drivers: flash: spi-nor: add support for 4-byte addressing

Add a function that uses the JESD216 SFDP BFP DW16 Enter 4-Byte
Addressing parameter to put the device into 4-byte addressing mode if
one of the entry modes that's supported by the driver is available on
the device.

Perform the transition if SFDP data is provided (either by devicetree
or at runtime), or if a special devicetree property provides the entry
mode descriptor.

Signed-off-by: Peter Bigot <[email protected]>

drivers/flash/spi_nor.c

@@ -83,6 +83,11 @@ struct spi_nor_config {
 	/* Optional bits in SR to be cleared on startup */
 	uint8_t has_lock;
 
+#if defined(CONFIG_SPI_NOR_SFDP_MINIMAL)
+	/* Optional support for entering 32-bit address mode. */
+	uint8_t enter_4byte_addr;
+#endif /* CONFIG_SPI_NOR_SFDP_MINIMAL */
+
 #if defined(CONFIG_SPI_NOR_SFDP_DEVICETREE)
 	/* Length of BFP structure, in 32-bit words. */
 	uint8_t bfp_len;
@@ -738,6 +743,67 @@ static int spi_nor_read_jedec_id(const struct device *dev,
 	return ret;
 }
 
+/* Put the device into the appropriate address mode, if supported.
+ *
+ * On successful return spi_nor_data::flag_access_32bit has been set
+ * (cleared) if the device is configured for 4-byte (3-byte) addresses
+ * for read, write, and erase commands.
+ *
+ * @param dev the device
+ *
+ * @param enter_4byte_addr the Enter 4-Byte Addressing bit set from
+ * DW16 of SFDP BFP.  A value of all zeros or all ones is interpreted
+ * as "not supported".
+ *
+ * @retval -ENOTSUP if 4-byte addressing is supported but not in a way
+ * that the driver can handle.
+ * @retval negative codes if the attempt was made and failed
+ * @retval 0 if the device is successfully left in 24-bit mode or
+ *         reconfigured to 32-bit mode.
+ */
+static int spi_nor_set_address_mode(const struct device *dev,
+				    uint8_t enter_4byte_addr)
+{
+	int ret = 0;
+
+	/* Do nothing if not provided (either no bits or all bits
+	 * set).
+	 */
+	if ((enter_4byte_addr == 0)
+	    || (enter_4byte_addr == 0xff)) {
+		return 0;
+	}
+
+	LOG_DBG("Checking enter-4byte-addr %02x", enter_4byte_addr);
+
+	/* This currently only supports command 0xB7 (Enter 4-Byte
+	 * Address Mode), with or without preceding WREN.
+	 */
+	if ((enter_4byte_addr & 0x03) == 0) {
+		return -ENOTSUP;
+	}
+
+	acquire_device(dev);
+
+	if ((enter_4byte_addr & 0x02) != 0) {
+		/* Enter after WREN. */
+		ret = spi_nor_cmd_write(dev, SPI_NOR_CMD_WREN);
+	}
+	if (ret == 0) {
+		ret = spi_nor_cmd_write(dev, SPI_NOR_CMD_4BA);
+	}
+
+	if (ret == 0) {
+		struct spi_nor_data *data = dev->data;
+
+		data->flag_access_32bit = true;
+	}
+
+	release_device(dev);
+
+	return ret;
+}
+
 #ifndef CONFIG_SPI_NOR_SFDP_MINIMAL
 
 static int spi_nor_process_bfp(const struct device *dev,
@@ -772,6 +838,21 @@ static int spi_nor_process_bfp(const struct device *dev,
 #endif /* CONFIG_SPI_NOR_SFDP_RUNTIME */
 
 	LOG_DBG("Page size %u bytes", data->page_size);
+
+	/* If 4-byte addressing is supported, switch to it. */
+	if (jesd216_bfp_addrbytes(bfp) != JESD216_SFDP_BFP_DW1_ADDRBYTES_VAL_3B) {
+		struct jesd216_bfp_dw16 dw16;
+		int rc = 0;
+
+		if (jesd216_bfp_decode_dw16(php, bfp, &dw16) == 0) {
+			rc = spi_nor_set_address_mode(dev, dw16.enter_4ba);
+		}
+
+		if (rc != 0) {
+			LOG_ERR("Unable to enter 4-byte mode: %d\n", rc);
+			return rc;
+		}
+	}
 	return 0;
 }
 
@@ -1005,7 +1086,20 @@ static int spi_nor_configure(const struct device *dev)
 		release_device(dev);
 	}
 
-#ifndef CONFIG_SPI_NOR_SFDP_MINIMAL
+#ifdef CONFIG_SPI_NOR_SFDP_MINIMAL
+	/* For minimal we support some overrides from specific
+	 * devicertee properties.
+	 */
+	if (cfg->enter_4byte_addr != 0) {
+		rc = spi_nor_set_address_mode(dev, cfg->enter_4byte_addr);
+
+		if (rc != 0) {
+			LOG_ERR("Unable to enter 4-byte mode: %d\n", rc);
+			return -ENODEV;
+		}
+	}
+
+#else /* CONFIG_SPI_NOR_SFDP_MINIMAL */
 	/* For devicetree and runtime we need to process BFP data and
 	 * set up or validate page layout.
 	 */
@@ -1159,6 +1253,10 @@ static const struct spi_nor_config spi_nor_config_0 = {
 #if DT_INST_NODE_HAS_PROP(0, has_lock)
 	.has_lock = DT_INST_PROP(0, has_lock),
 #endif
+#if defined(CONFIG_SPI_NOR_SFDP_MINIMAL)		\
+	&& DT_INST_NODE_HAS_PROP(0, enter_4byte_addr)
+	.enter_4byte_addr = DT_INST_PROP(0, enter_4byte_addr),
+#endif
 #ifdef CONFIG_SPI_NOR_SFDP_DEVICETREE
 	.bfp_len = sizeof(bfp_data_0) / 4,
 	.bfp = (const struct jesd216_bfp *)bfp_data_0,

drivers/flash/spi_nor.h

@@ -28,6 +28,7 @@
 #define SPI_NOR_CMD_CE          0xC7    /* Chip erase */
 #define SPI_NOR_CMD_RDID        0x9F    /* Read JEDEC ID */
 #define SPI_NOR_CMD_ULBPR       0x98    /* Global Block Protection Unlock */
+#define SPI_NOR_CMD_4BA         0xB7    /* Enter 4-Byte Address Mode */
 #define SPI_NOR_CMD_DPD         0xB9    /* Deep Power Down */
 #define SPI_NOR_CMD_RDPD        0xAB    /* Release from Deep Power Down */
 

dts/bindings/mtd/jedec,jesd216.yaml

@@ -62,3 +62,20 @@ properties:
       instruction.  Use S1B6 if QE is bit 6 of the first status register
       byte, and can be configured by reading then writing one byte with
       RDSR and WRSR.  For other fields see the specification.
+
+  enter-4byte-addr:
+    type: int
+    required: false
+    description: |
+      Enter 4-Byte Addressing value from JESD216 BFP DW16
+
+      This property is ignored if the device is configured to use SFDP data
+      from the sfdp-bfp property (CONFIG_SPI_NOR_SFDP_DEVICETREE) or to read
+      SFDP properties at runtime (CONFIG_SPI_NOR_SFDP_RUNTIME).
+
+      For CONFIG_SPI_NOR_SFDP_MINIMAL this is the 8-bit value from bits 31:24
+      of DW16 identifying ways a device can be placed into 4-byte addressing
+      mode.  If provided as a non-zero value the driver assumes that 4-byte
+      addressing is require to access the full address range, and
+      automatically puts the device into 4-byte address mode when the device
+      is initialized.