mtd: spinand: winbond: W35N octal DTR support

Extend the support for the W35N chip family by supporting the ODTR bus
interface. The chip is capable to run in this mode, which brings a
significant performance improvement.

1S-8S-8S:

   # flash_speed /dev/mtd0 -c1 -d
   eraseblock write speed is 7529 KiB/s
   eraseblock read speed is 15058 KiB/s

8D-8D-8D:

   # flash_speed /dev/mtd0 -c1 -d
   eraseblock write speed is 9481 KiB/s
   eraseblock read speed is 23272 KiB/s

This is +55% read speed and +26% write speed with the same hardware.

Tests have been conducted with a TI AM62A7 using the Cadence quad SPI
controller.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

Author: miquelraynal

drivers/mtd/nand/spi/winbond.c

@@ -36,6 +36,8 @@
  */
 
 static SPINAND_OP_VARIANTS(read_cache_octal_variants,
+		SPINAND_PAGE_READ_FROM_CACHE_8D_8D_8D_OP(0, 24, NULL, 0, 120 * HZ_PER_MHZ),
+		SPINAND_PAGE_READ_FROM_CACHE_8D_8D_8D_OP(0, 16, NULL, 0, 86 * HZ_PER_MHZ),
 		SPINAND_PAGE_READ_FROM_CACHE_1S_1D_8D_OP(0, 3, NULL, 0, 120 * HZ_PER_MHZ),
 		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, 20, NULL, 0, 0),
@@ -48,11 +50,13 @@ static SPINAND_OP_VARIANTS(read_cache_octal_variants,
 		SPINAND_PAGE_READ_FROM_CACHE_1S_1S_1S_OP(0, 1, NULL, 0, 0));
 
 static SPINAND_OP_VARIANTS(write_cache_octal_variants,
+		SPINAND_PROG_LOAD_8D_8D_8D_OP(true, 0, NULL, 0),
 		SPINAND_PROG_LOAD_1S_8S_8S_OP(true, 0, NULL, 0),
 		SPINAND_PROG_LOAD_1S_1S_8S_OP(0, NULL, 0),
 		SPINAND_PROG_LOAD_1S_1S_1S_OP(true, 0, NULL, 0));
 
 static SPINAND_OP_VARIANTS(update_cache_octal_variants,
+		SPINAND_PROG_LOAD_8D_8D_8D_OP(false, 0, NULL, 0),
 		SPINAND_PROG_LOAD_1S_8S_8S_OP(false, 0, NULL, 0),
 		SPINAND_PROG_LOAD_1S_1S_1S_OP(false, 0, NULL, 0));
 
@@ -93,13 +97,22 @@ static SPINAND_OP_VARIANTS(update_cache_variants,
 		   SPI_MEM_OP_NO_DUMMY,					\
 		   SPI_MEM_OP_DATA_OUT(1, buf, 1))
 
+#define SPINAND_WINBOND_WRITE_VCR_8D_8D_8D(reg, buf)			\
+	SPI_MEM_OP(SPI_MEM_DTR_OP_RPT_CMD(0x81, 8),			\
+		   SPI_MEM_DTR_OP_ADDR(4, reg, 8),			\
+		   SPI_MEM_OP_NO_DUMMY,					\
+		   SPI_MEM_DTR_OP_DATA_OUT(2, buf, 8))
+
 static SPINAND_OP_VARIANTS(winbond_w35_ops,
-		SPINAND_WINBOND_WRITE_VCR_1S_1S_1S(0, NULL));
+		SPINAND_WINBOND_WRITE_VCR_1S_1S_1S(0, NULL),
+		SPINAND_WINBOND_WRITE_VCR_8D_8D_8D(0, NULL));
 
 static struct spi_mem_op
 spinand_fill_winbond_write_vcr_op(struct spinand_device *spinand, u8 reg, void *valptr)
 {
-	return (struct spi_mem_op)SPINAND_WINBOND_WRITE_VCR_1S_1S_1S(reg, valptr);
+	return (spinand->bus_iface == SSDR) ?
+		(struct spi_mem_op)SPINAND_WINBOND_WRITE_VCR_1S_1S_1S(reg, valptr) :
+		(struct spi_mem_op)SPINAND_WINBOND_WRITE_VCR_8D_8D_8D(reg, valptr);
 }
 
 #define SPINAND_WINBOND_SELECT_TARGET_1S_0_1S(buf)			\
@@ -390,6 +403,9 @@ static int w35n0xjw_vcr_cfg(struct spinand_device *spinand,
 	case SSDR:
 		ref_op = spinand->ssdr_op_templates.read_cache;
 		break;
+	case ODTR:
+		ref_op = spinand->odtr_op_templates.read_cache;
+		break;
 	default:
 		return -EOPNOTSUPP;
 	};