[PATCH net-next] liquidio: fix kernel panic when NIC firmware is older than 1.7.2

[Felix Manlunas]

From: Rick Farrington <ricardo.farring...@cavium.com>

Pre-1.7.2 NIC firmware does not support (and does not respond to) the "get
speed" command which is sent by the 1.7.2 driver during modprobe.  Due to a
bug in older firmware (with respect to unknown commands), this unsupported
command causes a cascade of errors that ends in a kernel panic.

Fix it by making the sending of the "get speed" command conditional on the
firmware version.

Signed-off-by: Rick Farrington <ricardo.farring...@cavium.com>
Acked-by: Derek Chickles <derek.chick...@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlu...@cavium.com>
---
Note: To avoid checkpatch.pl "WARNING: line over 80 characters", the comma
      that separates the arguments in the call to strcmp() was placed one
      line below the usual spot.

 drivers/net/ethernet/cavium/liquidio/lio_main.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/cavium/liquidio/lio_main.c 
b/drivers/net/ethernet/cavium/liquidio/lio_main.c
index 7cb4e75..f83f884 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_main.c
@@ -3671,7 +3671,16 @@ static int setup_nic_devices(struct octeon_device 
*octeon_dev)
                        OCTEON_CN2350_25GB_SUBSYS_ID ||
                    octeon_dev->subsystem_id ==
                        OCTEON_CN2360_25GB_SUBSYS_ID) {
-                       liquidio_get_speed(lio);
+                       /* speed control unsupported in f/w older than 1.7.2 */
+                       if (strcmp(octeon_dev->fw_info.liquidio_firmware_version
+                          , "1.7.2") < 0) {
+                               dev_info(&octeon_dev->pci_dev->dev,
+                                        "speed setting not supported by f/w.");
+                               octeon_dev->speed_setting = 25;
+                               octeon_dev->no_speed_setting = 1;
+                       } else {
+                               liquidio_get_speed(lio);
+                       }
 
                        if (octeon_dev->speed_setting == 0) {
                                octeon_dev->speed_setting = 25;