net/mlx5: SD, Add debugfs

Add debugfs entries that describe the Socket-Direct group.

Example:
$ grep -H . /sys/kernel/debug/mlx5/0000\:08\:00.0/multi-pf/*
/sys/kernel/debug/mlx5/0000:08:00.0/multi-pf/group_id:0x00000101
/sys/kernel/debug/mlx5/0000:08:00.0/multi-pf/primary:0000:08:00.0 vhca 0x0
/sys/kernel/debug/mlx5/0000:08:00.0/multi-pf/secondary_0:0000:09:00.0 vhca 0x2
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c

@@ -6,6 +6,7 @@
 #include "lib/mlx5.h"
 #include "fs_cmd.h"
 #include <linux/mlx5/vport.h>
+#include <linux/debugfs.h>
 
 #define sd_info(__dev, format, ...) \
 	dev_info((__dev)->device, "Socket-Direct: " format, ##__VA_ARGS__)
@@ -16,6 +17,7 @@ struct mlx5_sd {
 	u32 group_id;
 	u8 host_buses;
 	struct mlx5_devcom_comp_dev *devcom;
+	struct dentry *dfs;
 	bool primary;
 	union {
 		struct { /* primary */
@@ -391,6 +393,26 @@ static void sd_print_group(struct mlx5_core_dev *primary)
 			MLX5_CAP_GEN(pos, vhca_id));
 }
 
+static ssize_t dev_read(struct file *filp, char __user *buf, size_t count,
+			loff_t *pos)
+{
+	struct mlx5_core_dev *dev;
+	char tbuf[32];
+	int ret;
+
+	dev = filp->private_data;
+	ret = snprintf(tbuf, sizeof(tbuf), "%s vhca %#x\n", pci_name(dev->pdev),
+		       MLX5_CAP_GEN(dev, vhca_id));
+
+	return simple_read_from_buffer(buf, count, pos, tbuf, ret);
+}
+
+static const struct file_operations dev_fops = {
+	.owner	= THIS_MODULE,
+	.open	= simple_open,
+	.read	= dev_read,
+};
+
 int mlx5_sd_init(struct mlx5_core_dev *dev)
 {
 	struct mlx5_core_dev *primary, *pos, *to;
@@ -422,10 +444,20 @@ int mlx5_sd_init(struct mlx5_core_dev *dev)
 	if (err)
 		goto err_sd_unregister;
 
+	sd->dfs = debugfs_create_dir("multi-pf", mlx5_debugfs_get_dev_root(primary));
+	debugfs_create_x32("group_id", 0400, sd->dfs, &sd->group_id);
+	debugfs_create_file("primary", 0400, sd->dfs, primary, &dev_fops);
+
 	mlx5_sd_for_each_secondary(i, primary, pos) {
+		char name[32];
+
 		err = sd_cmd_set_secondary(pos, primary, alias_key);
 		if (err)
 			goto err_unset_secondaries;
+
+		snprintf(name, sizeof(name), "secondary_%d", i - 1);
+		debugfs_create_file(name, 0400, sd->dfs, pos, &dev_fops);
+
 	}
 
 	sd_info(primary, "group id %#x, size %d, combined\n",
@@ -439,6 +471,7 @@ int mlx5_sd_init(struct mlx5_core_dev *dev)
 	mlx5_sd_for_each_secondary_to(i, primary, to, pos)
 		sd_cmd_unset_secondary(pos);
 	sd_cmd_unset_primary(primary);
+	debugfs_remove_recursive(sd->dfs);
 err_sd_unregister:
 	sd_unregister(dev);
 err_sd_cleanup:
@@ -462,6 +495,7 @@ void mlx5_sd_cleanup(struct mlx5_core_dev *dev)
 	mlx5_sd_for_each_secondary(i, primary, pos)
 		sd_cmd_unset_secondary(pos);
 	sd_cmd_unset_primary(primary);
+	debugfs_remove_recursive(sd->dfs);
 
 	sd_info(primary, "group id %#x, uncombined\n", sd->group_id);
 out: