6.7-stable review patch. If anyone has any objections, please let me know.
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From: Théo Lebrun theo.lebrun@bootlin.com
[ Upstream commit 959043afe53ae80633e810416cee6076da6e91c6 ]
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 theo.lebrun@bootlin.com Link: https://msgid.link/r/20240222-cdns-qspi-pm-fix-v4-2-6b6af8bcbf59@bootlin.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spi-cadence-quadspi.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c index 0d184d65dce76..731775d34d393 100644 --- a/drivers/spi/spi-cadence-quadspi.c +++ b/drivers/spi/spi-cadence-quadspi.c @@ -1930,14 +1930,10 @@ static void cqspi_remove(struct platform_device *pdev) static int cqspi_suspend(struct device *dev) { struct cqspi_st *cqspi = dev_get_drvdata(dev); - int ret;
- ret = spi_controller_suspend(cqspi->host); cqspi_controller_enable(cqspi, 0); - clk_disable_unprepare(cqspi->clk); - - return ret; + return 0; }
static int cqspi_resume(struct device *dev) @@ -1950,8 +1946,7 @@ static int cqspi_resume(struct device *dev)
cqspi->current_cs = -1; cqspi->sclk = 0; - - return spi_controller_resume(cqspi->host); + return 0; }
static DEFINE_RUNTIME_DEV_PM_OPS(cqspi_dev_pm_ops, cqspi_suspend,