enable it */
-	if (priv->flags & BRCMSTB_PRIV_FLAGS_GATE_CLOCK)
-		enable_clock_gating(host);
+	enable_clock_gating(host);
+}
+
+static void brcmstb_sdhci_reset_cmd_data(struct sdhci_host *host, u8 mask)
+{
+	u32 new_mask = (mask &  (SDHCI_RESET_CMD | SDHCI_RESET_DATA)) << 24;
+	int ret;
+	u32 reg;
+
+	/*
+	 * SDHCI_CLOCK_CONTROL register CARD_EN and CLOCK_INT_EN bits shall
+	 * be set along with SOFTWARE_RESET register RESET_CMD or RESET_DATA
+	 * bits, hence access SDHCI_CLOCK_CONTROL register as 32-bit register
+	 */
+	new_mask |= SDHCI_CLOCK_CARD_EN | SDHCI_CLOCK_INT_EN;
+	reg = sdhci_readl(host, SDHCI_CLOCK_CONTROL);
+	sdhci_writel(host, reg | new_mask, SDHCI_CLOCK_CONTROL);
+
+	reg = sdhci_readb(host, SDHCI_SOFTWARE_RESET);
+
+	ret = read_poll_timeout_atomic(sdhci_readb, reg, !(reg & mask),
+				       10, 10000, false,
+				       host, SDHCI_SOFTWARE_RESET);
+
+	if (ret) {
+		pr_err("%s: Reset 0x%x never completed.\n",
+		       mmc_hostname(host->mmc), (int)mask);
+		sdhci_err_stats_inc(host, CTRL_TIMEOUT);
+		sdhci_dumpregs(host);
+	}
+}
+
+static void brcmstb_reset_74165b0(struct sdhci_host *host, u8 mask)
+{
+	/* take care of RESET_ALL as usual */
+	if (mask & SDHCI_RESET_ALL)
+		sdhci_and_cqhci_reset(host, SDHCI_RESET_ALL);
+
+	/* cmd and/or data treated differently on this core */
+	if (mask & (SDHCI_RESET_CMD | SDHCI_RESET_DATA))
+		brcmstb_sdhci_reset_cmd_data(host, mask);
+
+	/* Reset will clear this, so re-enable it */
+	enable_clock_gating(host);
 }
 
 static void sdhci_brcmstb_hs400es(struct mmc_host *mmc, struct mmc_ios *ios)
@@ -162,6 +207,13 @@ static struct sdhci_ops sdhci_brcmstb_ops_7216 = {
 	.set_uhs_signaling = sdhci_brcmstb_set_uhs_signaling,
 };
 
+static struct sdhci_ops sdhci_brcmstb_ops_74165b0 = {
+	.set_clock = sdhci_brcmstb_set_clock,
+	.set_bus_width = sdhci_set_bus_width,
+	.reset = brcmstb_reset_74165b0,
+	.set_uhs_signaling = sdhci_brcmstb_set_uhs_signaling,
+};
+
 static struct brcmstb_match_priv match_priv_7425 = {
 	.flags = BRCMSTB_MATCH_FLAGS_NO_64BIT |
 	BRCMSTB_MATCH_FLAGS_BROKEN_TIMEOUT,
@@ -179,10 +231,17 @@ static const struct brcmstb_match_priv match_priv_7216 = {
 	.ops = &sdhci_brcmstb_ops_7216,
 };
 
+static struct brcmstb_match_priv match_priv_74165b0 = {
+	.flags = BRCMSTB_MATCH_FLAGS_HAS_CLOCK_GATE,
+	.hs400es = sdhci_brcmstb_hs400es,
+	.ops = &sdhci_brcmstb_ops_74165b0,
+};
+
 static const struct of_device_id __maybe_unused sdhci_brcm_of_match[] = {
 	{ .compatible = "brcm,bcm7425-sdhci", .data = &match_priv_7425 },
 	{ .compatible = "brcm,bcm7445-sdhci", .data = &match_priv_7445 },
 	{ .compatible = "brcm,bcm7216-sdhci", .data = &match_priv_7216 },
+	{ .compatible = "brcm,bcm74165b0-sdhci", .data = &match_priv_74165b0 },
 	{},
 };
 
-- 
2.17.1


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