1. Introduction of
OMAP4 Booting Sequence
Jiahe Jou, 2012/09/13

2. Revisions
DATE AUTHOR DESCRIPTION
2012/09/13 Jiahe Jou Draft.

3. Outlines
● Booting Types
● Booting Overview
● Before Booting
● Peripheral Booting
● Memory Booting
● Memory Map
● Make A Bootable SD Card
● OMAP Bootloader Overview

4. Booting Types
● To start a initialization software(bootstrap)
● Peripheral Booting
○ UART
○ USB
● Memory Booting
○ XIP(eXecution In Place)
■ NOR
○ Non-XIP
■ MMC(eMMC)
■ SD(eSD)
■ NAND

5. Booting Types
● sys_boot[5:0]
● Peripheral Preferred Booting
○ 0b0xxxxx
● Memory Preferred Booting
○ 0b1xxxxx
sys_boot[5:0] 1st 2nd 3rd 4th
0b010110 USB UART MMC1 MMC2(1)
0b110110 MMC2(1) USB UART MMC1

6. Booting Overview
ROM code
start
Booting
Start up and
configuration
Copying or
Image
download
Yes execution
successful?
Setup booting No
device list No Failed or returned
More
devices
in list? Wait for
reset
Select device
from the list
Yes

7. Booting Overview
Booting
Yes Permanent No
device?
Yes
CH Copy and
present? excute CH Download Image
No
No Yes
Is XIP Copy to Copy and
CH sent?
device? RAM excute CH
Yes No
Image
execution

8. Before Booting
● Start up and configuration
○ Reading SYSBOOT pins
○ Software booting configuration
● Setup booting device list
○ sys_boot[5:0]
○ Redefined by software booting configuration
● Select device from list
○ Select a device to start booting procedure

9. Before Booting
● Software booting configuration structure
○ Store in SAR RAM memory
○ PUBLIC_SW_BOOT_CFG_ADDR(0x4A326A00)
■ Be 0 if cold reset
■ Address of configuration structure on else
● Software booting configuration
○ Device booting list
○ Clock setting
○ Time-out mechanism of peripheral booting

10. Peripheral Booting
● Types
○ UART
○ USB
● Download a flash loader(Pre-flashing)
● Initial flash memories
● Update firmware

11. Peripheral Booting
Transfered
Peipheral Successed
Booting
Time-out
Transfer Phase
UART USB
or
USB
Synchronized
USB
Initialization
Time-out
Synchronization Phase Failed
UART UART
Initialization

12. Peripheral Booting
Synchronization Phase of USB
USB enumeration
3s time-out
Get ASIC ID
ASIC ID
Booting message
3s time-out

13. Peripheral Booting
Synchronization Phase of UART
ASIC ID
Get ASIC ID
ASIC ID
Booting message
300ms time-out

14. Peripheral Booting
Transfer Phase
Image size
1min time-out
Image
1min time-out

15. Peripheral Booting
● ASIC ID structure
○ Items, number of sub-blocks
○ ID sub-block, device identification
○ Checksum sub-block, CRC(not for UART)
○ 3 reserved sub-blocks
● Booting message
○ Peripheral booting, 0xF0030002
○ Change device, 0xF003xx06
○ Next device, 0xFFFFFFFF
○ Memory booting, Others
■ Get ASIC ID, 0xF003 0003

16. Memory Booting
● Types
○ XIP(eXecution In Place)
■ NOR
○ Non-XIP
■ MMC(eMMC)
■ SD(eSD)
● Code shadowing for Non-XIP
○ Copying code to RAM

17. Memory Booting
Yes
Memory Is XIP Execute
Booting dev? image
No
Copy image
to RAM

18. Memory Booting
SD/MMC Booting
Find and get
Successed
booting file
Initilization
No
Configure Yes
Is raw
card address Get raw data
mode?
(RCA)

19. Memory Booting
● SDMMCx interfaces
○ SDMMC1(SDCard)
■ Raw
■ File system
○ SDMMC2(eMMC)
■ Raw
● Avoid boot time penalty

20. Memory Booting
● Raw
○ Read image directly from sectors
○ Four consecutive location, offset 128KB
■ 0x00000(bytes)
■ 0x20000
■ 0x40000
■ 0x60000
● File system(FAT16, FAT32)
○ Read image from a booting file
○ SDMMC1 only
○ File name must be "MLO"

21. Memory Map
48KB

22. Make A Bootable SD Card
● http://code.google.com/p/beagleboard/wiki/LinuxBootDiskFormat
● Tool
○ fdisk
○ mkfs
● Procedure
○ Step 1. Prepre a SD card
○ Step 2. Delete all partitions
○ Step 3. Configure SD card
■ Heads, sectors, cylinders
○ Step 4. Create a FAT32 partition
○ Step 5. Mark it as bootable

23. OMAP Bootloader Overview
● http://omappedia.org/wiki/Bootloader_Project
● Two stages
○ x-loader
○ u-boot
ROM code x-loader u-boot Linux kernel
1st stage 2nd stage

24. End