[PATCH 18/21] mtd: spinand: winbond: Add octal read support

[Miquel Raynal]

Describe the octal read from cache operations (1S_1S_8S, 1S_8S_8S and
1S_1D_8D_OP) supported by the W35N01JW chip.

There is no observable improvement between the two octal SDR modes,
which anyway offered a great read speed improvement compared to single
mode.

flash_speed test results ran on the TI AM62A7 LP SK using a 25MHz SPI bus:

* Single mode:
eraseblock read speed is  2346 KiB/s
page       read speed is  2342 KiB/s

* Octal modes:
eraseblock read speed is 10801 KiB/s
page       read speed is 10711 KiB/s

However, testing on the cadence qspi controller driver did not allow
mixed modes (where SDR and DTR cycles are mixed in the same operation),
thus 1S-1D-8D mode could not be tested and is provided for reference (it
is anyway skipped on platforms not supporting this).

Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
---
 drivers/mtd/nand/spi/winbond.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mtd/nand/spi/winbond.c b/drivers/mtd/nand/spi/winbond.c
index 9b0369a077efadac8bd6be632f15b822d42a7227..4b1bfc15588ad3ffc8f2cb7615db6c14d0b62903 100644
--- a/drivers/mtd/nand/spi/winbond.c
+++ b/drivers/mtd/nand/spi/winbond.c
@@ -24,6 +24,9 @@
  */
 
 static SPINAND_OP_VARIANTS(read_cache_octal_variants,
+		SPINAND_PAGE_READ_FROM_CACHE_1S_1D_8D_OP(0, 2, NULL, 0, 105 * HZ_PER_MHZ),
+		SPINAND_PAGE_READ_FROM_CACHE_1S_8S_8S_OP(0, 16, NULL, 0, 86 * HZ_PER_MHZ),
+		SPINAND_PAGE_READ_FROM_CACHE_1S_1S_8S_OP(0, 1, NULL, 0, 133 * HZ_PER_MHZ),
 		SPINAND_PAGE_READ_FROM_CACHE_FAST_1S_1S_1S_OP(0, 1, NULL, 0),
 		SPINAND_PAGE_READ_FROM_CACHE_1S_1S_1S_OP(0, 1, NULL, 0));
 

-- 
2.48.1