Method and apparatus for accessing ROM PCI memory above 64 K

• US 20030105935A1
• Filed: 11/30/2001
• Published: 06/05/2003
• Est. Priority Date: 11/30/2001
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: LSI Logic Corporation (Broadcom, Inc.)
• Inventors: Moore, Derick G.
• Granted Patent: US 6,760,827 B2
• Time in Patent Office: Days
• US Class Current: 711/171
• CPC Class Codes: G06F 12/0623 for memory modules
• CPC Class Codes: G06F 9/32 Address formation of the next instruction, e.g. by incrementing the instruction counter G06F9/38 takes precedence
• CPC Class Codes: G06F 9/342 Extension of operand address space

Abstract

A method for augmenting the memory capabilities of an option ROM in which PCI function calls are used to access a larger sized non-volatile memory. Thirty two bit addressing is used in the PCI function call routines to allow for 4 GB addressing. An option ROM and the separate larger sized non-volatile memory or a single non-volatile memory may be used for storing the overflow images.

Claims

1. A method for accessing, via the commands of an adapter, from a read/limited write memory having a first size, and a memory area having a second size greater in size than the first size, comprising:

preparing a load image for transfer to the read/limited write memory;

making a determination of the size of the load image;

initializing the read/limited write memory to enable addressing of the memory area; and

making function calls to enable a configuration space for the adapter.

2. The method of claim 1, further comprising, if the size of the load image is determined to exceed the first size, then generating an overflow image which represents the difference in size between the size of the load image and the first size and generating a read/limited write memory image.

3. The method of claim 2, further comprising transferring the overflow image to the memory area and transferring the read/limited write memory image to the read/limited write memory.

4. The method of claim 3, further comprising accessing and validating the overflow image.

5. The method of claim 4, further comprising transferring the overflow image from an overflow area of the memory area into a main memory of the memory area.

6. The method of claim 5, further comprising, prior to making a determination of the size of the load image, running the read/limited write memory initialization code.

7. The method of claim 6, further comprising, after transferring the overflow image from an overflow area of the memory area into a main memory of the memory area, making function calls to disable or return the configuration space to a previous state.

8. The method of claim 7, further comprising, after making function calls to disable or return the configuration space to a previous state, continuing the initialization process by using data and instructions of the overflow image of the main memory.

9. The method of claim 1, the function calls being PCI function calls.

10. The method of claim 1, the read/limited write memory being a non-volatile memory.

11. The method of claim 10, the option ROM being a FLASH option ROM.

12. The method of claim 1, the memory area being a FLASH memory.

13. A computer system, comprising:

an adapter which provides control signals and data to other devices;

a read/limited write memory having a first size and being coupled to the adapter to effect data transfers; and

a main memory having a second size that is greater than the first size, the main memory being used to store an overflow image in a data transfer to the read/limited write memory when the load image to be transferred to the read/limited write memory has a size which exceeds the first size.

14. The computer system of claim 13, the computer system utilizing function calls to enable a configuration space for the adapter.

15. The computer system of claim 13, the adapter being an X86 processor.

16. The computer system of claim 13, the read/limited write memory being an option ROM.

17. The computer system of claim 16, the option ROM using FLASH technology.

18. The computer system of claim 17, the option ROM having a size of 64 K.

19. The computer system of claim 13, the main memory using FLASH technology.

20. The computer system of claim 19, the main memory being addressable by 32 address bits.

21. A computer system which presumes a first size for a FLASH option ROM, comprising:

an adapter having system BIOS; and

a non-volatile memory having a second size, the second size being greater than the first size,

the system BIOS initiating loading into the non-volatile memory,

PCI function calls being made to enable configuration space for the adapter in Big Real Mode.

22. The computer system of claim 21, an overflow image is accessed from the adapter and validated by the adapter.

23. The computer system of claim 22, the overflow image is copied from an overflow area of the non-volatile memory to a main area of memory.

24. A method for accessing a non-volatile memory as an expanded option ROM, comprising:

using a system BIOS to enter Big Real Mode;

making function calls to enable configuration space for an adapter on which the system BIOS resides.

25. The method of claim 24, accessing and validating an overflow image for the expanded option ROM.

26. The method of claim 25, copying data from an overflow area to a main memory of the non-volatile memory.

27. The method of claim 26, wherein the system BIOS uses Big Real Mode normally for internal processing only.

28. The method of claim 27, wherein process code apart from the system BIOS enables Big Real Mode and does not permit system BIOS to disable Big Real Mode.

29. The method of claim 24, wherein the function calls are PCI function calls.

30. The method of claim 29, wherein the PCI function calls enable configuration space for an adapter on which resides the system BIOS.

31. A method for switching operational modes for transferring data to and from an non-volatile memory, comprising:

placing a system BIOS in a first operational mode; and

initiating process code, separate from the system BIOS and responsive to processing by the system BIOS, that ensures the system BIOS enters a second operational mode or prevents the system BIOS from leaving the second operational mode,

the second operational mode supporting a larger address space than the first operational mode.

32. The method of claim 31, wherein the step of initiating process code involves invoking function calls.

33. The method of claim 32, wherein the function calls are PCI function calls which enable configuration space for an adapter on which resides the system BIOS.

34. The method of claim 31, wherein the first operational mode is Real Mode.

35. The method of claim 34, wherein the second operational mode is Big Real Mode.