drivers: flash: stm32_ospi: fix memory mapped mode

Set the OSPI memory mapped timeout period to avoid keeping the chip
select line asserted indefinitely after memory mapped accesses.

This is needed when OSPI1 and OSPI2 operate simultaneously with shared
IO0-IO3 and CLK lines, and both instances use memory mapped mode.

The timeout period follows the recommendation from the STM32U575xx and
STM32U585xx device errata, ES0499 section 2.6.4.

Allow dqs-port to be set to 0. The STM32 HAL uses value 0 to indicate
that the DQS port is not used.

Update the debug log printed when CONFIG_STM32_MEMMAP is not enabled,
because stm32_ospi_set_memorymap() is not called in that case.

Signed-off-by: Kirill Shypachov <kshypachov@outlook.com>

Author: kshypachov

drivers/flash/flash_stm32_ospi.c

@@ -67,6 +67,12 @@ LOG_MODULE_REGISTER(flash_stm32_ospi, CONFIG_FLASH_LOG_LEVEL);
 #define STM32_OSPI_SUBSECTOR_4K_ERASE_MAX_TIME  400U
 #define STM32_OSPI_WRITE_REG_MAX_TIME           40U
 
+/*
+ * Flash active hold timeout. Required when using the Octal SPI interface in
+ * pin multiplexing mode on STM32U5xx devices.
+ */
+#define STM32_OCTOSPIM_TIMEOUT 0x34
+
 /* used as default value for DTS writeoc */
 #define SPI_NOR_WRITEOC_NONE 0xFF
 
@@ -1112,7 +1118,12 @@ static int stm32_ospi_set_memorymap(const struct device *dev)
 	}
 
 	/* Enable the memory-mapping */
+#if defined(CONFIG_SOC_SERIES_STM32U5X) && defined(OCTOSPIM)
+	s_MemMappedCfg.TimeOutActivation = HAL_OSPI_TIMEOUT_COUNTER_ENABLE;
+	s_MemMappedCfg.TimeOutPeriod = STM32_OCTOSPIM_TIMEOUT;
+#else
 	s_MemMappedCfg.TimeOutActivation = HAL_OSPI_TIMEOUT_COUNTER_DISABLE;
+#endif /* CONFIG_SOC_SERIES_STM32U5X && OCTOSPIM*/
 
 	ret = HAL_OSPI_MemoryMapped(&dev_data->hospi, &s_MemMappedCfg);
 	if (ret != HAL_OK) {
@@ -2580,9 +2591,7 @@ static int flash_stm32_ospi_init(const struct device *dev)
 		(long)(STM32_OSPI_BASE_ADDRESS),
 		dev_cfg->flash_size);
 #else
-	LOG_DBG("NOR octo-flash at 0x%lx (0x%x bytes)",
-		(long)(STM32_OSPI_BASE_ADDRESS),
-		dev_cfg->flash_size);
+	LOG_DBG("Serial flash is in direct mode, not memory-mapped mode");
 #endif /* CONFIG_STM32_MEMMAP */
 
 	return 0;

dts/bindings/ospi/st,stm32-ospi.yaml

@@ -139,13 +139,14 @@ properties:
   dqs-port:
     type: int
     enum:
+      - 0
       - 1
       - 2
     description: |
       Specifies which port of the OCTOSPI IO Manager is used for the dqs pin.
 
       If absent, then n is used where `n` is the OSPI
-      instance number.
+      instance number, 0 means signal is not used.
 
       Note: You might need to enable the OCTOSPI I/O manager clock to use the
             property. Please refer to Reference Manual.