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Diffstat (limited to 'openpcd/firmware/doc/dfu.txt')
| -rw-r--r-- | openpcd/firmware/doc/dfu.txt | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/openpcd/firmware/doc/dfu.txt b/openpcd/firmware/doc/dfu.txt new file mode 100644 index 0000000..9b40c3c --- /dev/null +++ b/openpcd/firmware/doc/dfu.txt @@ -0,0 +1,89 @@ +- data that is needed from both app and dfu mode +- code that is needed from both app and dfu mode + - function pointers + - copy code to RAM in case of DFU switch +- data that is only needed in DFU mode + - can be overwritten in case of reset-to-application +- data that is only needed in app mode + - can be overwritten with DFU data in case of DFU switch +- code that is only needed in DFU mode + - has to be copied to ram in case of DFU switch +- code that is only needed in app mode + - can be read from flash, no action required + + +=> abandoned that complicated idea. +now all DFU functions are __ramfunc's and thus always present. + + +interaction between app and dfu code: + +- dfu_switch(void) +- dfu_status (can be put in accessor function, if required) +- dfu_cfg_descriptor +- dfu_dev_descriptor +- dfu_ep0_handler() + + +order of events at boot; + +- start at reset vector in flash + - AT91F_LowLevelInit() +- setup stack for each mode +- relocate 'data' of bootloader, including ramfunc/vectram +- clear 'bss' of bootloader +- call remap command + - call usb initialization (irq, clock) + - if keypress, + - call dfu_main() + - wait for ep0 / busreset interrupt + - else call main() + + +memory layout: + +0: lowlevel startup code + Cstartup.o 0x00bc + Cstartup_SAM7.o 0x0100 + dfufunc 0x1dcc + dfustruct 0x0038 + + text text 0x0070 +data data 0x0000 +bss bss 0x000c + +flash = text + data (= 8k) +ram/rel = data + bss (12 bytes) + + +If we drop the DFU-can-flash-DFU requirement, we can leave all DFU related code +in flash. no need for any function to be permanently in RAM. However, not +preventing this feature in some future version, we shouldn't do that. + + +Function DFU runtime +udp_init x x RAM +udp_ep0_send_data x x RAM +udp_ep0_send_zlp x x RAM +udp_sp0_send_stall x x RAM +handle_dnload x - flash/relocated +handle_upload x - flash/relocated +handle_getstatus x - flash/relocated +handle_getstate x - flash/relocated +dfu_ep0_handler x x RAM + +dfu_dev_descriptor x - flash/relocated +dfu_cfg_descriptor x - flash/relocated +dfu_udp_ep0_handler x - flash/relocated +dfu_udp_irq x - flash/relocated +dfu_switch - x RAM +dfu_main x - flash/relocated +vectram x x flash/relocated/switched +IRQ_Handler_EntryR x x flash/relocated/switched +_remap x - flash/reloaded + +dfu_api x x flash (const anyway) +dfu_state x x RAM + + + |