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Subject[PATCH v6 3/4] Bluetooth: mediatek: Add protocol support for MediaTek serial devices
Date
From: Sean Wang <sean.wang@mediatek.com>

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@mediatek.com>
---
drivers/bluetooth/Kconfig | 11 +
drivers/bluetooth/Makefile | 2 +
drivers/bluetooth/btmtkuart.c | 552 ++++++++++++++++++++++++++++++++++++++++++
drivers/bluetooth/btmtkuart.h | 83 +++++++
4 files changed, 648 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 a164ac4..074737c 100644
--- a/drivers/bluetooth/Kconfig
+++ b/drivers/bluetooth/Kconfig
@@ -74,6 +74,17 @@ config BT_HCIBTSDIO
Say Y here to compile support for Bluetooth SDIO devices into the
kernel or say M to compile it as module (btsdio).

+config BT_HCIBTUART_MTK
+ tristate "MediaTek HCI UART driver"
+ depends on SERIAL_DEV_BUS
+ 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 2fb6268..2aea62e 100644
--- a/drivers/bluetooth/Makefile
+++ b/drivers/bluetooth/Makefile
@@ -25,6 +25,8 @@ 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

btmrvl-y := btmrvl_main.o
diff --git a/drivers/bluetooth/btmtkuart.c b/drivers/bluetooth/btmtkuart.c
new file mode 100644
index 0000000..dd800ac
--- /dev/null
+++ b/drivers/bluetooth/btmtkuart.c
@@ -0,0 +1,552 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 MediaTek Inc.
+
+/*
+ * Bluetooth support for MediaTek serial devices
+ *
+ * Author: Sean Wang <sean.wang@mediatek.com>
+ *
+ */
+
+#include <asm/unaligned.h>
+#include <linux/atomic.h>
+#include <linux/clk.h>
+#include <linux/firmware.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm_runtime.h>
+#include <linux/serdev.h>
+#include <linux/skbuff.h>
+
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+
+#include "btmtkuart.h"
+#include "h4_recv.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 mtk_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 mtk_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) < sizeof(*shdr))) {
+ new_skb = skb_realloc_headroom(skb, sizeof(*shdr));
+ kfree_skb(skb);
+ skb = new_skb;
+ }
+
+ /* Build for STP packet format. */
+ shdr = skb_push(skb, sizeof(*shdr));
+ 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 hci_dev *hdev, u8 opcode, u8 flag,
+ u16 plen, const void *param)
+{
+ struct mtk_hci_wmt_cmd wc;
+ struct mtk_wmt_hdr *hdr;
+ struct sk_buff *skb;
+ u32 hlen;
+
+ hlen = sizeof(*hdr) + plen;
+ if (hlen > 255)
+ return -EINVAL;
+
+ hdr = (struct mtk_wmt_hdr *)&wc;
+ mtk_make_wmt_hdr(hdr, opcode, plen, flag);
+ memcpy(wc.data, param, plen);
+
+ atomic_inc(&hdev->cmd_cnt);
+
+ skb = __hci_cmd_sync_ev(hdev, 0xfc6f, hlen, &wc, HCI_VENDOR_PKT,
+ HCI_INIT_TIMEOUT);
+
+ if (IS_ERR(skb)) {
+ int err = PTR_ERR(skb);
+
+ bt_dev_err(hdev, "Failed to send wmt cmd (%d)", err);
+ return err;
+ }
+
+ kfree_skb(skb);
+
+ return 0;
+}
+
+static int mtk_setup_fw(struct hci_dev *hdev)
+{
+ const struct firmware *fw;
+ const char *fwname;
+ const u8 *fw_ptr;
+ size_t fw_size;
+ int err, dlen;
+ u8 flag;
+
+ fwname = FIRMWARE_MT7622;
+
+ err = request_firmware(&fw, fwname, &hdev->dev);
+ if (err < 0) {
+ bt_dev_err(hdev, "Failed to load firmware file (%d)", err);
+ return err;
+ }
+
+ fw_ptr = fw->data;
+ fw_size = fw->size;
+
+ /* The size of patch header is 30 bytes, should be skip. */
+ if (fw_size < 30)
+ return -EINVAL;
+
+ fw_size -= 30;
+ fw_ptr += 30;
+ flag = 1;
+
+ while (fw_size > 0) {
+ dlen = min_t(int, 250, fw_size);
+
+ /* Tell deivice the position in sequence. */
+ if (fw_size - dlen <= 0)
+ flag = 3;
+ else if (fw_size < fw->size - 30)
+ flag = 2;
+
+ err = mtk_hci_wmt_sync(hdev, MTK_WMT_PATCH_DWNLD, flag, dlen,
+ fw_ptr);
+ if (err < 0)
+ break;
+
+ fw_size -= dlen;
+ fw_ptr += dlen;
+ }
+
+ release_firmware(fw);
+
+ return err;
+}
+
+static int mtk_btuart_hci_frame(struct hci_dev *hdev, struct sk_buff *skb)
+{
+ struct hci_event_hdr *hdr = (void *)skb->data;
+
+ /* Fix up the vendor event id with HCI_VENDOR_PKT instead of
+ * 0xe4 so that btmon can parse the kind of vendor event properly.
+ */
+ if (hdr->evt == 0xe4)
+ hdr->evt = HCI_VENDOR_PKT;
+
+ /* Each HCI event would go through the core. */
+ return hci_recv_frame(hdev, skb);
+}
+
+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 int mtk_btuart_recv(struct hci_dev *hdev, const u8 *data, size_t count)
+{
+ struct mtk_btuart_dev *bdev = hci_get_drvdata(hdev);
+ const unsigned char *p_left = data, *p_h4;
+ int sz_left = count, sz_h4, adv;
+ int err;
+
+ 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 doesn'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 that means extra STP header + length doesn't
+ * indicate a full H:4 frame, things can fragment. Whose length
+ * recorded in STP header just shows up the most length the
+ * H:4 engine can handle currently.
+ */
+
+ p_h4 = mtk_stp_split(bdev, bdev->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, mtk_recv_pkts,
+ sizeof(mtk_recv_pkts));
+ 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;
+}
+
+static void mtk_btuart_tx_work(struct work_struct *work)
+{
+ struct mtk_btuart_dev *bdev = container_of(work, struct mtk_btuart_dev,
+ tx_work);
+ struct serdev_device *serdev = bdev->serdev;
+ struct hci_dev *hdev = bdev->hdev;
+
+ while (1) {
+ clear_bit(BTUART_TX_STATE_WAKEUP, &bdev->tx_state);
+
+ while (1) {
+ struct sk_buff *skb = skb_dequeue(&bdev->txq);
+ int len;
+
+ if (!skb)
+ break;
+
+ len = serdev_device_write_buf(serdev, skb->data,
+ skb->len);
+ hdev->stat.byte_tx += len;
+
+ skb_pull(skb, len);
+ if (skb->len > 0) {
+ skb_queue_head(&bdev->txq, skb);
+ break;
+ }
+
+ switch (hci_skb_pkt_type(skb)) {
+ case HCI_COMMAND_PKT:
+ hdev->stat.cmd_tx++;
+ break;
+ case HCI_ACLDATA_PKT:
+ hdev->stat.acl_tx++;
+ break;
+ case HCI_SCODATA_PKT:
+ hdev->stat.sco_tx++;
+ break;
+ }
+
+ kfree_skb(skb);
+ }
+
+ if (!test_bit(BTUART_TX_STATE_WAKEUP, &bdev->tx_state))
+ break;
+ }
+
+ clear_bit(BTUART_TX_STATE_ACTIVE, &bdev->tx_state);
+}
+
+static int mtk_btuart_tx_wakeup(struct mtk_btuart_dev *bdev)
+{
+ if (test_and_set_bit(BTUART_TX_STATE_ACTIVE, &bdev->tx_state)) {
+ set_bit(BTUART_TX_STATE_WAKEUP, &bdev->tx_state);
+ return 0;
+ }
+
+ schedule_work(&bdev->tx_work);
+
+ return 0;
+}
+
+static int mtk_btuart_receive_buf(struct serdev_device *serdev, const u8 *data,
+ size_t count)
+{
+ struct mtk_btuart_dev *bdev = serdev_device_get_drvdata(serdev);
+ int err;
+
+ err = mtk_btuart_recv(bdev->hdev, data, count);
+ if (err < 0)
+ return err;
+
+ bdev->hdev->stat.byte_rx += count;
+
+ return count;
+}
+
+static void mtk_btuart_write_wakeup(struct serdev_device *serdev)
+{
+ struct mtk_btuart_dev *bdev = serdev_device_get_drvdata(serdev);
+
+ mtk_btuart_tx_wakeup(bdev);
+}
+
+static const struct serdev_device_ops mtk_btuart_client_ops = {
+ .receive_buf = mtk_btuart_receive_buf,
+ .write_wakeup = mtk_btuart_write_wakeup,
+};
+
+static int mtk_btuart_open(struct hci_dev *hdev)
+{
+ struct mtk_btuart_dev *bdev = hci_get_drvdata(hdev);
+ int err;
+
+ err = serdev_device_open(bdev->serdev);
+ if (err)
+ bt_dev_err(hdev, "Unable to open UART device %s",
+ dev_name(&bdev->serdev->dev));
+
+ return err;
+}
+
+static int mtk_btuart_close(struct hci_dev *hdev)
+{
+ struct mtk_btuart_dev *bdev = hci_get_drvdata(hdev);
+
+ serdev_device_close(bdev->serdev);
+
+ return 0;
+}
+
+static int mtk_btuart_flush(struct hci_dev *hdev)
+{
+ struct mtk_btuart_dev *bdev = hci_get_drvdata(hdev);
+
+ /* Flush any pending characters */
+ serdev_device_write_flush(bdev->serdev);
+ skb_queue_purge(&bdev->txq);
+
+ cancel_work_sync(&bdev->tx_work);
+
+ kfree_skb(bdev->rx_skb);
+ bdev->rx_skb = NULL;
+
+ return 0;
+}
+
+static int mtk_btuart_setup(struct hci_dev *hdev)
+{
+ struct mtk_btuart_dev *bdev = hci_get_drvdata(hdev);
+ struct device *dev;
+ u8 param = 0x1;
+ int err = 0;
+
+ dev = &bdev->serdev->dev;
+
+ mtk_stp_reset(bdev->sp);
+
+ /* Enable the power domain and clock the device requires. */
+ pm_runtime_enable(dev);
+ err = pm_runtime_get_sync(dev);
+ if (err < 0) {
+ pm_runtime_put_noidle(dev);
+ goto err_disable_rpm;
+ }
+
+ err = clk_prepare_enable(bdev->clk);
+ if (err < 0)
+ goto err_put_rpm;
+
+ /* Setup a firmware which the device definitely requires. */
+ err = mtk_setup_fw(hdev);
+ if (err < 0)
+ goto err_clk;
+
+ /* Activate funciton the firmware providing to. */
+ err = mtk_hci_wmt_sync(hdev, MTK_WMT_RST, 0x4, 0, 0);
+ if (err < 0)
+ goto err_clk;
+
+ /* Enable Bluetooth protocol. */
+ err = mtk_hci_wmt_sync(hdev, 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(bdev->clk);
+err_put_rpm:
+ pm_runtime_put_sync(dev);
+err_disable_rpm:
+ pm_runtime_disable(dev);
+
+ return err;
+}
+
+static int mtk_btuart_shutdown(struct hci_dev *hdev)
+{
+ struct mtk_btuart_dev *bdev = hci_get_drvdata(hdev);
+ struct device *dev = &bdev->serdev->dev;
+ u8 param = 0x0;
+
+ /* Disable the device. */
+ mtk_hci_wmt_sync(hdev, MTK_WMT_FUNC_CTRL, 0x0, sizeof(param), &param);
+
+ /* Shutdown the clock and power domain the device requires. */
+ clk_disable_unprepare(bdev->clk);
+ pm_runtime_put_sync(dev);
+ pm_runtime_disable(dev);
+
+ return 0;
+}
+
+static int mtk_btuart_send(struct hci_dev *hdev, struct sk_buff *skb)
+{
+ struct mtk_btuart_dev *bdev = hci_get_drvdata(hdev);
+ int err;
+
+ err = mtk_stp_send(bdev, skb);
+ if (err < 0)
+ return err;
+
+ err = mtk_btuart_tx_wakeup(bdev);
+
+ return err;
+}
+
+static int mtk_btuart_probe(struct serdev_device *serdev)
+{
+ struct mtk_btuart_dev *bdev;
+ struct hci_dev *hdev;
+
+ bdev = devm_kzalloc(&serdev->dev, sizeof(*bdev), GFP_KERNEL);
+ if (!bdev)
+ return -ENOMEM;
+
+ bdev->sp = devm_kzalloc(&serdev->dev, sizeof(*bdev->sp), GFP_KERNEL);
+ if (!bdev->sp)
+ return -ENOMEM;
+
+ bdev->clk = devm_clk_get(&serdev->dev, "ref");
+ if (IS_ERR(bdev->clk))
+ return PTR_ERR(bdev->clk);
+
+ bdev->serdev = serdev;
+ serdev_device_set_drvdata(serdev, bdev);
+
+ serdev_device_set_client_ops(serdev, &mtk_btuart_client_ops);
+
+ INIT_WORK(&bdev->tx_work, mtk_btuart_tx_work);
+ skb_queue_head_init(&bdev->txq);
+
+ /* Initialize and register HCI device */
+ hdev = hci_alloc_dev();
+ if (!hdev) {
+ dev_err(&serdev->dev, "Can't allocate HCI device\n");
+ return -ENOMEM;
+ }
+
+ bdev->hdev = hdev;
+
+ hdev->bus = HCI_UART;
+ hdev->manufacturer = 70;
+ hci_set_drvdata(hdev, bdev);
+
+ hdev->open = mtk_btuart_open;
+ hdev->close = mtk_btuart_close;
+ hdev->flush = mtk_btuart_flush;
+ hdev->setup = mtk_btuart_setup;
+ hdev->shutdown = mtk_btuart_shutdown;
+ hdev->send = mtk_btuart_send;
+ SET_HCIDEV_DEV(hdev, &serdev->dev);
+
+ if (hci_register_dev(hdev) < 0) {
+ dev_err(&serdev->dev, "Can't register HCI device\n");
+ hci_free_dev(hdev);
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+static void mtk_btuart_remove(struct serdev_device *serdev)
+{
+ struct mtk_btuart_dev *bdev = serdev_device_get_drvdata(serdev);
+ struct hci_dev *hdev = bdev->hdev;
+
+ hci_unregister_dev(hdev);
+ hci_free_dev(hdev);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id mtk_of_match_table[] = {
+ { .compatible = "mediatek,mt7622-bluetooth"},
+ { }
+};
+MODULE_DEVICE_TABLE(of, mtk_of_match_table);
+#endif
+
+static struct serdev_device_driver mtk_btuart_driver = {
+ .probe = mtk_btuart_probe,
+ .remove = mtk_btuart_remove,
+ .driver = {
+ .name = "btmtkuart",
+ .of_match_table = of_match_ptr(mtk_of_match_table),
+ },
+};
+
+module_serdev_device_driver(mtk_btuart_driver);
+
+MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
+MODULE_DESCRIPTION("MediaTek Bluetooth Serial driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/bluetooth/btmtkuart.h b/drivers/bluetooth/btmtkuart.h
new file mode 100644
index 0000000..b77d175
--- /dev/null
+++ b/drivers/bluetooth/btmtkuart.h
@@ -0,0 +1,83 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2018 MediaTek Inc.
+ *
+ * Bluetooth support for MediaTek serial devices
+ *
+ * Author: Sean Wang <sean.wang@mediatek.com>
+ *
+ */
+
+#define FIRMWARE_MT7622 "mediatek/mt7622pr2h.bin"
+
+#define MTK_STP_TLR_SIZE 2
+
+#define BTUART_TX_STATE_ACTIVE 1
+#define BTUART_TX_STATE_WAKEUP 2
+
+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;
+ 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[256];
+} __packed;
+
+struct mtk_stp_splitter {
+ u8 pad[6];
+ u8 cursor;
+ u16 dlen;
+};
+
+struct mtk_btuart_dev {
+ struct hci_dev *hdev;
+ struct serdev_device *serdev;
+
+ struct work_struct tx_work;
+ unsigned long tx_state;
+ struct sk_buff_head txq;
+
+ struct sk_buff *rx_skb;
+
+ struct mtk_stp_splitter *sp;
+ struct clk *clk;
+};
+
+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;
+}
--
2.7.4
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