From: Remi Pommarel repk@triplefau.lt

commit 7fbcb5da811be7d47468417c7795405058abb3da upstream.

advk_pcie_wait_pio() can be called while holding a spinlock (from pci_bus_read_config_dword()), then depends on jiffies in order to timeout while polling on PIO state registers. In the case the PIO transaction failed, the timeout will never happen and will also cause the cpu to stall.

This decrements a variable and wait instead of using jiffies.

Signed-off-by: Remi Pommarel repk@triplefau.lt Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Reviewed-by: Andrew Murray andrew.murray@arm.com Acked-by: Thomas Petazzoni thomas.petazzoni@bootlin.com --- This is backport to 4.14 kernel. Backport of upstream commit can be done automatically by git cherry-pick command if merge.renamelimit variable is set to at least 12711. --- drivers/pci/host/pci-aardvark.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/host/pci-aardvark.c b/drivers/pci/host/pci-aardvark.c index c1db09fbbe04..5dbbf3d7de36 100644 --- a/drivers/pci/host/pci-aardvark.c +++ b/drivers/pci/host/pci-aardvark.c @@ -185,7 +185,8 @@ (PCIE_CONF_BUS(bus) | PCIE_CONF_DEV(PCI_SLOT(devfn)) | \ PCIE_CONF_FUNC(PCI_FUNC(devfn)) | PCIE_CONF_REG(where))

-#define PIO_TIMEOUT_MS 1 +#define PIO_RETRY_CNT 500 +#define PIO_RETRY_DELAY 2 /* 2 us*/

#define LINK_WAIT_MAX_RETRIES 10 #define LINK_WAIT_USLEEP_MIN 90000 @@ -413,17 +414,16 @@ static void advk_pcie_check_pio_status(struct advk_pcie *pcie) static int advk_pcie_wait_pio(struct advk_pcie *pcie) { struct device *dev = &pcie->pdev->dev; - unsigned long timeout; - - timeout = jiffies + msecs_to_jiffies(PIO_TIMEOUT_MS); + int i;

- while (time_before(jiffies, timeout)) { + for (i = 0; i < PIO_RETRY_CNT; i++) { u32 start, isr;

start = advk_readl(pcie, PIO_START); isr = advk_readl(pcie, PIO_ISR); if (!start && isr) return 0; + udelay(PIO_RETRY_DELAY); }

dev_err(dev, "config read/write timed out\n");