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

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On Wed, May 28, 2014 at 10:17 PM, Jaehoon Chung <jh80.chung@xxxxxxxxxxx> wrote:
> 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@xxxxxxxxxxxx>
>> Signed-off-by: Yuvaraj Kumar C D <yuvaraj.cd@xxxxxxxxxxx>
>> ---
>> 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?

Well, it does still clear the fifo, but I can remove the comment since
we are now doing more than that.

>> -                             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) & ...)".
>

Ok, I'll move this error message inside the if block and make it more specific.

>> +             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 (.....)
>

ok I'll make a macro in dw_mmc.h for this.

>> +     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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