[PATCH] mmc: dw_mmc: change to use recommended reset procedure

Sonny Rao
2014-08-05T01:19:56Z

This patch changes the fifo reset code to follow the reset procedure
outlined in the documentation of Synopsys Mobile storage host databook.

Signed-off-by: Sonny Rao <sonnyrao@chromium.org>
Signed-off-by: Yuvaraj Kumar C D <yuvaraj.cd@samsung.com>
Acked-by: Seungwon Jeon <tgih.jun@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[sonnyrao: fix compile for !CONFIG_MMC_DW_IDMAC case]
---
drivers/mmc/host/dw_mmc.c | 87 ++++++++++++++++++++++++++++++++++-------------
drivers/mmc/host/dw_mmc.h | 5 +++
2 files changed, 69 insertions(+), 23 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 1ac227c..39cf54f 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -111,8 +111,7 @@ static const u8 tuning_blk_pattern_8bit[] = {
0xff, 0x77, 0x77, 0xff, 0x77, 0xbb, 0xdd, 0xee,
};

-static inline bool dw_mci_fifo_reset(struct dw_mci *host);
-static inline bool dw_mci_ctrl_all_reset(struct dw_mci *host);
+static bool dw_mci_reset(struct dw_mci *host);

#if defined(CONFIG_DEBUG_FS)
static int dw_mci_req_show(struct seq_file *s, void *v)
@@ -1235,7 +1234,7 @@ static int dw_mci_data_complete(struct dw_mci *host, struct mmc_data *data)
* After an error, there may be data lingering
* in the FIFO
*/
- dw_mci_fifo_reset(host);
+ dw_mci_reset(host);
} else {
data->bytes_xfered = data->blocks * data->blksz;
data->error = 0;
@@ -1352,7 +1351,7 @@ static void dw_mci_tasklet_func(unsigned long priv)

/* CMD error in data command */
if (mrq->cmd->error && mrq->data)
- dw_mci_fifo_reset(host);
+ dw_mci_reset(host);

host->cmd = NULL;
host->data = NULL;
@@ -1963,14 +1962,8 @@ static void dw_mci_work_routine_card(struct work_struct *work)
}

/* Power down slot */
- if (present == 0) {
- /* Clear down the FIFO */
- dw_mci_fifo_reset(host);
-#ifdef CONFIG_MMC_DW_IDMAC
- dw_mci_idmac_reset(host);
-#endif
-
- }
+ if (present == 0)
+ dw_mci_reset(host);

spin_unlock_bh(&host->lock);

@@ -2208,8 +2201,11 @@ static bool dw_mci_ctrl_reset(struct dw_mci *host, u32 reset)
return false;
}

-static inline bool dw_mci_fifo_reset(struct dw_mci *host)
+static bool dw_mci_reset(struct dw_mci *host)
{
+ u32 flags = SDMMC_CTRL_RESET | SDMMC_CTRL_FIFO_RESET;
+ bool ret = false;
+
/*
* Reseting generates a block interrupt, hence setting
* the scatter-gather pointer to NULL.
@@ -2219,15 +2215,60 @@ static inline bool dw_mci_fifo_reset(struct dw_mci *host)
host->sg = NULL;
}

- return dw_mci_ctrl_reset(host, SDMMC_CTRL_FIFO_RESET);
-}
+ if (host->use_dma)
+ flags |= SDMMC_CTRL_DMA_RESET;

-static inline bool dw_mci_ctrl_all_reset(struct dw_mci *host)
-{
- return dw_mci_ctrl_reset(host,
- SDMMC_CTRL_FIFO_RESET |
- SDMMC_CTRL_RESET |
- SDMMC_CTRL_DMA_RESET);
+ if (dw_mci_ctrl_reset(host, flags)) {
+ /*
+ * In all cases we clear the RAWINTS register to clear any
+ * interrupts.
+ */
+ mci_writel(host, RINTSTS, 0xFFFFFFFF);
+
+ /* if using dma we wait for dma_req to clear */
+ if (host->use_dma) {
+ unsigned long timeout = jiffies + msecs_to_jiffies(500);
+ u32 status;
+ do {
+ status = mci_readl(host, STATUS);
+ if (!(status & SDMMC_STATUS_DMA_REQ))
+ break;
+ cpu_relax();
+ } while (time_before(jiffies, timeout));
+
+ if (status & SDMMC_STATUS_DMA_REQ) {
+ dev_err(host->dev,
+ "%s: Timeout waiting for dma_req to "
+ "clear during reset\n", __func__);
+ goto ciu_out;
+ }
+
+ /* when using DMA next we reset the fifo again */
+ if (!dw_mci_ctrl_reset(host, SDMMC_CTRL_FIFO_RESET))
+ goto ciu_out;
+ }
+ } else {
+ /* if the controller reset bit did clear, then set clock regs */
+ if (!(mci_readl(host, CTRL) & SDMMC_CTRL_RESET)) {
+ dev_err(host->dev, "%s: fifo/dma reset bits didn't "
+ "clear but ciu was reset, doing clock update\n",
+ __func__);
+ goto ciu_out;
+ }
+ }
+
+#if IS_ENABLED(CONFIG_MMC_DW_IDMAC)
+ /* It is also recommended that we reset and reprogram idmac */
+ dw_mci_idmac_reset(host);
+#endif
+
+ ret = true;
+
+ciu_out:
+ /* After a CTRL reset we need to have CIU set clock registers */
+ mci_send_cmd(host->cur_slot, SDMMC_CMD_UPD_CLK, 0);
+
+ return ret;
}

#ifdef CONFIG_OF
@@ -2425,7 +2466,7 @@ int dw_mci_probe(struct dw_mci *host)
}

/* Reset all blocks */
- if (!dw_mci_ctrl_all_reset(host))
+ if (!dw_mci_ctrl_reset(host, SDMMC_CTRL_ALL_RESET_FLAGS))
return -ENODEV;

host->dma_ops = host->pdata->dma_ops;
@@ -2612,7 +2653,7 @@ int dw_mci_resume(struct dw_mci *host)
}
}

- if (!dw_mci_ctrl_all_reset(host)) {
+ if (!dw_mci_ctrl_reset(host, SDMMC_CTRL_ALL_RESET_FLAGS)) {
ret = -ENODEV;
return ret;
}
diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
index 738fa24..08fd956 100644
--- a/drivers/mmc/host/dw_mmc.h
+++ b/drivers/mmc/host/dw_mmc.h
@@ -129,6 +129,7 @@
#define SDMMC_CMD_INDX(n) ((n) & 0x1F)
/* Status register defines */
#define SDMMC_GET_FCNT(x) (((x)>>17) & 0x1FFF)
+#define SDMMC_STATUS_DMA_REQ BIT(31)
/* FIFOTH register defines */
#define SDMMC_SET_FIFOTH(m, r, t) (((m) & 0x7) << 28 | \
((r) & 0xFFF) << 16 | \
@@ -150,6 +151,10 @@
/* Card read threshold */
#define SDMMC_SET_RD_THLD(v, x) (((v) & 0x1FFF) << 16 | (x))

+/* All ctrl reset bits */
+#define SDMMC_CTRL_ALL_RESET_FLAGS \
+ (SDMMC_CTRL_RESET | SDMMC_CTRL_FIFO_RESET | SDMMC_CTRL_DMA_RESET)
+
/* Register access macros */
#define mci_readl(dev, reg) \
__raw_readl((dev)->regs + SDMMC_##reg)
--
1.8.3.2