is it a right BANK2_OFFSET define in flash_stm32l5x.c?

[liweifeng81]

the below bold code is for avoiding the range is crossing bank. but the define of BANK2_OFFSET is not right.
e.g. I'm using stm32u545, the flash size is 512k, and BANK2_OFFSET should be 256k.
I think it should not use BANK2_OFFSET, but FLASH_SIZE / 2 instead.

#if defined(CONFIG_SOC_SERIES_STM32H5X)
/* at this time stm32h5 mcus have 128KB (stm32h50x) or 2MB (stm32h56x/57x) /
#define STM32_SERIES_MAX_FLASH 2048
#elif defined(CONFIG_SOC_SERIES_STM32L5X)
#define STM32_SERIES_MAX_FLASH 512
#elif defined(CONFIG_SOC_SERIES_STM32U5X)
/ at this time stm32u5 mcus have 1MB (stm32u575) or 2MB (stm32u585) */
#define STM32_SERIES_MAX_FLASH 2048
#endif

#define PAGES_PER_BANK ((FLASH_SIZE / FLASH_PAGE_SIZE) / 2)

#define BANK2_OFFSET (KB(STM32_SERIES_MAX_FLASH) / 2)

bool flash_stm32_valid_range(const struct device dev, off_t offset,
uint32_t len,
bool write)
{
if (stm32_flash_has_2_banks(dev) &&
(CONFIG_FLASH_SIZE < STM32_SERIES_MAX_FLASH)) {
/
* In case of bank1/2 discontinuity, the range should not
* start before bank2 and end beyond bank1 at the same time.
* Locations beyond bank2 are caught by
* flash_stm32_range_exists.
*/
if ((offset < BANK2_OFFSET) &&
(offset + len > FLASH_SIZE / 2)) {
return 0;
}
}

return (!write || (offset % 8 == 0 && len % 8 == 0U)) &&
	flash_stm32_range_exists(dev, offset, len);

}

[erwango]

@liweifeng81 Looks you're right. When this code has been implemented we didn't support as much as flash variant as today.
Can you create a PR?

[liweifeng81]

Thanks @erwango for your quick reply. I will study how to create a PR.
and there's another issue on the same file blocking me. in function "flash_stm32_page_layout", there's the following code.
the "Dummy page" seems not on stm32u57x according to ST's spec RM0456, and also for stm32l552xx according to RM0438.
If I remove the "Dummy page" and change the array size of "stm32_flash_layout" to 2, it works in my project.
Can you help me check it as well?

if (stm32_flash_has_2_banks(dev) &&
		(CONFIG_FLASH_SIZE < STM32_SERIES_MAX_FLASH)) {
	/*
	 * For stm32l552xx with 256 kB flash or stm32u57x with 1MB flash
	 * which have space between banks 1 and 2.
	 */

	/* Bank1 */
	stm32_flash_layout[0].pages_count = PAGES_PER_BANK;
	stm32_flash_layout[0].pages_size = FLASH_PAGE_SIZE;

	/* Dummy page corresponding to space between banks 1 and 2 */
	stm32_flash_layout[1].pages_count = 1;
	stm32_flash_layout[1].pages_size = BANK2_OFFSET
			- (PAGES_PER_BANK * FLASH_PAGE_SIZE);

	/* Bank2 */
	stm32_flash_layout[2].pages_count = PAGES_PER_BANK;
	stm32_flash_layout[2].pages_size = FLASH_PAGE_SIZE;

	stm32_flash_layout_size = ARRAY_SIZE(stm32_flash_layout);

[erwango]

It might be that your case should fall in the else part with CONFIG_FLASH_SIZE = STM32_SERIES_MAX_FLASH.

Can you check if fixing STM32_SERIES_MAX_FLASH wouldn't fix both issues at same time ?

[liweifeng81]

you are right, it works good by changing STM32_SERIES_MAX_FLASH to 512(CONFIG_FLASH_SIZE).

I changed BANK2_OFFSET to FLASH_SIZE / 2 as the bold code in my original post.

I'm not sure whether I misunderstood the design.
If I change STM32_SERIES_MAX_FLASH to 512, it's not check "bank1/2 discontinuity" case and this "stm32_flash_layout" become 1. actually the bank 1 and 2 are continuous on both STM32U535/545 and STM32U575/585 according to Table51/52 in RM0456. so it should be OK. But that will conflict with the feature "Bank swapping" and Trust Zone, but the 2 feature is not supported yet in Zephyr, am I right?

So a simple fix is just define STM32_SERIES_MAX_FLASH as CONFIG_FLASH_SIZE, then the "BANK2_OFFSET" is also right.
...
#elif defined(CONFIG_SOC_SERIES_STM32U5X)
/* at this time stm32u5 mcus have 1MB (stm32u575) or 2MB (stm32u585) */
#define STM32_SERIES_MAX_FLASH (CONFIG_FLASH_SIZE)
#endif
...