[PATCH v2 05/11] scsi: ufs: core: Add debugfs entries for TX Equalization params

[Can Guo]

Add debugfs support for UFS TX Equalization and UFS TX Equalization
Training (EQTR) to facilitate runtime inspection of link quality. These
entries allow developers to monitor and optimize TX Equalization
parameters and EQTR records during live operation.

The debugfs entries are organized on a per-gear basis under the HBA's
debugfs root. Since TX EQTR is only defined for High Speed Gear 4 (HS-G4)
and above, EQTR-related entries are explicitly excluded for HS-G1
through HS-G3 to avoid exposing unsupported attributes.

The ufshcd's debugfs folder structure will look like below:

/sys/kernel/debug/ufshcd/*ufs*/
|--tx_eq_hs_gear1/
|  |--device_tx_eq_params
|  |--host_tx_eq_params
|--tx_eq_hs_gear2/
|--tx_eq_hs_gear3/
|--tx_eq_hs_gear4/
|--tx_eq_hs_gear5/
|--tx_eq_hs_gear6/
   |--device_tx_eq_params
   |--device_tx_eqtr_record
   |--host_tx_eq_params
   |--host_tx_eqtr_record

Signed-off-by: Can Guo <can.guo@xxxxxxxxxxxxxxxx>
---
 drivers/ufs/core/ufs-debugfs.c | 211 +++++++++++++++++++++++++++++++++
 1 file changed, 211 insertions(+)

diff --git a/drivers/ufs/core/ufs-debugfs.c b/drivers/ufs/core/ufs-debugfs.c
index e3baed6c70bd..b618d9b11dc9 100644
--- a/drivers/ufs/core/ufs-debugfs.c
+++ b/drivers/ufs/core/ufs-debugfs.c
@@ -209,6 +209,186 @@ static const struct ufs_debugfs_attr ufs_attrs[] = {
 	{ }
 };
 
+static int ufs_tx_eq_params_show(struct seq_file *s, void *data)
+{
+	struct ufs_hba *hba = hba_from_file(s->file);
+	struct ufshcd_tx_eq_settings *settings;
+	struct ufshcd_tx_eq_params *params;
+	const char *file_name = s->file->f_path.dentry->d_name.name;
+	u32 gear = (u32)(uintptr_t)s->file->f_inode->i_private;
+	u32 rate = hba->pwr_info.hs_rate;
+	u32 num_lanes;
+	int lane;
+
+	if (!ufshcd_is_tx_eq_supported(hba))
+		return -EOPNOTSUPP;
+
+	if (gear < UFS_HS_G1 || gear >= UFS_HS_GEAR_MAX) {
+		seq_printf(s, "Invalid gear selected: %u\n", gear);
+		return 0;
+	}
+
+	params = &hba->tx_eq_params[gear - 1];
+	if (!params->is_valid) {
+		seq_printf(s, "TX EQ params are invalid for HS-G%u, Rate-%s\n",
+			   gear, UFS_HS_RATE_STRING(rate));
+		return 0;
+	}
+
+	if (strcmp(file_name, "host_tx_eq_params") == 0) {
+		settings = params->host;
+		num_lanes = params->tx_lanes;
+		seq_printf(s, "Host TX EQ PreShoot Cap: 0x%02x, DeEmphasis Cap: 0x%02x\n",
+			   hba->host_preshoot_cap, hba->host_deemphasis_cap);
+	} else if (strcmp(file_name, "device_tx_eq_params") == 0) {
+		settings = params->device;
+		num_lanes = params->rx_lanes;
+		seq_printf(s, "Device TX EQ PreShoot Cap: 0x%02x, DeEmphasis Cap: 0x%02x\n",
+			   hba->device_preshoot_cap, hba->device_deemphasis_cap);
+	} else {
+		return -ENOENT;
+	}
+
+	seq_printf(s, "TX EQ setting for HS-G%u, Rate-%s:\n", gear,
+		   UFS_HS_RATE_STRING(rate));
+	for (lane = 0; lane < num_lanes; lane++)
+		seq_printf(s, "TX Lane %d - PreShoot: %d, DeEmphasis: %d, Pre-Coding %senabled\n",
+			   lane, settings[lane].preshoot,
+			   settings[lane].deemphasis,
+			   settings[lane].precode_en ? "" : "not ");
+
+	return 0;
+}
+
+static int ufs_tx_eq_params_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, ufs_tx_eq_params_show, inode->i_private);
+}
+
+static const struct file_operations ufs_tx_eq_params_fops = {
+	.owner		= THIS_MODULE,
+	.open		= ufs_tx_eq_params_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static const struct ufs_debugfs_attr ufs_tx_eq_attrs[] = {
+	{ "host_tx_eq_params", 0400, &ufs_tx_eq_params_fops },
+	{ "device_tx_eq_params", 0400, &ufs_tx_eq_params_fops },
+	{ }
+};
+
+static int ufs_tx_eqtr_record_show(struct seq_file *s, void *data)
+{
+	struct ufs_hba *hba = hba_from_file(s->file);
+	struct ufshcd_tx_eq_params *params;
+	unsigned long preshoot_bitmap, deemphasis_bitmap;
+	unsigned int preshoot, deemphasis;
+	const char *file_name = s->file->f_path.dentry->d_name.name;
+	u32 (*record)[TX_HS_NUM_PRESHOOT][TX_HS_NUM_DEEMPHASIS];
+	u32 gear = (u32)(uintptr_t)s->file->f_inode->i_private;
+	u32 rate = hba->pwr_info.hs_rate;
+	u32 num_lanes;
+	int lane;
+	char name[32];
+
+	if (!ufshcd_is_tx_eq_supported(hba))
+		return -EOPNOTSUPP;
+
+	if (gear < UFS_HS_G1 || gear >= UFS_HS_GEAR_MAX) {
+		seq_printf(s, "Invalid gear selected: %u\n", gear);
+		return 0;
+	}
+
+	params = &hba->tx_eq_params[gear - 1];
+	if (!params->is_valid) {
+		seq_printf(s, "TX EQ params are invalid for HS-G%u, Rate-%s\n",
+			   gear, UFS_HS_RATE_STRING(rate));
+		return 0;
+	}
+
+	if (!params->num_eqtr_records) {
+		seq_printf(s, "No TX EQTR records found for HS-G%u, Rate-%s.\n",
+			   gear, UFS_HS_RATE_STRING(rate));
+		return 0;
+	}
+
+	if (strcmp(file_name, "host_tx_eqtr_record") == 0) {
+		record = params->host_eqtr_record;
+		preshoot_bitmap = (hba->host_preshoot_cap << 0x1) | 0x1;
+		deemphasis_bitmap = (hba->host_deemphasis_cap << 0x1) | 0x1;
+		num_lanes = params->tx_lanes;
+		snprintf(name, 32, "%s", "Host");
+	} else if (strcmp(file_name, "device_tx_eqtr_record") == 0) {
+		record = params->device_eqtr_record;
+		preshoot_bitmap = (hba->device_preshoot_cap << 0x1) | 0x1;
+		deemphasis_bitmap = (hba->device_deemphasis_cap << 0x1) | 0x1;
+		num_lanes = params->rx_lanes;
+		snprintf(name, 32, "%s", "Device");
+	} else {
+		return -ENOENT;
+	}
+
+	seq_printf(s, "%s TX EQTR record summary -\n", name);
+	seq_printf(s, "Target Power Mode: HS-G%u, Rate-%s\n", gear,
+		   UFS_HS_RATE_STRING(rate));
+	seq_printf(s, "Number of records: %d\n", params->num_eqtr_records);
+	seq_printf(s, "Last record timestamp: %llu us\n",
+		   ktime_to_us(params->last_eqtr_ts));
+
+	for (lane = 0; lane < num_lanes; lane++) {
+		seq_printf(s, "\nTX Lane %d FOM - %s\n", lane, "PreShoot\\DeEmphasis");
+		seq_puts(s, "\\");
+		/* Print DeEmphasis header as X-axis. */
+		for (deemphasis = 0; deemphasis < TX_HS_NUM_DEEMPHASIS; deemphasis++)
+			seq_printf(s, "%8d%s", deemphasis, " ");
+		seq_puts(s, "\n");
+		/* Print matrix rows with PreShoot as Y-axis. */
+		for (preshoot = 0; preshoot < TX_HS_NUM_PRESHOOT; preshoot++) {
+			seq_printf(s, "%d", preshoot);
+			for (deemphasis = 0; deemphasis < TX_HS_NUM_DEEMPHASIS; deemphasis++) {
+				if (test_bit(preshoot, &preshoot_bitmap) &&
+				    test_bit(deemphasis, &deemphasis_bitmap)) {
+					u32 fom = record[lane][preshoot][deemphasis];
+					u32 fom_val = fom & RX_FOM_VALUE_MASK;
+					bool precode_en = !!(fom & RX_FOM_PRECODING_EN_MASK);
+
+					if (fom == 0xFFFFFFFF)
+						seq_printf(s, "%8s%s", "-", " ");
+					else
+						seq_printf(s, "%8u%s", fom_val,
+							   precode_en ? "*" : " ");
+				} else {
+					seq_printf(s, "%8s%s", "x", " ");
+				}
+			}
+			seq_puts(s, "\n");
+		}
+	}
+
+	return 0;
+}
+
+static int ufs_tx_eqtr_record_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, ufs_tx_eqtr_record_show, inode->i_private);
+}
+
+static const struct file_operations ufs_tx_eqtr_record_fops = {
+	.owner		= THIS_MODULE,
+	.open		= ufs_tx_eqtr_record_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static const struct ufs_debugfs_attr ufs_tx_eqtr_attrs[] = {
+	{ "host_tx_eqtr_record", 0400, &ufs_tx_eqtr_record_fops },
+	{ "device_tx_eqtr_record", 0400, &ufs_tx_eqtr_record_fops },
+	{ }
+};
+
 void ufs_debugfs_hba_init(struct ufs_hba *hba)
 {
 	const struct ufs_debugfs_attr *attr;
@@ -230,6 +410,37 @@ void ufs_debugfs_hba_init(struct ufs_hba *hba)
 			    hba, &ee_usr_mask_fops);
 	debugfs_create_u32("exception_event_rate_limit_ms", 0600, hba->debugfs_root,
 			   &hba->debugfs_ee_rate_limit_ms);
+
+	if (!(hba->caps & UFSHCD_CAP_TX_EQUALIZATION))
+		return;
+
+	for (u32 gear = UFS_HS_G1; gear < UFS_HS_GEAR_MAX; gear++) {
+		struct dentry *txeq_dir;
+		char name[32];
+
+		snprintf(name, 32, "tx_eq_hs_gear%d", gear);
+		txeq_dir = debugfs_create_dir(name, hba->debugfs_root);
+		if (IS_ERR_OR_NULL(txeq_dir))
+			return;
+
+		d_inode(txeq_dir)->i_private = hba;
+
+		/* Create files for TX Equalization parameters */
+		for (attr = ufs_tx_eq_attrs; attr->name; attr++)
+			debugfs_create_file(attr->name, attr->mode, txeq_dir,
+					    (void *)(uintptr_t)gear,
+					    attr->fops);
+
+		/* TX EQTR is supported for HS-G4 and higher Gears */
+		if (gear < UFS_HS_G4)
+			continue;
+
+		/* Create files for TX EQTR related attributes */
+		for (attr = ufs_tx_eqtr_attrs; attr->name; attr++)
+			debugfs_create_file(attr->name, attr->mode, txeq_dir,
+					    (void *)(uintptr_t)gear,
+					    attr->fops);
+	}
 }
 
 void ufs_debugfs_hba_exit(struct ufs_hba *hba)
-- 
2.34.1