wifi: brcmfmac: common: Add support for external calibration blobs

The calibration blob for a chip is normally stored in SROM and loaded
internally by the firmware. However, Apple ARM64 platforms instead store
it as part of platform configuration data, and provide it via the Apple
Device Tree. We forward this into the Linux DT in the bootloader.

Add support for taking this blob from the DT and loading it into the
dongle. The loading mechanism is the same as used for the CLM and TxCap
blobs.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230214092423.15175-10-marcan@marcan.st

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

@@ -246,6 +246,23 @@ static const u8 brcmf_default_mac_address[ETH_ALEN] = {
 	0x00, 0x90, 0x4c, 0xc5, 0x12, 0x38
 };
 
+static int brcmf_c_process_cal_blob(struct brcmf_if *ifp)
+{
+	struct brcmf_pub *drvr = ifp->drvr;
+	struct brcmf_mp_device *settings = drvr->settings;
+	s32 err;
+
+	brcmf_dbg(TRACE, "Enter\n");
+
+	if (!settings->cal_blob || !settings->cal_size)
+		return 0;
+
+	brcmf_info("Calibration blob provided by platform, loading\n");
+	err = brcmf_c_download_blob(ifp, settings->cal_blob, settings->cal_size,
+				    "calload", "calload_status");
+	return err;
+}
+
 int brcmf_c_preinit_dcmds(struct brcmf_if *ifp)
 {
 	struct brcmf_pub *drvr = ifp->drvr;
@@ -336,6 +353,13 @@ int brcmf_c_preinit_dcmds(struct brcmf_if *ifp)
 		goto done;
 	}
 
+	/* Download external calibration blob, if available */
+	err = brcmf_c_process_cal_blob(ifp);
+	if (err < 0) {
+		bphy_err(drvr, "download calibration blob file failed, %d\n", err);
+		goto done;
+	}
+
 	/* query for 'ver' to get version info from firmware */
 	memset(buf, 0, sizeof(buf));
 	err = brcmf_fil_iovar_data_get(ifp, "ver", buf, sizeof(buf));

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

@@ -54,6 +54,8 @@ struct brcmf_mp_device {
 	const char	*board_type;
 	unsigned char	mac[ETH_ALEN];
 	const char	*antenna_sku;
+	const void	*cal_blob;
+	int		cal_size;
 	union {
 		struct brcmfmac_sdio_pd sdio;
 	} bus;

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

@@ -86,6 +86,13 @@ void brcmf_of_probe(struct device *dev, enum brcmf_bus_type bus_type,
 	if (!of_property_read_string(np, "apple,antenna-sku", &prop))
 		settings->antenna_sku = prop;
 
+	/* The WLAN calibration blob is normally stored in SROM, but Apple
+	 * ARM64 platforms pass it via the DT instead.
+	 */
+	prop = of_get_property(np, "brcm,cal-blob", &settings->cal_size);
+	if (prop && settings->cal_size)
+		settings->cal_blob = prop;
+
 	/* Set board-type to the first string of the machine compatible prop */
 	root = of_find_node_by_path("/");
 	if (root && err) {