On 06/17/2014 03:45 PM, Ulf Hansson wrote:
On 17 June 2014 03:04, micky <micky_ch...@realsil.com.cn> wrote:
On 06/16/2014 08:40 PM, Ulf Hansson wrote:
On 16 June 2014 11:09, micky <micky_ch...@realsil.com.cn> wrote:
On 06/16/2014 04:42 PM, Ulf Hansson wrote:
@@ -36,7 +37,10 @@ struct realtek_pci_sdmmc {
struct rtsx_pcr *pcr;
struct mmc_host *mmc;
struct mmc_request *mrq;
+ struct workqueue_struct *workq;
+#define SDMMC_WORKQ_NAME "rtsx_pci_sdmmc_workq"
+ struct work_struct work;
I am trying to understand why you need a work/workqueue to implement
this feature. Is that really the case?
Could you elaborate on the reasons?
Hi Uffe,
we need return as fast as possible in mmc_host_ops request(ops->request)
callback,
so the mmc core can continue handle next request.
when next request everything is ready, it will wait previous done(if not
done),
then call ops->request().
we can't use atomic context, because we use mutex_lock() to protect
ops->request should never executed in atomic context. Is that your
concern?
Yes.
Okay. Unless I missed your point, I don't think you need the work/workqueue.
any other method?
Because, ops->request isn't ever executed in atomic context. That's
due to the mmc core, which handles the async mechanism, are waiting
for a completion variable in process context, before it invokes the
ops->request() callback.
That completion variable will be kicked, from your host driver, when
you invoke mmc_request_done(), .
Sorry, I don't understand here, how kicked?
I think the flow is:
- not wait for first req
- init mrq->done
- ops->request() --- A.rtsx: start queue
work.
- continue fetch next req
- prepare next req ok,
- wait previous done. --- B.(mmc_request_done() may be
called at any time from A to B)
- init mrq->done
- ops->request() --- C.rtsx: start queue
next work.
...
and seems no problem.
Best Regards.
micky.
Kind regards
Uffe
resource, and we have to hold the lock during handle request.
So I use workq, we just queue a work and return in ops->request(),
The mmc core can continue without blocking at ops->request().
Best Regards.
micky.
Kind regards
Uffe
.
.
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