mtd: spi-nor: debugfs: Add a locked sectors map

In order to get a very clear view of the sectors being locked, besides
the `params` output giving the ranges, we may want to see a proper map
of the sectors and for each of them, their status. Depending on the use
case, this map may be easier to parse by humans and gives a more acurate
feeling of the situation. At least myself, for the few locking-related
developments I recently went through, I found it very useful to get a
clearer mental model of what was locked/unlocked.

Here is an example of output:

$ cat /sys/kernel/debug/spi-nor/spi0.0/locked-sectors-map
Locked sectors map (x: locked, .: unlocked, unit: 64kiB)
 0x00000000 (#    0): ................ ................ ................ ................
 0x00400000 (#   64): ................ ................ ................ ................
 0x00800000 (#  128): ................ ................ ................ ................
 0x00c00000 (#  192): ................ ................ ................ ................
 0x01000000 (#  256): ................ ................ ................ ................
 0x01400000 (#  320): ................ ................ ................ ................
 0x01800000 (#  384): ................ ................ ................ ................
 0x01c00000 (#  448): ................ ................ ................ ................
 0x02000000 (#  512): ................ ................ ................ ................
 0x02400000 (#  576): ................ ................ ................ ................
 0x02800000 (#  640): ................ ................ ................ ................
 0x02c00000 (#  704): ................ ................ ................ ................
 0x03000000 (#  768): ................ ................ ................ ................
 0x03400000 (#  832): ................ ................ ................ ................
 0x03800000 (#  896): ................ ................ ................ ................
 0x03c00000 (#  960): ................ ................ ................ ..............xx

The output is wrapped at 64 sectors, spaces every 16 sectors are
improving the readability, every line starts by the first sector
offset (hex) and number (decimal).

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
[pratyush@kernel.org: split the debugfs_create_file() into two lines]
Signed-off-by: Pratyush Yadav <pratyush@kernel.org>

1 files changed, 38 insertions, 0 deletions

diff --git a/drivers/mtd/spi-nor/debugfs.c b/drivers/mtd/spi-nor/debugfs.c
index 82df8ad4176c..ef710bd4f307 100644
--- a/drivers/mtd/spi-nor/debugfs.c
+++ b/drivers/mtd/spi-nor/debugfs.c
@@ -191,6 +191,41 @@ static int spi_nor_params_show(struct seq_file *s, void *data)
 }
 DEFINE_SHOW_ATTRIBUTE(spi_nor_params);
 
+static int spi_nor_locked_sectors_map_show(struct seq_file *s, void *data)
+{
+	struct spi_nor *nor = s->private;
+	struct spi_nor_flash_parameter *params = nor->params;
+	u64 min_prot_len = spi_nor_get_min_prot_length_sr(nor);
+	unsigned int sector = 0;
+	u64 offset = 0;
+	bool locked;
+	int i;
+
+	seq_printf(s, "Locked sectors map (x: locked, .: unlocked, unit: %lldkiB)\n",
+		   min_prot_len / 1024);
+	while (offset < params->size) {
+		seq_printf(s, " 0x%08llx (#%5d): ", offset, sector);
+		for (i = 0; i < 64 && offset < params->size; i++) {
+			locked = spi_nor_is_locked_sr(nor, offset, min_prot_len,
+						      nor->dfs_sr_cache);
+			if (locked)
+				seq_puts(s, "x");
+			else
+				seq_puts(s, ".");
+
+			if (((i + 1) % 16) == 0)
+				seq_puts(s, " ");
+
+			offset += min_prot_len;
+			sector++;
+		}
+		seq_puts(s, "\n");
+	}
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(spi_nor_locked_sectors_map);
+
 static void spi_nor_print_read_cmd(struct seq_file *s, u32 cap,
 				   struct spi_nor_read_command *cmd)
 {
@@ -276,6 +311,9 @@ void spi_nor_debugfs_register(struct spi_nor *nor)
 	debugfs_create_file("params", 0444, d, nor, &spi_nor_params_fops);
 	debugfs_create_file("capabilities", 0444, d, nor,
 			    &spi_nor_capabilities_fops);
+	if (spi_nor_has_default_locking_ops(nor))
+		debugfs_create_file("locked-sectors-map", 0444, d, nor,
+				    &spi_nor_locked_sectors_map_fops);
 }
 
 void spi_nor_debugfs_shutdown(void)