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

Ritesh Harjani
2016-06-27T06:48:27Z

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