[RFC PATCH v3.1 15/27] mmc: sdhci-uhs2: add set_timeout()

AKASHI Takahiro
2020-11-06T02:29:37Z

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

Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
drivers/mmc/host/sdhci-uhs2.c | 85 +++++++++++++++++++++++++++++++++++
drivers/mmc/host/sdhci-uhs2.h | 1 +
2 files changed, 86 insertions(+)

diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
index 1eca89359351..d9e98c097bfe 100644
--- a/drivers/mmc/host/sdhci-uhs2.c
+++ b/drivers/mmc/host/sdhci-uhs2.c
@@ -178,6 +178,91 @@ void sdhci_uhs2_set_power(struct sdhci_host *host, unsigned char mode,
}
EXPORT_SYMBOL_GPL(sdhci_uhs2_set_power);

+static u8 sdhci_calc_timeout_uhs2(struct sdhci_host *host, u8 *cmd_res,
+ u8 *dead_lock)
+{
+ u8 count;
+ unsigned int cmd_res_timeout, dead_lock_timeout, current_timeout;
+
+ /*
+ * If the host controller provides us with an incorrect timeout
+ * value, just skip the check and use 0xE. The hardware may take
+ * longer to time out, but that's much better than having a too-short
+ * timeout value.
+ */
+ if (host->quirks & SDHCI_QUIRK_BROKEN_TIMEOUT_VAL) {
+ *cmd_res = 0xE;
+ *dead_lock = 0xE;
+ return 0xE;
+ }
+
+ /* timeout in us */
+ cmd_res_timeout = 5 * 1000;
+ dead_lock_timeout = 1 * 1000 * 1000;
+
+ /*
+ * 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 |= dead_lock << SDHCI_UHS2_TIMER_CTRL_DEADLOCK_SHIFT;
+ 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 (host->mmc->flags & MMC_UHS2_SUPPORT)
+ __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 3c19d8e44c36..efe70577bc74 100644
--- a/drivers/mmc/host/sdhci-uhs2.h
+++ b/drivers/mmc/host/sdhci-uhs2.h
@@ -213,5 +213,6 @@ void sdhci_uhs2_dump_regs(struct sdhci_host *host);
void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask);
void sdhci_uhs2_set_power(struct sdhci_host *host, unsigned char mode,
unsigned short vdd);
+void sdhci_uhs2_set_timeout(struct sdhci_host *host, struct mmc_command *cmd);

#endif /* __SDHCI_UHS2_H */
--
2.28.0