Bluetooth: btusb: Add Realtek 8723A/8723B/8761A/8821A support

Realtek ship a variety of bluetooth USB devices that identify
themselves with standard USB Bluetooth device class values, but
require a special driver to actually work. Without that driver,
you never get any scan results.

More recently however, Realtek appear to have wisened up and simply
posted a firmware update that makes these devices comply with
normal btusb protocols. The firmware needs to be uploaded on each boot.

Based on Realtek code from https://github.com/lwfinger/rtl8723au_bt
('new' branch).

This enables bluetooth support in the Gigabyte Brix GB-BXBT-2807 which
has this RTL8723BE USB device:

T:  Bus=01 Lev=01 Prnt=01 Port=01 Cnt=02 Dev#=  3 Spd=12   MxCh= 0
D:  Ver= 2.10 Cls=e0(wlcon) Sub=01 Prot=01 MxPS=64 #Cfgs=  1
P:  Vendor=13d3 ProdID=3410 Rev= 2.00
S:  Manufacturer=Realtek
S:  Product=Bluetooth Radio
S:  SerialNumber=00e04c000001
C:* #Ifs= 2 Cfg#= 1 Atr=e0 MxPwr=500mA
I:* If#= 0 Alt= 0 #EPs= 3 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
E:  Ad=81(I) Atr=03(Int.) MxPS=  16 Ivl=1ms
E:  Ad=02(O) Atr=02(Bulk) MxPS=  64 Ivl=0ms
E:  Ad=82(I) Atr=02(Bulk) MxPS=  64 Ivl=0ms
I:* If#= 1 Alt= 0 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
E:  Ad=03(O) Atr=01(Isoc) MxPS=   0 Ivl=1ms
E:  Ad=83(I) Atr=01(Isoc) MxPS=   0 Ivl=1ms
I:  If#= 1 Alt= 1 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
E:  Ad=03(O) Atr=01(Isoc) MxPS=   9 Ivl=1ms
E:  Ad=83(I) Atr=01(Isoc) MxPS=   9 Ivl=1ms
I:  If#= 1 Alt= 2 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
E:  Ad=03(O) Atr=01(Isoc) MxPS=  17 Ivl=1ms
E:  Ad=83(I) Atr=01(Isoc) MxPS=  17 Ivl=1ms
I:  If#= 1 Alt= 3 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
E:  Ad=03(O) Atr=01(Isoc) MxPS=  25 Ivl=1ms
E:  Ad=83(I) Atr=01(Isoc) MxPS=  25 Ivl=1ms
I:  If#= 1 Alt= 4 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
E:  Ad=03(O) Atr=01(Isoc) MxPS=  33 Ivl=1ms
E:  Ad=83(I) Atr=01(Isoc) MxPS=  33 Ivl=1ms
I:  If#= 1 Alt= 5 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
E:  Ad=03(O) Atr=01(Isoc) MxPS=  49 Ivl=1ms
E:  Ad=83(I) Atr=01(Isoc) MxPS=  49 Ivl=1ms

There is no change to the USB descriptor after firmware update,
however the version read by HCI_OP_READ_LOCAL_VERSION changes from
0x8723 to 0x3083.

This has also been tested on RTL8723AE and RTL8821AE. Support for
RTL8761A has also been added, but that is untested.

Signed-off-by: Daniel Drake <drake@endlessm.com>
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/btusb.c

@@ -24,6 +24,7 @@
 #include <linux/module.h>
 #include <linux/usb.h>
 #include <linux/firmware.h>
+#include <asm/unaligned.h>
 
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
@@ -57,6 +58,7 @@ static struct usb_driver btusb_driver;
 #define BTUSB_AMP		0x4000
 #define BTUSB_QCA_ROME		0x8000
 #define BTUSB_BCM_APPLE		0x10000
+#define BTUSB_REALTEK		0x20000
 
 static const struct usb_device_id btusb_table[] = {
 	/* Generic Bluetooth USB device */
@@ -288,6 +290,28 @@ static const struct usb_device_id blacklist_table[] = {
 	{ USB_VENDOR_AND_INTERFACE_INFO(0x8087, 0xe0, 0x01, 0x01),
 	  .driver_info = BTUSB_IGNORE },
 
+	/* Realtek Bluetooth devices */
+	{ USB_VENDOR_AND_INTERFACE_INFO(0x0bda, 0xe0, 0x01, 0x01),
+	  .driver_info = BTUSB_REALTEK },
+
+	/* Additional Realtek 8723AE Bluetooth devices */
+	{ USB_DEVICE(0x0930, 0x021d), .driver_info = BTUSB_REALTEK },
+	{ USB_DEVICE(0x13d3, 0x3394), .driver_info = BTUSB_REALTEK },
+
+	/* Additional Realtek 8723BE Bluetooth devices */
+	{ USB_DEVICE(0x0489, 0xe085), .driver_info = BTUSB_REALTEK },
+	{ USB_DEVICE(0x0489, 0xe08b), .driver_info = BTUSB_REALTEK },
+	{ USB_DEVICE(0x13d3, 0x3410), .driver_info = BTUSB_REALTEK },
+	{ USB_DEVICE(0x13d3, 0x3416), .driver_info = BTUSB_REALTEK },
+	{ USB_DEVICE(0x13d3, 0x3459), .driver_info = BTUSB_REALTEK },
+
+	/* Additional Realtek 8821AE Bluetooth devices */
+	{ USB_DEVICE(0x0b05, 0x17dc), .driver_info = BTUSB_REALTEK },
+	{ USB_DEVICE(0x13d3, 0x3414), .driver_info = BTUSB_REALTEK },
+	{ USB_DEVICE(0x13d3, 0x3458), .driver_info = BTUSB_REALTEK },
+	{ USB_DEVICE(0x13d3, 0x3461), .driver_info = BTUSB_REALTEK },
+	{ USB_DEVICE(0x13d3, 0x3462), .driver_info = BTUSB_REALTEK },
+
 	{ }	/* Terminating entry */
 };
 
@@ -1345,6 +1369,378 @@ static int btusb_setup_csr(struct hci_dev *hdev)
 	return ret;
 }
 
+#define RTL_FRAG_LEN 252
+
+struct rtl_download_cmd {
+	__u8 index;
+	__u8 data[RTL_FRAG_LEN];
+} __packed;
+
+struct rtl_download_response {
+	__u8 status;
+	__u8 index;
+} __packed;
+
+struct rtl_rom_version_evt {
+	__u8 status;
+	__u8 version;
+} __packed;
+
+struct rtl_epatch_header {
+	__u8 signature[8];
+	__le32 fw_version;
+	__le16 num_patches;
+} __packed;
+
+#define RTL_EPATCH_SIGNATURE	"Realtech"
+#define RTL_ROM_LMP_3499	0x3499
+#define RTL_ROM_LMP_8723A	0x1200
+#define RTL_ROM_LMP_8723B	0x8723
+#define RTL_ROM_LMP_8821A	0x8821
+#define RTL_ROM_LMP_8761A	0x8761
+
+static int rtl_read_rom_version(struct hci_dev *hdev, u8 *version)
+{
+	struct rtl_rom_version_evt *rom_version;
+	struct sk_buff *skb;
+	int ret;
+
+	/* Read RTL ROM version command */
+	skb = __hci_cmd_sync(hdev, 0xfc6d, 0, NULL, HCI_INIT_TIMEOUT);
+	if (IS_ERR(skb)) {
+		BT_ERR("%s: Read ROM version failed (%ld)",
+		       hdev->name, PTR_ERR(skb));
+		return PTR_ERR(skb);
+	}
+
+	if (skb->len != sizeof(*rom_version)) {
+		BT_ERR("%s: RTL version event length mismatch", hdev->name);
+		kfree_skb(skb);
+		return -EIO;
+	}
+
+	rom_version = (struct rtl_rom_version_evt *)skb->data;
+	BT_INFO("%s: rom_version status=%x version=%x",
+		hdev->name, rom_version->status, rom_version->version);
+
+	ret = rom_version->status;
+	if (ret == 0)
+		*version = rom_version->version;
+
+	kfree_skb(skb);
+	return ret;
+}
+
+static int rtl8723b_parse_firmware(struct hci_dev *hdev, u16 lmp_subver,
+				   const struct firmware *fw,
+				   unsigned char **_buf)
+{
+	const u8 extension_sig[] = { 0x51, 0x04, 0xfd, 0x77 };
+	struct rtl_epatch_header *epatch_info;
+	unsigned char *buf;
+	int i, ret, len;
+	size_t min_size;
+	u8 opcode, length, data, rom_version = 0;
+	int project_id = -1;
+	const unsigned char *fwptr, *chip_id_base;
+	const unsigned char *patch_length_base, *patch_offset_base;
+	u32 patch_offset = 0;
+	u16 patch_length, num_patches;
+	const u16 project_id_to_lmp_subver[] = {
+		RTL_ROM_LMP_8723A,
+		RTL_ROM_LMP_8723B,
+		RTL_ROM_LMP_8821A,
+		RTL_ROM_LMP_8761A
+	};
+
+	ret = rtl_read_rom_version(hdev, &rom_version);
+	if (ret)
+		return -bt_to_errno(ret);
+
+	min_size = sizeof(struct rtl_epatch_header) + sizeof(extension_sig) + 3;
+	if (fw->size < min_size)
+		return -EINVAL;
+
+	fwptr = fw->data + fw->size - sizeof(extension_sig);
+	if (memcmp(fwptr, extension_sig, sizeof(extension_sig)) != 0) {
+		BT_ERR("%s: extension section signature mismatch", hdev->name);
+		return -EINVAL;
+	}
+
+	/* Loop from the end of the firmware parsing instructions, until
+	 * we find an instruction that identifies the "project ID" for the
+	 * hardware supported by this firwmare file.
+	 * Once we have that, we double-check that that project_id is suitable
+	 * for the hardware we are working with.
+	 */
+	while (fwptr >= fw->data + (sizeof(struct rtl_epatch_header) + 3)) {
+		opcode = *--fwptr;
+		length = *--fwptr;
+		data = *--fwptr;
+
+		BT_DBG("check op=%x len=%x data=%x", opcode, length, data);
+
+		if (opcode == 0xff) /* EOF */
+			break;
+
+		if (length == 0) {
+			BT_ERR("%s: found instruction with length 0",
+			       hdev->name);
+			return -EINVAL;
+		}
+
+		if (opcode == 0 && length == 1) {
+			project_id = data;
+			break;
+		}
+
+		fwptr -= length;
+	}
+
+	if (project_id < 0) {
+		BT_ERR("%s: failed to find version instruction", hdev->name);
+		return -EINVAL;
+	}
+
+	if (project_id > ARRAY_SIZE(project_id_to_lmp_subver)) {
+		BT_ERR("%s: unknown project id %d", hdev->name, project_id);
+		return -EINVAL;
+	}
+
+	if (lmp_subver != project_id_to_lmp_subver[project_id]) {
+		BT_ERR("%s: firmware is for %x but this is a %x", hdev->name,
+		       project_id_to_lmp_subver[project_id], lmp_subver);
+		return -EINVAL;
+	}
+
+	epatch_info = (struct rtl_epatch_header *)fw->data;
+	if (memcmp(epatch_info->signature, RTL_EPATCH_SIGNATURE, 8) != 0) {
+		BT_ERR("%s: bad EPATCH signature", hdev->name);
+		return -EINVAL;
+	}
+
+	num_patches = le16_to_cpu(epatch_info->num_patches);
+	BT_DBG("fw_version=%x, num_patches=%d",
+	       le32_to_cpu(epatch_info->fw_version), num_patches);
+
+	/* After the rtl_epatch_header there is a funky patch metadata section.
+	 * Assuming 2 patches, the layout is:
+	 * ChipID1 ChipID2 PatchLength1 PatchLength2 PatchOffset1 PatchOffset2
+	 *
+	 * Find the right patch for this chip.
+	 */
+	min_size += 8 * num_patches;
+	if (fw->size < min_size)
+		return -EINVAL;
+
+	chip_id_base = fw->data + sizeof(struct rtl_epatch_header);
+	patch_length_base = chip_id_base + (sizeof(u16) * num_patches);
+	patch_offset_base = patch_length_base + (sizeof(u16) * num_patches);
+	for (i = 0; i < num_patches; i++) {
+		u16 chip_id = get_unaligned_le16(chip_id_base +
+						 (i * sizeof(u16)));
+		if (chip_id == rom_version + 1) {
+			patch_length = get_unaligned_le16(patch_length_base +
+							  (i * sizeof(u16)));
+			patch_offset = get_unaligned_le32(patch_offset_base +
+							  (i * sizeof(u32)));
+			break;
+		}
+	}
+
+	if (!patch_offset) {
+		BT_ERR("%s: didn't find patch for chip id %d",
+		       hdev->name, rom_version);
+		return -EINVAL;
+	}
+
+	BT_DBG("length=%x offset=%x index %d", patch_length, patch_offset, i);
+	min_size = patch_offset + patch_length;
+	if (fw->size < min_size)
+		return -EINVAL;
+
+	/* Copy the firmware into a new buffer and write the version at
+	 * the end.
+	 */
+	len = patch_length;
+	buf = kmemdup(fw->data + patch_offset, patch_length, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	memcpy(buf + patch_length - 4, &epatch_info->fw_version, 4);
+
+	*_buf = buf;
+	return len;
+}
+
+static int rtl_download_firmware(struct hci_dev *hdev,
+				 const unsigned char *data, int fw_len)
+{
+	struct rtl_download_cmd *dl_cmd;
+	int frag_num = fw_len / RTL_FRAG_LEN + 1;
+	int frag_len = RTL_FRAG_LEN;
+	int ret = 0;
+	int i;
+
+	dl_cmd = kmalloc(sizeof(struct rtl_download_cmd), GFP_KERNEL);
+	if (!dl_cmd)
+		return -ENOMEM;
+
+	for (i = 0; i < frag_num; i++) {
+		struct rtl_download_response *dl_resp;
+		struct sk_buff *skb;
+
+		BT_DBG("download fw (%d/%d)", i, frag_num);
+
+		dl_cmd->index = i;
+		if (i == (frag_num - 1)) {
+			dl_cmd->index |= 0x80; /* data end */
+			frag_len = fw_len % RTL_FRAG_LEN;
+		}
+		memcpy(dl_cmd->data, data, frag_len);
+
+		/* Send download command */
+		skb = __hci_cmd_sync(hdev, 0xfc20, frag_len + 1, dl_cmd,
+				     HCI_INIT_TIMEOUT);
+		if (IS_ERR(skb)) {
+			BT_ERR("%s: download fw command failed (%ld)",
+			       hdev->name, PTR_ERR(skb));
+			ret = -PTR_ERR(skb);
+			goto out;
+		}
+
+		if (skb->len != sizeof(*dl_resp)) {
+			BT_ERR("%s: download fw event length mismatch",
+			       hdev->name);
+			kfree_skb(skb);
+			ret = -EIO;
+			goto out;
+		}
+
+		dl_resp = (struct rtl_download_response *)skb->data;
+		if (dl_resp->status != 0) {
+			kfree_skb(skb);
+			ret = bt_to_errno(dl_resp->status);
+			goto out;
+		}
+
+		kfree_skb(skb);
+		data += RTL_FRAG_LEN;
+	}
+
+out:
+	kfree(dl_cmd);
+	return ret;
+}
+
+static int btusb_setup_rtl8723a(struct hci_dev *hdev)
+{
+	struct btusb_data *data = dev_get_drvdata(&hdev->dev);
+	struct usb_device *udev = interface_to_usbdev(data->intf);
+	const struct firmware *fw;
+	int ret;
+
+	BT_INFO("%s: rtl: loading rtl_bt/rtl8723a_fw.bin", hdev->name);
+	ret = request_firmware(&fw, "rtl_bt/rtl8723a_fw.bin", &udev->dev);
+	if (ret < 0) {
+		BT_ERR("%s: Failed to load rtl_bt/rtl8723a_fw.bin", hdev->name);
+		return ret;
+	}
+
+	if (fw->size < 8) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* Check that the firmware doesn't have the epatch signature
+	 * (which is only for RTL8723B and newer).
+	 */
+	if (!memcmp(fw->data, RTL_EPATCH_SIGNATURE, 8)) {
+		BT_ERR("%s: unexpected EPATCH signature!", hdev->name);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = rtl_download_firmware(hdev, fw->data, fw->size);
+
+out:
+	release_firmware(fw);
+	return ret;
+}
+
+static int btusb_setup_rtl8723b(struct hci_dev *hdev, u16 lmp_subver,
+				const char *fw_name)
+{
+	struct btusb_data *data = dev_get_drvdata(&hdev->dev);
+	struct usb_device *udev = interface_to_usbdev(data->intf);
+	unsigned char *fw_data = NULL;
+	const struct firmware *fw;
+	int ret;
+
+	BT_INFO("%s: rtl: loading %s", hdev->name, fw_name);
+	ret = request_firmware(&fw, fw_name, &udev->dev);
+	if (ret < 0) {
+		BT_ERR("%s: Failed to load %s", hdev->name, fw_name);
+		return ret;
+	}
+
+	ret = rtl8723b_parse_firmware(hdev, lmp_subver, fw, &fw_data);
+	if (ret < 0)
+		goto out;
+
+	ret = rtl_download_firmware(hdev, fw_data, ret);
+	kfree(fw_data);
+	if (ret < 0)
+		goto out;
+
+out:
+	release_firmware(fw);
+	return ret;
+}
+
+static int btusb_setup_realtek(struct hci_dev *hdev)
+{
+	struct sk_buff *skb;
+	struct hci_rp_read_local_version *resp;
+	u16 lmp_subver;
+
+	skb = btusb_read_local_version(hdev);
+	if (IS_ERR(skb))
+		return -PTR_ERR(skb);
+
+	resp = (struct hci_rp_read_local_version *)skb->data;
+	BT_INFO("%s: rtl: examining hci_ver=%02x hci_rev=%04x lmp_ver=%02x "
+		"lmp_subver=%04x", hdev->name, resp->hci_ver, resp->hci_rev,
+		resp->lmp_ver, resp->lmp_subver);
+
+	lmp_subver = le16_to_cpu(resp->lmp_subver);
+	kfree_skb(skb);
+
+	/* Match a set of subver values that correspond to stock firmware,
+	 * which is not compatible with standard btusb.
+	 * If matched, upload an alternative firmware that does conform to
+	 * standard btusb. Once that firmware is uploaded, the subver changes
+	 * to a different value.
+	 */
+	switch (lmp_subver) {
+	case RTL_ROM_LMP_8723A:
+	case RTL_ROM_LMP_3499:
+		return btusb_setup_rtl8723a(hdev);
+	case RTL_ROM_LMP_8723B:
+		return btusb_setup_rtl8723b(hdev, lmp_subver,
+					    "rtl_bt/rtl8723b_fw.bin");
+	case RTL_ROM_LMP_8821A:
+		return btusb_setup_rtl8723b(hdev, lmp_subver,
+					    "rtl_bt/rtl8821a_fw.bin");
+	case RTL_ROM_LMP_8761A:
+		return btusb_setup_rtl8723b(hdev, lmp_subver,
+					    "rtl_bt/rtl8761a_fw.bin");
+	default:
+		BT_INFO("rtl: assuming no firmware upload needed.");
+		return 0;
+	}
+}
+
 static const struct firmware *btusb_setup_intel_get_fw(struct hci_dev *hdev,
 						       struct intel_version *ver)
 {
@@ -2776,6 +3172,9 @@ static int btusb_probe(struct usb_interface *intf,
 		hdev->set_bdaddr = btusb_set_bdaddr_ath3012;
 	}
 
+	if (id->driver_info & BTUSB_REALTEK)
+		hdev->setup = btusb_setup_realtek;
+
 	if (id->driver_info & BTUSB_AMP) {
 		/* AMP controllers do not support SCO packets */
 		data->isoc = NULL;