Bluetooth: hci_uart: Add basic support for Intel Lightning Peak devices [Linux 4.3]

This Linux kernel change "Bluetooth: hci_uart: Add basic support for Intel Lightning Peak devices" is included in the Linux 4.3 release. This change is authored by Loic Poulain <loic.poulain [at] intel.com> on Wed Jul 1 12:20:26 2015 +0200. The commit for this change in Linux stable tree is ca93cee (patch).

Bluetooth: hci_uart: Add basic support for Intel Lightning Peak devices

The Intel Lightning Peak devices do not come with Bluetooth firmware
loaded and thus require a full download of the operational Bluetooth
firmware when the device is attached via the Bluetooth line discipline.

Lightning Peak devices start with a bootloader mode that only accepts
a very limited set of HCI commands. The supported commands are enough
to identify the hardware and select the right firmware to load.

Signed-off-by: Loic Poulain <loic.poulain@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

There are 616 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/bluetooth/Kconfig     |   1 +
 drivers/bluetooth/hci_intel.c | 604 ++++++++++++++++++++++++++++++++++++++++++
 drivers/bluetooth/hci_ldisc.c |   6 +
 drivers/bluetooth/hci_uart.h  |   5 +
 4 files changed, 616 insertions(+)

diff --git a/drivers/bluetooth/Kconfig b/drivers/bluetooth/Kconfig
index 2e77707..79e8234 100644
--- a/drivers/bluetooth/Kconfig
+++ b/drivers/bluetooth/Kconfig
@@ -132,6 +132,7 @@ config BT_HCIUART_3WIRE
 config BT_HCIUART_INTEL
    bool "Intel protocol support"
    depends on BT_HCIUART
+   select BT_HCIUART_H4
    select BT_INTEL
    help
      The Intel protocol support enables Bluetooth HCI over serial
diff --git a/drivers/bluetooth/hci_intel.c b/drivers/bluetooth/hci_intel.c
index 5dd07bf..ade19aa 100644
--- a/drivers/bluetooth/hci_intel.c
+++ b/drivers/bluetooth/hci_intel.c
@@ -24,8 +24,612 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/skbuff.h>
+#include <linux/firmware.h>
+#include <linux/wait.h>

 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>

 #include "hci_uart.h"
+#include "btintel.h"
+
+#define STATE_BOOTLOADER   0
+#define STATE_DOWNLOADING  1
+#define STATE_FIRMWARE_LOADED  2
+#define STATE_FIRMWARE_FAILED  3
+#define STATE_BOOTING      4
+
+struct intel_data {
+   struct sk_buff *rx_skb;
+   struct sk_buff_head txq;
+   unsigned long flags;
+};
+
+static int intel_open(struct hci_uart *hu)
+{
+   struct intel_data *intel;
+
+   BT_DBG("hu %p", hu);
+
+   intel = kzalloc(sizeof(*intel), GFP_KERNEL);
+   if (!intel)
+       return -ENOMEM;
+
+   skb_queue_head_init(&intel->txq);
+
+   hu->priv = intel;
+   return 0;
+}
+
+static int intel_close(struct hci_uart *hu)
+{
+   struct intel_data *intel = hu->priv;
+
+   BT_DBG("hu %p", hu);
+
+   skb_queue_purge(&intel->txq);
+   kfree_skb(intel->rx_skb);
+   kfree(intel);
+
+   hu->priv = NULL;
+   return 0;
+}
+
+static int intel_flush(struct hci_uart *hu)
+{
+   struct intel_data *intel = hu->priv;
+
+   BT_DBG("hu %p", hu);
+
+   skb_queue_purge(&intel->txq);
+
+   return 0;
+}
+
+static int inject_cmd_complete(struct hci_dev *hdev, __u16 opcode)
+{
+   struct sk_buff *skb;
+   struct hci_event_hdr *hdr;
+   struct hci_ev_cmd_complete *evt;
+
+   skb = bt_skb_alloc(sizeof(*hdr) + sizeof(*evt) + 1, GFP_ATOMIC);
+   if (!skb)
+       return -ENOMEM;
+
+   hdr = (struct hci_event_hdr *)skb_put(skb, sizeof(*hdr));
+   hdr->evt = HCI_EV_CMD_COMPLETE;
+   hdr->plen = sizeof(*evt) + 1;
+
+   evt = (struct hci_ev_cmd_complete *)skb_put(skb, sizeof(*evt));
+   evt->ncmd = 0x01;
+   evt->opcode = cpu_to_le16(opcode);
+
+   *skb_put(skb, 1) = 0x00;
+
+   bt_cb(skb)->pkt_type = HCI_EVENT_PKT;
+
+   return hci_recv_frame(hdev, skb);
+}
+
+static int intel_secure_send(struct hci_dev *hdev, u8 fragment_type,
+                u32 plen, const void *param)
+{
+   while (plen > 0) {
+       struct sk_buff *skb;
+       u8 cmd_param[253], fragment_len = (plen > 252) ? 252 : plen;
+
+       cmd_param[0] = fragment_type;
+       memcpy(cmd_param + 1, param, fragment_len);
+
+       skb = __hci_cmd_sync(hdev, 0xfc09, fragment_len + 1,
+                    cmd_param, HCI_INIT_TIMEOUT);
+       if (IS_ERR(skb))
+           return PTR_ERR(skb);
+
+       kfree_skb(skb);
+
+       plen -= fragment_len;
+       param += fragment_len;
+   }
+
+   return 0;
+}
+
+static void intel_version_info(struct hci_dev *hdev,
+                  struct intel_version *ver)
+{
+   const char *variant;
+
+   switch (ver->fw_variant) {
+   case 0x06:
+       variant = "Bootloader";
+       break;
+   case 0x23:
+       variant = "Firmware";
+       break;
+   default:
+       return;
+   }
+
+   BT_INFO("%s: %s revision %u.%u build %u week %u %u", hdev->name,
+       variant, ver->fw_revision >> 4, ver->fw_revision & 0x0f,
+       ver->fw_build_num, ver->fw_build_ww, 2000 + ver->fw_build_yy);
+}
+
+static int intel_setup(struct hci_uart *hu)
+{
+   static const u8 reset_param[] = { 0x00, 0x01, 0x00, 0x01,
+                     0x00, 0x08, 0x04, 0x00 };
+   struct intel_data *intel = hu->priv;
+   struct hci_dev *hdev = hu->hdev;
+   struct sk_buff *skb;
+   struct intel_version *ver;
+   struct intel_boot_params *params;
+   const struct firmware *fw;
+   const u8 *fw_ptr;
+   char fwname[64];
+   u32 frag_len;
+   ktime_t calltime, delta, rettime;
+   unsigned long long duration;
+   int err;
+
+   BT_DBG("%s", hdev->name);
+
+   calltime = ktime_get();
+
+   set_bit(STATE_BOOTLOADER, &intel->flags);
+
+   /* Read the Intel version information to determine if the device
+    * is in bootloader mode or if it already has operational firmware
+    * loaded.
+    */
+   skb = __hci_cmd_sync(hdev, 0xfc05, 0, NULL, HCI_INIT_TIMEOUT);
+   if (IS_ERR(skb)) {
+       BT_ERR("%s: Reading Intel version information failed (%ld)",
+              hdev->name, PTR_ERR(skb));
+       return PTR_ERR(skb);
+   }
+
+   if (skb->len != sizeof(*ver)) {
+       BT_ERR("%s: Intel version event size mismatch", hdev->name);
+       kfree_skb(skb);
+       return -EILSEQ;
+   }
+
+   ver = (struct intel_version *)skb->data;
+   if (ver->status) {
+       BT_ERR("%s: Intel version command failure (%02x)",
+              hdev->name, ver->status);
+       err = -bt_to_errno(ver->status);
+       kfree_skb(skb);
+       return err;
+   }
+
+   /* The hardware platform number has a fixed value of 0x37 and
+    * for now only accept this single value.
+    */
+   if (ver->hw_platform != 0x37) {
+       BT_ERR("%s: Unsupported Intel hardware platform (%u)",
+              hdev->name, ver->hw_platform);
+       kfree_skb(skb);
+       return -EINVAL;
+   }
+
+   /* At the moment only the hardware variant iBT 3.0 (LnP/SfP) is
+    * supported by this firmware loading method. This check has been
+    * put in place to ensure correct forward compatibility options
+    * when newer hardware variants come along.
+    */
+   if (ver->hw_variant != 0x0b) {
+       BT_ERR("%s: Unsupported Intel hardware variant (%u)",
+              hdev->name, ver->hw_variant);
+       kfree_skb(skb);
+       return -EINVAL;
+   }
+
+   intel_version_info(hdev, ver);
+
+   /* The firmware variant determines if the device is in bootloader
+    * mode or is running operational firmware. The value 0x06 identifies
+    * the bootloader and the value 0x23 identifies the operational
+    * firmware.
+    *
+    * When the operational firmware is already present, then only
+    * the check for valid Bluetooth device address is needed. This
+    * determines if the device will be added as configured or
+    * unconfigured controller.
+    *
+    * It is not possible to use the Secure Boot Parameters in this
+    * case since that command is only available in bootloader mode.
+    */
+   if (ver->fw_variant == 0x23) {
+       kfree_skb(skb);
+       clear_bit(STATE_BOOTLOADER, &intel->flags);
+       btintel_check_bdaddr(hdev);
+       return 0;
+   }
+
+   /* If the device is not in bootloader mode, then the only possible
+    * choice is to return an error and abort the device initialization.
+    */
+   if (ver->fw_variant != 0x06) {
+       BT_ERR("%s: Unsupported Intel firmware variant (%u)",
+              hdev->name, ver->fw_variant);
+       kfree_skb(skb);
+       return -ENODEV;
+   }
+
+   kfree_skb(skb);
+
+   /* Read the secure boot parameters to identify the operating
+    * details of the bootloader.
+    */
+   skb = __hci_cmd_sync(hdev, 0xfc0d, 0, NULL, HCI_INIT_TIMEOUT);
+   if (IS_ERR(skb)) {
+       BT_ERR("%s: Reading Intel boot parameters failed (%ld)",
+              hdev->name, PTR_ERR(skb));
+       return PTR_ERR(skb);
+   }
+
+   if (skb->len != sizeof(*params)) {
+       BT_ERR("%s: Intel boot parameters size mismatch", hdev->name);
+       kfree_skb(skb);
+       return -EILSEQ;
+   }
+
+   params = (struct intel_boot_params *)skb->data;
+   if (params->status) {
+       BT_ERR("%s: Intel boot parameters command failure (%02x)",
+              hdev->name, params->status);
+       err = -bt_to_errno(params->status);
+       kfree_skb(skb);
+       return err;
+   }
+
+   BT_INFO("%s: Device revision is %u", hdev->name,
+       le16_to_cpu(params->dev_revid));
+
+   BT_INFO("%s: Secure boot is %s", hdev->name,
+       params->secure_boot ? "enabled" : "disabled");
+
+   BT_INFO("%s: Minimum firmware build %u week %u %u", hdev->name,
+       params->min_fw_build_nn, params->min_fw_build_cw,
+       2000 + params->min_fw_build_yy);
+
+   /* It is required that every single firmware fragment is acknowledged
+    * with a command complete event. If the boot parameters indicate
+    * that this bootloader does not send them, then abort the setup.
+    */
+   if (params->limited_cce != 0x00) {
+       BT_ERR("%s: Unsupported Intel firmware loading method (%u)",
+              hdev->name, params->limited_cce);
+       kfree_skb(skb);
+       return -EINVAL;
+   }
+
+   /* If the OTP has no valid Bluetooth device address, then there will
+    * also be no valid address for the operational firmware.
+    */
+   if (!bacmp(&params->otp_bdaddr, BDADDR_ANY)) {
+       BT_INFO("%s: No device address configured", hdev->name);
+       set_bit(HCI_QUIRK_INVALID_BDADDR, &hdev->quirks);
+   }
+
+   /* With this Intel bootloader only the hardware variant and device
+    * revision information are used to select the right firmware.
+    *
+    * Currently this bootloader support is limited to hardware variant
+    * iBT 3.0 (LnP/SfP) which is identified by the value 11 (0x0b).
+    */
+   snprintf(fwname, sizeof(fwname), "intel/ibt-11-%u.sfi",
+        le16_to_cpu(params->dev_revid));
+
+   err = request_firmware(&fw, fwname, &hdev->dev);
+   if (err < 0) {
+       BT_ERR("%s: Failed to load Intel firmware file (%d)",
+              hdev->name, err);
+       kfree_skb(skb);
+       return err;
+   }
+
+   BT_INFO("%s: Found device firmware: %s", hdev->name, fwname);
+
+   kfree_skb(skb);
+
+   if (fw->size < 644) {
+       BT_ERR("%s: Invalid size of firmware file (%zu)",
+              hdev->name, fw->size);
+       err = -EBADF;
+       goto done;
+   }
+
+   set_bit(STATE_DOWNLOADING, &intel->flags);
+
+   /* Start the firmware download transaction with the Init fragment
+    * represented by the 128 bytes of CSS header.
+    */
+   err = intel_secure_send(hdev, 0x00, 128, fw->data);
+   if (err < 0) {
+       BT_ERR("%s: Failed to send firmware header (%d)",
+              hdev->name, err);
+       goto done;
+   }
+
+   /* Send the 256 bytes of public key information from the firmware
+    * as the PKey fragment.
+    */
+   err = intel_secure_send(hdev, 0x03, 256, fw->data + 128);
+   if (err < 0) {
+       BT_ERR("%s: Failed to send firmware public key (%d)",
+              hdev->name, err);
+       goto done;
+   }
+
+   /* Send the 256 bytes of signature information from the firmware
+    * as the Sign fragment.
+    */
+   err = intel_secure_send(hdev, 0x02, 256, fw->data + 388);
+   if (err < 0) {
+       BT_ERR("%s: Failed to send firmware signature (%d)",
+              hdev->name, err);
+       goto done;
+   }
+
+   fw_ptr = fw->data + 644;
+   frag_len = 0;
+
+   while (fw_ptr - fw->data < fw->size) {
+       struct hci_command_hdr *cmd = (void *)(fw_ptr + frag_len);
+
+       frag_len += sizeof(*cmd) + cmd->plen;
+
+       BT_DBG("%s: patching %td/%zu", hdev->name,
+              (fw_ptr - fw->data), fw->size);
+
+       /* The parameter length of the secure send command requires
+        * a 4 byte alignment. It happens so that the firmware file
+        * contains proper Intel_NOP commands to align the fragments
+        * as needed.
+        *
+        * Send set of commands with 4 byte alignment from the
+        * firmware data buffer as a single Data fragement.
+        */
+       if (frag_len % 4)
+           continue;
+
+       /* Send each command from the firmware data buffer as
+        * a single Data fragment.
+        */
+       err = intel_secure_send(hdev, 0x01, frag_len, fw_ptr);
+       if (err < 0) {
+           BT_ERR("%s: Failed to send firmware data (%d)",
+                  hdev->name, err);
+           goto done;
+       }
+
+       fw_ptr += frag_len;
+       frag_len = 0;
+   }
+
+   set_bit(STATE_FIRMWARE_LOADED, &intel->flags);
+
+   BT_INFO("%s: Waiting for firmware download to complete", hdev->name);
+
+   /* Before switching the device into operational mode and with that
+    * booting the loaded firmware, wait for the bootloader notification
+    * that all fragments have been successfully received.
+    *
+    * When the event processing receives the notification, then the
+    * STATE_DOWNLOADING flag will be cleared.
+    *
+    * The firmware loading should not take longer than 5 seconds
+    * and thus just timeout if that happens and fail the setup
+    * of this device.
+    */
+   err = wait_on_bit_timeout(&intel->flags, STATE_DOWNLOADING,
+                 TASK_INTERRUPTIBLE,
+                 msecs_to_jiffies(5000));
+   if (err == 1) {
+       BT_ERR("%s: Firmware loading interrupted", hdev->name);
+       err = -EINTR;
+       goto done;
+   }
+
+   if (err) {
+       BT_ERR("%s: Firmware loading timeout", hdev->name);
+       err = -ETIMEDOUT;
+       goto done;
+   }
+
+   if (test_bit(STATE_FIRMWARE_FAILED, &intel->flags)) {
+       BT_ERR("%s: Firmware loading failed", hdev->name);
+       err = -ENOEXEC;
+       goto done;
+   }
+
+   rettime = ktime_get();
+   delta = ktime_sub(rettime, calltime);
+   duration = (unsigned long long) ktime_to_ns(delta) >> 10;
+
+   BT_INFO("%s: Firmware loaded in %llu usecs", hdev->name, duration);
+
+done:
+   release_firmware(fw);
+
+   if (err < 0)
+       return err;
+
+   calltime = ktime_get();
+
+   set_bit(STATE_BOOTING, &intel->flags);
+
+   skb = __hci_cmd_sync(hdev, 0xfc01, sizeof(reset_param), reset_param,
+                HCI_INIT_TIMEOUT);
+   if (IS_ERR(skb))
+       return PTR_ERR(skb);
+
+   kfree_skb(skb);
+
+   /* The bootloader will not indicate when the device is ready. This
+    * is done by the operational firmware sending bootup notification.
+    *
+    * Booting into operational firmware should not take longer than
+    * 1 second. However if that happens, then just fail the setup
+    * since something went wrong.
+    */
+   BT_INFO("%s: Waiting for device to boot", hdev->name);
+
+   err = wait_on_bit_timeout(&intel->flags, STATE_BOOTING,
+                 TASK_INTERRUPTIBLE,
+                 msecs_to_jiffies(1000));
+
+   if (err == 1) {
+       BT_ERR("%s: Device boot interrupted", hdev->name);
+       return -EINTR;
+   }
+
+   if (err) {
+       BT_ERR("%s: Device boot timeout", hdev->name);
+       return -ETIMEDOUT;
+   }
+
+   rettime = ktime_get();
+   delta = ktime_sub(rettime, calltime);
+   duration = (unsigned long long) ktime_to_ns(delta) >> 10;
+
+   BT_INFO("%s: Device booted in %llu usecs", hdev->name, duration);
+
+   clear_bit(STATE_BOOTLOADER, &intel->flags);
+
+   return 0;
+}
+
+static int intel_recv_event(struct hci_dev *hdev, struct sk_buff *skb)
+{
+   struct hci_uart *hu = hci_get_drvdata(hdev);
+   struct intel_data *intel = hu->priv;
+   struct hci_event_hdr *hdr;
+
+   if (!test_bit(STATE_BOOTLOADER, &intel->flags))
+       goto recv;
+
+   hdr = (void *)skb->data;
+
+   /* When the firmware loading completes the device sends
+    * out a vendor specific event indicating the result of
+    * the firmware loading.
+    */
+   if (skb->len == 7 && hdr->evt == 0xff && hdr->plen == 0x05 &&
+       skb->data[2] == 0x06) {
+       if (skb->data[3] != 0x00)
+           set_bit(STATE_FIRMWARE_FAILED, &intel->flags);
+
+       if (test_and_clear_bit(STATE_DOWNLOADING, &intel->flags) &&
+           test_bit(STATE_FIRMWARE_LOADED, &intel->flags)) {
+           smp_mb__after_atomic();
+           wake_up_bit(&intel->flags, STATE_DOWNLOADING);
+       }
+
+   /* When switching to the operational firmware the device
+    * sends a vendor specific event indicating that the bootup
+    * completed.
+    */
+   } else if (skb->len == 9 && hdr->evt == 0xff && hdr->plen == 0x07 &&
+          skb->data[2] == 0x02) {
+       if (test_and_clear_bit(STATE_BOOTING, &intel->flags)) {
+           smp_mb__after_atomic();
+           wake_up_bit(&intel->flags, STATE_BOOTING);
+       }
+   }
+recv:
+   return hci_recv_frame(hdev, skb);
+}
+
+static const struct h4_recv_pkt intel_recv_pkts[] = {
+   { H4_RECV_ACL,   .recv = hci_recv_frame },
+   { H4_RECV_SCO,   .recv = hci_recv_frame },
+   { H4_RECV_EVENT, .recv = intel_recv_event },
+};
+
+static int intel_recv(struct hci_uart *hu, const void *data, int count)
+{
+   struct intel_data *intel = hu->priv;
+
+   if (!test_bit(HCI_UART_REGISTERED, &hu->flags))
+       return -EUNATCH;
+
+   intel->rx_skb = h4_recv_buf(hu->hdev, intel->rx_skb, data, count,
+                   intel_recv_pkts,
+                   ARRAY_SIZE(intel_recv_pkts));
+   if (IS_ERR(intel->rx_skb)) {
+       int err = PTR_ERR(intel->rx_skb);
+       BT_ERR("%s: Frame reassembly failed (%d)", hu->hdev->name, err);
+       intel->rx_skb = NULL;
+       return err;
+   }
+
+   return count;
+}
+
+static int intel_enqueue(struct hci_uart *hu, struct sk_buff *skb)
+{
+   struct intel_data *intel = hu->priv;
+
+   BT_DBG("hu %p skb %p", hu, skb);
+
+   skb_queue_tail(&intel->txq, skb);
+
+   return 0;
+}
+
+static struct sk_buff *intel_dequeue(struct hci_uart *hu)
+{
+   struct intel_data *intel = hu->priv;
+   struct sk_buff *skb;
+
+   skb = skb_dequeue(&intel->txq);
+   if (!skb)
+       return skb;
+
+   if (test_bit(STATE_BOOTLOADER, &intel->flags) &&
+       (bt_cb(skb)->pkt_type == HCI_COMMAND_PKT)) {
+       struct hci_command_hdr *cmd = (void *)skb->data;
+       __u16 opcode = le16_to_cpu(cmd->opcode);
+
+       /* When the 0xfc01 command is issued to boot into
+        * the operational firmware, it will actually not
+        * send a command complete event. To keep the flow
+        * control working inject that event here.
+        */
+       if (opcode == 0xfc01)
+           inject_cmd_complete(hu->hdev, opcode);
+   }
+
+   /* Prepend skb with frame type */
+   memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
+
+   return skb;
+}
+
+static const struct hci_uart_proto intel_proto = {
+   .id     = HCI_UART_INTEL,
+   .name       = "Intel",
+   .init_speed = 115200,
+   .open       = intel_open,
+   .close      = intel_close,
+   .flush      = intel_flush,
+   .setup      = intel_setup,
+   .recv       = intel_recv,
+   .enqueue    = intel_enqueue,
+   .dequeue    = intel_dequeue,
+};
+
+int __init intel_init(void)
+{
+   return hci_uart_register_proto(&intel_proto);
+}
+
+int __exit intel_deinit(void)
+{
+   return hci_uart_unregister_proto(&intel_proto);
+}
diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index 177dd69..051f821 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -804,6 +804,9 @@ static int __init hci_uart_init(void)
 #ifdef CONFIG_BT_HCIUART_3WIRE
    h5_init();
 #endif
+#ifdef CONFIG_BT_HCIUART_INTEL
+   intel_init();
+#endif
 #ifdef CONFIG_BT_HCIUART_BCM
    bcm_init();
 #endif
@@ -830,6 +833,9 @@ static void __exit hci_uart_exit(void)
 #ifdef CONFIG_BT_HCIUART_3WIRE
    h5_deinit();
 #endif
+#ifdef CONFIG_BT_HCIUART_INTEL
+   intel_deinit();
+#endif
 #ifdef CONFIG_BT_HCIUART_BCM
    bcm_deinit();
 #endif
diff --git a/drivers/bluetooth/hci_uart.h b/drivers/bluetooth/hci_uart.h
index ce9c670..496587a 100644
--- a/drivers/bluetooth/hci_uart.h
+++ b/drivers/bluetooth/hci_uart.h
@@ -167,6 +167,11 @@ struct sk_buff *h4_recv_buf(struct hci_dev *hdev, struct sk_buff *skb,
 int h5_deinit(void);
 #endif

+#ifdef CONFIG_BT_HCIUART_INTEL
+int intel_init(void);
+int intel_deinit(void);
+#endif
+
 #ifdef CONFIG_BT_HCIUART_BCM
 int bcm_init(void);
 int bcm_deinit(void);

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