[PATCH v4 11/28] mtd: spi-nor: winbond: W25Q64JV-Q/N: Add quad page program capability

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 -dc10
eraseblock write speed is 539 KiB/s
page write speed is 535 KiB/s
2 page write speed is 536 KiB/s

After:
$ flash_speed /dev/mtd0 -dc10
eraseblock write speed is 556 KiB/s
page write speed is 549 KiB/s
2 page write speed is 552 KiB/s

The QUAD_PP capability was historically not supported by non-SFDP chips,
so a Winbond wide late hook already makes sure the capability remains
disabled for them, for backward compatibility reasons.

Signed-off-by: Miquel Raynal <[email protected]>
---
$ cat /sys/kernel/debug/spi-nor/spi0.0/params
name		(null)
id		ef 40 17 00 00 00
size		8.00 MiB
write size	1
page size	256
address nbytes	3
flags		HAS_16BIT_SR | SOFT_RESET | NO_WP

opcodes
 read		0xeb
  dummy cycles	6
 erase		0xd8
 program	0x32
 8D extension	none

protocols
 read		1S-4S-4S
 write		1S-1S-4S
 register	1S-1S-1S

erase commands
 20 (4.00 KiB) [1]
 52 (32.0 KiB) [2]
 d8 (64.0 KiB) [3]
 c7 (8.00 MiB)

sector map
 region (in hex)   | erase mask | overlaid
 ------------------+------------+---------
 00000000-007fffff |     [   3] | no
$ 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
mtd_debug read /dev/mtd0 0 2097152 spi_readErased 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*
36667197a637b731cc2068022138e6963a9499ce9b0ddda1a1585f7f5ebe66ff  spi_read
36667197a637b731cc2068022138e6963a9499ce9b0ddda1a1585f7f5ebe66ff  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
36667197a637b731cc2068022138e6963a9499ce9b0ddda1a1585f7f5ebe66ff  spi_test
---
 drivers/mtd/spi-nor/winbond.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/mtd/spi-nor/winbond.c b/drivers/mtd/spi-nor/winbond.c
index 2e53f16a9f93..15df3cc26fbc 100644
--- a/drivers/mtd/spi-nor/winbond.c
+++ b/drivers/mtd/spi-nor/winbond.c
@@ -210,6 +210,7 @@ static const struct flash_info winbond_nor_parts[] = {
 		.name = "w25q64",
 		.size = SZ_8M,
 		.no_sfdp_flags = SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ,
+		.flags = SPI_NOR_QUAD_PP,
 	}, {
 		/* W25Q128JV-Q/N */
 		.id = SNOR_ID(0xef, 0x40, 0x18),

-- 
2.54.0