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mmc: tmio: avoid glitches when resetting

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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>
This commit is contained in:
Wolfram Sang 2022-06-25 15:17:22 +02:00 committed by Ulf Hansson
parent aabf199c4e
commit 2e586f8a5b
4 changed files with 42 additions and 23 deletions
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29
drivers/mmc/host/renesas_sdhi_core.c
View File

@ -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) {

2
drivers/mmc/host/tmio_mmc.c
View File

@ -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);

6
drivers/mmc/host/tmio_mmc.h
View File

@ -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);

28
drivers/mmc/host/tmio_mmc_core.c
View File

@ -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);