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BIOS: Flashboot without main ram 

Modified flashboot() to skip copy to main ram if there is no main
ram, and instead execute in place out of SPI flash.  (For this to
work the linker .ld will also need to redirect references to be
inside the SPI flash mapping.)
This commit is contained in:
Ewen McNeill 2018-01-19 12:37:53 +11:00 committed by Rohit Singh
parent 3a5f93db5d
commit 75e7f9505a
1 changed files with 16 additions and 2 deletions
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18
litex/soc/software/bios/boot.c
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@ -290,6 +290,17 @@ void netboot(void)
#endif #endif
#ifdef FLASH_BOOT_ADDRESS #ifdef FLASH_BOOT_ADDRESS
/* On systems with exernal SDRAM we copy out of the SPI flash into the SDRAM
before running, as it is faster. If we have no SDRAM then we have to
execute directly out of the SPI flash. */
#ifdef MAIN_RAM_BASE
#define FIRMWARE_BASE_ADDRESS MAIN_RAM_BASE
#else
/* Firmware code starts after (a) length and (b) CRC -- both unsigned ints */
#define FIRMWARE_BASE_ADDRESS (FLASH_BOOT_ADDRESS + 2 * sizeof(unsigned int))
#endif
void flashboot(void) void flashboot(void)
{ {
unsigned int *flashbase; unsigned int *flashbase;
@ -306,14 +317,17 @@ void flashboot(void)
return; return;
} }
#ifdef MAIN_RAM_BASE
printf("Loading %d bytes from flash...\n", length); printf("Loading %d bytes from flash...\n", length);
memcpy((void *)MAIN_RAM_BASE, flashbase, length); memcpy((void *)MAIN_RAM_BASE, flashbase, length);
got_crc = crc32((unsigned char *)MAIN_RAM_BASE, length); #endif
got_crc = crc32((unsigned char *)FIRMWARE_BASE_ADDRESS, length);
if(crc != got_crc) { if(crc != got_crc) {
printf("CRC failed (expected %08x, got %08x)\n", crc, got_crc); printf("CRC failed (expected %08x, got %08x)\n", crc, got_crc);
return; return;
} }
boot(0, 0, 0, MAIN_RAM_BASE); boot(0, 0, 0, FIRMWARE_BASE_ADDRESS);
} }
#endif #endif