From: Théo Lebrun <[email protected]>
commit 959043afe53ae80633e810416cee6076da6e91c6 upstream.
The ->runtime_suspend() and ->runtime_resume() callbacks are not
expected to call spi_controller_suspend() and spi_controller_resume().
Remove calls to those in the cadence-qspi driver.
Those helpers have two roles currently:
- They stop/start the queue, including dealing with the kworker.
- They toggle the SPI controller SPI_CONTROLLER_SUSPENDED flag. It
requires acquiring ctlr->bus_lock_mutex.
Step one is irrelevant because cadence-qspi is not queued. Step two
however has two implications:
- A deadlock occurs, because ->runtime_resume() is called in a context
where the lock is already taken (in the ->exec_op() callback, where
the usage count is incremented).
- It would disallow all operations once the device is auto-suspended.
Here is a brief call tree highlighting the mutex deadlock:
spi_mem_exec_op()
...
spi_mem_access_start()
mutex_lock(&ctlr->bus_lock_mutex)
cqspi_exec_mem_op()
pm_runtime_resume_and_get()
cqspi_resume()
spi_controller_resume()
mutex_lock(&ctlr->bus_lock_mutex)
...
spi_mem_access_end()
mutex_unlock(&ctlr->bus_lock_mutex)
...
Fixes: 0578a6dbfe75 ("spi: spi-cadence-quadspi: add runtime pm support")
Signed-off-by: Théo Lebrun <[email protected]>
Link:
https://msgid.link/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>
Signed-off-by: Guocai He <[email protected]>
---
drivers/spi/spi-cadence-quadspi.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/drivers/spi/spi-cadence-quadspi.c
b/drivers/spi/spi-cadence-quadspi.c
index d3e36dbabbbd..d573954c6cd1 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -2632,14 +2632,10 @@ static void __maybe_unused cqspi_restore_context(struct
cqspi_st *cqspi)
static int cqspi_suspend(struct device *dev)
{
struct cqspi_st *cqspi = dev_get_drvdata(dev);
- int ret;
- ret = spi_master_suspend(cqspi->master);
cqspi_controller_enable(cqspi, 0);
-
clk_disable_unprepare(cqspi->clk);
-
- return ret;
+ return 0;
}
static int cqspi_resume(struct device *dev)
@@ -2659,7 +2655,7 @@ static int cqspi_resume(struct device *dev)
if ((cqspi->f_pdata->use_phy) == true)
cqspi_restore_context(cqspi);
- return spi_master_resume(cqspi->master);
+ return 0;
}
static DEFINE_RUNTIME_DEV_PM_OPS(cqspi_dev_pm_ops, cqspi_suspend,
--
2.34.1
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