Replicant

h1. XMMBoot

{{toc}}

h2.  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.

h2. Abstraction

* hci_power -> link_power

TODO:

* Find the difference between power_on and boot_power_on

** Look at the GPIOs and understand what they do

** Just read the code that use the GPIOs

** Diff both procedures

h2. GPIOs

h3. Devices GPIOs assignement and drivers

|_. Variant |_. SOC |_. Modem  |_. GPIO usage |_. GPIO assignement |

| GT-I9300 | Exynos 4412 | XMM6262 | "CONFIG_UMTS_MODEM_XMM6262=y":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/arch/arm/configs/lineageos_i9300_defconfig#n1350

"Makefile":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/drivers/misc/modem_if/Makefile#n10

"modem_modemctl_device_xmm6262.c":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/drivers/misc/modem_if/modem_modemctl_device_xmm6262.c | "CONFIG_SEC_MODEM_M0=y":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/arch/arm/configs/lineageos_i9300_defconfig#n541

"Makefile":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/arch/arm/mach-exynos/Makefile#n320

"board-m0-modems.c":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/arch/arm/mach-exynos/board-m0-modems.c 

"CONFIG_MACH_M0=y":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/arch/arm/configs/lineageos_i9300_defconfig#n455

"gpio-midas.h":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/arch/arm/mach-exynos/include/mach/gpio-midas.h#n28

"gpio-rev00-m0.h":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/arch/arm/mach-exynos/include/mach/gpio-rev00-m0.h |

h3. GPIOs usage

TODO: make sure to mention what applies to what device

* Start with I9300. Assume I9300 if device is not mentioned. Mention device when not I9300

* Add more devices and mention them

|_. gpio platform data name |_. present |_. absent |_. Implementation |_. comments |

| gpio_cp_on | | | | powers on the modem? in which state (PMIC?, CPU?)

* On GT-I9100 it's connected to the ON1 modem pin and ON2 is not connected. |

| gpio_cp_reset | | | | Resets the modem CPU? PMIC?:

* "''check the reset timming with C2C connection''":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/drivers/misc/modem_if/modem_modemctl_device_xmm6262.c#n106 : Here C2C probably means chip to chip

Can also read the modem CPU? and/or PMIC? reset state?

* "Reads from the GPIO and ''CP not ready, Active State low'' comment":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/arch/arm/mach-exynos/board-m0-modems.c#n287 |

| gpio_reset_req_n | | | |

| gpio_pda_active | | | | Tell the modem if the SOC CPUs are sleeping/active or not?

* "PDA == Application processor":https://android.stackexchange.com/questions/176515/what-do-the-terms-bl-ap-cp-and-csc-mean-in-odin

* "''PDA_ACTIVE, let cp know AP sleep'' comment in status gc1-gpio.c":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/arch/arm/mach-exynos/gc1-gpio.c#n213

* "PDA_ACTIVE set to 0 right after cpu_pm_enter()":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/arch/arm/mach-exynos/cpuidle-exynos4.c#n701

* "PDA_ACTIVE set to 1 right before cpu_pm_exit()":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/arch/arm/mach-exynos/cpuidle-exynos4.c#n796

* GPIO direction is output on AP side and input on BP side, which is also confirmed by the "pinout table in XDA":https://forum.xda-developers.com/galaxy-s2/help/how-to-talk-to-modem-commands-t1471241/page4 |

| gpio_phone_active | | | | |

| gpio_cp_dump_int | | | | cp: baseband processor |

| gpio_flm_uart_sel |\2. Only used for the Galaxy Nexus in libsamsung-ipc | | 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 ? |

h3. Libsamsung-ipc

|/2. ioctl / function |\6. Devices |

| GT-I9250 (maguro) | GT-I9100 | GT-I9300 | GT-N5100 | GT-N7100 | GT-P3100 / GT-P5100 (piranah) |

| open, close, read, write 

fmt/rfs

gprs

power |\6. Yes |

| boot_power

status_online_wait | Yes |\5. No |

| hci_power

link_control_enable

link_control_active

link_control_wait

link_get_hostwake_wait | No |\4. Yes | No |

h3. libsamsung-ipc <-> kernel functions <-> gpios

|_. libsamsung-ipc |_\3. Kernel |

|_. Function using the ioctl |_. ioctl name |_. function pointer name |_. GPIO used |

| xmm626_kernel_smdk4412_power | IOCTL_MODEM_ON

IOCTL_MODEM_OFF | modem_on

modem_off | gpio_cp_on

gpio_cp_reset

gpio_reset_req_n

gpio_pda_active |

| | | | gpio_phone_active |

| | | | gpio_cp_dump_int |

| xmm626_kernel_smdk4412_boot_power | IOCTL_MODEM_BOOT_ON

IOCTL_MODEM_BOOT_OFF | modem_boot_on

modem_boot_off | gpio_flm_uart_sel |

| | | | gpio_cp_warm_reset |

| | | | gpio_revers_bias_clear |

| | | | gpio_revers_bias_restore |

| | | | gpio_sim_detect |

h3. Glossary

Terms for the modem:

* BP: Baseband processor

* CP: Cellular? processor

Term for the system on a chip running Replicant:

* AP: Application processor

TODO: move in its own page and point to it

h3. 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.

h3. TODO

* check gpio_flm_uart_sel in smdk4412 kernel too

h2. Modem partitions

h3. 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

h4. GT-I9300 and GT-N7100 modem partition table dump

<pre>

$ 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  |................|

*

[...]

</pre>

h3. Devices without a partition table or with a different one

* GT-I9250

h2. Links

* "modem_modemctl_device_xmm6262.c":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/drivers/misc/modem_if/modem_modemctl_device_xmm6262.c

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

* http://www.arteris.com/blog/bid/59433/Interchip-Connectivity-HSIC-UniPro-HSI-C2C-LLI-oh-my

** TODO: move this link somewhere where it's more useful