mtd: spi-nor: Create a ->set_4byte() method

The procedure used to enable 4 byte addressing mode depends on the NOR
device, so let's provide a hook so that manufacturer specific handling
can be implemented in a sane way.
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
[tudor.ambarus@microchip.com: use nor->params.set_4byte() instead of
nor->set_4byte()]
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>

drivers/mtd/spi-nor/spi-nor.c

@@ -633,6 +633,17 @@ static int macronix_set_4byte(struct spi_nor *nor, bool enable)
 			      NULL, 0);
 }
 
+static int st_micron_set_4byte(struct spi_nor *nor, bool enable)
+{
+	int ret;
+
+	write_enable(nor);
+	ret = macronix_set_4byte(nor, enable);
+	write_disable(nor);
+
+	return ret;
+}
+
 static int spansion_set_4byte(struct spi_nor *nor, bool enable)
 {
 	nor->bouncebuf[0] = enable << 7;
@@ -667,45 +678,24 @@ static int spi_nor_write_ear(struct spi_nor *nor, u8 ear)
 	return nor->write_reg(nor, SPINOR_OP_WREAR, nor->bouncebuf, 1);
 }
 
-/* Enable/disable 4-byte addressing mode. */
-static int set_4byte(struct spi_nor *nor, bool enable)
+static int winbond_set_4byte(struct spi_nor *nor, bool enable)
 {
-	int status;
-	bool need_wren = false;
-
-	switch (JEDEC_MFR(nor->info)) {
-	case SNOR_MFR_ST:
-	case SNOR_MFR_MICRON:
-		/* Some Micron need WREN command; all will accept it */
-		need_wren = true;
-		/* fall through */
-	case SNOR_MFR_MACRONIX:
-	case SNOR_MFR_WINBOND:
-		if (need_wren)
-			write_enable(nor);
+	int ret;
 
-		status = macronix_set_4byte(nor, enable);
-		if (need_wren)
-			write_disable(nor);
+	ret = macronix_set_4byte(nor, enable);
+	if (ret || enable)
+		return ret;
 
-		if (!status && !enable &&
-		    JEDEC_MFR(nor->info) == SNOR_MFR_WINBOND) {
-			/*
-			 * On Winbond W25Q256FV, leaving 4byte mode causes
-			 * the Extended Address Register to be set to 1, so all
-			 * 3-byte-address reads come from the second 16M.
-			 * We must clear the register to enable normal behavior.
-			 */
-			write_enable(nor);
-			spi_nor_write_ear(nor, 0);
-			write_disable(nor);
-		}
+	/*
+	 * On Winbond W25Q256FV, leaving 4byte mode causes the Extended Address
+	 * Register to be set to 1, so all 3-byte-address reads come from the
+	 * second 16M. We must clear the register to enable normal behavior.
+	 */
+	write_enable(nor);
+	ret = spi_nor_write_ear(nor, 0);
+	write_disable(nor);
 
-		return status;
-	default:
-		/* Spansion style */
-		return spansion_set_4byte(nor, enable);
-	}
+	return ret;
 }
 
 static int spi_nor_xread_sr(struct spi_nor *nor, u8 *sr)
@@ -4153,11 +4143,18 @@ static int spi_nor_parse_sfdp(struct spi_nor *nor,
 static void macronix_set_default_init(struct spi_nor *nor)
 {
 	nor->params.quad_enable = macronix_quad_enable;
+	nor->params.set_4byte = macronix_set_4byte;
 }
 
 static void st_micron_set_default_init(struct spi_nor *nor)
 {
 	nor->params.quad_enable = NULL;
+	nor->params.set_4byte = st_micron_set_4byte;
+}
+
+static void winbond_set_default_init(struct spi_nor *nor)
+{
+	nor->params.set_4byte = winbond_set_4byte;
 }
 
 /**
@@ -4178,6 +4175,10 @@ static void spi_nor_manufacturer_init_params(struct spi_nor *nor)
 		st_micron_set_default_init(nor);
 		break;
 
+	case SNOR_MFR_WINBOND:
+		winbond_set_default_init(nor);
+		break;
+
 	default:
 		break;
 	}
@@ -4222,6 +4223,7 @@ static void spi_nor_info_init_params(struct spi_nor *nor)
 
 	/* Initialize legacy flash parameters and settings. */
 	params->quad_enable = spansion_quad_enable;
+	params->set_4byte = spansion_set_4byte;
 
 	/* Set SPI NOR sizes. */
 	params->size = (u64)info->sector_size * info->n_sectors;
@@ -4587,7 +4589,7 @@ static int spi_nor_init(struct spi_nor *nor)
 		 */
 		WARN_ONCE(nor->flags & SNOR_F_BROKEN_RESET,
 			  "enabling reset hack; may not recover from unexpected reboots\n");
-		set_4byte(nor, true);
+		nor->params.set_4byte(nor, true);
 	}
 
 	return 0;
@@ -4611,7 +4613,7 @@ void spi_nor_restore(struct spi_nor *nor)
 	/* restore the addressing mode */
 	if (nor->addr_width == 4 && !(nor->flags & SNOR_F_4B_OPCODES) &&
 	    nor->flags & SNOR_F_BROKEN_RESET)
-		set_4byte(nor, false);
+		nor->params.set_4byte(nor, false);
 }
 EXPORT_SYMBOL_GPL(spi_nor_restore);
 

include/linux/mtd/spi-nor.h

@@ -482,6 +482,7 @@ struct spi_nor;
  * @erase_map:		the erase map parsed from the SFDP Sector Map Parameter
  *                      Table.
  * @quad_enable:	enables SPI NOR quad mode.
+ * @set_4byte:		puts the SPI NOR in 4 byte addressing mode.
  */
 struct spi_nor_flash_parameter {
 	u64				size;
@@ -494,6 +495,7 @@ struct spi_nor_flash_parameter {
 	struct spi_nor_erase_map        erase_map;
 
 	int (*quad_enable)(struct spi_nor *nor);
+	int (*set_4byte)(struct spi_nor *nor, bool enable);
 };
 
 /**