brcmfmac: reset PCIe bus on a firmware crash

This includes bus reset & reloading a firmware. It should be sufficient
for a user space to (setup and) use a wireless device again.

Support for reset on USB & SDIO can be added later.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/broadcom/brcm80211/brcmfmac/bus.h

@@ -91,6 +91,7 @@ struct brcmf_bus_ops {
 	int (*get_fwname)(struct device *dev, const char *ext,
 			  unsigned char *fw_name);
 	void (*debugfs_create)(struct device *dev);
+	int (*reset)(struct device *dev);
 };
 
 
@@ -245,6 +246,15 @@ void brcmf_bus_debugfs_create(struct brcmf_bus *bus)
 	return bus->ops->debugfs_create(bus->dev);
 }
 
+static inline
+int brcmf_bus_reset(struct brcmf_bus *bus)
+{
+	if (!bus->ops->reset)
+		return -EOPNOTSUPP;
+
+	return bus->ops->reset(bus->dev);
+}
+
 /*
  * interface functions from common layer
  */

drivers/net/wireless/broadcom/brcm80211/brcmfmac/core.c

@@ -1084,6 +1084,14 @@ static int brcmf_revinfo_read(struct seq_file *s, void *data)
 	return 0;
 }
 
+static void brcmf_core_bus_reset(struct work_struct *work)
+{
+	struct brcmf_pub *drvr = container_of(work, struct brcmf_pub,
+					      bus_reset);
+
+	brcmf_bus_reset(drvr->bus_if);
+}
+
 static int brcmf_bus_started(struct brcmf_pub *drvr, struct cfg80211_ops *ops)
 {
 	int ret = -1;
@@ -1155,6 +1163,8 @@ static int brcmf_bus_started(struct brcmf_pub *drvr, struct cfg80211_ops *ops)
 #endif
 #endif /* CONFIG_INET */
 
+	INIT_WORK(&drvr->bus_reset, brcmf_core_bus_reset);
+
 	/* populate debugfs */
 	brcmf_debugfs_add_entry(drvr, "revinfo", brcmf_revinfo_read);
 	brcmf_feat_debugfs_create(drvr);
@@ -1281,6 +1291,8 @@ void brcmf_fw_crashed(struct device *dev)
 	bphy_err(drvr, "Firmware has halted or crashed\n");
 
 	brcmf_dev_coredump(dev);
+
+	schedule_work(&drvr->bus_reset);
 }
 
 void brcmf_detach(struct device *dev)

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 work_struct bus_reset;
+
 	u8 clmver[BRCMF_DCMD_SMLEN];
 };
 

drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c

@@ -345,6 +345,10 @@ static const u32 brcmf_ring_itemsize[BRCMF_NROF_COMMON_MSGRINGS] = {
 	BRCMF_D2H_MSGRING_RX_COMPLETE_ITEMSIZE
 };
 
+static void brcmf_pcie_setup(struct device *dev, int ret,
+			     struct brcmf_fw_request *fwreq);
+static struct brcmf_fw_request *
+brcmf_pcie_prepare_fw_request(struct brcmf_pciedev_info *devinfo);
 
 static u32
 brcmf_pcie_read_reg32(struct brcmf_pciedev_info *devinfo, u32 reg_offset)
@@ -1409,6 +1413,36 @@ int brcmf_pcie_get_fwname(struct device *dev, const char *ext, u8 *fw_name)
 	return 0;
 }
 
+static int brcmf_pcie_reset(struct device *dev)
+{
+	struct brcmf_bus *bus_if = dev_get_drvdata(dev);
+	struct brcmf_pciedev *buspub = bus_if->bus_priv.pcie;
+	struct brcmf_pciedev_info *devinfo = buspub->devinfo;
+	struct brcmf_fw_request *fwreq;
+	int err;
+
+	brcmf_detach(dev);
+
+	brcmf_pcie_release_irq(devinfo);
+	brcmf_pcie_release_scratchbuffers(devinfo);
+	brcmf_pcie_release_ringbuffers(devinfo);
+	brcmf_pcie_reset_device(devinfo);
+
+	fwreq = brcmf_pcie_prepare_fw_request(devinfo);
+	if (!fwreq) {
+		dev_err(dev, "Failed to prepare FW request\n");
+		return -ENOMEM;
+	}
+
+	err = brcmf_fw_get_firmwares(dev, fwreq, brcmf_pcie_setup);
+	if (err) {
+		dev_err(dev, "Failed to prepare FW request\n");
+		kfree(fwreq);
+	}
+
+	return err;
+}
+
 static const struct brcmf_bus_ops brcmf_pcie_bus_ops = {
 	.txdata = brcmf_pcie_tx,
 	.stop = brcmf_pcie_down,
@@ -1418,6 +1452,7 @@ static const struct brcmf_bus_ops brcmf_pcie_bus_ops = {
 	.get_ramsize = brcmf_pcie_get_ramsize,
 	.get_memdump = brcmf_pcie_get_memdump,
 	.get_fwname = brcmf_pcie_get_fwname,
+	.reset = brcmf_pcie_reset,
 };