2,939
edits
Changes
→IRAM
= IRAM =
= IRAM =
== [[BIT|BIT]] ==
== BIT ==
During boot, the BootROM saves the BCT in IRAM at address 0x40000100. The preceding 0x100 bytes (IRAM memory range from 0x40000000 to 0x40000100) contain a structure called BIT (Boot Info Table) which encapsulates the BCT in IRAM and is initialized by the BootROM as follows:
{| class="wikitable" border="1"
{| class="wikitable" border="1"
| 0x00
| 0x00
| 0x04
| 0x04
| unk_version0
| br_version
|
| Set to 0x00210001 (BOOTDATA_VERSION_T210).
0x00210001
|-
|-
| 0x04
| 0x04
| 0x04
| 0x04
| unk_version1
| bd_version
|
| Set to 0x00210001 (BOOTDATA_VERSION_T210).
0x00210001
|-
|-
| 0x08
| 0x08
| 0x04
| 0x04
| unk_version2
| rcm_version
|
| Set to 0x00210001 (BOOTDATA_VERSION_T210).
0x00210001
|-
|-
| 0x0C
| 0x0C
BOOT_TYPE_EXIT_RCM = 4
BOOT_TYPE_EXIT_RCM = 4
|-
|-
0x4C: bct_data_addr (address of the actual BCT)
| 0x10
| 0x04
| unk0
| Set to 0x05 on coldboot.
|-
| 0x14
| 0x04
| boot_device_type
|
|-
| 0x18
| 0x04
| boot_start_time
| Value from TIMERUS_CNTR_1US when the BootROM enters its main function.
|-
| 0x1C
| 0x04
| unk1
|
|-
| 0x20
| 0x04
| boot_read_bct_time
| Time spent reading the BCT.
|-
| 0x24
| 0x04
| boot_parse_bootloader_time
| Time spent parsing the bootloader info from the BCT.
|-
| 0x28
| 0x04
| osc_freq
| Value from CLK_RST_CONTROLLER_OSC_CTRL.
|-
| 0x2C
| 0x01
| is_boot_device_loaded
| Set to 1 after the boot device is initialized.
|-
| 0x2D
| 0x01
| is_sdram_configured
| Set to 1 after the SDRAM parameters are parsed.
|-
| 0x2E
| 0x01
| is_forced_rcm_pmc
| Set to 1 if bit 2 was set in APBDEV_PMC_SCRATCH0.
|-
| 0x2F
| 0x01
| is_enable_fail_back_pmc
| Set to 1 if bit 4 was set in APBDEV_PMC_SCRATCH0.
|-
| 0x30
| 0x02
| is_bootloader_version_mismatch
| Set to 1 if the bootloaders have different versions in the BCT.
|-
| 0x32
| 0x02
| is_bct_valid
| Set to 1 if the BCT was parsed successfully.
|-
| 0x34
| 0x04
| unk2
|
|-
| 0x38
| 0x04
| unk3
|
|-
| 0x3C
| 0x04
| active_bootloader_idx
| Value from 0 to 3 that represents which bootloader is active.
|-
| 0x40
| 0x04
| bct_start_block
| Block number where the BCT was found.
|-
| 0x44
| 0x04
| bct_start_page
| Page number where the BCT was found.
|-
| 0x48
| 0x04
| bct_size
| Size of the BCT in IRAM (0x2800).
|-
| 0x4C
| 0x04
| bct_ptr
| Pointer to the BCT in IRAM (0x40000100).
|-
|-
| 0x50
| 0x50
| 0x00
| 0x00
| 0x04
| 0x04
| is_active
| bootloader_idx
|-
|-
| 0x04
| 0x04
| 0x04
| 0x04
| start_block
| bootloader_start_block
|-
|-
| 0x08
| 0x08
| 0x04
| 0x04
| start_page
| bootloader_start_page
|-
|-
| 0x0C
| 0x0C
| 0x04
| 0x04
| length
| bootloader_length
|-
|-
| 0x10
| 0x10
| 0x04
| 0x04
| signed_start
| bootloader_signed_start
|-
|-
| 0x14
| 0x14
| 0x04
| 0x04
| signature
| bootloader_signature
|}
|}
|-
|-
| 0xB0
| 0xB0
| 0x40
| 0x40
|
| boot_device_info
|
| Structure to hold boot device parameters.
|-
|-
| 0xF0
| 0xF0
| 0x04
| 0x04
|
| bct_end_ptr
|
| Pointer to the end of the BCT in IRAM (0x40002900).
|-
|-
| 0xF4
| 0xF4
| 0x0C
| 0x0C
|
| padding
|
| Must be empty.
|}
|}
= Notes =
= Notes =