drivers: flash: qspi stm32 driver supporting requires_ulbpr

drivers/flash/Kconfig.stm32

@@ -84,4 +84,12 @@ config FLASH_STM32_BLOCK_REGISTERS
 	  registers improves system security, because flash content (or
 	  protection settings) can't be changed even when exploit was found.
 
+config USE_MICROCHIP_QSPI_FLASH_WITH_STM32
+	bool "Include patch for Microchip qspi flash when running with stm32"
+	depends on DT_HAS_ST_STM32_QSPI_NOR_ENABLED
+	help
+	  Set to use Microchip qspi flash memories which supports
+	  the Global Block Protection Unlock instruction (ULBPR - 98H),
+	  and write with SPI_NOR_CMD_PP_1_1_4 on 4 lines
+
 endif # SOC_FLASH_STM32

drivers/flash/flash_stm32_qspi.c

@@ -187,9 +187,16 @@
 			dev_data->qspi_write_cmd == SPI_NOR_CMD_PP_1_4_4);
 
 	cmd->Instruction = dev_data->qspi_write_cmd;
+#if defined(CONFIG_USE_MICROCHIP_QSPI_FLASH_WITH_STM32)
+	/* Microchip qspi-NOR flash, does not follow the standard rules */
+	if (cmd->Instruction == SPI_NOR_CMD_PP_1_1_4) {
+		cmd->AddressMode = QSPI_ADDRESS_4_LINES;
+	}
+#else
 	cmd->AddressMode = ((cmd->Instruction == SPI_NOR_CMD_PP_1_1_4)
 				? QSPI_ADDRESS_1_LINE
 				: QSPI_ADDRESS_4_LINES);
+#endif /* CONFIG_USE_MICROCHIP_QSPI_FLASH_WITH_STM32 */
 	cmd->DataMode = QSPI_DATA_4_LINES;
 	cmd->DummyCycles = 0;
 
@@ -345,6 +352,27 @@
 }
 #endif /* CONFIG_FLASH_JESD216_API */
 
+static int qspi_write_unprotect(const struct device *dev)
+{
+	int ret = 0;
+	QSPI_CommandTypeDef cmd_unprotect = {
+			.Instruction = SPI_NOR_CMD_ULBPR,
+			.InstructionMode = QSPI_INSTRUCTION_1_LINE,
+	};
+
+	if (IS_ENABLED(DT_INST_PROP(0, requires_ulbpr))) {
+		ret = qspi_send_cmd(dev, &cmd_write_en);
+
+		if (ret != 0) {
+			return ret;
+		}
+
+		ret = qspi_send_cmd(dev, &cmd_unprotect);
+	}
+
+	return ret;
+}
+
 /*
  * Read Serial Flash Discovery Parameter
  */
@@ -1491,6 +1519,13 @@
 	}
 #endif /* CONFIG_FLASH_PAGE_LAYOUT */
 
+	ret = qspi_write_unprotect(dev);
+	if (ret != 0) {
+		LOG_ERR("write unprotect failed: %d", ret);
+		return -ENODEV;
+	}
+	LOG_DBG("Write Un-protected");
+
 #ifdef CONFIG_STM32_MEMMAP
 #if DT_PROP(DT_NODELABEL(quadspi), dual_flash) && defined(QUADSPI_CR_DFM)
 	/*

dts/bindings/flash_controller/st,stm32-qspi-nor.yaml

@@ -61,3 +61,13 @@ properties:
       supporting 1-4-4 mode also would support fast page programming.
 
       If absent, then 1-4-4 program page is used in quad mode.
+
+  requires-ulbpr:
+    type: boolean
+    description: |
+      Indicates the device requires the ULBPR (0x98) command.
+
+      Some flash chips such as the Microchip SST26VF series have a block
+      protection register that initializes to write-protected.  Use this
+      property to indicate that the BPR must be unlocked before write
+      operations can proceed.