XMMBoot¶

Introduction¶

For both libsamsung-ipc and the Linux driver it's interesting to understand better the boot of the modem in order to come with good names for the abstraction.

GPIOs¶

The GPIO platform data names were taken from the modem_modemctl_device_xmm6260.c file

ioctl name	function pointer name	gpio platform data name	present	absent	comments
		gpio_cp_on			cp baseband processor
		gpio_reset_req_n
		gpio_cp_reset			cp baseband processor
		gpio_pda_active
		gpio_phone_active
		gpio_cp_dump_int			cp baseband processor
IOCTL_MODEM_BOOT_ON IOCTL_MODEM_BOOT_OFF	modem_boot_on modem_boot_off	gpio_flm_uart_sel	Galaxy Nexus	Not used in libsamsung-ipc for other Replicant compatible devices	Modem download mode ?
		gpio_cp_warm_reset			cp baseband processor
		gpio_revers_bias_clear
		gpio_revers_bias_restore
		gpio_sim_detect			Detect SIM card presence ?

SIM card presence detection¶

Do we really want to check the SIM card presence?

Would it be possible not to for privacy reasons?

Example:

• Boot a modem with a SIM
• Take away the SIM card
• Go to a protest with only the SIM card and a phone with no data on it to be able to call if necessary.

TODO¶

• check gpio_flm_uart_sel in smdk4412 kernel too

Modem partitions¶

GT-I9300, GT-N7100¶

Location	Name	Content
[ 0x0 -> 0xfff ]	?	Partition table?
[ 0x1000 -> 0xefff ]	PSIRAM	First stage bootloader?
[ 0xF000 -> 0x27fff ]	EBL	Second stage bootloader ?
[ 0x28000 -> 0x9ff7ff ]	MAIN	?
[ 0x9ff800 -> 0x9fffff ]	SECPACK	?
[ 0xa00000 -> 0xbfffff ]	NV	?

References for the table:

• https://git.replicant.us/replicant/external_libsamsung-ipc/tree/samsung-ipc/devices/i9300/i9300.h?id=9ff9785a7f48e32f107ca7fb2e298b1320ad4cbc
• https://git.replicant.us/replicant/external_libsamsung-ipc/tree/samsung-ipc/devices/n7100/n7100.h?id=9ff9785a7f48e32f107ca7fb2e298b1320ad4cbc
• Verified on GT-I9300 and GT-N7100 modem partition table

Partition table ?¶

$ hexdump -C RADIO.img
00000000  50 53 49 52 41 4d 00 00  00 00 00 00 00 10 00 00  |PSIRAM..........|
00000010  00 00 00 00 00 e0 00 00  00 00 00 00 00 00 00 00  |................|
00000020  45 42 4c 00 00 00 00 00  00 00 00 00 00 f0 00 00  |EBL.............|
00000030  00 00 00 60 00 90 01 00  00 00 00 00 00 00 00 00  |...`............|
00000040  4d 41 49 4e 00 00 00 00  00 00 00 00 00 80 02 00  |MAIN............|
00000050  00 00 30 60 00 78 9d 00  00 00 00 00 00 00 00 00  |..0`.x..........|
00000060  53 45 43 50 41 43 4b 00  00 00 00 00 00 f8 9f 00  |SECPACK.........|
00000070  00 00 00 00 00 08 00 00  00 00 00 00 00 00 00 00  |................|
00000080  4e 56 00 00 00 00 00 00  00 00 00 00 00 00 a0 00  |NV..............|
00000090  00 00 e8 60 00 00 20 00  00 00 00 00 00 00 00 00  |...`.. .........|
000000a0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
[...]

Links¶

• modem_modemctl_device_xmm6260.c
• https://forum.xda-developers.com/galaxy-s2/help/how-to-talk-to-modem-commands-t1471241/page4