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seeking.that , 05-22-2018, 12:32 PM

Hi Robert,

I don't have an openrex board, but I see a note on SPI is_locked freeze in the source code diffs as follows:



static inline int spi_flash_cmd_write_enable(struct spi_flash *flash)
{
+#ifdef CONFIG_SPI_FLASH_SST26
+ //quick fix to unlock Global Block-Protection of SST26
+ //this may only need to be executed once, after power up
+ //TODO: do it properly in the flash initialization process
+ spi_flash_cmd(flash->spi, CMD_WRITE_ENABLE, NULL, 0);
+ spi_flash_cmd(flash->spi, CMD_SST_ULBPR, NULL, 0);
+#endif
return spi_flash_cmd(flash->spi, CMD_WRITE_ENABLE, NULL, 0);
}


...
+#ifdef CONFIG_SPI_FLASH_SST26
+ //is_locked will freeze SST26, has to be fixed
+#else
if (flash->is_locked(flash, offset, len) > 0) {
printf("offset 0x%x is protected and cannot be erased\n", offset);
return -EINVAL;
}
-
+#endif


In the spi_flash_write_enable() API, the sequence unlock followed by write_enable() sounds logical.
But there is also a write_enable() before unlock. Does this in anyway contribute to the freeze ?
Is there a reason why the write_enable() is used before unlock ?

Thanks!

robertferanec , 05-23-2018, 12:22 PM

This depends on SPI which you use. If I remember right, the SPI which is on OpenRex will be locked (protected) after power up. And if I remember right, there were some problems to unlock it (I think it didn't work exactly as described in datasheet or we missed something). So, once it worked, we left it that way and made the note.