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mmc: core: Add support for re-tuning before each request 

At the start of each request, re-tune if needed and
then hold off re-tuning again until the request is done.

Note that though there is one function that starts
requests (mmc_start_request) there are two that wait for
the request to be done (mmc_wait_for_req_done and
mmc_wait_for_data_req_done).  Also note that
mmc_wait_for_data_req_done can return even when the
request is not done (which allows the block driver
to prepare a newly arrived request while still
waiting for the previous request).

This patch ensures re-tuning is held for the duration
of a request.  Subsequent patches will also hold
re-tuning at other times when it might cause a
conflict.

In addition, possibly a command is failing because
re-tuning is needed. Use mmc_retune_recheck() to check
re-tuning. At that point re-tuning is held, at least by
the request, so mmc_retune_recheck() flags host->retune_now
if the hold count is 1.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Adrian Hunter 2015-05-07 13:10:14 +03:00 committed by Ulf Hansson
parent 79d5a65aee
commit 90a81489b0
1 changed files with 28 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
drivers/mmc/core/core.c
View File

@ -186,12 +186,29 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
EXPORT_SYMBOL(mmc_request_done);
static void __mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
{
int err;
/* Assumes host controller has been runtime resumed by mmc_claim_host */
err = mmc_retune(host);
if (err) {
mrq->cmd->error = err;
mmc_request_done(host, mrq);
return;
}
host->ops->request(host, mrq);
}
static int mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
{
#ifdef CONFIG_MMC_DEBUG
unsigned int i, sz;
struct scatterlist *sg;
#endif
mmc_retune_hold(host);
if (mmc_card_removed(host->card))
return -ENOMEDIUM;
@ -252,7 +269,7 @@ static int mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
}
mmc_host_clk_hold(host);
led_trigger_event(host->led, LED_FULL);
host->ops->request(host, mrq);
__mmc_start_request(host, mrq);
return 0;
}
@ -417,22 +434,22 @@ static int mmc_wait_for_data_req_done(struct mmc_host *host,
host->areq);
break; /* return err */
} else {
mmc_retune_recheck(host);
pr_info("%s: req failed (CMD%u): %d, retrying...\n",
mmc_hostname(host),
cmd->opcode, cmd->error);
cmd->retries--;
cmd->error = 0;
host->ops->request(host, mrq);
__mmc_start_request(host, mrq);
continue; /* wait for done/new event again */
}
} else if (context_info->is_new_req) {
context_info->is_new_req = false;
if (!next_req) {
err = MMC_BLK_NEW_REQUEST;
break; /* return err */
}
if (!next_req)
return MMC_BLK_NEW_REQUEST;
}
}
mmc_retune_release(host);
return err;
}
@ -467,12 +484,16 @@ static void mmc_wait_for_req_done(struct mmc_host *host,
mmc_card_removed(host->card))
break;
mmc_retune_recheck(host);
pr_debug("%s: req failed (CMD%u): %d, retrying...\n",
mmc_hostname(host), cmd->opcode, cmd->error);
cmd->retries--;
cmd->error = 0;
host->ops->request(host, mrq);
__mmc_start_request(host, mrq);
}
mmc_retune_release(host);
}
/**