PCI: aardvark: Don't rely on jiffies while holding spinlock

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>

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index cb4327657136d690fbeeaf423574c603805f41e3..79be0afc9b1e7ea5b4e50da533e817207e3c9c30 100644 (file)
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -175,7 +175,8 @@
        (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
@@ -404,17 +405,16 @@ 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;
+       int i;
 
-       timeout = jiffies + msecs_to_jiffies(PIO_TIMEOUT_MS);
-
-       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");