linux-t2-patches/8002-brcmfmac-firmware-Support-having-multiple-alt-paths.patch

From 59c61aa5ad2e12fdbccb5712d35c203cf9079230 Mon Sep 17 00:00:00 2001
From: Hector Martin <marcan@marcan.st>
Date: Sat, 18 Dec 2021 20:38:34 +0900
Subject: [PATCH 02/30] brcmfmac: firmware: Support having multiple alt paths

Apple platforms have firmware and config files identified with multiple
dimensions. We want to be able to find the most specific firmware
available for any given platform, progressively trying more general
firmwares.

First, add support for having multiple alternate firmware paths.

Signed-off-by: Hector Martin <marcan@marcan.st>
---
 .../broadcom/brcm80211/brcmfmac/firmware.c    | 74 ++++++++++++++-----
 1 file changed, 55 insertions(+), 19 deletions(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
index 0eb13e5df..dff974955 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.c
@@ -427,6 +427,8 @@ void brcmf_fw_nvram_free(void *nvram)
 struct brcmf_fw {
 	struct device *dev;
 	struct brcmf_fw_request *req;
+	const char **alt_paths;
+	int alt_index;
 	u32 curpos;
 	void (*done)(struct device *dev, int err, struct brcmf_fw_request *req);
 };
@@ -592,9 +594,10 @@ static int brcmf_fw_complete_request(const struct firmware *fw,
 	return (cur->flags & BRCMF_FW_REQF_OPTIONAL) ? 0 : ret;
 }
 
-static char *brcm_alt_fw_path(const char *path, const char *board_type)
+static const char **brcm_alt_fw_paths(const char *path, const char *board_type)
 {
 	char alt_path[BRCMF_FW_NAME_LEN];
+	char **alt_paths;
 	char suffix[5];
 
 	strscpy(alt_path, path, BRCMF_FW_NAME_LEN);
@@ -609,27 +612,45 @@ static char *brcm_alt_fw_path(const char *path, const char *board_type)
 	strlcat(alt_path, board_type, BRCMF_FW_NAME_LEN);
 	strlcat(alt_path, suffix, BRCMF_FW_NAME_LEN);
 
-	return kstrdup(alt_path, GFP_KERNEL);
+	alt_paths = kzalloc(sizeof(char *) * 2, GFP_KERNEL);
+	alt_paths[0] = kstrdup(alt_path, GFP_KERNEL);
+
+	return (const char **)alt_paths;
+}
+
+static void brcm_free_alt_fw_paths(const char **alt_paths)
+{
+	int i;
+
+	if (!alt_paths)
+		return;
+
+	for (i = 0; alt_paths[i]; i++)
+		kfree(alt_paths[i]);
+
+	kfree(alt_paths);
 }
 
 static int brcmf_fw_request_firmware(const struct firmware **fw,
 				     struct brcmf_fw *fwctx)
 {
 	struct brcmf_fw_item *cur = &fwctx->req->items[fwctx->curpos];
-	int ret;
+	int ret, i;
 
 	/* Files can be board-specific, first try a board-specific path */
 	if (cur->type == BRCMF_FW_TYPE_NVRAM && fwctx->req->board_type) {
-		char *alt_path;
-
-		alt_path = brcm_alt_fw_path(cur->path, fwctx->req->board_type);
-		if (!alt_path)
+		const char **alt_paths = brcm_alt_fw_paths(cur->path, fwctx);
+		if (!alt_paths)
 			goto fallback;
 
-		ret = request_firmware(fw, alt_path, fwctx->dev);
-		kfree(alt_path);
-		if (ret == 0)
-			return ret;
+		for (i = 0; alt_paths[i]; i++) {
+			ret = firmware_request_nowarn(fw, alt_paths[i], fwctx->dev);
+			if (ret == 0) {
+				brcm_free_alt_fw_paths(alt_paths);
+				return ret;
+			}
+		}
+		brcm_free_alt_fw_paths(alt_paths);
 	}
 
 fallback:
@@ -641,6 +662,9 @@ static void brcmf_fw_request_done(const struct firmware *fw, void *ctx)
 	struct brcmf_fw *fwctx = ctx;
 	int ret;
 
+	brcm_free_alt_fw_paths(fwctx->alt_paths);
+	fwctx->alt_paths = NULL;
+
 	ret = brcmf_fw_complete_request(fw, fwctx);
 
 	while (ret == 0 && ++fwctx->curpos < fwctx->req->n_items) {
@@ -662,13 +686,26 @@ static void brcmf_fw_request_done_alt_path(const struct firmware *fw, void *ctx)
 	struct brcmf_fw_item *first = &fwctx->req->items[0];
 	int ret = 0;
 
-	/* Fall back to canonical path if board firmware not found */
-	if (!fw)
+	if (fw) {
+		brcmf_fw_request_done(fw, ctx);
+		return;
+	}
+
+	fwctx->alt_index++;
+	if (fwctx->alt_paths[fwctx->alt_index]) {
+		/* Try the next alt firmware */
+		ret = request_firmware_nowait(THIS_MODULE, true,
+					      fwctx->alt_paths[fwctx->alt_index],
+					      fwctx->dev, GFP_KERNEL, fwctx,
+					      brcmf_fw_request_done_alt_path);
+	} else {
+		/* Fall back to canonical path if board firmware not found */
 		ret = request_firmware_nowait(THIS_MODULE, true, first->path,
 					      fwctx->dev, GFP_KERNEL, fwctx,
 					      brcmf_fw_request_done);
+	}
 
-	if (fw || ret < 0)
+	if (ret < 0)
 		brcmf_fw_request_done(fw, ctx);
 }
 
@@ -693,7 +730,6 @@ int brcmf_fw_get_firmwares(struct device *dev, struct brcmf_fw_request *req,
 {
 	struct brcmf_fw_item *first = &req->items[0];
 	struct brcmf_fw *fwctx;
-	char *alt_path;
 	int ret;
 
 	brcmf_dbg(TRACE, "enter: dev=%s\n", dev_name(dev));
@@ -712,12 +748,12 @@ int brcmf_fw_get_firmwares(struct device *dev, struct brcmf_fw_request *req,
 	fwctx->done = fw_cb;
 
 	/* First try alternative board-specific path if any */
-	alt_path = brcm_alt_fw_path(first->path, fwctx->req->board_type);
-	if (alt_path) {
-		ret = request_firmware_nowait(THIS_MODULE, true, alt_path,
+	fwctx->alt_paths = brcm_alt_fw_paths(first->path, fwctx);
+	if (fwctx->alt_paths) {
+		fwctx->alt_index = 0;
+		ret = request_firmware_nowait(THIS_MODULE, true, fwctx->alt_paths[0],
 					      fwctx->dev, GFP_KERNEL, fwctx,
 					      brcmf_fw_request_done_alt_path);
-		kfree(alt_path);
 	} else {
 		ret = request_firmware_nowait(THIS_MODULE, true, first->path,
 					      fwctx->dev, GFP_KERNEL, fwctx,
-- 
2.34.1