[PATCH V2 net-next] liquidio: fix kernel panic when NIC firmware is older than 1.7.2

[Felix Manlunas <felix.manlunas@cavium.com>]

From: Rick Farrington <ricardo.farrington@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 (for CN23XX-225 cards
only) 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.farrington@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
---
Patch Change Log:
  V1 -> V2:
    * In the if-statement that checks the firmware version, replace the
      boolean expression that calls strcmp() (which is not suitable when
      the firmware micro version has more than one digit) with a boolean
      expression that works in all cases.

    * In the patch description, specify which types of liquidio cards are
      afffected.

 drivers/net/ethernet/cavium/liquidio/lio_main.c    | 26 ++++++++++++++++++++--
 .../net/ethernet/cavium/liquidio/octeon_device.h   |  9 ++++++++
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/cavium/liquidio/lio_main.c b/drivers/net/ethernet/cavium/liquidio/lio_main.c
index 7cb4e75..ebda6ef 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_main.c
@@ -3299,7 +3299,9 @@ static int setup_nic_devices(struct octeon_device *octeon_dev)
 {
 	struct lio *lio = NULL;
 	struct net_device *netdev;
-	u8 mac[6], i, j, *fw_ver;
+	u8 mac[6], i, j, *fw_ver, *micro_ver;
+	unsigned long micro;
+	u32 cur_ver;
 	struct octeon_soft_command *sc;
 	struct liquidio_if_cfg_context *ctx;
 	struct liquidio_if_cfg_resp *resp;
@@ -3429,6 +3431,14 @@ static int setup_nic_devices(struct octeon_device *octeon_dev)
 				 fw_ver);
 		}
 
+		/* extract micro version field; point past '<maj>.<min>.' */
+		micro_ver = fw_ver + strlen(LIQUIDIO_BASE_VERSION) + 1;
+		if (kstrtoul(micro_ver, 10, &micro) != 0)
+			micro = 0;
+		octeon_dev->fw_info.ver.maj = LIQUIDIO_BASE_MAJOR_VERSION;
+		octeon_dev->fw_info.ver.min = LIQUIDIO_BASE_MINOR_VERSION;
+		octeon_dev->fw_info.ver.rev = micro;
+
 		octeon_swap_8B_data((u64 *)(&resp->cfg_info),
 				    (sizeof(struct liquidio_if_cfg_info)) >> 3);
 
@@ -3671,7 +3681,19 @@ 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);
+			cur_ver = OCT_FW_VER(octeon_dev->fw_info.ver.maj,
+					     octeon_dev->fw_info.ver.min,
+					     octeon_dev->fw_info.ver.rev);
+
+			/* speed control unsupported in f/w older than 1.7.2 */
+			if (cur_ver < OCT_FW_VER(1, 7, 2)) {
+				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;
diff --git a/drivers/net/ethernet/cavium/liquidio/octeon_device.h b/drivers/net/ethernet/cavium/liquidio/octeon_device.h
index 94a4ed88d..d99ca6b 100644
--- a/drivers/net/ethernet/cavium/liquidio/octeon_device.h
+++ b/drivers/net/ethernet/cavium/liquidio/octeon_device.h
@@ -288,8 +288,17 @@ struct oct_fw_info {
 	 */
 	u32 app_mode;
 	char   liquidio_firmware_version[32];
+	/* Fields extracted from legacy string 'liquidio_firmware_version' */
+	struct {
+		u8  maj;
+		u8  min;
+		u8  rev;
+	} ver;
 };
 
+#define OCT_FW_VER(maj, min, rev) \
+	(((u32)(maj) << 16) | ((u32)(min) << 8) | ((u32)(rev)))
+
 /* wrappers around work structs */
 struct cavium_wk {
 	struct delayed_work work;