[PATCH v2 05/23] mtd: spi-nor: winbond: W25Q32JV-Q/N: Add quad page program capability

[Miquel Raynal]

The benefit is not massive @25MHz, yet it is a supported feature
of the chip which is already handled by a flag, so let's enable it and
earn that little 1% write throughput.

Before:
$ flash_speed /dev/mtd0 -d -c10
eraseblock write speed is 560 KiB/s
page write speed is 540 KiB/s
2 page write speed is 550 KiB/s

After:
eraseblock write speed is 578 KiB/s
page write speed is 557 KiB/s
2 page write speed is 567 KiB/s

The QUAD_PP capability was historically not supported by non-SFDP chips,
so a Winbond wide late hook is added to make sure the capability remains
disabled for them, for backward compatiblity reasons.

Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
---
$ cat /sys/kernel/debug/spi-nor/spi0.0/capabilities
Supported read modes by the flash
 1S-1S-1S
  opcode	0x03
  mode cycles	0
  dummy cycles	0
 1S-1S-2S
  opcode	0x3b
  mode cycles	0
  dummy cycles	8
 1S-2S-2S
  opcode	0xbb
  mode cycles	2
  dummy cycles	2
 1S-1S-4S
  opcode	0x6b
  mode cycles	0
  dummy cycles	8
 1S-4S-4S
  opcode	0xeb
  mode cycles	2
  dummy cycles	4
 4S-4S-4S
  opcode	0xeb
  mode cycles	2
  dummy cycles	0

Supported page program modes by the flash
 1S-1S-1S
  opcode	0x02
 1S-1S-4S
  opcode	0x32

$ dd if=/dev/urandom of=./spi_test bs=1M count=2
2+0 records in
2+0 records out
$ mtd_debug erase /dev/mtd0 0 2097152
Erased 2097152 bytes from address 0x00000000 in flash
$ mtd_debug read /dev/mtd0 0 2097152 spi_read
Copied 2097152 bytes from address 0x00000000 in flash to spi_read
$ hexdump spi_read
0000000 ffff ffff ffff ffff ffff ffff ffff ffff
*
0200000
$ sha256sum spi_read
4bda3a28f4ffe603c0ec1258c0034d65a1a0d35ab7bd523a834608adabf03cc5  spi_read
$ mtd_debug write /dev/mtd0 0 2097152 spi_test
Copied 2097152 bytes from spi_test to address 0x00000000 in flash
$ mtd_debug read /dev/mtd0 0 2097152 spi_read
Copied 2097152 bytes from address 0x00000000 in flash to spi_read
$ sha256sum spi*
83e7d587bce3b2031c82939839cc1fbcf62b8939b35882d176f207b0722d0dba  spi_read
83e7d587bce3b2031c82939839cc1fbcf62b8939b35882d176f207b0722d0dba  spi_test
$ mtd_debug erase /dev/mtd0 0 2097152
Erased 2097152 bytes from address 0x00000000 in flash
$ mtd_debug read /dev/mtd0 0 2097152 spi_read
Copied 2097152 bytes from address 0x00000000 in flash to spi_read
$ sha256sum spi*
4bda3a28f4ffe603c0ec1258c0034d65a1a0d35ab7bd523a834608adabf03cc5  spi_read
83e7d587bce3b2031c82939839cc1fbcf62b8939b35882d176f207b0722d0dba  spi_test
---
 drivers/mtd/spi-nor/winbond.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/mtd/spi-nor/winbond.c b/drivers/mtd/spi-nor/winbond.c
index b3ff99116335..a391efb926ab 100644
--- a/drivers/mtd/spi-nor/winbond.c
+++ b/drivers/mtd/spi-nor/winbond.c
@@ -203,6 +203,7 @@ static const struct flash_info winbond_nor_parts[] = {
 		.name = "w25q32",
 		.size = SZ_4M,
 		.no_sfdp_flags = SECT_4K,
+		.flags = SPI_NOR_QUAD_PP,
 	}, {
 		/* W25Q64JV-Q/N */
 		.id = SNOR_ID(0xef, 0x40, 0x17),
@@ -504,6 +505,22 @@ static int winbond_nor_late_init(struct spi_nor *nor)
 	if (nor->info->id->bytes[1] > 0x30)
 		nor->flags &= ~SNOR_F_NO_READ_CR;
 
+	/*
+	 * Winbond has reused many IDs, up to four times at this
+	 * stage. In general, most of the chips with SFDP support are
+	 * correctly described by the ID table, but the non-SFDP chips,
+	 * however, are known to not feature as many capabilities. Make
+	 * sure we filter out those capabilities to keep backward
+	 * compatibility with these devices manufactured until ~2016.
+	 */
+	if (!nor->sfdp) {
+		struct spi_nor_flash_parameter *p = nor->params;
+
+		/* SPI_NOR_QUAD_PP was unsupported */
+		p->hwcaps.mask &= ~SNOR_HWCAPS_PP_1_1_4;
+		spi_nor_set_pp_settings(&p->page_programs[SNOR_CMD_PP_1_1_4], 0, 0);
+	}
+
 	return 0;
 }
 

-- 
2.54.0