[PATCH] brcmfmac: run firmware state watchdog on the host machine

["Rafał Miłecki" <zajec5@gmail.com>]

From: Rafał Miłecki <rafal@milecki.pl>

FullMAC firmware may happen to crash due to some potential bugs exposed
by e.g. a specific traffic or host-requested setup. It usually results
in various timeouts & running our of resources (e.g. ring slots).

Monitoring firmware state allows handling such a situation more
gracefully. At this point the watchdog:
1) Prints a clear error message about a firmware crash
2) Tries to dump a crash info data

That should be helpful for users & should allow providing a valuable
reports for the Broadcom developers. It obviously doesn't really fix
anything.

This watchdog is important for USB & SDIO devices which don't have
anything alike implemented yet. It's also there to complement PCIe with
its FWHALT signal which does not work in all situations.

It has been successfully tested with the recently released
brcmfmac4366c-pcie.bin.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201853
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
 .../broadcom/brcm80211/brcmfmac/core.c        | 28 +++++++++++++++++++
 .../broadcom/brcm80211/brcmfmac/core.h        |  2 ++
 2 files changed, 30 insertions(+)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
index 4fbe8791f674..ab7a54b2d831 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c
@@ -40,6 +40,7 @@
 #include "common.h"
 
 #define MAX_WAIT_FOR_8021X_TX			msecs_to_jiffies(950)
+#define BRCMF_FW_WATCHDOG_POLL			msecs_to_jiffies(1000)
 
 #define BRCMF_BSSIDX_INVALID			-1
 
@@ -1084,6 +1085,28 @@ static int brcmf_revinfo_read(struct seq_file *s, void *data)
 	return 0;
 }
 
+static void brcmf_fw_watchdog(struct work_struct *work)
+{
+	struct brcmf_pub *drvr = container_of(work, struct brcmf_pub,
+					      fw_watchdog.work);
+
+	if (drvr->bus_if->state == BRCMF_BUS_UP) {
+		struct brcmf_if *ifp = drvr->iflist[0];
+		s32 ver;
+		int err;
+
+		err = brcmf_fil_cmd_int_get(ifp, BRCMF_C_GET_VERSION, &ver);
+		if (err) {
+			bphy_err(drvr, "Firmware has most likely crashed and didn't respond: %d\n",
+				 err);
+			brcmf_dev_coredump(drvr->bus_if->dev);
+			return;
+		}
+	}
+
+	schedule_delayed_work(&drvr->fw_watchdog, BRCMF_FW_WATCHDOG_POLL);
+}
+
 static int brcmf_bus_started(struct brcmf_pub *drvr, struct cfg80211_ops *ops)
 {
 	int ret = -1;
@@ -1155,6 +1178,9 @@ static int brcmf_bus_started(struct brcmf_pub *drvr, struct cfg80211_ops *ops)
 #endif
 #endif /* CONFIG_INET */
 
+	INIT_DELAYED_WORK(&drvr->fw_watchdog, brcmf_fw_watchdog);
+	schedule_delayed_work(&drvr->fw_watchdog, BRCMF_FW_WATCHDOG_POLL);
+
 	/* populate debugfs */
 	brcmf_debugfs_add_entry(drvr, "revinfo", brcmf_revinfo_read);
 	brcmf_feat_debugfs_create(drvr);
@@ -1284,6 +1310,8 @@ void brcmf_detach(struct device *dev)
 	if (drvr == NULL)
 		return;
 
+	cancel_delayed_work_sync(&drvr->fw_watchdog);
+
 #ifdef CONFIG_INET
 	unregister_inetaddr_notifier(&drvr->inetaddr_notifier);
 #endif
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.h b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.h
index d8085ce579f4..1b44d243d05f 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.h
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.h
@@ -143,6 +143,8 @@ struct brcmf_pub {
 	struct notifier_block inet6addr_notifier;
 	struct brcmf_mp_device *settings;
 
+	struct delayed_work fw_watchdog;
+
 	u8 clmver[BRCMF_DCMD_SMLEN];
 };
 
-- 
2.20.1