Re: [PATCH RFC 09/10] mmc: cmdq-host: add halt support to command queue host

[Ritesh Harjani <riteshh@codeaurora.org>]

Hi,


On 6/17/2016 2:21 PM, Shawn Lin wrote:
> 在 2016/6/15 21:01, Ritesh Harjani 写道:
>> From: Asutosh Das <asutoshd@codeaurora.org>
>>
>> Halt can be used in error cases to get control of the
>> bus. This is used to remove a task from device queue
>> and/or other recovery mechanisms.
>
> where to ues it? cmdq_irq or sdhci_irq?
Below cmdq_halt will be used by higher
layers to get legacy bus control to send legacy commands.
Like during clock-scaling, we may need to send tuning commands
for which we may wait for the device queue to be empty and then halt
the controller to send legacy tuning commands.


>
>>
>> Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
>> Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
>> [riteshh@codeaurora.org: fixed merge conflicts]
>> Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>
>> ---
>>  drivers/mmc/host/cmdq_hci.c | 35 +++++++++++++++++++++++++++++++++++
>>  1 file changed, 35 insertions(+)
>>
>> diff --git a/drivers/mmc/host/cmdq_hci.c b/drivers/mmc/host/cmdq_hci.c
>> index 68c8e03..64be0ce 100644
>> --- a/drivers/mmc/host/cmdq_hci.c
>> +++ b/drivers/mmc/host/cmdq_hci.c
>> @@ -29,6 +29,9 @@
>>  #define DCMD_SLOT 31
>>  #define NUM_SLOTS 32
>>
>> +/* 1 sec */
>> +#define HALT_TIMEOUT_MS 1000
>> +
>>  static inline u8 *get_desc(struct cmdq_host *cq_host, u8 tag)
>>  {
>>      return cq_host->desc_base + (tag * cq_host->slot_sz);
>> @@ -570,11 +573,42 @@ irqreturn_t cmdq_irq(struct mmc_host *mmc, u32
>> intmask)
>>          cmdq_dumpregs(cq_host);
>>      }
>>
>> +    if (status & CQIS_HAC) {
>> +        /* halt is completed, wakeup waiting thread */
>> +        complete(&cq_host->halt_comp);
>> +    }
>> +
>>  out:
>>      return IRQ_HANDLED;
>>  }
>>  EXPORT_SYMBOL(cmdq_irq);
>>
>> +/* May sleep */
>> +static int cmdq_halt(struct mmc_host *mmc, bool halt)
>> +{
>> +    struct cmdq_host *cq_host = (struct cmdq_host
>> *)mmc_cmdq_private(mmc);
>> +    u32 val;
>> +
>> +    if (halt) {
>> +        cmdq_writel(cq_host, cmdq_readl(cq_host, CQCTL) | HALT,
>> +                CQCTL);
>> +        val = wait_for_completion_timeout(&cq_host->halt_comp,
>> +                      msecs_to_jiffies(HALT_TIMEOUT_MS));
>> +        /* halt done: re-enable legacy interrupts */
>> +        if (cq_host->ops->clear_set_irqs)
>> +            cq_host->ops->clear_set_irqs(mmc, false);
>> +
>> +        return val ? 0 : -ETIMEDOUT;
>> +    } else {
>> +        if (cq_host->ops->clear_set_irqs)
>> +            cq_host->ops->clear_set_irqs(mmc, true);
>> +        cmdq_writel(cq_host, cmdq_readl(cq_host, CQCTL) & ~HALT,
>> +                CQCTL);
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>>  static void cmdq_post_req(struct mmc_host *host, struct mmc_request
>> *mrq,
>>                int err)
>>  {
>> @@ -597,6 +631,7 @@ static const struct mmc_cmdq_host_ops
>> cmdq_host_ops = {
>>      .disable = cmdq_disable,
>>      .request = cmdq_request,
>>      .post_req = cmdq_post_req,
>> +    .halt = cmdq_halt,
>>  };
>>
>>  struct cmdq_host *cmdq_pltfm_init(struct platform_device *pdev)
>>
>
>

--
BR
Ritesh