drivers: flash_stm32_ospi: workaround for corrupted data

this is a workaround for an errata which leads to corrupted data on the
first read after exiting stop 2 or 3

Signed-off-by: Martin Gysel <[email protected]>

Author: bearsh

drivers/flash/Kconfig.stm32_ospi

@@ -24,3 +24,27 @@ config FLASH_STM32_OSPI
 					$(DT_STM32_OCTOSPI_HAS_DMA)
 	help
 	  Enable OSPI-NOR support on the STM32 family of processors.
+
+if FLASH_STM32_OSPI
+
+if SOC_STM32U595XX || SOC_STM32U595XX || SOC_STM32U595XX || SOC_STM32U595XX \
+	|| SOC_STM32U595XX || SOC_STM32U595XX || SOC_STM32U595XX || SOC_STM32U595XX \
+	|| SOC_STM32U595XX || SOC_STM32U595XX || SOC_STM32U599XX || SOC_STM32U599XX \
+	|| SOC_STM32U599XX || SOC_STM32U599XX || SOC_STM32U599XX || SOC_STM32U599XX \
+	|| SOC_STM32U599XX || SOC_STM32U5A5XX || SOC_STM32U5A5XX || SOC_STM32U5A5XX \
+	|| SOC_STM32U5A5XX || SOC_STM32U5A5XX || SOC_STM32U5A9XX || SOC_STM32U5A9XX \
+	|| SOC_STM32U5A9XX || SOC_STM32U5A9XX
+
+config FLASH_STM32U5_ES0553_2_5_13
+	bool "Workaround for errata 2.5.13 of ES0553"
+	default y if PM
+	default n if !PM
+	help
+	  Handles erratum "OCTOSPI external memory read issue after exiting
+	  Stop 2 or Stop 3 mode when using DQS and delay block."
+	  Seen in Errata Sheet ES0553 §2.5.13 for STM32U5x5/STM32U5x9.
+
+
+endif # SOC_STM32U5xxxx
+
+endif # FLASH_STM32_OSPI

drivers/flash/flash_stm32_ospi.c

@@ -183,6 +183,9 @@ struct flash_stm32_ospi_data {
 #if STM32_OSPI_USE_DMA
 	struct stream dma;
 #endif /* STM32_OSPI_USE_DMA */
+#if CONFIG_FLASH_STM32U5_ES0553_2_5_13
+	bool errata_u59_2_5_13;
+#endif
 };
 
 
@@ -226,6 +229,18 @@ static int ospi_read_access(const struct device *dev, OSPI_RegularCmdTypeDef *cm
 	struct flash_stm32_ospi_data *dev_data = dev->data;
 	HAL_StatusTypeDef hal_ret;
 
+#if CONFIG_FLASH_STM32U5_ES0553_2_5_13
+	int err;
+
+	if (dev_data->errata_u59_2_5_13) {
+		dev_data->errata_u59_2_5_13 = false;
+		err = ospi_read_access(dev, cmd, data, 1);
+		if (err) {
+			return err;
+		}
+	}
+#endif
+
 	LOG_DBG("Instruction 0x%x", cmd->Instruction);
 
 	cmd->NbData = size;
@@ -2692,6 +2707,9 @@ static int flash_stm32_ospi_pm_action(const struct device *dev, enum pm_device_a
 
 	switch (action) {
 	case PM_DEVICE_ACTION_RESUME:
+#if CONFIG_FLASH_STM32U5_ES0553_2_5_13
+		dev_data->errata_u59_2_5_13 = true;
+#endif
 		err = flash_stm32_ospi_activate(dev);
 		break;
 	case PM_DEVICE_ACTION_SUSPEND: