PCI: Add debug print for device ready delay

Currently, the time it took a PCI device to become ready after reset is
only printed if it was longer than 1000ms ('PCI_RESET_WAIT'). However,
for debugging purposes it is useful to know this time even if it was
shorter. For example, with the device I am working on, hardware
engineers asked to verify that it becomes ready on the first try (no
delay).

To that end, add a debug level print that can be enabled using dynamic
debug. Example:

 # echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/reset
 # dmesg -c | grep ready
 # echo "file drivers/pci/pci.c +p" > /sys/kernel/debug/dynamic_debug/control
 # echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/reset
 # dmesg -c | grep ready
 [  396.060335] mlxsw_spectrum4 0000:01:00.0: ready 0ms after bus reset
 # echo "file drivers/pci/pci.c -p" > /sys/kernel/debug/dynamic_debug/control
 # echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/reset
 # dmesg -c | grep ready

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 55bc3576a98562807522e233223119f047822056..69d20d585f889a2ecb33a5bf55a75774ec5ae568 100644 (file)
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1219,6 +1219,9 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout)
        if (delay > PCI_RESET_WAIT)
                pci_info(dev, "ready %dms after %s\n", delay - 1,
                         reset_type);
+       else
+               pci_dbg(dev, "ready %dms after %s\n", delay - 1,
+                       reset_type);
 
        return 0;
 }