mtd: spi-nor: expose internal parameters via debugfs

There is no way to gather all information to verify support for a new
flash chip. Also if you want to convert an existing flash chip to the
new SFDP parsing, there is not enough information to determine if the
flash will work like before. To ease this development, expose internal
parameters via the debugfs.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Pratyush Yadav <p.yadav@ti.com>
Link: https://lore.kernel.org/r/20220429102018.2361038-2-michael@walle.cc

4 files changed, 259 insertions, 0 deletions

diff --git a/drivers/mtd/spi-nor/Makefile b/drivers/mtd/spi-nor/Makefile
index 6b904e439372..e347b435a038 100644
--- a/drivers/mtd/spi-nor/Makefile
+++ b/drivers/mtd/spi-nor/Makefile
@@ -17,6 +17,7 @@ spi-nor-objs			+= sst.o
 spi-nor-objs			+= winbond.o
 spi-nor-objs			+= xilinx.o
 spi-nor-objs			+= xmc.o
+spi-nor-$(CONFIG_DEBUG_FS)	+= debugfs.o
 obj-$(CONFIG_MTD_SPI_NOR)	+= spi-nor.o
 
 obj-$(CONFIG_MTD_SPI_NOR)	+= controllers/
diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 8377bd1842da..502967c76c5f 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -3132,6 +3132,8 @@ static int spi_nor_probe(struct spi_mem *spimem)
 	if (ret)
 		return ret;
 
+	spi_nor_debugfs_register(nor);
+
 	/*
 	 * None of the existing parts have > 512B pages, but let's play safe
 	 * and add this logic so that if anyone ever adds support for such
diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
index ef37e179c615..3f841ec36e56 100644
--- a/drivers/mtd/spi-nor/core.h
+++ b/drivers/mtd/spi-nor/core.h
@@ -114,6 +114,7 @@
 		   SPI_MEM_OP_NO_ADDR,					\
 		   SPI_MEM_OP_NO_DATA)
 
+/* Keep these in sync with the list in debugfs.c */
 enum spi_nor_option_flags {
 	SNOR_F_HAS_SR_TB	= BIT(0),
 	SNOR_F_NO_OP_CHIP_ERASE	= BIT(1),
@@ -700,4 +701,10 @@ static inline struct spi_nor *mtd_to_spi_nor(struct mtd_info *mtd)
 	return container_of(mtd, struct spi_nor, mtd);
 }
 
+#ifdef CONFIG_DEBUG_FS
+void spi_nor_debugfs_register(struct spi_nor *nor);
+#else
+static inline void spi_nor_debugfs_register(struct spi_nor *nor) {}
+#endif
+
 #endif /* __LINUX_MTD_SPI_NOR_INTERNAL_H */
diff --git a/drivers/mtd/spi-nor/debugfs.c b/drivers/mtd/spi-nor/debugfs.c
new file mode 100644
index 000000000000..1949905eefea
--- /dev/null
+++ b/drivers/mtd/spi-nor/debugfs.c
@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/mtd/spi-nor.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi-mem.h>
+#include <linux/debugfs.h>
+
+#include "core.h"
+
+#define SPI_NOR_DEBUGFS_ROOT "spi-nor"
+
+#define SNOR_F_NAME(name) [ilog2(SNOR_F_##name)] = #name
+static const char *const snor_f_names[] = {
+	SNOR_F_NAME(HAS_SR_TB),
+	SNOR_F_NAME(NO_OP_CHIP_ERASE),
+	SNOR_F_NAME(BROKEN_RESET),
+	SNOR_F_NAME(4B_OPCODES),
+	SNOR_F_NAME(HAS_4BAIT),
+	SNOR_F_NAME(HAS_LOCK),
+	SNOR_F_NAME(HAS_16BIT_SR),
+	SNOR_F_NAME(NO_READ_CR),
+	SNOR_F_NAME(HAS_SR_TB_BIT6),
+	SNOR_F_NAME(HAS_4BIT_BP),
+	SNOR_F_NAME(HAS_SR_BP3_BIT6),
+	SNOR_F_NAME(IO_MODE_EN_VOLATILE),
+	SNOR_F_NAME(SOFT_RESET),
+	SNOR_F_NAME(SWP_IS_VOLATILE),
+};
+#undef SNOR_F_NAME
+
+static const char *spi_nor_protocol_name(enum spi_nor_protocol proto)
+{
+	switch (proto) {
+	case SNOR_PROTO_1_1_1:     return "1S-1S-1S";
+	case SNOR_PROTO_1_1_2:     return "1S-1S-2S";
+	case SNOR_PROTO_1_1_4:     return "1S-1S-4S";
+	case SNOR_PROTO_1_1_8:     return "1S-1S-8S";
+	case SNOR_PROTO_1_2_2:     return "1S-2S-2S";
+	case SNOR_PROTO_1_4_4:     return "1S-4S-4S";
+	case SNOR_PROTO_1_8_8:     return "1S-8S-8S";
+	case SNOR_PROTO_2_2_2:     return "2S-2S-2S";
+	case SNOR_PROTO_4_4_4:     return "4S-4S-4S";
+	case SNOR_PROTO_8_8_8:     return "8S-8S-8S";
+	case SNOR_PROTO_1_1_1_DTR: return "1D-1D-1D";
+	case SNOR_PROTO_1_2_2_DTR: return "1D-2D-2D";
+	case SNOR_PROTO_1_4_4_DTR: return "1D-4D-4D";
+	case SNOR_PROTO_1_8_8_DTR: return "1D-8D-8D";
+	case SNOR_PROTO_8_8_8_DTR: return "8D-8D-8D";
+	}
+
+	return "<unknown>";
+}
+
+static void spi_nor_print_flags(struct seq_file *s, unsigned long flags,
+				const char *const *names, int names_len)
+{
+	bool sep = false;
+	int i;
+
+	for (i = 0; i < sizeof(flags) * BITS_PER_BYTE; i++) {
+		if (!(flags & BIT(i)))
+			continue;
+		if (sep)
+			seq_puts(s, " | ");
+		sep = true;
+		if (i < names_len && names[i])
+			seq_puts(s, names[i]);
+		else
+			seq_printf(s, "1<<%d", i);
+	}
+}
+
+static int spi_nor_params_show(struct seq_file *s, void *data)
+{
+	struct spi_nor *nor = s->private;
+	struct spi_nor_flash_parameter *params = nor->params;
+	struct spi_nor_erase_map *erase_map = &params->erase_map;
+	struct spi_nor_erase_region *region;
+	const struct flash_info *info = nor->info;
+	char buf[16], *str;
+	int i;
+
+	seq_printf(s, "name\t\t%s\n", info->name);
+	seq_printf(s, "id\t\t%*phn\n", info->id_len, info->id);
+	string_get_size(params->size, 1, STRING_UNITS_2, buf, sizeof(buf));
+	seq_printf(s, "size\t\t%s\n", buf);
+	seq_printf(s, "write size\t%u\n", params->writesize);
+	seq_printf(s, "page size\t%u\n", params->page_size);
+	seq_printf(s, "address width\t%u\n", nor->addr_width);
+
+	seq_puts(s, "flags\t\t");
+	spi_nor_print_flags(s, nor->flags, snor_f_names, sizeof(snor_f_names));
+	seq_puts(s, "\n");
+
+	seq_puts(s, "\nopcodes\n");
+	seq_printf(s, " read\t\t0x%02x\n", nor->read_opcode);
+	seq_printf(s, "  dummy cycles\t%u\n", nor->read_dummy);
+	seq_printf(s, " erase\t\t0x%02x\n", nor->erase_opcode);
+	seq_printf(s, " program\t0x%02x\n", nor->program_opcode);
+
+	switch (nor->cmd_ext_type) {
+	case SPI_NOR_EXT_NONE:
+		str = "none";
+		break;
+	case SPI_NOR_EXT_REPEAT:
+		str = "repeat";
+		break;
+	case SPI_NOR_EXT_INVERT:
+		str = "invert";
+		break;
+	default:
+		str = "<unknown>";
+		break;
+	}
+	seq_printf(s, " 8D extension\t%s\n", str);
+
+	seq_puts(s, "\nprotocols\n");
+	seq_printf(s, " read\t\t%s\n",
+		   spi_nor_protocol_name(nor->read_proto));
+	seq_printf(s, " write\t\t%s\n",
+		   spi_nor_protocol_name(nor->write_proto));
+	seq_printf(s, " register\t%s\n",
+		   spi_nor_protocol_name(nor->reg_proto));
+
+	seq_puts(s, "\nerase commands\n");
+	for (i = 0; i < SNOR_ERASE_TYPE_MAX; i++) {
+		struct spi_nor_erase_type *et = &erase_map->erase_type[i];
+
+		if (et->size) {
+			string_get_size(et->size, 1, STRING_UNITS_2, buf,
+					sizeof(buf));
+			seq_printf(s, " %02x (%s) [%d]\n", et->opcode, buf, i);
+		}
+	}
+
+	if (!(nor->flags & SNOR_F_NO_OP_CHIP_ERASE)) {
+		string_get_size(params->size, 1, STRING_UNITS_2, buf, sizeof(buf));
+		seq_printf(s, " %02x (%s)\n", SPINOR_OP_CHIP_ERASE, buf);
+	}
+
+	seq_puts(s, "\nsector map\n");
+	seq_puts(s, " region (in hex)   | erase mask | flags\n");
+	seq_puts(s, " ------------------+------------+----------\n");
+	for (region = erase_map->regions;
+	     region;
+	     region = spi_nor_region_next(region)) {
+		u64 start = region->offset & ~SNOR_ERASE_FLAGS_MASK;
+		u64 flags = region->offset & SNOR_ERASE_FLAGS_MASK;
+		u64 end = start + region->size - 1;
+
+		seq_printf(s, " %08llx-%08llx |     [%c%c%c%c] | %s\n",
+			   start, end,
+			   flags & BIT(0) ? '0' : ' ',
+			   flags & BIT(1) ? '1' : ' ',
+			   flags & BIT(2) ? '2' : ' ',
+			   flags & BIT(3) ? '3' : ' ',
+			   flags & SNOR_OVERLAID_REGION ? "overlaid" : "");
+	}
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(spi_nor_params);
+
+static void spi_nor_print_read_cmd(struct seq_file *s, u32 cap,
+				   struct spi_nor_read_command *cmd)
+{
+	seq_printf(s, " %s%s\n", spi_nor_protocol_name(cmd->proto),
+		   cap == SNOR_HWCAPS_READ_FAST ? " (fast read)" : "");
+	seq_printf(s, "  opcode\t0x%02x\n", cmd->opcode);
+	seq_printf(s, "  mode cycles\t%u\n", cmd->num_mode_clocks);
+	seq_printf(s, "  dummy cycles\t%u\n", cmd->num_wait_states);
+}
+
+static void spi_nor_print_pp_cmd(struct seq_file *s,
+				 struct spi_nor_pp_command *cmd)
+{
+	seq_printf(s, " %s\n", spi_nor_protocol_name(cmd->proto));
+	seq_printf(s, "  opcode\t0x%02x\n", cmd->opcode);
+}
+
+static int spi_nor_capabilities_show(struct seq_file *s, void *data)
+{
+	struct spi_nor *nor = s->private;
+	struct spi_nor_flash_parameter *params = nor->params;
+	u32 hwcaps = params->hwcaps.mask;
+	int i, cmd;
+
+	seq_puts(s, "Supported read modes by the flash\n");
+	for (i = 0; i < sizeof(hwcaps) * BITS_PER_BYTE; i++) {
+		if (!(hwcaps & BIT(i)))
+			continue;
+
+		cmd = spi_nor_hwcaps_read2cmd(BIT(i));
+		if (cmd < 0)
+			continue;
+
+		spi_nor_print_read_cmd(s, BIT(i), &params->reads[cmd]);
+		hwcaps &= ~BIT(i);
+	}
+
+	seq_puts(s, "\nSupported page program modes by the flash\n");
+	for (i = 0; i < sizeof(hwcaps) * BITS_PER_BYTE; i++) {
+		if (!(hwcaps & BIT(i)))
+			continue;
+
+		cmd = spi_nor_hwcaps_pp2cmd(BIT(i));
+		if (cmd < 0)
+			continue;
+
+		spi_nor_print_pp_cmd(s, &params->page_programs[cmd]);
+		hwcaps &= ~BIT(i);
+	}
+
+	if (hwcaps)
+		seq_printf(s, "\nunknown hwcaps 0x%x\n", hwcaps);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(spi_nor_capabilities);
+
+static void spi_nor_debugfs_unregister(void *data)
+{
+	struct spi_nor *nor = data;
+
+	debugfs_remove(nor->debugfs_root);
+	nor->debugfs_root = NULL;
+}
+
+void spi_nor_debugfs_register(struct spi_nor *nor)
+{
+	struct dentry *rootdir, *d;
+	int ret;
+
+	/* Create rootdir once. Will never be deleted again. */
+	rootdir = debugfs_lookup(SPI_NOR_DEBUGFS_ROOT, NULL);
+	if (!rootdir)
+		rootdir = debugfs_create_dir(SPI_NOR_DEBUGFS_ROOT, NULL);
+
+	ret = devm_add_action(nor->dev, spi_nor_debugfs_unregister, nor);
+	if (ret)
+		return;
+
+	d = debugfs_create_dir(dev_name(nor->dev), rootdir);
+	nor->debugfs_root = d;
+
+	debugfs_create_file("params", 0444, d, nor, &spi_nor_params_fops);
+	debugfs_create_file("capabilities", 0444, d, nor,
+			    &spi_nor_capabilities_fops);
+}