driver.s

ucos下的driver的抽象层, 有了这一层porting将更容易

;/*****************************************************************************
; * Copyright (C) ARM Limited 1998. All rights reserved. 
; *****************************************************************************/
;/*****************************************************************************
;
;	PID specific assembly source code.  
;  
;******************************************************************************/

	INCLUDE	bits.s
	INCLUDE	sizes.s
	INCLUDE	platform.s
	INCLUDE	mmu_h.s
	GET	target.s
		
	EXPORT	uHALir_InitTargetMem	; Initialise memory
	EXPORT	uHALir_FindRAMTop		; Find top of memory

	IMPORT	uHALir_EnterLockedSvcMode	; Enter Supervisor mode & disable IRQ.
	IMPORT	uHALir_ExitSvcMode	; Exit Supervisor mode.
	IMPORT	uHALiv_TopOfMemory	; Top of RAM.

	EXPORT	Level1tab
	EXPORT	Level2tab_ROM
	EXPORT	MPUMaptab

	KEEP
	AREA    |C$$code$$__pid|, CODE, READONLY


; -------------------------------------------------------------------
; Routine to initialise the target-specific RAM:
;
; See INIT_RAM macro for description

; NOTE:	lr contains return address
;	a1 returns top of memory

uHALir_InitTargetMem
	;; Initialise the DRAM (if present)
	INIT_RAM	a1,v1,v2,v3,v4
	LDR	a1, =uHAL_MEMORY_SIZE 
	GET_RAMSIZE	a1,v1,v2,v3,v4	
	MOV	pc, lr			; All done, return


uHALir_FindRAMTop
	STMFD	r13!,{v1,v2,v3,v4}
	GET_RAMSIZE	a1,v1,v2,v3,v4
	LDMFD	r13!,{v1,v2,v3,v4}
	MOV	pc, lr			; All done, return


	AREA uHAL_TTentries, DATA, NOINIT, ALIGN=14

;------------------------------------------------------------------
; MMU lookup tables. Because the SETUPMMU macro is shared with
; semihosted, it uses simple names, these are aliased to uHAL
; standard for internal use.
;
; NOTE: These areas are declared even for processors without MMUs


; 4-byte entries,1MB sections
uHALiv_Level1tab
Level1tab 	% (L1_TABLE_ENTRIES * 4)

; 4-byte entries, 64kB pages; x16 alias
uHALiv_Level2tab_ROM
Level2tab_ROM	% (L2_TABLE_ENTRIES * L2_ENTRY_SIZE * 4)

; 4-byte entries, 8 regions + 3 flags
uHALiv_MPUMaptab
MPUMaptab	% (MPU_TABLE_ENTRIES * 4)


	END