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mmc: atmel-mci: fix race between stop command and start of next command 

This commit fixes a race between completion of stop command and start of a
new command.
Previously the command ready interrupt was enabled before stop command
was written to the command register. This caused the command ready
interrupt to fire immediately since the CMDRDY flag is asserted constantly
while there is no command in progress.
Consequently the command state machine will immediately advance to the
next state when the tasklet function is executed again, no matter
actual completion state of the stop command.
Thus a new command can then be dispatched immediately, interrupting and
corrupting the stop command on the CMD line.
Fix that by dropping the command ready interrupt enable before calling
atmci_send_stop_cmd. atmci_send_stop_cmd does already enable the
command ready interrupt, no further writes to ATMCI_IER are necessary.

Signed-off-by: Tobias Schramm <t.schramm@manjaro.org>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Link: https://lore.kernel.org/r/20221230194315.809903-2-t.schramm@manjaro.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Tobias Schramm 2022-12-30 20:43:15 +01:00 committed by Ulf Hansson
parent d5d4a2bc5f
commit eca5bd666b
1 changed files with 0 additions and 3 deletions
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3
drivers/mmc/host/atmel-mci.c
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@ -1817,7 +1817,6 @@ static void atmci_tasklet_func(struct tasklet_struct *t)
atmci_writel(host, ATMCI_IER, ATMCI_NOTBUSY);
state = STATE_WAITING_NOTBUSY;
} else if (host->mrq->stop) {
atmci_writel(host, ATMCI_IER, ATMCI_CMDRDY);
atmci_send_stop_cmd(host, data);
state = STATE_SENDING_STOP;
} else {
@ -1850,8 +1849,6 @@ static void atmci_tasklet_func(struct tasklet_struct *t)
* command to send.
*/
if (host->mrq->stop) {
atmci_writel(host, ATMCI_IER,
ATMCI_CMDRDY);
atmci_send_stop_cmd(host, data);
state = STATE_SENDING_STOP;
} else {