[PATCH] brcmfmac: firmware: Fix firmware loading

[Linus Walleij <linus.walleij@linaro.org>]

The patch that would first try the board-specific firmware
had a bug because the fallback would not be called: the
asynchronous interface is used meaning request_firmware_nowait()
returns 0 immediately.

Harden the firmware loading like this:

- If we cannot build an alt_path (like if no board_type is
  specified) just request the first firmware without any
  suffix, like in the past.

- If the lookup of a board specific firmware fails, we get
  a NULL fw in the async callback, so just try again without
  the alt_path. Use a static variable to check that we do not
  try this indefinitely.

- Rename the brcm_fw_request_done to brcm_fw_request_done_first
  reflecting the fact that this callback is only used for the
  first (main) firmware file, and drop the unnecessary
  prototype.

Fixes: 5ff013914c62 ("brcmfmac: firmware: Allow per-board firmware binaries")
Cc: Dmitry Osipenko <digetx@gmail.com>
Cc: Stefan Hansson <newbyte@disroot.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 .../broadcom/brcm80211/brcmfmac/firmware.c    | 29 +++++++++++++------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
index adfdfc654b10..71ca4a517e42 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
@@ -431,8 +431,6 @@ struct brcmf_fw {
 	void (*done)(struct device *dev, int err, struct brcmf_fw_request *req);
 };
 
-static void brcmf_fw_request_done(const struct firmware *fw, void *ctx);
-
 #ifdef CONFIG_EFI
 /* In some cases the EFI-var stored nvram contains "ccode=ALL" or "ccode=XV"
  * to specify "worldwide" compatible settings, but these 2 ccode-s do not work
@@ -638,11 +636,26 @@ static int brcmf_fw_request_firmware(const struct firmware **fw,
 	return request_firmware(fw, cur->path, fwctx->dev);
 }
 
-static void brcmf_fw_request_done(const struct firmware *fw, void *ctx)
+static void brcmf_fw_request_done_first(const struct firmware *fw, void *ctx)
 {
 	struct brcmf_fw *fwctx = ctx;
+	struct brcmf_fw_item *first = &fwctx->req->items[0];
+	static bool retry = true;
 	int ret;
 
+	/*Something failed with the first firmware request , such as not
+	 * getting the per-board firmware. Retry this, now using the less
+	 * specific path for the first firmware item, i.e. without the board
+	 * suffix.
+	 */
+	if (!fw && retry) {
+		ret = request_firmware_nowait(THIS_MODULE, true, first->path,
+					      fwctx->dev, GFP_KERNEL, fwctx,
+					      brcmf_fw_request_done_first);
+		retry = false;
+		return;
+	}
+
 	ret = brcmf_fw_complete_request(fw, fwctx);
 
 	while (ret == 0 && ++fwctx->curpos < fwctx->req->n_items) {
@@ -702,17 +715,15 @@ int brcmf_fw_get_firmwares(struct device *dev, struct brcmf_fw_request *req,
 	if (alt_path) {
 		ret = request_firmware_nowait(THIS_MODULE, true, alt_path,
 					      fwctx->dev, GFP_KERNEL, fwctx,
-					      brcmf_fw_request_done);
+					      brcmf_fw_request_done_first);
 		kfree(alt_path);
-	}
-	/* Else try canonical path */
-	if (ret) {
+	} else {
 		ret = request_firmware_nowait(THIS_MODULE, true, first->path,
 					      fwctx->dev, GFP_KERNEL, fwctx,
-					      brcmf_fw_request_done);
+					      brcmf_fw_request_done_first);
 	}
 	if (ret < 0)
-		brcmf_fw_request_done(NULL, fwctx);
+		brcmf_fw_request_done_first(NULL, fwctx);
 
 	return 0;
 }
-- 
2.31.1