mmc: renesas_sdhi: do hard reset if possible

All recent SDHI instances can be reset via the reset controller. If one
is found, use it instead of the open coded reset. This is to get a
future-proof sane reset state.

Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20210317091622.31890-4-wsa+renesas@sang-engineering.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index e911eb5..a4d4c75 100644 (file)
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -708,6 +708,7 @@ config MMC_SDHI
        tristate "Renesas SDHI SD/SDIO controller support"
        depends on SUPERH || ARCH_RENESAS || COMPILE_TEST
        select MMC_TMIO_CORE
+       select RESET_CONTROLLER if ARCH_RENESAS
        help
          This provides support for the SDHI SD/SDIO controller found in
          Renesas SuperH, ARM and ARM64 based SoCs

diff --git a/drivers/mmc/host/renesas_sdhi.h b/drivers/mmc/host/renesas_sdhi.h
index cb962c7..53eded8 100644 (file)
--- a/drivers/mmc/host/renesas_sdhi.h
+++ b/drivers/mmc/host/renesas_sdhi.h
@@ -70,6 +70,8 @@ struct renesas_sdhi {
        DECLARE_BITMAP(smpcmp, BITS_PER_LONG);
        unsigned int tap_num;
        unsigned int tap_set;
+
+       struct reset_control *rstc;
 };
 
 #define host_to_priv(host) \

diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
index db75382..d36181b 100644 (file)
--- a/drivers/mmc/host/renesas_sdhi_core.c
+++ b/drivers/mmc/host/renesas_sdhi_core.c
@@ -20,6 +20,7 @@
 
 #include <linux/clk.h>
 #include <linux/delay.h>
+#include <linux/iopoll.h>
 #include <linux/kernel.h>
 #include <linux/mfd/tmio.h>
 #include <linux/mmc/host.h>
@@ -32,6 +33,7 @@
 #include <linux/platform_device.h>
 #include <linux/pm_domain.h>
 #include <linux/regulator/consumer.h>
+#include <linux/reset.h>
 #include <linux/sh_dma.h>
 #include <linux/slab.h>
 #include <linux/sys_soc.h>
@@ -572,10 +574,19 @@ static void renesas_sdhi_scc_reset(struct tmio_mmc_host *host, struct renesas_sd
 static void renesas_sdhi_reset(struct tmio_mmc_host *host)
 {
        struct renesas_sdhi *priv = host_to_priv(host);
+       int ret;
        u16 val;
 
-       if (priv->scc_ctl)
+       if (priv->rstc) {
+               reset_control_reset(priv->rstc);
+               /* Unknown why but without polling reset status, it will hang */
+               read_poll_timeout(reset_control_status, ret, ret == 0, 1, 100,
+                                 false, priv->rstc);
+               priv->needs_adjust_hs400 = false;
+               renesas_sdhi_set_clock(host, host->clk_cache);
+       } else if (priv->scc_ctl) {
                renesas_sdhi_scc_reset(host, priv);
+       }
 
        sd_ctrl_write32_as_16_and_16(host, CTL_IRQ_MASK, TMIO_MASK_ALL_RCAR2);
 
@@ -1081,6 +1092,10 @@ int renesas_sdhi_probe(struct platform_device *pdev,
        if (ret)
                goto efree;
 
+       priv->rstc = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
+       if (IS_ERR(priv->rstc))
+               return PTR_ERR(priv->rstc);
+
        ver = sd_ctrl_read16(host, CTL_VERSION);
        /* GEN2_SDR104 is first known SDHI to use 32bit block count */
        if (ver < SDHI_VER_GEN2_SDR104 && mmc_data->max_blk_count > U16_MAX)