mmc: tmio: set max_busy_timeout

Set max_busy_timeouts for variants known to support the TOPxx bits in
the SD_OPTION register. The timeout mechanism was running in the
background but not yet properly handled in the driver. So, let the MMC
core know when to not use R1B to avoid unhandled timeouts.

My datasheets for older variants (tmio_mmc.c) suggest that they support
it, too. However, actual bit descriptions are lacking, so I chose an
opt-in approach.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20201125213001.15003-2-wsa+renesas@sang-engineering.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/renesas_sdhi_core.c

@@ -1041,6 +1041,9 @@ int renesas_sdhi_probe(struct platform_device *pdev,
 	/* All SDHI have SDIO status bits which must be 1 */
 	mmc_data->flags |= TMIO_MMC_SDIO_STATUS_SETBITS;
 
+	/* All SDHI support HW busy detection */
+	mmc_data->flags |= TMIO_MMC_USE_BUSY_TIMEOUT;
+
 	dev_pm_domain_start(&pdev->dev);
 
 	ret = renesas_sdhi_clk_enable(host);

drivers/mmc/host/tmio_mmc.h

@@ -80,6 +80,8 @@
 #define	CLK_CTL_SCLKEN		BIT(8)
 
 /* Definitions for values the CTL_SD_MEM_CARD_OPT register can take */
+#define CARD_OPT_TOP_MASK	0xf0
+#define CARD_OPT_TOP_SHIFT	4
 #define CARD_OPT_WIDTH8		BIT(13)
 #define CARD_OPT_WIDTH		BIT(15)
 

drivers/mmc/host/tmio_mmc_core.c

@@ -887,6 +887,18 @@ static void tmio_mmc_set_bus_width(struct tmio_mmc_host *host,
 	sd_ctrl_write16(host, CTL_SD_MEM_CARD_OPT, reg);
 }
 
+static void tmio_mmc_max_busy_timeout(struct tmio_mmc_host *host)
+{
+	u16 val = sd_ctrl_read16(host, CTL_SD_MEM_CARD_OPT);
+	unsigned int clk_rate = host->mmc->actual_clock ?: host->mmc->f_max;
+	unsigned int cycles;
+
+	val = (val & CARD_OPT_TOP_MASK) >> CARD_OPT_TOP_SHIFT;
+	cycles = 1 << (13 + val);
+
+	host->mmc->max_busy_timeout = cycles / (clk_rate / MSEC_PER_SEC);
+}
+
 /* Set MMC clock / power.
  * Note: This controller uses a simple divider scheme therefore it cannot
  * run a MMC card at full speed (20MHz). The max clock is 24MHz on SD, but as
@@ -945,6 +957,9 @@ static void tmio_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 		break;
 	}
 
+	if (host->pdata->flags & TMIO_MMC_USE_BUSY_TIMEOUT)
+		tmio_mmc_max_busy_timeout(host);
+
 	/* Let things settle. delay taken from winCE driver */
 	usleep_range(140, 200);
 	if (PTR_ERR(host->mrq) == -EINTR)

drivers/mmc/host/uniphier-sd.c

@@ -586,6 +586,7 @@ static int uniphier_sd_probe(struct platform_device *pdev)
 
 	tmio_data = &priv->tmio_data;
 	tmio_data->flags |= TMIO_MMC_32BIT_DATA_PORT;
+	tmio_data->flags |= TMIO_MMC_USE_BUSY_TIMEOUT;
 
 	host = tmio_mmc_host_alloc(pdev, tmio_data);
 	if (IS_ERR(host))

include/linux/mfd/tmio.h

@@ -55,7 +55,12 @@
  */
 #define TMIO_MMC_HAS_IDLE_WAIT		BIT(4)
 
-/* BIT(5) is unused */
+/*
+ * Use the busy timeout feature. Probably all TMIO versions support it. Yet,
+ * we don't have documentation for old variants, so we enable only known good
+ * variants with this flag. Can be removed once all variants are known good.
+ */
+#define TMIO_MMC_USE_BUSY_TIMEOUT	BIT(5)
 
 /*
  * Some controllers have CMD12 automatically