[PATCH] mmc: dw_mmc: change to use recommended reset procedure
Jaehoon Chung
jh80.chung at samsung.com
Wed May 28 22:17:25 PDT 2014
Hi, Sonny.
On 05/29/2014 09:35 AM, Sonny Rao wrote:
> 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 at chromium.org>
> Signed-off-by: Yuvaraj Kumar C D <yuvaraj.cd at samsung.com>
> ---
> v2: Add Generic DMA support
> per the documentation, move interrupt clear before wait
> make the test for DMA host->use_dma rather than host->using_dma
> add proper return values (although it appears no caller checks)
> v3: rename fifo reset function, and change callers
> use this combined reset function in dw_mci_resume()
> just one caller left (probe), so get rid of dw_mci_ctrl_all_reset()
> use DMA reset bit for all systems which use DMA
> remove extra IDMAC reset in dw_mci_work_routine_card()
> do CIU clock update in error path, if CIU reset cleared
>
> drivers/mmc/host/dw_mmc.c | 85 +++++++++++++++++++++++++++++++++++------------
> drivers/mmc/host/dw_mmc.h | 1 +
> 2 files changed, 64 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 55cd110..988492c 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 inline 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)
> @@ -1254,7 +1253,7 @@ 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;
> @@ -1371,7 +1370,7 @@ 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;
> @@ -1982,14 +1981,9 @@ static void dw_mci_work_routine_card(struct work_struct *work)
> }
>
> /* Power down slot */
> - if (present == 0) {
> + if (present == 0)
> /* Clear down the FIFO */
Didn't Need to change the Comment?
> - dw_mci_fifo_reset(host);
> -#ifdef CONFIG_MMC_DW_IDMAC
> - dw_mci_idmac_reset(host);
> -#endif
> -
> - }
> + dw_mci_reset(host);
>
> spin_unlock_bh(&host->lock);
>
> @@ -2323,8 +2317,11 @@ 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 inline 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.
> @@ -2334,15 +2331,57 @@ 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", __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 {
> + dev_err(host->dev, "%s: Reset bits didn't clear", __func__);
> +
> + /* if the controller reset bit did clear, then set clock regs */
I have some confusion at this point. you added the above error message "Reset bits didn't clear".
But this comment is "if the controller reset bit did clear..".
I think that dev_err message would be better to locate into "if (!(mci_read(host, CTRL) & ...)".
> + if (!(mci_readl(host, CTRL) & SDMMC_CTRL_RESET))
> + 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);
> +
> + 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
> @@ -2432,6 +2471,7 @@ int dw_mci_probe(struct dw_mci *host)
> const struct dw_mci_drv_data *drv_data = host->drv_data;
> int width, i, ret = 0;
> u32 fifo_size;
> + u32 flags;
> int init_slots = 0;
>
> if (!host->pdata) {
> @@ -2555,7 +2595,8 @@ int dw_mci_probe(struct dw_mci *host)
> }
>
> /* Reset all blocks */
> - if (!dw_mci_ctrl_all_reset(host))
> + flags = SDMMC_CTRL_RESET | SDMMC_CTRL_FIFO_RESET | SDMMC_CTRL_DMA_RESET;
how about adding the SDMMC_CTRL_ALL_RESET macro into header file?
#define SDMMC_CTRL_ALL_RESET (.....)
> + if (!dw_mci_ctrl_reset(host, flags))
> return -ENODEV;
>
> host->dma_ops = host->pdata->dma_ops;
> @@ -2744,7 +2785,7 @@ int dw_mci_resume(struct dw_mci *host)
> }
> }
>
> - if (!dw_mci_ctrl_all_reset(host)) {
> + if (!dw_mci_reset(host)) {
> ret = -ENODEV;
> return ret;
> }
> diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
> index 6bf24ab..2505804 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 | \
>
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