mmc: core: clarify how to use post_req in case of errors

The err condition in post_req() is set to undo a call made to pre_req()
that hasn't been started yet.  The err condition is not set if an MMC
request returns an error.

Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Per Forlin
2011-08-29 15:35:58 +02:00
committed by Chris Ball
parent 4466903481
commit 7c8a2829c2
2 changed files with 9 additions and 0 deletions

View File

@@ -109,6 +109,9 @@ struct mmc_host_ops {
* It is optional for the host to implement pre_req and post_req in
* order to support double buffering of requests (prepare one
* request while another request is active).
* pre_req() must always be followed by a post_req().
* To undo a call made to pre_req(), call post_req() with
* a nonzero err condition.
*/
void (*post_req)(struct mmc_host *host, struct mmc_request *req,
int err);