lib_udp.sav.txt

ARM9200开发板的ROM boot程序源码1.0

;------------------------------------------------------------------------------
;-         ATMEL Microcontroller Software Support  -  ROUSSET  -
;------------------------------------------------------------------------------
; The software is delivered "AS IS" without warranty or condition of any
; kind, either express, implied or statutory. This includes without
; limitation any warranty or condition with respect to merchantability or
; fitness for any particular purpose, or against the infringements of
; intellectual property rights of others.
;------------------------------------------------------------------------------
;- File Name            : lib_udp.arm
;- Object               : Assembler USB device FIQ handler.
;-
;- 1.0 17/09/01 ODi     : Creation
;------------------------------------------------------------------------------
	AREA    AT91Lib_fiq, CODE, READONLY, INTERWORK

        INCLUDE         ../../periph/udp/udp.inc
        INCLUDE         ../../periph/udp/lib_udp.mac
        INCLUDE         ../../periph/aic/aic.inc
        INCLUDE         ../../parts/booster/booster.inc
         
; ============================================
;- DMA FIQ Handler
;- ---------------
BeginFiqHandler:
;- Look for the origin of the IRQ...
;	ldr         r8, =UDP_BASE
	ldr         r9,  [r8, #UDP_UISR]

	mov         r10, sp	
	ands        r11, r9,  #UDP_EP0INT
	ldmneia     r10,  {r11, r12, pc}
;	add         r10, r10, #12

	ands        r11, r9,  #UDP_EP1INT
	ldmneia     r10,  {r11, r12, pc}
;	add         r10, r10, #12

	ands        r11, r9,  #UDP_EP2INT
	ldmneia     r10,  {r11, r12, pc}
;	add         r10, r10, #12
	
;- By default notify the ISR
	b           dma_notify_isr
	
;- ---------------------------------------------------------
;- FIQ ending functions invoked by endpoints handlers
;- There are 2 # functions dma_achieve_fiq and dma_notify_isr

;- ---- Exit the FIQ checking there is not another FIQ pending
dma_achieve_fiq:
;- Exit the FIQ, should the interrupt should be pending in the AIC
	sub         pc, lr, #4

;- ---- Exit the FIQ handler for the following reasons:
;-   . the buffer descriptor counter == 0
;-   . there is an un handled exception
dma_notify_isr:
;- Disable the fast forcing for the UDP
	ldr         r9, =AIC_BASE
	mov         r10, #AIC_UDP
	str         r10, [r9, #AIC_FFDR]

;- Force an IRQ corresponding to the UDB ISR
	mov         r10, #AIC_UDP_ISR 
	mov         r10, [r9, #AIC_ISCR]
	
;- Exit the FIQ, should the interrupt should be pending in the AIC
	sub         pc, lr, #4

;- ---------------------------------------------------------
;- Endpoint handlers referenced by the endpoint DMA descriptor
fiq_udp_ep0:
	ldr         r9,  [r8, #UDP_EP0]	
;	MAC_DMA_RX  fiq_udp_ep0_rcv
	ldr         r9,  [r8, #UDP_EP0]	
;	MAC_DMA_TX  fiq_udp_ep0_tx
	b           dma_notify_isr
	
fiq_udp_ep1:
	ldr         r9,  [r8, #UDP_EP1]
;	MAC_DMA_RX  fiq_udp_ep1_rcv
	b           dma_notify_isr
	
fiq_udp_ep2:
	ldr         r9,  [r8, #UDP_EP2]
;	MAC_DMA_RX  fiq_udp_ep2_rcv
	b           dma_notify_isr

;- ---------------------------------------------------------
dma_rx:
;- Get how many bytes have to be copied and compare with the buffer length
;- (udpCsr becomes a scratch register)
	mov         r9, r9, LSR 16
	cmp         r9, r12
	movge       r9, r12
	
;- Update dma descriptor counter 
;- (bufferLength becomes a scratch register)
	add         r12, r12, r9
	str         r12, [r10, #0]
;- Update dma pointer value	
	add         r12, r11, r9
	str         $r11, [r10, #1]
	
;- Pop values from the FIFO and copy them in the RAM
;	MAC_DMA     dma_rx, MAX_DMA_POP, r11, r8, r9, r10, r12

;- Beware r9 and r10 are modified
	ret

dma_tx:
;- Get how many bytes have to be copied and compare with the buffer length
;- (udpCsr becomes a scratch register)
	mov         r9, r9, LSR 16
	cmp         r9, r12
	movge       r9, r12
	
;- Update dma descriptor counter 
;- (bufferLength becomes a scratch register)
	sub         r12, r12, r9
	str         r12, [r10, #0]
;- Update dma pointer value	
	add         r12, r11, r9
	str         r11, [r10, #1]
	
;- Pop values from the FIFO and copy them in the RAM
;	MAC_DMA     dma_tx, MAX_DMA_PUSH, r11, r8, r9, r10, r12
	ret

	END