ath11k: add dbring debug support

Target copies spectral report and CFR report through dbring to
host for further processing. This mechanism involves ring and
buffer management in the Host, FW, and uCode, where improper
tail pointer update issues are seen.

This dbring debug support help to debug such issues by tracking
head and tail pointer movement along with the timestamp at which
each buffer is received and replenished.

Provide a debugfs interface to enalbe/disable dbring debug
support and dump the dbring debug entries.

Also introduced a new hardware param to add dbring debugfs support
for few hardwares which are using dbings.

Usage:

echo <dbr_id> <val> > /sys/kernel/debug/ath11k/ipq8074_2/
mac0/enable_dbr_debug

dbr_id: 0 for spectral and 1 for CFR
val: 0 - disable, 1 - enable.

Tested-on: IPQ8074 WLAN.HK.2.4.0.1-01467-QCAHKSWPL_SILICONZ-1

Signed-off-by: Venkateswara Naralasetty <quic_vnaralas@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/1645366059-11798-1-git-send-email-quic_vnaralas@quicinc.com

1 files changed, 221 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath11k/debugfs.c b/drivers/net/wireless/ath/ath11k/debugfs.c
index c0ebdb1262f0..a82266c8befc 100644
--- a/drivers/net/wireless/ath/ath11k/debugfs.c
+++ b/drivers/net/wireless/ath/ath11k/debugfs.c
@@ -52,6 +52,45 @@ static const char *htt_bp_lmac_ring[HTT_SW_LMAC_RING_IDX_MAX] = {
 	"MONITOR_DEST_RING",
 };
 
+void ath11k_debugfs_add_dbring_entry(struct ath11k *ar,
+				     enum wmi_direct_buffer_module id,
+				     enum ath11k_dbg_dbr_event event,
+				     struct hal_srng *srng)
+{
+	struct ath11k_debug_dbr *dbr_debug;
+	struct ath11k_dbg_dbr_data *dbr_data;
+	struct ath11k_dbg_dbr_entry *entry;
+
+	if (id >= WMI_DIRECT_BUF_MAX || event >= ATH11K_DBG_DBR_EVENT_MAX)
+		return;
+
+	dbr_debug = ar->debug.dbr_debug[id];
+	if (!dbr_debug)
+		return;
+
+	if (!dbr_debug->dbr_debug_enabled)
+		return;
+
+	dbr_data = &dbr_debug->dbr_dbg_data;
+
+	spin_lock_bh(&dbr_data->lock);
+
+	if (dbr_data->entries) {
+		entry = &dbr_data->entries[dbr_data->dbr_debug_idx];
+		entry->hp = srng->u.src_ring.hp;
+		entry->tp = *srng->u.src_ring.tp_addr;
+		entry->timestamp = jiffies;
+		entry->event = event;
+
+		dbr_data->dbr_debug_idx++;
+		if (dbr_data->dbr_debug_idx ==
+		    dbr_data->num_ring_debug_entries)
+			dbr_data->dbr_debug_idx = 0;
+	}
+
+	spin_unlock_bh(&dbr_data->lock);
+}
+
 static void ath11k_fw_stats_pdevs_free(struct list_head *head)
 {
 	struct ath11k_fw_stats_pdev *i, *tmp;
@@ -1176,6 +1215,169 @@ static const struct file_operations fops_simulate_radar = {
 	.open = simple_open
 };
 
+static ssize_t ath11k_debug_dump_dbr_entries(struct file *file,
+					     char __user *user_buf,
+					     size_t count, loff_t *ppos)
+{
+	struct ath11k_dbg_dbr_data *dbr_dbg_data = file->private_data;
+	static const char * const event_id_to_string[] = {"empty", "Rx", "Replenish"};
+	int size = ATH11K_DEBUG_DBR_ENTRIES_MAX * 100;
+	char *buf;
+	int i, ret;
+	int len = 0;
+
+	buf = kzalloc(size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	len += scnprintf(buf + len, size - len,
+			 "-----------------------------------------\n");
+	len += scnprintf(buf + len, size - len,
+			 "| idx |  hp  |  tp  | timestamp |  event |\n");
+	len += scnprintf(buf + len, size - len,
+			 "-----------------------------------------\n");
+
+	spin_lock_bh(&dbr_dbg_data->lock);
+
+	for (i = 0; i < dbr_dbg_data->num_ring_debug_entries; i++) {
+		len += scnprintf(buf + len, size - len,
+				 "|%4u|%8u|%8u|%11llu|%8s|\n", i,
+				 dbr_dbg_data->entries[i].hp,
+				 dbr_dbg_data->entries[i].tp,
+				 dbr_dbg_data->entries[i].timestamp,
+				 event_id_to_string[dbr_dbg_data->entries[i].event]);
+	}
+
+	spin_unlock_bh(&dbr_dbg_data->lock);
+
+	ret = simple_read_from_buffer(user_buf, count, ppos, buf, len);
+	kfree(buf);
+
+	return ret;
+}
+
+static const struct file_operations fops_debug_dump_dbr_entries = {
+	.read = ath11k_debug_dump_dbr_entries,
+	.open = simple_open,
+	.owner = THIS_MODULE,
+	.llseek = default_llseek,
+};
+
+static void ath11k_debugfs_dbr_dbg_destroy(struct ath11k *ar, int dbr_id)
+{
+	struct ath11k_debug_dbr *dbr_debug;
+	struct ath11k_dbg_dbr_data *dbr_dbg_data;
+
+	if (!ar->debug.dbr_debug[dbr_id])
+		return;
+
+	dbr_debug = ar->debug.dbr_debug[dbr_id];
+	dbr_dbg_data = &dbr_debug->dbr_dbg_data;
+
+	debugfs_remove_recursive(dbr_debug->dbr_debugfs);
+	kfree(dbr_dbg_data->entries);
+	kfree(dbr_debug);
+	ar->debug.dbr_debug[dbr_id] = NULL;
+}
+
+static int ath11k_debugfs_dbr_dbg_init(struct ath11k *ar, int dbr_id)
+{
+	struct ath11k_debug_dbr *dbr_debug;
+	struct ath11k_dbg_dbr_data *dbr_dbg_data;
+	static const char * const dbr_id_to_str[] = {"spectral", "CFR"};
+
+	if (ar->debug.dbr_debug[dbr_id])
+		return 0;
+
+	ar->debug.dbr_debug[dbr_id] = kzalloc(sizeof(*dbr_debug),
+					      GFP_KERNEL);
+
+	if (!ar->debug.dbr_debug[dbr_id])
+		return -ENOMEM;
+
+	dbr_debug = ar->debug.dbr_debug[dbr_id];
+	dbr_dbg_data = &dbr_debug->dbr_dbg_data;
+
+	if (dbr_debug->dbr_debugfs)
+		return 0;
+
+	dbr_debug->dbr_debugfs = debugfs_create_dir(dbr_id_to_str[dbr_id],
+						    ar->debug.debugfs_pdev);
+	if (IS_ERR_OR_NULL(dbr_debug->dbr_debugfs)) {
+		if (IS_ERR(dbr_debug->dbr_debugfs))
+			return PTR_ERR(dbr_debug->dbr_debugfs);
+		return -ENOMEM;
+	}
+
+	dbr_debug->dbr_debug_enabled = true;
+	dbr_dbg_data->num_ring_debug_entries = ATH11K_DEBUG_DBR_ENTRIES_MAX;
+	dbr_dbg_data->dbr_debug_idx = 0;
+	dbr_dbg_data->entries = kcalloc(ATH11K_DEBUG_DBR_ENTRIES_MAX,
+					sizeof(struct ath11k_dbg_dbr_entry),
+					GFP_KERNEL);
+	if (!dbr_dbg_data->entries)
+		return -ENOMEM;
+
+	spin_lock_init(&dbr_dbg_data->lock);
+
+	debugfs_create_file("dump_dbr_debug", 0444, dbr_debug->dbr_debugfs,
+			    dbr_dbg_data, &fops_debug_dump_dbr_entries);
+
+	return 0;
+}
+
+static ssize_t ath11k_debugfs_write_enable_dbr_dbg(struct file *file,
+						   const char __user *ubuf,
+						   size_t count, loff_t *ppos)
+{
+	struct ath11k *ar = file->private_data;
+	char buf[32] = {0};
+	u32 dbr_id, enable;
+	int ret;
+
+	mutex_lock(&ar->conf_mutex);
+
+	if (ar->state != ATH11K_STATE_ON) {
+		ret = -ENETDOWN;
+		goto out;
+	}
+
+	ret = simple_write_to_buffer(buf, sizeof(buf) - 1, ppos, ubuf, count);
+	if (ret < 0)
+		goto out;
+
+	buf[ret] = '\0';
+	ret = sscanf(buf, "%u %u", &dbr_id, &enable);
+	if (ret != 2 || dbr_id > 1 || enable > 1) {
+		ret = -EINVAL;
+		ath11k_warn(ar->ab, "usage: echo <dbr_id> <val> dbr_id:0-Spectral 1-CFR val:0-disable 1-enable\n");
+		goto out;
+	}
+
+	if (enable) {
+		ret = ath11k_debugfs_dbr_dbg_init(ar, dbr_id);
+		if (ret) {
+			ath11k_warn(ar->ab, "db ring module debugfs init failed: %d\n",
+				    ret);
+			goto out;
+		}
+	} else {
+		ath11k_debugfs_dbr_dbg_destroy(ar, dbr_id);
+	}
+
+	ret = count;
+out:
+	mutex_unlock(&ar->conf_mutex);
+	return ret;
+}
+
+static const struct file_operations fops_dbr_debug = {
+	.write = ath11k_debugfs_write_enable_dbr_dbg,
+	.open = simple_open,
+	.owner = THIS_MODULE,
+	.llseek = default_llseek,
+};
+
 int ath11k_debugfs_register(struct ath11k *ar)
 {
 	struct ath11k_base *ab = ar->ab;
@@ -1218,11 +1420,30 @@ int ath11k_debugfs_register(struct ath11k *ar)
 				    &ar->dfs_block_radar_events);
 	}
 
+	if (ab->hw_params.dbr_debug_support)
+		debugfs_create_file("enable_dbr_debug", 0200, ar->debug.debugfs_pdev,
+				    ar, &fops_dbr_debug);
+
 	return 0;
 }
 
 void ath11k_debugfs_unregister(struct ath11k *ar)
 {
+	struct ath11k_debug_dbr *dbr_debug;
+	struct ath11k_dbg_dbr_data *dbr_dbg_data;
+	int i;
+
+	for (i = 0; i < WMI_DIRECT_BUF_MAX; i++) {
+		dbr_debug = ar->debug.dbr_debug[i];
+		if (!dbr_debug)
+			continue;
+
+		dbr_dbg_data = &dbr_debug->dbr_dbg_data;
+		kfree(dbr_dbg_data->entries);
+		debugfs_remove_recursive(dbr_debug->dbr_debugfs);
+		kfree(dbr_debug);
+		ar->debug.dbr_debug[i] = NULL;
+	}
 }
 
 static ssize_t ath11k_write_twt_add_dialog(struct file *file,