[PATCH AUTOSEL 5.19 37/64] mmc: tmio: avoid glitches when resetting

Sasha Levin
2022-08-14T15:31:23Z

From: Wolfram Sang <wsa+renesas@sang-engineering.com>

[ Upstream commit 2e586f8a5b0ed4a525014a692923ac96f6647816 ]

If we reset because of an error, we need to preserve values for the
clock frequency. Otherwise, glitches may be seen on the bus.

To achieve that, we introduce a 'preserve' parameter to the reset
function and the IP core specific reset callbacks to handle everything
accordingly.

Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20220625131722.1397-1-wsa@kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/mmc/host/renesas_sdhi_core.c | 29 ++++++++++++++--------------
drivers/mmc/host/tmio_mmc.c | 2 +-
drivers/mmc/host/tmio_mmc.h | 6 +++++-
drivers/mmc/host/tmio_mmc_core.c | 28 +++++++++++++++++++++------
4 files changed, 42 insertions(+), 23 deletions(-)

diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
index 4404ca1f98d8..5fa365d0c7fd 100644
--- a/drivers/mmc/host/renesas_sdhi_core.c
+++ b/drivers/mmc/host/renesas_sdhi_core.c
@@ -49,9 +49,6 @@
#define HOST_MODE_GEN3_32BIT (HOST_MODE_GEN3_WMODE | HOST_MODE_GEN3_BUSWIDTH)
#define HOST_MODE_GEN3_64BIT 0

-#define CTL_SDIF_MODE 0xe6
-#define SDIF_MODE_HS400 BIT(0)
-
#define SDHI_VER_GEN2_SDR50 0x490c
#define SDHI_VER_RZ_A1 0x820b
/* very old datasheets said 0x490c for SDR104, too. They are wrong! */
@@ -562,23 +559,25 @@ static void renesas_sdhi_scc_reset(struct tmio_mmc_host *host, struct renesas_sd
}

/* only populated for TMIO_MMC_MIN_RCAR2 */
-static void renesas_sdhi_reset(struct tmio_mmc_host *host)
+static void renesas_sdhi_reset(struct tmio_mmc_host *host, bool preserve)
{
struct renesas_sdhi *priv = host_to_priv(host);
int ret;
u16 val;

- 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);
- /* At least SDHI_VER_GEN2_SDR50 needs manual release of reset */
- sd_ctrl_write16(host, CTL_RESET_SD, 0x0001);
- priv->needs_adjust_hs400 = false;
- renesas_sdhi_set_clock(host, host->clk_cache);
- } else if (priv->scc_ctl) {
- renesas_sdhi_scc_reset(host, priv);
+ if (!preserve) {
+ 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);
+ /* At least SDHI_VER_GEN2_SDR50 needs manual release of reset */
+ sd_ctrl_write16(host, CTL_RESET_SD, 0x0001);
+ priv->needs_adjust_hs400 = false;
+ renesas_sdhi_set_clock(host, host->clk_cache);
+ } else if (priv->scc_ctl) {
+ renesas_sdhi_scc_reset(host, priv);
+ }
}

if (sd_ctrl_read16(host, CTL_VERSION) >= SDHI_VER_GEN3_SD) {
diff --git a/drivers/mmc/host/tmio_mmc.c b/drivers/mmc/host/tmio_mmc.c
index b55a29c53d9c..53a2ad9a24b8 100644
--- a/drivers/mmc/host/tmio_mmc.c
+++ b/drivers/mmc/host/tmio_mmc.c
@@ -75,7 +75,7 @@ static void tmio_mmc_set_clock(struct tmio_mmc_host *host,
tmio_mmc_clk_start(host);
}

-static void tmio_mmc_reset(struct tmio_mmc_host *host)
+static void tmio_mmc_reset(struct tmio_mmc_host *host, bool preserve)
{
sd_ctrl_write16(host, CTL_RESET_SDIO, 0x0000);
usleep_range(10000, 11000);
diff --git a/drivers/mmc/host/tmio_mmc.h b/drivers/mmc/host/tmio_mmc.h
index e754bb3f5c32..501613c74406 100644
--- a/drivers/mmc/host/tmio_mmc.h
+++ b/drivers/mmc/host/tmio_mmc.h
@@ -42,6 +42,7 @@
#define CTL_DMA_ENABLE 0xd8
#define CTL_RESET_SD 0xe0
#define CTL_VERSION 0xe2
+#define CTL_SDIF_MODE 0xe6 /* only known on R-Car 2+ */

/* Definitions for values the CTL_STOP_INTERNAL_ACTION register can take */
#define TMIO_STOP_STP BIT(0)
@@ -98,6 +99,9 @@
/* Definitions for values the CTL_DMA_ENABLE register can take */
#define DMA_ENABLE_DMASDRW BIT(1)

+/* Definitions for values the CTL_SDIF_MODE register can take */
+#define SDIF_MODE_HS400 BIT(0) /* only known on R-Car 2+ */
+
/* Define some IRQ masks */
/* This is the mask used at reset by the chip */
#define TMIO_MASK_ALL 0x837f031d
@@ -181,7 +185,7 @@ struct tmio_mmc_host {
int (*multi_io_quirk)(struct mmc_card *card,
unsigned int direction, int blk_size);
int (*write16_hook)(struct tmio_mmc_host *host, int addr);
- void (*reset)(struct tmio_mmc_host *host);
+ void (*reset)(struct tmio_mmc_host *host, bool preserve);
bool (*check_retune)(struct tmio_mmc_host *host, struct mmc_request *mrq);
void (*fixup_request)(struct tmio_mmc_host *host, struct mmc_request *mrq);
unsigned int (*get_timeout_cycles)(struct tmio_mmc_host *host);
diff --git a/drivers/mmc/host/tmio_mmc_core.c b/drivers/mmc/host/tmio_mmc_core.c
index a5850d83908b..437048bb8027 100644
--- a/drivers/mmc/host/tmio_mmc_core.c
+++ b/drivers/mmc/host/tmio_mmc_core.c
@@ -179,8 +179,17 @@ 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_reset(struct tmio_mmc_host *host)
+static void tmio_mmc_reset(struct tmio_mmc_host *host, bool preserve)
{
+ u16 card_opt, clk_ctrl, sdif_mode;
+
+ if (preserve) {
+ card_opt = sd_ctrl_read16(host, CTL_SD_MEM_CARD_OPT);
+ clk_ctrl = sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL);
+ if (host->pdata->flags & TMIO_MMC_MIN_RCAR2)
+ sdif_mode = sd_ctrl_read16(host, CTL_SDIF_MODE);
+ }
+
/* FIXME - should we set stop clock reg here */
sd_ctrl_write16(host, CTL_RESET_SD, 0x0000);
usleep_range(10000, 11000);
@@ -190,7 +199,7 @@ static void tmio_mmc_reset(struct tmio_mmc_host *host)
tmio_mmc_abort_dma(host);

if (host->reset)
- host->reset(host);
+ host->reset(host, preserve);

sd_ctrl_write32_as_16_and_16(host, CTL_IRQ_MASK, host->sdcard_irq_mask_all);
host->sdcard_irq_mask = host->sdcard_irq_mask_all;
@@ -206,6 +215,13 @@ static void tmio_mmc_reset(struct tmio_mmc_host *host)
sd_ctrl_write16(host, CTL_TRANSACTION_CTL, 0x0001);
}

+ if (preserve) {
+ sd_ctrl_write16(host, CTL_SD_MEM_CARD_OPT, card_opt);
+ sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, clk_ctrl);
+ if (host->pdata->flags & TMIO_MMC_MIN_RCAR2)
+ sd_ctrl_write16(host, CTL_SDIF_MODE, sdif_mode);
+ }
+
if (host->mmc->card)
mmc_retune_needed(host->mmc);
}
@@ -248,7 +264,7 @@ static void tmio_mmc_reset_work(struct work_struct *work)

spin_unlock_irqrestore(&host->lock, flags);

- tmio_mmc_reset(host);
+ tmio_mmc_reset(host, true);

/* Ready for new calls */
host->mrq = NULL;
@@ -961,7 +977,7 @@ static void tmio_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
tmio_mmc_power_off(host);
/* For R-Car Gen2+, we need to reset SDHI specific SCC */
if (host->pdata->flags & TMIO_MMC_MIN_RCAR2)
- tmio_mmc_reset(host);
+ tmio_mmc_reset(host, false);

host->set_clock(host, 0);
break;
@@ -1189,7 +1205,7 @@ int tmio_mmc_host_probe(struct tmio_mmc_host *_host)
_host->sdcard_irq_mask_all = TMIO_MASK_ALL;

_host->set_clock(_host, 0);
- tmio_mmc_reset(_host);
+ tmio_mmc_reset(_host, false);

spin_lock_init(&_host->lock);
mutex_init(&_host->ios_lock);
@@ -1285,7 +1301,7 @@ int tmio_mmc_host_runtime_resume(struct device *dev)
struct tmio_mmc_host *host = dev_get_drvdata(dev);

tmio_mmc_clk_enable(host);
- tmio_mmc_reset(host);
+ tmio_mmc_reset(host, false);

if (host->clk_cache)
host->set_clock(host, host->clk_cache);
--
2.35.1