drivers: flash: flash_stm32_xspi: Allow flash driver init in ram load

Current driver protections prevent to initialize driver when run as from
an external application running from ext flash. Aim is to avoid performing
full driver initialization of the NOR flash controller the application
is read from.
But this problem is actually only valid when application is running in XIP
mode (read in memory mapped mode at run time).

In ram load mode, since there is no direct activity from the application
on the NOR device, nothing prevents the ext flash driver to be used fully.
Hence, we should allow the controller initialization to happen, with some
adjustments. Mostly, what we need is to:
- skip the hal init
- abort memory mapping afterwards to let the jedec reading happen.

Remove conditions around `stm32_xspi_is_memorymap()` and
`stm32_xspi_abort()` which can finally be useful in various cases.

Signed-off-by: Erwan Gouriou <[email protected]>

Author: erwango

drivers/flash/flash_stm32_xspi.c

@@ -997,6 +997,7 @@ static int stm32_xspi_set_memorymap(const struct device *dev)
 	LOG_DBG("MemoryMap mode enabled");
 	return 0;
 }
+#endif /* CONFIG_STM32_MEMMAP */
 
 static int stm32_xspi_abort(const struct device *dev)
 {
@@ -1009,18 +1010,14 @@ static int stm32_xspi_abort(const struct device *dev)
 
 	return 0;
 }
-#endif /* CONFIG_STM32_MEMMAP */
 
-
-#if defined(CONFIG_STM32_MEMMAP) || defined(CONFIG_STM32_APP_IN_EXT_FLASH)
 /* Function to return true if the octoflash is in MemoryMapped else false */
 static bool stm32_xspi_is_memorymap(const struct device *dev)
 {
 	struct flash_stm32_xspi_data *dev_data = dev->data;
 
 	return stm32_reg_read_bits(&dev_data->hxspi.Instance->CR, XSPI_CR_FMODE) == XSPI_CR_FMODE;
 }
-#endif
 
 /*
  * Function to erase the flash : chip or sector with possible OCTO/SPI and STR/DTR
@@ -1218,7 +1215,7 @@ static int flash_stm32_xspi_read(const struct device *dev, off_t addr,
 		return 0;
 	}
 
-#if defined(CONFIG_STM32_MEMMAP) || defined(CONFIG_STM32_APP_IN_EXT_FLASH)
+#if defined(CONFIG_STM32_MEMMAP) || defined(CONFIG_STM32_APP_IN_EXT_FLASH) && defined(CONFIG_XIP)
 	ARG_UNUSED(dev_cfg);
 	ARG_UNUSED(dev_data);
 	/*
@@ -2093,7 +2090,7 @@ static int flash_stm32_xspi_init(const struct device *dev)
 		return -ENODEV;
 	}
 
-#ifdef CONFIG_STM32_APP_IN_EXT_FLASH
+#if defined(CONFIG_STM32_APP_IN_EXT_FLASH) && defined(CONFIG_XIP)
 	/* If MemoryMapped then configure skip init
 	 * Check clock status first as reading CR register without bus clock doesn't work on N6
 	 * If clock is off, then MemoryMapped is off too and we do init
@@ -2195,13 +2192,29 @@ static int flash_stm32_xspi_init(const struct device *dev)
 		dev_data->hxspi.Init.DelayHoldQuarterCycle = HAL_XSPI_DHQC_ENABLE;
 	}
 
+	if (stm32_xspi_is_memorymap(dev)) {
+		/* Memory map could have been set by previous application */
+		/* Force HAL instance in correct state */
+		dev_data->hxspi.State = HAL_XSPI_STATE_BUSY_MEM_MAPPED;
+	}
+
 	if (HAL_XSPI_Init(&dev_data->hxspi) != HAL_OK) {
 		LOG_ERR("XSPI Init failed");
 		return -EIO;
 	}
 
 	LOG_DBG("XSPI Init'd");
 
+	if (stm32_xspi_is_memorymap(dev)) {
+		/* Memory map could have been set by previous application */
+		/* Abort to allow following card oriented transactions */
+		/* If needed by the application, it will be re-enabled just after */
+		ret = stm32_xspi_abort(dev);
+		if (ret != 0) {
+			LOG_ERR("Failed to abort memory-mapped access before init");
+		}
+	}
+
 #if defined(HAL_XSPIM_IOPORT_1) || defined(HAL_XSPIM_IOPORT_2) || \
 	defined(XSPIM) || defined(XSPIM1) || defined(XSPIM2)
 	/* XSPI I/O manager init Function */