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From:   Victor Shih <victorshihgli@gmail.com>
To:     ulf.hansson@linaro.org, adrian.hunter@intel.com
Cc:     linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
        benchuanggli@gmail.com, HL.Liu@genesyslogic.com.tw,
        Greg.tu@genesyslogic.com.tw, takahiro.akashi@linaro.org,
        dlunev@chromium.org, Victor Shih <victorshihgli@gmail.com>,
        Ben Chuang <ben.chuang@genesyslogic.com.tw>,
        Victor Shih <victor.shih@genesyslogic.com.tw>
Subject: [PATCH V9 10/23] mmc: sdhci-uhs2: add reset function and uhs2_mode function
Date:   Fri, 21 Jul 2023 18:13:36 +0800
Message-Id: <20230721101349.12387-11-victorshihgli@gmail.com>
In-Reply-To: <20230721101349.12387-1-victorshihgli@gmail.com>
References: <20230721101349.12387-1-victorshihgli@gmail.com>
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From: Victor Shih <victor.shih@genesyslogic.com.tw>

Sdhci_uhs2_reset() does a UHS-II specific reset operation.

Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Victor Shih <victor.shih@genesyslogic.com.tw>
---

Updates in V8:
 - Adjust the position of matching brackets.

Updates in V6:
 - Remove unnecessary functions and simplify code.

---

 drivers/mmc/host/sdhci-uhs2.c | 45 +++++++++++++++++++++++++++++++++++
 drivers/mmc/host/sdhci-uhs2.h |  2 ++
 2 files changed, 47 insertions(+)

diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
index e339821d3504..dfc80a7f1bad 100644
--- a/drivers/mmc/host/sdhci-uhs2.c
+++ b/drivers/mmc/host/sdhci-uhs2.c
@@ -10,7 +10,9 @@
  *  Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
  */
 
+#include <linux/delay.h>
 #include <linux/module.h>
+#include <linux/iopoll.h>
 
 #include "sdhci.h"
 #include "sdhci-uhs2.h"
@@ -49,6 +51,49 @@ void sdhci_uhs2_dump_regs(struct sdhci_host *host)
 }
 EXPORT_SYMBOL_GPL(sdhci_uhs2_dump_regs);
 
+/*****************************************************************************\
+ *                                                                           *
+ * Low level functions                                                       *
+ *                                                                           *
+\*****************************************************************************/
+
+bool sdhci_uhs2_mode(struct sdhci_host *host)
+{
+	return host->mmc->flags & MMC_UHS2_SUPPORT;
+}
+
+/**
+ * sdhci_uhs2_reset - invoke SW reset
+ * @host: SDHCI host
+ * @mask: Control mask
+ *
+ * Invoke SW reset, depending on a bit in @mask and wait for completion.
+ */
+void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask)
+{
+	unsigned long timeout;
+	u32 val;
+
+	sdhci_writew(host, mask, SDHCI_UHS2_SW_RESET);
+
+	if (mask & SDHCI_UHS2_SW_RESET_FULL)
+		host->clock = 0;
+
+	/* Wait max 100 ms */
+	timeout = 100000;
+
+	/* hw clears the bit when it's done */
+	if (read_poll_timeout_atomic(sdhci_readw, val, !(val & mask), 10,
+				     timeout, true, host, SDHCI_UHS2_SW_RESET)) {
+		pr_err("%s: %s: Reset 0x%x never completed.\n", __func__,
+		       mmc_hostname(host->mmc), (int)mask);
+		pr_err("%s: clean reset bit\n", mmc_hostname(host->mmc));
+		sdhci_writeb(host, 0, SDHCI_UHS2_SW_RESET);
+		return;
+	}
+}
+EXPORT_SYMBOL_GPL(sdhci_uhs2_reset);
+
 /*****************************************************************************\
  *                                                                           *
  * Driver init/exit                                                          *
diff --git a/drivers/mmc/host/sdhci-uhs2.h b/drivers/mmc/host/sdhci-uhs2.h
index 2bfe18d29bca..8253d50f7852 100644
--- a/drivers/mmc/host/sdhci-uhs2.h
+++ b/drivers/mmc/host/sdhci-uhs2.h
@@ -177,5 +177,7 @@
 struct sdhci_host;
 
 void sdhci_uhs2_dump_regs(struct sdhci_host *host);
+bool sdhci_uhs2_mode(struct sdhci_host *host);
+void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask);
 
 #endif /* __SDHCI_UHS2_H */
-- 
2.25.1