We will collect the ramdump of BT controller when hardware error event
received before rebooting the HCI layer. Before restarting a subsystem
or a process running on a subsystem, it is often required to request
either a subsystem or a process to perform proper cache dump and
software failure reason into a memory buffer which application
processor can retrieve afterwards. SW developers can often provide
initial investigation by looking into that debugging information.

Signed-off-by: Balakrishna Godavarthi <bgoda...@codeaurora.org>
---
changes v2:
 * entirely an newer approach handling with an work queue.
  
---
 drivers/bluetooth/hci_qca.c | 289 ++++++++++++++++++++++++++++++++++--
 1 file changed, 278 insertions(+), 11 deletions(-)

diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index f036c8f98ea3..62b768bc32ec 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c
@@ -32,6 +32,7 @@
 #include <linux/clk.h>
 #include <linux/debugfs.h>
 #include <linux/delay.h>
+#include <linux/devcoredump.h>
 #include <linux/device.h>
 #include <linux/gpio/consumer.h>
 #include <linux/mod_devicetable.h>
@@ -57,9 +58,10 @@
 /* Controller states */
 #define STATE_IN_BAND_SLEEP_ENABLED    1
 
-#define IBS_WAKE_RETRANS_TIMEOUT_MS    100
+#define        IBS_WAKE_RETRANS_TIMEOUT_MS     100
 #define IBS_TX_IDLE_TIMEOUT_MS         2000
-#define BAUDRATE_SETTLE_TIMEOUT_MS     300
+#define        BAUDRATE_SETTLE_TIMEOUT_MS      300
+#define MEMDUMP_COLLECTION_TIMEOUT_MS  8000
 
 /* susclk rate */
 #define SUSCLK_RATE_32KHZ      32768
@@ -67,6 +69,13 @@
 /* Controller debug log header */
 #define QCA_DEBUG_HANDLE       0x2EDC
 
+/* Controller dump header */
+#define QCA_SSR_DUMP_HANDLE            0x0108
+#define QCA_DUMP_PACKET_SIZE           255
+#define QCA_LAST_SEQUENCE_NUM          0xFFFF
+#define QCA_CRASHBYTE_PACKET_LEN       1100
+#define QCA_MEMDUMP_BYTE               0xFB
+
 /* HCI_IBS transmit side sleep protocol states */
 enum tx_ibs_states {
        HCI_IBS_TX_ASLEEP,
@@ -89,12 +98,41 @@ enum hci_ibs_clock_state_vote {
        HCI_IBS_RX_VOTE_CLOCK_OFF,
 };
 
+/* Controller memory dump states */
+enum qca_memdump_states {
+       QCA_MEMDUMP_IDLE,
+       QCA_MEMDUMP_COLLECTING,
+       QCA_MEMDUMP_COLLECTED,
+       QCA_MEMDUMP_TIMEOUT,
+};
+
+struct qca_memdump_data {
+       char *memdump_buf_head;
+       char *memdump_buf_tail;
+       u32 current_seq_no;
+       u32 received_dump;
+};
+
+struct qca_memdump_event_hdr {
+       __u8    evt;
+       __u8    plen;
+       __u16   opcode;
+       __u16   seq_no;
+       __u8    reserved;
+} __packed;
+
+
+struct qca_dump_size {
+       u32 dump_size;
+} __packed;
+
 struct qca_data {
        struct hci_uart *hu;
        struct sk_buff *rx_skb;
        struct sk_buff_head txq;
-       struct sk_buff_head tx_wait_q;  /* HCI_IBS wait queue   */
-       spinlock_t hci_ibs_lock;        /* HCI_IBS state lock   */
+       struct sk_buff_head tx_wait_q;          /* HCI_IBS wait queue   */
+       struct sk_buff_head rx_memdump_q;       /* Memdump wait queue   */
+       spinlock_t hci_ibs_lock;                /* HCI_IBS state lock   */
        u8 tx_ibs_state;        /* HCI_IBS transmit side power state*/
        u8 rx_ibs_state;        /* HCI_IBS receive side power state */
        bool tx_vote;           /* Clock must be on for TX */
@@ -103,12 +141,17 @@ struct qca_data {
        u32 tx_idle_delay;
        struct timer_list wake_retrans_timer;
        u32 wake_retrans;
+       struct timer_list memdump_timer;
+       u32 memdump_delay;
        struct workqueue_struct *workqueue;
        struct work_struct ws_awake_rx;
        struct work_struct ws_awake_device;
        struct work_struct ws_rx_vote_off;
        struct work_struct ws_tx_vote_off;
+       struct work_struct ctrl_memdump_evt;
+       struct qca_memdump_data *qca_memdump;
        unsigned long flags;
+       enum qca_memdump_states memdump_state;
 
        /* For debugging purpose */
        u64 ibs_sent_wacks;
@@ -173,6 +216,7 @@ struct qca_serdev {
 static int qca_power_setup(struct hci_uart *hu, bool on);
 static void qca_power_shutdown(struct hci_uart *hu);
 static int qca_power_off(struct hci_dev *hdev);
+static void qca_controller_memdump(struct work_struct *work);
 
 static void __serial_clock_on(struct tty_struct *tty)
 {
@@ -446,6 +490,21 @@ static void hci_ibs_wake_retrans_timeout(struct timer_list 
*t)
                hci_uart_tx_wakeup(hu);
 }
 
+static void hci_memdump_timeout(struct timer_list *t)
+{
+       struct qca_data *qca = from_timer(qca, t, tx_idle_timer);
+       struct hci_uart *hu = qca->hu;
+       struct qca_memdump_data *qca_memdump = qca->qca_memdump;
+       char *memdump_buf = qca_memdump->memdump_buf_tail;
+
+       bt_dev_err(hu->hdev, "clearing allocated memory due to memdump 
timeout");
+       kfree(memdump_buf);
+       kfree(qca_memdump);
+       qca->memdump_state = QCA_MEMDUMP_TIMEOUT;
+       del_timer(&qca->memdump_timer);
+       cancel_work_sync(&qca->ctrl_memdump_evt);
+}
+
 /* Initialize protocol */
 static int qca_open(struct hci_uart *hu)
 {
@@ -461,6 +520,7 @@ static int qca_open(struct hci_uart *hu)
 
        skb_queue_head_init(&qca->txq);
        skb_queue_head_init(&qca->tx_wait_q);
+       skb_queue_head_init(&qca->rx_memdump_q);
        spin_lock_init(&qca->hci_ibs_lock);
        qca->workqueue = alloc_ordered_workqueue("qca_wq", 0);
        if (!qca->workqueue) {
@@ -473,6 +533,7 @@ static int qca_open(struct hci_uart *hu)
        INIT_WORK(&qca->ws_awake_device, qca_wq_awake_device);
        INIT_WORK(&qca->ws_rx_vote_off, qca_wq_serial_rx_clock_vote_off);
        INIT_WORK(&qca->ws_tx_vote_off, qca_wq_serial_tx_clock_vote_off);
+       INIT_WORK(&qca->ctrl_memdump_evt, qca_controller_memdump);
 
        qca->hu = hu;
 
@@ -500,7 +561,7 @@ static int qca_open(struct hci_uart *hu)
        qca->tx_votes_off = 0;
        qca->rx_votes_on = 0;
        qca->rx_votes_off = 0;
-
+       qca->memdump_state = QCA_MEMDUMP_IDLE;
        hu->priv = qca;
 
        if (hu->serdev) {
@@ -528,6 +589,9 @@ static int qca_open(struct hci_uart *hu)
        timer_setup(&qca->tx_idle_timer, hci_ibs_tx_idle_timeout, 0);
        qca->tx_idle_delay = IBS_TX_IDLE_TIMEOUT_MS;
 
+       timer_setup(&qca->memdump_timer, hci_memdump_timeout, 0);
+       qca->memdump_delay = MEMDUMP_COLLECTION_TIMEOUT_MS;
+
        BT_DBG("HCI_UART_QCA open, tx_idle_delay=%u, wake_retrans=%u",
               qca->tx_idle_delay, qca->wake_retrans);
 
@@ -605,8 +669,10 @@ static int qca_close(struct hci_uart *hu)
 
        skb_queue_purge(&qca->tx_wait_q);
        skb_queue_purge(&qca->txq);
+       skb_queue_purge(&qca->rx_memdump_q);
        del_timer(&qca->tx_idle_timer);
        del_timer(&qca->wake_retrans_timer);
+       del_timer(&qca->memdump_timer);
        destroy_workqueue(qca->workqueue);
        qca->hu = NULL;
 
@@ -866,6 +932,141 @@ static int qca_recv_acl_data(struct hci_dev *hdev, struct 
sk_buff *skb)
        return hci_recv_frame(hdev, skb);
 }
 
+static void qca_controller_memdump(struct work_struct *work)
+{
+       struct qca_data *qca = container_of(work, struct qca_data,
+                                           ctrl_memdump_evt);
+       struct hci_uart *hu = qca->hu;
+       struct sk_buff *skb;
+       struct qca_memdump_event_hdr *cmd_hdr;
+       struct qca_memdump_data *qca_memdump = qca->qca_memdump;
+       struct qca_dump_size *dump;
+       char *memdump_buf;
+       char nullBuff[QCA_DUMP_PACKET_SIZE] = { 0 };
+       u16 opcode, seq_no;
+       u32 dump_size;
+
+       while ((skb = skb_dequeue(&qca->rx_memdump_q))) {
+
+               if (!qca_memdump) {
+                       qca_memdump = kzalloc(sizeof(struct qca_memdump_data),
+                                             GFP_ATOMIC);
+                       if (!qca_memdump)
+                               return;
+
+                       qca->qca_memdump = qca_memdump;
+               }
+
+               qca->memdump_state = QCA_MEMDUMP_COLLECTING;
+               cmd_hdr = (void *) skb->data;
+               opcode = __le16_to_cpu(cmd_hdr->opcode);
+               seq_no = __le16_to_cpu(cmd_hdr->seq_no);
+               skb_pull(skb, sizeof(struct qca_memdump_event_hdr));
+
+               if (!seq_no) {
+
+                       /* This is the first frame of memdump packet from
+                        * the controller, Disable IBS to recevie dump
+                        * with out any interruption, ideally time required for
+                        * the controller to send the dump is 8 seconds. let us
+                        * start timer to handle this asynchronous activity.
+                        */
+                       clear_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);
+
+                       dump = (void *) skb->data;
+                       dump_size = __le32_to_cpu(dump->dump_size);
+                       if (!(dump_size)) {
+                               bt_dev_err(hu->hdev, "QCA invalid memdump 
size");
+                               kfree_skb(skb);
+                               return;
+                       }
+
+                       bt_dev_info(hu->hdev, "QCA: collecting memdump started"
+                                    "of size:%u", dump_size);
+                       mod_timer(&qca->memdump_timer, (jiffies +
+                                 msecs_to_jiffies(qca->memdump_delay)));
+
+                       skb_pull(skb, sizeof(dump_size));
+                       memdump_buf = vmalloc(dump_size);
+                       qca_memdump->memdump_buf_head = memdump_buf;
+                       qca_memdump->memdump_buf_tail = memdump_buf;
+               }
+
+               memdump_buf = qca_memdump->memdump_buf_tail;
+
+               /* If sequence no 0 is missed then there is no point in
+                * accepting the other sequences.
+                */
+               if (!memdump_buf) {
+                       bt_dev_err(hu->hdev, "QCA: Discarding other packets");
+                       kfree(qca_memdump);
+                       kfree_skb(skb);
+                       qca->qca_memdump = NULL;
+                       return;
+               }
+
+               /* There could be chance of missing some packets from
+                * the controller. In such cases let us store the dummy
+                * packets in the buffer.
+                */
+               while ((seq_no > qca_memdump->current_seq_no + 1) &&
+                       seq_no != QCA_LAST_SEQUENCE_NUM) {
+                       bt_dev_err(hu->hdev, "QCA controller missed packet:%d",
+                                  qca_memdump->current_seq_no);
+                       memcpy(memdump_buf, nullBuff, QCA_DUMP_PACKET_SIZE);
+                       memdump_buf = memdump_buf + QCA_DUMP_PACKET_SIZE;
+                       qca_memdump->received_dump += QCA_DUMP_PACKET_SIZE;
+                       qca_memdump->current_seq_no++;
+               }
+
+               memcpy(memdump_buf, (unsigned char *) skb->data, skb->len);
+               memdump_buf = memdump_buf + skb->len;
+               qca_memdump->memdump_buf_tail = memdump_buf;
+               qca_memdump->current_seq_no = seq_no + 1;
+               qca_memdump->received_dump += skb->len;
+               qca->qca_memdump = qca_memdump;
+               kfree_skb(skb);
+               if (seq_no == QCA_LAST_SEQUENCE_NUM) {
+                       bt_dev_info(hu->hdev, "QCA writing crash dump of size 
%d bytes",
+                                  qca_memdump->received_dump);
+                       memdump_buf = qca_memdump->memdump_buf_head;
+                       dev_coredumpv(&hu->serdev->dev, memdump_buf,
+                                     qca_memdump->received_dump, GFP_KERNEL);
+                       // Revisit for free(memdump) if needed.
+                       del_timer(&qca->memdump_timer);
+                       kfree(qca->qca_memdump);
+                       qca->qca_memdump = NULL;
+                       qca->memdump_state = QCA_MEMDUMP_COLLECTED;
+               }
+       }
+
+}
+
+int qca_controller_memdump_event(struct hci_dev *hdev, struct sk_buff *skb)
+{
+       struct hci_uart *hu = hci_get_drvdata(hdev);
+       struct qca_data *qca = hu->priv;
+
+       skb_queue_tail(&qca->rx_memdump_q, skb);
+       queue_work(qca->workqueue, &qca->ctrl_memdump_evt);
+
+       return 0;
+}
+
+static int qca_recv_event_data(struct hci_dev *hdev, struct sk_buff *skb)
+{
+       /* We receive chip memory dump as an event packet, With a dedicated
+        * handler followed by a hardware error event. When this event is
+        * received we store dump into a file before closing hci. This
+        * dump will help in triaging the issues.
+        */
+       if ((skb->data[0] == HCI_VENDOR_PKT) &&
+           (get_unaligned_be16((skb->data) + 2) == QCA_SSR_DUMP_HANDLE))
+               return qca_controller_memdump_event(hdev, skb);
+
+       return hci_recv_frame(hdev, skb);
+}
+
 #define QCA_IBS_SLEEP_IND_EVENT \
        .type = HCI_IBS_SLEEP_IND, \
        .hlen = 0, \
@@ -888,12 +1089,12 @@ static int qca_recv_acl_data(struct hci_dev *hdev, 
struct sk_buff *skb)
        .maxlen = HCI_MAX_IBS_SIZE
 
 static const struct h4_recv_pkt qca_recv_pkts[] = {
-       { H4_RECV_ACL,             .recv = qca_recv_acl_data },
-       { H4_RECV_SCO,             .recv = hci_recv_frame    },
-       { H4_RECV_EVENT,           .recv = hci_recv_frame    },
-       { QCA_IBS_WAKE_IND_EVENT,  .recv = qca_ibs_wake_ind  },
-       { QCA_IBS_WAKE_ACK_EVENT,  .recv = qca_ibs_wake_ack  },
-       { QCA_IBS_SLEEP_IND_EVENT, .recv = qca_ibs_sleep_ind },
+       { H4_RECV_ACL,             .recv = qca_recv_acl_data    },
+       { H4_RECV_SCO,             .recv = hci_recv_frame       },
+       { H4_RECV_EVENT,           .recv = qca_recv_event_data  },
+       { QCA_IBS_WAKE_IND_EVENT,  .recv = qca_ibs_wake_ind     },
+       { QCA_IBS_WAKE_ACK_EVENT,  .recv = qca_ibs_wake_ack     },
+       { QCA_IBS_SLEEP_IND_EVENT, .recv = qca_ibs_sleep_ind    },
 };
 
 static int qca_recv(struct hci_uart *hu, const void *data, int count)
@@ -1114,6 +1315,68 @@ static int qca_set_speed(struct hci_uart *hu, enum 
qca_speed_type speed_type)
        return 0;
 }
 
+static int qca_send_crashbuffer(struct hci_uart *hu)
+{
+       struct qca_data *qca = hu->priv;
+       struct sk_buff *skb;
+       unsigned char buf[QCA_CRASHBYTE_PACKET_LEN];
+
+       bt_dev_dbg(hu->hdev, "sending soc crash buffer to controller");
+
+       /* We forcefully crash the controller, by sending 0xfb byte for
+        * 1024 times. We also might have chance of losing data, To be
+        * on safer side we send 1100 bytes to the SoC.
+        */
+       memset(buf, QCA_MEMDUMP_BYTE, QCA_CRASHBYTE_PACKET_LEN);
+
+       skb = bt_skb_alloc(QCA_CRASHBYTE_PACKET_LEN, GFP_KERNEL);
+       if (!skb) {
+               bt_dev_err(hu->hdev, "Failed to allocate memory for skb 
packet");
+               return -ENOMEM;
+       }
+
+       skb_put_data(skb, buf, QCA_CRASHBYTE_PACKET_LEN);
+       hci_skb_pkt_type(skb) = HCI_COMMAND_PKT;
+
+       skb_queue_tail(&qca->txq, skb);
+       hci_uart_tx_wakeup(hu);
+
+       return 0;
+}
+
+static void qca_hw_error(struct hci_dev *hdev, u8 code)
+{
+       struct hci_uart *hu = hci_get_drvdata(hdev);
+       struct qca_data *qca = hu->priv;
+
+       bt_dev_info(hdev, "mem_dump_status: %d", qca->memdump_state);
+
+       if (qca->memdump_state == QCA_MEMDUMP_IDLE) {
+               /* If hardware error event received for other than QCA
+                * soc memory dump event, then we need to crash the SOC
+                * and wait here for 8 seconds to get the dump packets.
+                * This will block main thread to be on hold until we
+                * collect dump.
+                */
+               mod_timer(&qca->memdump_timer,
+                         (jiffies + msecs_to_jiffies(qca->memdump_delay)));
+               qca_send_crashbuffer(hu);
+
+               while (qca->memdump_state != QCA_MEMDUMP_COLLECTED &&
+                       qca->memdump_state != QCA_MEMDUMP_TIMEOUT)
+                       ;
+       } else if (qca->memdump_state == QCA_MEMDUMP_COLLECTING) {
+               /* Let us wait here until memory dump collected or
+                * memory dump timer expired.
+                */
+               bt_dev_info(hdev, "waiting for dump to complete");
+               while (qca->memdump_state == QCA_MEMDUMP_COLLECTING)
+                       ;
+       }
+
+       qca->memdump_state = QCA_MEMDUMP_IDLE;
+}
+
 static int qca_wcn3990_init(struct hci_uart *hu)
 {
        struct hci_dev *hdev = hu->hdev;
@@ -1229,6 +1492,10 @@ static int qca_setup(struct hci_uart *hu)
        if (!ret) {
                set_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);
                qca_debugfs_init(hdev);
+               /* We only get controller dump when fw download is
+                * successful.
+                */
+               hu->hdev->hw_error = qca_hw_error;
        } else if (ret == -ENOENT) {
                /* No patch/nvm-config found, run with original fw/config */
                ret = 0;
-- 
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