[PATCH V10 13/23] mmc: sdhci-uhs2: add set_timeout()

[Victor Shih]

From: Victor Shih <victor.shih@xxxxxxxxxxxxxxxxxxx>

This is a UHS-II version of sdhci's set_timeout() operation.

Signed-off-by: Ben Chuang <ben.chuang@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
Signed-off-by: Victor Shih <victor.shih@xxxxxxxxxxxxxxxxxxx>
Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---

Updates in V8:
 - Initialization be combined with declaration and realigned
   in sdhci_calc_timeout_uhs2().
 - Forward declare struct mmc_command in sdhci_uhs2.h.

Updates in V6:
 - Use GENMASK() and FIELD_PREP() in some case.
 - Use sdhci_uhs2_mode() to simplify code.
 - Remove unnecessary functions.

---

 drivers/mmc/host/sdhci-uhs2.c | 72 +++++++++++++++++++++++++++++++++++
 drivers/mmc/host/sdhci-uhs2.h |  2 +
 2 files changed, 74 insertions(+)

diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
index 92fb69b7e209..d519e6ce6199 100644
--- a/drivers/mmc/host/sdhci-uhs2.c
+++ b/drivers/mmc/host/sdhci-uhs2.c
@@ -13,6 +13,7 @@
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/iopoll.h>
+#include <linux/bitfield.h>
 
 #include "sdhci.h"
 #include "sdhci-uhs2.h"
@@ -142,6 +143,77 @@ static void sdhci_uhs2_set_power(struct sdhci_host *host, unsigned char mode, un
 	}
 }
 
+static u8 sdhci_calc_timeout_uhs2(struct sdhci_host *host, u8 *cmd_res, u8 *dead_lock)
+{
+	/* timeout in us */
+	unsigned int dead_lock_timeout = 1 * 1000 * 1000;
+	unsigned int cmd_res_timeout = 5 * 1000;
+	unsigned int current_timeout;
+	u8 count;
+
+	/*
+	 * Figure out needed cycles.
+	 * We do this in steps in order to fit inside a 32 bit int.
+	 * The first step is the minimum timeout, which will have a
+	 * minimum resolution of 6 bits:
+	 * (1) 2^13*1000 > 2^22,
+	 * (2) host->timeout_clk < 2^16
+	 *     =>
+	 *     (1) / (2) > 2^6
+	 */
+	count = 0;
+	current_timeout = (1 << 13) * 1000 / host->timeout_clk;
+	while (current_timeout < cmd_res_timeout) {
+		count++;
+		current_timeout <<= 1;
+		if (count >= 0xF)
+			break;
+	}
+
+	if (count >= 0xF) {
+		DBG("%s: Too large timeout 0x%x requested for CMD_RES!\n",
+		    mmc_hostname(host->mmc), count);
+		count = 0xE;
+	}
+	*cmd_res = count;
+
+	count = 0;
+	current_timeout = (1 << 13) * 1000 / host->timeout_clk;
+	while (current_timeout < dead_lock_timeout) {
+		count++;
+		current_timeout <<= 1;
+		if (count >= 0xF)
+			break;
+	}
+
+	if (count >= 0xF) {
+		DBG("%s: Too large timeout 0x%x requested for DEADLOCK!\n",
+		    mmc_hostname(host->mmc), count);
+		count = 0xE;
+	}
+	*dead_lock = count;
+
+	return count;
+}
+
+static void __sdhci_uhs2_set_timeout(struct sdhci_host *host)
+{
+	u8 cmd_res, dead_lock;
+
+	sdhci_calc_timeout_uhs2(host, &cmd_res, &dead_lock);
+	cmd_res |= FIELD_PREP(SDHCI_UHS2_TIMER_CTRL_DEADLOCK_MASK, dead_lock);
+	sdhci_writeb(host, cmd_res, SDHCI_UHS2_TIMER_CTRL);
+}
+
+void sdhci_uhs2_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
+{
+	__sdhci_set_timeout(host, cmd);
+
+	if (sdhci_uhs2_mode(host))
+		__sdhci_uhs2_set_timeout(host);
+}
+EXPORT_SYMBOL_GPL(sdhci_uhs2_set_timeout);
+
 /*****************************************************************************\
  *                                                                           *
  * MMC callbacks                                                             *
diff --git a/drivers/mmc/host/sdhci-uhs2.h b/drivers/mmc/host/sdhci-uhs2.h
index 8253d50f7852..ccf4e1834c2d 100644
--- a/drivers/mmc/host/sdhci-uhs2.h
+++ b/drivers/mmc/host/sdhci-uhs2.h
@@ -175,9 +175,11 @@
 #define SDHCI_UHS2_VENDOR_PTR			0xE8
 
 struct sdhci_host;
+struct mmc_command;
 
 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);
+void sdhci_uhs2_set_timeout(struct sdhci_host *host, struct mmc_command *cmd);
 
 #endif /* __SDHCI_UHS2_H */
-- 
2.25.1