[PATCH v2 6/7] Bluetooth: mediatek: Add protocol support for MediaTek serial devices

From: sean.wang
Date: Tue May 15 2018 - 04:55:18 EST

From: Sean Wang <sean.wang@xxxxxxxxxxxx>

This adds a driver to run on the top of btuart driver for the MediaTek
serial protocol based on running H:4, which can enable the built-in
Bluetooth device inside MT7622 SoC.

Signed-off-by: Sean Wang <sean.wang@xxxxxxxxxxxx>
---
drivers/bluetooth/Kconfig | 12 ++
drivers/bluetooth/Makefile | 2 +
drivers/bluetooth/btmtkuart.c | 383 ++++++++++++++++++++++++++++++++++++++++++
drivers/bluetooth/btmtkuart.h | 119 +++++++++++++
drivers/bluetooth/btuart.c | 18 ++
5 files changed, 534 insertions(+)
create mode 100644 drivers/bluetooth/btmtkuart.c
create mode 100644 drivers/bluetooth/btmtkuart.h

diff --git a/drivers/bluetooth/Kconfig b/drivers/bluetooth/Kconfig
index 6d69ac2..13aff1ed 100644
--- a/drivers/bluetooth/Kconfig
+++ b/drivers/bluetooth/Kconfig
@@ -85,6 +85,18 @@ config BT_HCIBTUART
Say Y here to compile support for Bluetooth UART devices into the
kernel or say M to compile it as module (btuart).

+config BT_HCIBTUART_MTK
+ tristate "MediaTek HCI UART driver"
+ depends on BT_HCIBTUART
+ default y
+ help
+ MediaTek Bluetooth HCI UART driver.
+ This driver is required if you want to use MediaTek Bluetooth
+ with serial interface.
+
+ Say Y here to compile support for MediaTek Bluetooth UART devices
+ into the kernel or say M to compile it as module (btmtkuart).
+
config BT_HCIUART
tristate "HCI UART driver"
depends on SERIAL_DEV_BUS || !SERIAL_DEV_BUS
diff --git a/drivers/bluetooth/Makefile b/drivers/bluetooth/Makefile
index 60a19cb..c9a8926 100644
--- a/drivers/bluetooth/Makefile
+++ b/drivers/bluetooth/Makefile
@@ -26,6 +26,8 @@ obj-$(CONFIG_BT_BCM) += btbcm.o
obj-$(CONFIG_BT_RTL) += btrtl.o
obj-$(CONFIG_BT_QCA) += btqca.o

+obj-$(CONFIG_BT_HCIBTUART_MTK) += btmtkuart.o
+
obj-$(CONFIG_BT_HCIUART_NOKIA) += hci_nokia.o

obj-$(CONFIG_BT_HCIRSI) += btrsi.o
diff --git a/drivers/bluetooth/btmtkuart.c b/drivers/bluetooth/btmtkuart.c
new file mode 100644
index 0000000..0e43a4ae
--- /dev/null
+++ b/drivers/bluetooth/btmtkuart.c
@@ -0,0 +1,383 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 MediaTek Inc.
+
+/*
+ * Bluetooth support for MediaTek serial devices
+ *
+ * Author: Sean Wang <sean.wang@xxxxxxxxxxxx>
+ *
+ */
+
+#include <asm/unaligned.h>
+#include <linux/clk.h>
+#include <linux/firmware.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/serdev.h>
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+
+#include "h4_recv.h"
+#include "btuart.h"
+#include "btmtkuart.h"
+
+static void mtk_stp_reset(struct mtk_stp_splitter *sp)
+{
+ sp->cursor = 2;
+ sp->dlen = 0;
+}
+
+static const unsigned char *
+mtk_stp_split(struct btuart_dev *bdev, struct mtk_stp_splitter *sp,
+ const unsigned char *data, int count, int *sz_h4)
+{
+ struct mtk_stp_hdr *shdr;
+
+ /* The cursor is reset when all the data of STP is consumed out. */
+ if (!sp->dlen && sp->cursor >= 6)
+ sp->cursor = 0;
+
+ /* Filling pad until all STP info is obtained. */
+ while (sp->cursor < 6 && count > 0) {
+ sp->pad[sp->cursor] = *data;
+ sp->cursor++;
+ data++;
+ count--;
+ }
+
+ /* Retrieve STP info and have a sanity check. */
+ if (!sp->dlen && sp->cursor >= 6) {
+ shdr = (struct mtk_stp_hdr *)&sp->pad[2];
+ sp->dlen = shdr->dlen1 << 8 | shdr->dlen2;
+
+ /* Resync STP when unexpected data is being read. */
+ if (shdr->prefix != 0x80 || sp->dlen > 2048) {
+ bt_dev_err(bdev->hdev, "stp format unexpect (%d, %d)",
+ shdr->prefix, sp->dlen);
+ mtk_stp_reset(sp);
+ }
+ }
+
+ /* Directly quit when there's no data found for H4 can process. */
+ if (count <= 0)
+ return NULL;
+
+ /* Tranlate to how much the size of data H4 can handle so far. */
+ *sz_h4 = min_t(int, count, sp->dlen);
+ /* Update the remaining size of STP packet. */
+ sp->dlen -= *sz_h4;
+
+ /* Data points to STP payload which can be handled by H4. */
+ return data;
+}
+
+static int mtk_stp_send(struct btuart_dev *bdev, struct sk_buff *skb)
+{
+ struct mtk_stp_hdr *shdr;
+ struct sk_buff *new_skb;
+ int dlen;
+
+ memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
+ dlen = skb->len;
+
+ /* Make sure of STP header at least has 4-bytes free space to fill. */
+ if (unlikely(skb_headroom(skb) < MTK_STP_HDR_SIZE)) {
+ new_skb = skb_realloc_headroom(skb, MTK_STP_HDR_SIZE);
+ kfree_skb(skb);
+ skb = new_skb;
+ }
+
+ /* Build for STP packet format. */
+ shdr = skb_push(skb, MTK_STP_HDR_SIZE);
+ mtk_make_stp_hdr(shdr, 0, dlen);
+ skb_put_zero(skb, MTK_STP_TLR_SIZE);
+
+ skb_queue_tail(&bdev->txq, skb);
+
+ return 0;
+}
+
+static int mtk_hci_wmt_sync(struct btuart_dev *bdev, u8 opcode, u8 flag,
+ u16 plen, const void *param)
+{
+ struct mtk_hci_wmt_cmd wc;
+ struct mtk_wmt_hdr *hdr;
+ struct sk_buff *skb;
+
+ hdr = (struct mtk_wmt_hdr *)&wc;
+ mtk_make_wmt_hdr(hdr, opcode, plen, flag);
+ memcpy(wc.data, param, plen);
+
+ skb = __hci_cmd_sync_ev(bdev->hdev, 0xfc6f, sizeof(*hdr) + plen, &wc,
+ 0xe4, HCI_INIT_TIMEOUT);
+
+ if (IS_ERR(skb)) {
+ int err = PTR_ERR(skb);
+
+ bt_dev_err(bdev->hdev, "Failed to send wmt cmd (%d)\n", err);
+ return err;
+ }
+
+ kfree_skb(skb);
+
+ return 0;
+}
+
+static int mtk_acl_wmt_sync(struct btuart_dev *bdev, u8 opcode, u8 flag,
+ u16 plen, const void *param)
+{
+ struct mtk_bt_dev *soc = bdev->data;
+ struct hci_acl_hdr *ahdr;
+ struct mtk_wmt_hdr *whdr;
+ struct sk_buff *skb;
+ int ret = 0;
+
+ init_completion(&soc->wmt_cmd);
+
+ skb = bt_skb_alloc(plen + MTK_WMT_CMD_SIZE, GFP_KERNEL);
+ if (!skb)
+ return -ENOMEM;
+
+ /* The SoC-specific ACL data is going with an opcode 0xfc6f. */
+ ahdr = skb_put(skb, HCI_ACL_HDR_SIZE);
+ ahdr->handle = cpu_to_le16(0xfc6f);
+ ahdr->dlen = cpu_to_le16(plen + MTK_WMT_HDR_SIZE);
+ hci_skb_pkt_type(skb) = HCI_ACLDATA_PKT;
+
+ /* Then add a WMT header and its actual payload. */
+ whdr = skb_put(skb, MTK_WMT_HDR_SIZE);
+ mtk_make_wmt_hdr(whdr, opcode, plen, flag);
+ skb_put_data(skb, param, plen);
+
+ mtk_stp_send(bdev, skb);
+
+ if (test_and_set_bit(BTUART_TX_STATE_ACTIVE, &bdev->tx_state))
+ set_bit(BTUART_TX_STATE_WAKEUP, &bdev->tx_state);
+ else
+ schedule_work(&bdev->tx_work);
+
+ /* Wait for its event back. */
+ ret = wait_for_completion_interruptible_timeout(&soc->wmt_cmd,
+ HZ);
+ return ret > 0 ? 0 : ret < 0 ? ret : -ETIMEDOUT;
+}
+
+static int mtk_setup_fw(struct btuart_dev *bdev)
+{
+ const struct firmware *fw;
+ struct device *dev;
+ const char *fwname;
+ const u8 *fw_ptr;
+ size_t fw_size;
+ int err, dlen;
+ u8 flag;
+
+ dev = &bdev->serdev->dev;
+ fwname = FIRMWARE_MT7622;
+
+ err = request_firmware(&fw, fwname, dev);
+ if (err < 0) {
+ bt_dev_err(bdev->hdev, "Failed to load firmware file (%d)",
+ err);
+ return err;
+ }
+
+ fw_ptr = fw->data;
+ fw_size = fw->size;
+
+ /* The size of a patch header at least has 30 bytes. */
+ if (fw_size < 30)
+ return -EINVAL;
+
+ while (fw_size > 0) {
+ dlen = min_t(int, 1000, fw_size);
+
+ /* Tell deivice the position in sequence. */
+ flag = (fw_size - dlen <= 0) ? 3 :
+ (fw_size < fw->size) ? 2 : 1;
+
+ err = mtk_acl_wmt_sync(bdev, MTK_WMT_PATCH_DWNLD, flag, dlen,
+ fw_ptr);
+ if (err < 0)
+ break;
+
+ fw_size -= dlen;
+ fw_ptr += dlen;
+ }
+
+ release_firmware(fw);
+
+ return err;
+}
+
+void *mtk_btuart_init(struct device *dev)
+{
+ struct mtk_bt_dev *soc;
+
+ soc = devm_kzalloc(dev, sizeof(*soc), GFP_KERNEL);
+ if (!soc)
+ return ERR_PTR(-ENOMEM);
+
+ soc->sp = devm_kzalloc(dev, sizeof(*soc->sp), GFP_KERNEL);
+ if (!soc->sp)
+ return ERR_PTR(-ENOMEM);
+
+ soc->clk = devm_clk_get(dev, "ref");
+ if (IS_ERR(soc->clk))
+ return ERR_CAST(soc->clk);
+
+ return soc;
+}
+EXPORT_SYMBOL_GPL(mtk_btuart_init);
+
+int mtk_btuart_send(struct hci_dev *hdev, struct sk_buff *skb)
+{
+ struct btuart_dev *bdev = hci_get_drvdata(hdev);
+
+ return mtk_stp_send(bdev, skb);
+}
+EXPORT_SYMBOL_GPL(mtk_btuart_send);
+
+int mtk_btuart_hci_frame(struct hci_dev *hdev, struct sk_buff *skb)
+{
+ struct hci_event_hdr *hdr = (void *)skb->data;
+ struct btuart_dev *bdev = hci_get_drvdata(hdev);
+ struct mtk_bt_dev *soc = bdev->data;
+
+ /* Complete the SoC-specific data being sent. */
+ if (hdr->evt == 0xe4)
+ complete(&soc->wmt_cmd);
+
+ /* Each HCI event would go through the core. */
+ return hci_recv_frame(hdev, skb);
+}
+EXPORT_SYMBOL_GPL(mtk_btuart_hci_frame);
+
+int mtk_btuart_recv(struct hci_dev *hdev, const u8 *data, size_t count)
+{
+ struct btuart_dev *bdev = hci_get_drvdata(hdev);
+ const unsigned char *p_left = data, *p_h4;
+ const struct btuart_vnd *vnd = bdev->vnd;
+ struct mtk_bt_dev *soc = bdev->data;
+ int sz_left = count, sz_h4, adv;
+ struct device *dev;
+ int err;
+
+ dev = &bdev->serdev->dev;
+
+ while (sz_left > 0) {
+ /* The serial data received from MT7622 BT controller is
+ * at all time padded around with the STP header and tailer.
+ *
+ * A full STP packet is looking like
+ * -----------------------------------
+ * | STP header | H:4 | STP tailer |
+ * -----------------------------------
+ * but it don't guarantee to contain a full H:4 packet which
+ * means that it's possible for multiple STP packets forms a
+ * full H:4 packet and whose length recorded in STP header can
+ * shows up the most length the H:4 engine can handle in one
+ * time.
+ */
+
+ p_h4 = mtk_stp_split(bdev, soc->sp, p_left, sz_left, &sz_h4);
+ if (!p_h4)
+ break;
+
+ adv = p_h4 - p_left;
+ sz_left -= adv;
+ p_left += adv;
+
+ bdev->rx_skb = h4_recv_buf(bdev->hdev, bdev->rx_skb, p_h4,
+ sz_h4, vnd->recv_pkts,
+ vnd->recv_pkts_cnt);
+ if (IS_ERR(bdev->rx_skb)) {
+ err = PTR_ERR(bdev->rx_skb);
+ bt_dev_err(bdev->hdev,
+ "Frame reassembly failed (%d)", err);
+ bdev->rx_skb = NULL;
+ return err;
+ }
+
+ sz_left -= sz_h4;
+ p_left += sz_h4;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mtk_btuart_recv);
+
+int mtk_btuart_setup(struct hci_dev *hdev)
+{
+ struct btuart_dev *bdev = hci_get_drvdata(hdev);
+ struct mtk_bt_dev *soc = bdev->data;
+ struct device *dev;
+ u8 param = 0x1;
+ int err = 0;
+
+ dev = &bdev->serdev->dev;
+
+ mtk_stp_reset(soc->sp);
+
+ /* Enable the power domain and clock the device requires. */
+ pm_runtime_enable(dev);
+ err = pm_runtime_get_sync(dev);
+ if (err < 0)
+ goto err_pm2;
+
+ err = clk_prepare_enable(soc->clk);
+ if (err < 0)
+ goto err_pm1;
+
+ /* Setup a firmware which the device definitely requires. */
+ err = mtk_setup_fw(bdev);
+ if (err < 0)
+ goto err_clk;
+
+ /* Activate funciton the firmware providing to. */
+ err = mtk_hci_wmt_sync(bdev, MTK_WMT_RST, 0x4, 0, 0);
+ if (err < 0)
+ goto err_clk;
+
+ /* Enable Bluetooth protocol. */
+ err = mtk_hci_wmt_sync(bdev, MTK_WMT_FUNC_CTRL, 0x0, sizeof(param),
+ &param);
+ if (err < 0)
+ goto err_clk;
+
+ set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);
+
+ return 0;
+err_clk:
+ clk_disable_unprepare(soc->clk);
+err_pm1:
+ pm_runtime_put_sync(dev);
+err_pm2:
+ pm_runtime_disable(dev);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(mtk_btuart_setup);
+
+int mtk_btuart_shutdown(struct hci_dev *hdev)
+{
+ struct btuart_dev *bdev = hci_get_drvdata(hdev);
+ struct device *dev = &bdev->serdev->dev;
+ struct mtk_bt_dev *soc = bdev->data;
+ u8 param = 0x0;
+
+ /* Disable the device. */
+ mtk_hci_wmt_sync(bdev, MTK_WMT_FUNC_CTRL, 0x0, sizeof(param), &param);
+
+ /* Shutdown the clock and power domain the device requires. */
+ clk_disable_unprepare(soc->clk);
+ pm_runtime_put_sync(dev);
+ pm_runtime_disable(dev);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mtk_btuart_shutdown);
+
+MODULE_AUTHOR("Sean Wang <sean.wang@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Bluetooth Support for MediaTek Serial Devices");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/bluetooth/btmtkuart.h b/drivers/bluetooth/btmtkuart.h
new file mode 100644
index 0000000..ea6fc36
--- /dev/null
+++ b/drivers/bluetooth/btmtkuart.h
@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 MediaTek Inc.
+
+/*
+ * Bluetooth support for MediaTek serial devices
+ *
+ * Author: Sean Wang <sean.wang@xxxxxxxxxxxx>
+ *
+ */
+
+#define FIRMWARE_MT7622 "mediatek/mt7622_patch_firmware.bin"
+
+#define MTK_STP_HDR_SIZE 4
+#define MTK_STP_TLR_SIZE 2
+#define MTK_WMT_HDR_SIZE 5
+#define MTK_WMT_CMD_SIZE (MTK_WMT_HDR_SIZE + MTK_STP_HDR_SIZE + \
+ MTK_STP_TLR_SIZE + HCI_ACL_HDR_SIZE)
+
+enum {
+ MTK_WMT_PATCH_DWNLD = 0x1,
+ MTK_WMT_FUNC_CTRL = 0x6,
+ MTK_WMT_RST = 0x7
+};
+
+struct mtk_stp_hdr {
+ __u8 prefix;
+ __u8 dlen1:4;
+ __u8 type:4;
+ __u8 dlen2:8;
+ __u8 cs;
+} __packed;
+
+struct mtk_wmt_hdr {
+ __u8 dir;
+ __u8 op;
+ __le16 dlen;
+ __u8 flag;
+} __packed;
+
+struct mtk_hci_wmt_cmd {
+ struct mtk_wmt_hdr hdr;
+ __u8 data[16];
+} __packed;
+
+struct mtk_stp_splitter {
+ u8 pad[6];
+ u8 cursor;
+ u16 dlen;
+};
+
+struct mtk_bt_dev {
+ struct clk *clk;
+ struct completion wmt_cmd;
+ struct mtk_stp_splitter *sp;
+};
+
+static inline void mtk_make_stp_hdr(struct mtk_stp_hdr *hdr, u8 type, u32 dlen)
+{
+ __u8 *p = (__u8 *)hdr;
+
+ hdr->prefix = 0x80;
+ hdr->dlen1 = (dlen & 0xf00) >> 8;
+ hdr->type = type;
+ hdr->dlen2 = dlen & 0xff;
+ hdr->cs = p[0] + p[1] + p[2];
+}
+
+static inline void mtk_make_wmt_hdr(struct mtk_wmt_hdr *hdr, u8 op, u16 plen,
+ u8 flag)
+{
+ hdr->dir = 1;
+ hdr->op = op;
+ hdr->dlen = cpu_to_le16(plen + 1);
+ hdr->flag = flag;
+}
+
+#if IS_ENABLED(CONFIG_BT_HCIBTUART_MTK)
+
+void *mtk_btuart_init(struct device *dev);
+int mtk_btuart_setup(struct hci_dev *hdev);
+int mtk_btuart_shutdown(struct hci_dev *hdev);
+int mtk_btuart_send(struct hci_dev *hdev, struct sk_buff *skb);
+int mtk_btuart_hci_frame(struct hci_dev *hdev, struct sk_buff *skb);
+int mtk_btuart_recv(struct hci_dev *hdev, const u8 *data, size_t count);
+
+#else
+
+static void *mtk_btuart_init(struct device *dev)
+{
+ return 0;
+}
+
+static inline int mtk_btuart_setup(struct hci_dev *hdev)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int mtk_btuart_shutdown(struct hci_dev *hdev)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int mtk_btuart_send(struct hci_dev *hdev, struct sk_buff *skb)
+{
+ return -EOPNOTSUPP;
+}
+
+static int mtk_btuart_hci_frame(struct hci_dev *hdev, struct sk_buff *skb)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int mtk_btuart_recv(struct hci_dev *hdev, const u8 *data,
+ size_t count)
+{
+ return -EOPNOTSUPP;
+}
+
+#endif
diff --git a/drivers/bluetooth/btuart.c b/drivers/bluetooth/btuart.c
index ab7f836..169bf1a 100644
--- a/drivers/bluetooth/btuart.c
+++ b/drivers/bluetooth/btuart.c
@@ -35,6 +35,7 @@
#include "h4_recv.h"
#include "btuart.h"
#include "btbcm.h"
+#include "btmtkuart.h"

#define VERSION "1.0"

@@ -396,6 +397,12 @@ static const struct h4_recv_pkt bcm_recv_pkts[] = {
{ BCM_RECV_NULL, .recv = hci_recv_diag },
};

+static const struct h4_recv_pkt mtk_recv_pkts[] = {
+ { H4_RECV_ACL, .recv = hci_recv_frame },
+ { H4_RECV_SCO, .recv = hci_recv_frame },
+ { H4_RECV_EVENT, .recv = mtk_btuart_hci_frame },
+};
+
static const struct btuart_vnd bcm_vnd = {
.recv_pkts = bcm_recv_pkts,
.recv_pkts_cnt = ARRAY_SIZE(bcm_recv_pkts),
@@ -403,6 +410,16 @@ static const struct btuart_vnd bcm_vnd = {
.setup = bcm_setup,
};

+static const struct btuart_vnd mtk_vnd = {
+ .recv_pkts = mtk_recv_pkts,
+ .recv_pkts_cnt = ARRAY_SIZE(mtk_recv_pkts),
+ .init = mtk_btuart_init,
+ .setup = mtk_btuart_setup,
+ .shutdown = mtk_btuart_shutdown,
+ .send = mtk_btuart_send,
+ .recv = mtk_btuart_recv,
+};
+
static const struct h4_recv_pkt default_recv_pkts[] = {
{ H4_RECV_ACL, .recv = hci_recv_frame },
{ H4_RECV_SCO, .recv = hci_recv_frame },
@@ -487,6 +504,7 @@ static void btuart_remove(struct serdev_device *serdev)
#ifdef CONFIG_OF
static const struct of_device_id btuart_of_match_table[] = {
{ .compatible = "brcm,bcm43438-bt", .data = &bcm_vnd },
+ { .compatible = "mediatek,mt7622-bluetooth", .data = &mtk_vnd },
{ }
};
MODULE_DEVICE_TABLE(of, btuart_of_match_table);
--
2.7.4