wifi: ath12k: initial debugfs support

The initial debugfs infra bringup in ath12k driver and create the ath12k debugfs
and soc-specific directories in /sys/kernel/debug/

For each ath12k device, directory will be created in <bus>-<devname>
schema under ath12k root directory.

Example with one ath12k device:
/sys/kernel/debug/ath12k/pci-0000:06:00.0

ath12k
`-- pci-0000:06:00.0
    |-- mac0

To enable ath12k debugfs support (CONFIG_ATH12K_DEBUGFS=y)

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1

Signed-off-by: Ramasamy Kaliappan <quic_rkaliapp@quicinc.com>
Signed-off-by: Ramya Gnanasekar <quic_rgnanase@quicinc.com>
Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://msgid.link/20240320171305.655288-2-quic_rgnanase@quicinc.com

drivers/net/wireless/ath/ath12k/Kconfig

@@ -24,6 +24,15 @@ config ATH12K_DEBUG
 	  If unsure, say Y to make it easier to debug problems. But if
 	  you want optimal performance choose N.
 
+config ATH12K_DEBUGFS
+	bool "QTI ath12k debugfs support"
+	depends on ATH12K && MAC80211_DEBUGFS
+	help
+	  Enable ath12k debugfs support
+
+	  If unsure, say Y to make it easier to debug problems. But if
+	  you want optimal performance choose N.
+
 config ATH12K_TRACING
 	bool "ath12k tracing support"
 	depends on ATH12K && EVENT_TRACING

drivers/net/wireless/ath/ath12k/Makefile

@@ -23,6 +23,7 @@ ath12k-y += core.o \
 	    fw.o \
 	    p2p.o
 
+ath12k-$(CONFIG_ATH12K_DEBUGFS) += debugfs.o
 ath12k-$(CONFIG_ATH12K_TRACING) += trace.o
 
 # for tracing framework to find trace.h

drivers/net/wireless/ath/ath12k/core.c

@@ -15,6 +15,7 @@
 #include "debug.h"
 #include "hif.h"
 #include "fw.h"
+#include "debugfs.h"
 
 unsigned int ath12k_debug_mask;
 module_param_named(debug_mask, ath12k_debug_mask, uint, 0644);
@@ -628,6 +629,8 @@ static int ath12k_core_soc_create(struct ath12k_base *ab)
 		return ret;
 	}
 
+	ath12k_debugfs_soc_create(ab);
+
 	ret = ath12k_hif_power_up(ab);
 	if (ret) {
 		ath12k_err(ab, "failed to power up :%d\n", ret);
@@ -637,6 +640,7 @@ static int ath12k_core_soc_create(struct ath12k_base *ab)
 	return 0;
 
 err_qmi_deinit:
+	ath12k_debugfs_soc_destroy(ab);
 	ath12k_qmi_deinit_service(ab);
 	return ret;
 }
@@ -645,6 +649,7 @@ static void ath12k_core_soc_destroy(struct ath12k_base *ab)
 {
 	ath12k_dp_free(ab);
 	ath12k_reg_free(ab);
+	ath12k_debugfs_soc_destroy(ab);
 	ath12k_qmi_deinit_service(ab);
 }
 

drivers/net/wireless/ath/ath12k/core.h

@@ -453,6 +453,10 @@ struct ath12k_fw_stats {
 	struct list_head bcn;
 };
 
+struct ath12k_debug {
+	struct dentry *debugfs_pdev;
+};
+
 struct ath12k_per_peer_tx_stats {
 	u32 succ_bytes;
 	u32 retry_bytes;
@@ -592,6 +596,9 @@ struct ath12k {
 	struct ath12k_per_peer_tx_stats cached_stats;
 	u32 last_ppdu_id;
 	u32 cached_ppdu_id;
+#ifdef CONFIG_ATH12K_DEBUGFS
+	struct ath12k_debug debug;
+#endif
 
 	bool dfs_block_radar_events;
 	bool monitor_conf_enabled;
@@ -782,6 +789,9 @@ struct ath12k_base {
 	/* Current DFS Regulatory */
 	enum ath12k_dfs_region dfs_region;
 	struct ath12k_soc_dp_stats soc_stats;
+#ifdef CONFIG_ATH12K_DEBUGFS
+	struct dentry *debugfs_soc;
+#endif
 
 	unsigned long dev_flags;
 	struct completion driver_recovery;

drivers/net/wireless/ath/ath12k/debugfs.c

@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: BSD-3-Clause-Clear
+/*
+ * Copyright (c) 2018-2021 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2021-2024 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include "core.h"
+#include "debugfs.h"
+
+void ath12k_debugfs_soc_create(struct ath12k_base *ab)
+{
+	bool dput_needed;
+	char soc_name[64] = { 0 };
+	struct dentry *debugfs_ath12k;
+
+	debugfs_ath12k = debugfs_lookup("ath12k", NULL);
+	if (debugfs_ath12k) {
+		/* a dentry from lookup() needs dput() after we don't use it */
+		dput_needed = true;
+	} else {
+		debugfs_ath12k = debugfs_create_dir("ath12k", NULL);
+		if (IS_ERR_OR_NULL(debugfs_ath12k))
+			return;
+		dput_needed = false;
+	}
+
+	scnprintf(soc_name, sizeof(soc_name), "%s-%s", ath12k_bus_str(ab->hif.bus),
+		  dev_name(ab->dev));
+
+	ab->debugfs_soc = debugfs_create_dir(soc_name, debugfs_ath12k);
+
+	if (dput_needed)
+		dput(debugfs_ath12k);
+}
+
+void ath12k_debugfs_soc_destroy(struct ath12k_base *ab)
+{
+	debugfs_remove_recursive(ab->debugfs_soc);
+	ab->debugfs_soc = NULL;
+	/* We are not removing ath12k directory on purpose, even if it
+	 * would be empty. This simplifies the directory handling and it's
+	 * a minor cosmetic issue to leave an empty ath12k directory to
+	 * debugfs.
+	 */
+}
+
+void ath12k_debugfs_register(struct ath12k *ar)
+{
+	struct ath12k_base *ab = ar->ab;
+	struct ieee80211_hw *hw = ar->ah->hw;
+	char pdev_name[5];
+	char buf[100] = {0};
+
+	scnprintf(pdev_name, sizeof(pdev_name), "%s%d", "mac", ar->pdev_idx);
+
+	ar->debug.debugfs_pdev = debugfs_create_dir(pdev_name, ab->debugfs_soc);
+
+	/* Create a symlink under ieee80211/phy* */
+	scnprintf(buf, sizeof(buf), "../../ath12k/%pd2", ar->debug.debugfs_pdev);
+	debugfs_create_symlink("ath12k", hw->wiphy->debugfsdir, buf);
+}

drivers/net/wireless/ath/ath12k/debugfs.h

@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: BSD-3-Clause-Clear */
+/*
+ * Copyright (c) 2018-2021 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2021-2024 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef _ATH12K_DEBUGFS_H_
+#define _ATH12K_DEBUGFS_H_
+
+#ifdef CONFIG_ATH12K_DEBUGFS
+void ath12k_debugfs_soc_create(struct ath12k_base *ab);
+void ath12k_debugfs_soc_destroy(struct ath12k_base *ab);
+void ath12k_debugfs_register(struct ath12k *ar);
+
+#else
+static inline void ath12k_debugfs_soc_create(struct ath12k_base *ab)
+{
+}
+
+static inline void ath12k_debugfs_soc_destroy(struct ath12k_base *ab)
+{
+}
+
+static inline void ath12k_debugfs_register(struct ath12k *ar)
+{
+}
+
+#endif /* CONFIG_ATH12K_DEBUGFS */
+
+#endif /* _ATH12K_DEBUGFS_H_ */

drivers/net/wireless/ath/ath12k/mac.c

@@ -14,6 +14,7 @@
 #include "dp_tx.h"
 #include "dp_rx.h"
 #include "peer.h"
+#include "debugfs.h"
 
 #define CHAN2G(_channel, _freq, _flags) { \
 	.band                   = NL80211_BAND_2GHZ, \
@@ -8105,6 +8106,8 @@ static int ath12k_mac_hw_register(struct ath12k_hw *ah)
 		goto err_unregister_hw;
 	}
 
+	ath12k_debugfs_register(ar);
+
 	return 0;
 
 err_unregister_hw: