[PATCH RFT v2 1/3] mmc: tmio: set max_busy_timeout

Wolfram Sang
2020-11-20T15:07:05Z

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>
---

Change since v1:
* fix wrong multiplication to correct division due to a bad merge
conflict resolution

drivers/mmc/host/renesas_sdhi_core.c | 3 +++
drivers/mmc/host/tmio_mmc.h | 2 ++
drivers/mmc/host/tmio_mmc_core.c | 15 +++++++++++++++
drivers/mmc/host/uniphier-sd.c | 1 +
include/linux/mfd/tmio.h | 7 ++++++-
5 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
index bb937411c2ec..153767054c05 100644
--- a/drivers/mmc/host/renesas_sdhi_core.c
+++ b/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);
diff --git a/drivers/mmc/host/tmio_mmc.h b/drivers/mmc/host/tmio_mmc.h
index 7ff41185896a..819198af17f4 100644
--- a/drivers/mmc/host/tmio_mmc.h
+++ b/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)

diff --git a/drivers/mmc/host/tmio_mmc_core.c b/drivers/mmc/host/tmio_mmc_core.c
index 7f4a28125010..4727fcfdf95f 100644
--- a/drivers/mmc/host/tmio_mmc_core.c
+++ b/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)
diff --git a/drivers/mmc/host/uniphier-sd.c b/drivers/mmc/host/uniphier-sd.c
index 3092466a99ab..a6cd16771d4e 100644
--- a/drivers/mmc/host/uniphier-sd.c
+++ b/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))
diff --git a/include/linux/mfd/tmio.h b/include/linux/mfd/tmio.h
index 8ba042430d8e..27264fe4b3b9 100644
--- a/include/linux/mfd/tmio.h
+++ b/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
--
2.28.0