uwb: i1480/GUWA100U: fix firmware download issues

IOGear firmware versions >= 1.4.12224 fail to be downloaded because of a
spurious (and harmless) RCEB received after the download notification. This
patch handles this RCEB and keeps compatibility with future versions that might
not emit this RCEB.

i1480_rceb_check() is reused to check for the RCEB. It is also refactored with
improved comments and reused in another place in mac.c where the checking was
being duplicated.

This patch was tested on both i1480 and GUWA100U HWAs, with all firmware
versions currently available.
Signed-off-by: Anderson Lizardo <anderson.lizardo@indt.org.br>

drivers/uwb/i1480/dfu/dfu.c

@@ -37,29 +37,45 @@
 #define D_LOCAL 0
 #include <linux/uwb/debug.h>
 
-/** @return 0 if If @evt is a valid reply event; otherwise complain */
+/**
+ * i1480_rceb_check - Check RCEB for expected field values
+ * @i1480: pointer to device for which RCEB is being checked
+ * @rceb: RCEB being checked
+ * @cmd: which command the RCEB is related to
+ * @context: expected context
+ * @expected_type: expected event type
+ * @expected_event: expected event
+ *
+ * If @cmd is NULL, do not print error messages, but still return an error
+ * code.
+ *
+ * Return 0 if @rceb matches the expected values, -EINVAL otherwise.
+ */
 int i1480_rceb_check(const struct i1480 *i1480, const struct uwb_rceb *rceb,
-		     const char *cmd, u8 context,
-		     unsigned expected_type, unsigned expected_event)
+		     const char *cmd, u8 context, u8 expected_type,
+		     unsigned expected_event)
 {
 	int result = 0;
 	struct device *dev = i1480->dev;
 	if (rceb->bEventContext != context) {
-		dev_err(dev, "%s: "
-			"unexpected context id 0x%02x (expected 0x%02x)\n",
-			cmd, rceb->bEventContext, context);
+		if (cmd)
+			dev_err(dev, "%s: unexpected context id 0x%02x "
+				"(expected 0x%02x)\n", cmd,
+				rceb->bEventContext, context);
 		result = -EINVAL;
 	}
 	if (rceb->bEventType != expected_type) {
-		dev_err(dev, "%s: "
-			"unexpected event type 0x%02x (expected 0x%02x)\n",
-			cmd, rceb->bEventType, expected_type);
+		if (cmd)
+			dev_err(dev, "%s: unexpected event type 0x%02x "
+				"(expected 0x%02x)\n", cmd,
+				rceb->bEventType, expected_type);
 		result = -EINVAL;
 	}
 	if (le16_to_cpu(rceb->wEvent) != expected_event) {
-		dev_err(dev, "%s: "
-			"unexpected event 0x%04x (expected 0x%04x)\n",
-			cmd, le16_to_cpu(rceb->wEvent), expected_event);
+		if (cmd)
+			dev_err(dev, "%s: unexpected event 0x%04x "
+				"(expected 0x%04x)\n", cmd,
+				le16_to_cpu(rceb->wEvent), expected_event);
 		result = -EINVAL;
 	}
 	return result;
@@ -110,6 +126,20 @@ ssize_t i1480_cmd(struct i1480 *i1480, const char *cmd_name, size_t cmd_size,
 			cmd_name, result);
 		goto error;
 	}
+	/*
+	 * Firmware versions >= 1.4.12224 for IOGear GUWA100U generate a
+	 * spurious notification after firmware is downloaded. So check whether
+	 * the receibed RCEB is such notification before assuming that the
+	 * command has failed.
+	 */
+	if (i1480_rceb_check(i1480, i1480->evt_buf, NULL,
+			     0, 0xfd, 0x0022) == 0) {
+		/* Now wait for the actual RCEB for this command. */
+		result = i1480->wait_init_done(i1480);
+		if (result < 0)
+			goto error;
+		result = i1480->evt_result;
+	}
 	if (result != reply_size) {
 		dev_err(i1480->dev, "%s returned only %zu bytes, %zu expected\n",
 			cmd_name, result, reply_size);

drivers/uwb/i1480/dfu/i1480-dfu.h

@@ -145,7 +145,7 @@ extern int i1480_phy_fw_upload(struct i1480 *);
 extern ssize_t i1480_cmd(struct i1480 *, const char *, size_t, size_t);
 extern int i1480_rceb_check(const struct i1480 *,
 			    const struct uwb_rceb *, const char *, u8,
-			    unsigned, unsigned);
+			    u8, unsigned);
 
 enum {
 	/* Vendor specific command type */

drivers/uwb/i1480/dfu/mac.c

@@ -507,8 +507,8 @@ int i1480_mac_fw_upload(struct i1480 *i1480)
 		goto error_size;
 	}
 	result = -EIO;
-	if (rcebe->rceb.bEventType != i1480_CET_VS1
-	    || le16_to_cpu(rcebe->rceb.wEvent) != i1480_EVT_RM_INIT_DONE) {
+	if (i1480_rceb_check(i1480, &rcebe->rceb, NULL, 0, i1480_CET_VS1,
+			     i1480_EVT_RM_INIT_DONE) < 0) {
 		dev_err(i1480->dev, "wrong initialization event 0x%02x/%04x/%02x "
 			"received; expected 0x%02x/%04x/00\n",
 			rcebe->rceb.bEventType, le16_to_cpu(rcebe->rceb.wEvent),