1/* linux/drivers/spi/spi_s3c24xx_fiq.S
2 *
3 * Copyright 2009 Simtec Electronics
4 *	Ben Dooks <ben@simtec.co.uk>
5 *
6 * S3C24XX SPI - FIQ pseudo-DMA transfer code
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11*/
12
13#include <linux/linkage.h>
14#include <asm/assembler.h>
15
16#include <mach/map.h>
17#include <mach/regs-irq.h>
18#include <plat/regs-spi.h>
19
20#include "spi_s3c24xx_fiq.h"
21
22	.text
23
24	@ entry to these routines is as follows, with the register names
25	@ defined in fiq.h so that they can be shared with the C files which
26	@ setup the calling registers.
27	@
28	@ fiq_rirq	The base of the IRQ registers to find S3C2410_SRCPND
29	@ fiq_rtmp	Temporary register to hold tx/rx data
30	@ fiq_rspi	The base of the SPI register block
31	@ fiq_rtx	The tx buffer pointer
32	@ fiq_rrx	The rx buffer pointer
33	@ fiq_rcount	The number of bytes to move
34
35	@ each entry starts with a word entry of how long it is
36	@ and an offset to the irq acknowledgment word
37
38ENTRY(s3c24xx_spi_fiq_rx)
39s3c24xx_spi_fix_rx:
40	.word	fiq_rx_end - fiq_rx_start
41	.word	fiq_rx_irq_ack - fiq_rx_start
42fiq_rx_start:
43	ldr	fiq_rtmp, fiq_rx_irq_ack
44	str	fiq_rtmp, [ fiq_rirq, # S3C2410_SRCPND - S3C24XX_VA_IRQ ]
45
46	ldrb	fiq_rtmp, [ fiq_rspi, #  S3C2410_SPRDAT ]
47	strb	fiq_rtmp, [ fiq_rrx ], #1
48
49	mov	fiq_rtmp, #0xff
50	strb	fiq_rtmp, [ fiq_rspi, # S3C2410_SPTDAT ]
51
52	subs	fiq_rcount, fiq_rcount, #1
53	subnes	pc, lr, #4		@@ return, still have work to do
54
55	@@ set IRQ controller so that next op will trigger IRQ
56	mov	fiq_rtmp, #0
57	str	fiq_rtmp, [ fiq_rirq, # S3C2410_INTMOD  - S3C24XX_VA_IRQ ]
58	subs	pc, lr, #4
59
60fiq_rx_irq_ack:
61	.word	0
62fiq_rx_end:
63
64ENTRY(s3c24xx_spi_fiq_txrx)
65s3c24xx_spi_fiq_txrx:
66	.word	fiq_txrx_end - fiq_txrx_start
67	.word	fiq_txrx_irq_ack - fiq_txrx_start
68fiq_txrx_start:
69
70	ldrb	fiq_rtmp, [ fiq_rspi, #  S3C2410_SPRDAT ]
71	strb	fiq_rtmp, [ fiq_rrx ], #1
72
73	ldr	fiq_rtmp, fiq_txrx_irq_ack
74	str	fiq_rtmp, [ fiq_rirq, # S3C2410_SRCPND - S3C24XX_VA_IRQ ]
75
76	ldrb	fiq_rtmp, [ fiq_rtx ], #1
77	strb	fiq_rtmp, [ fiq_rspi, # S3C2410_SPTDAT ]
78
79	subs	fiq_rcount, fiq_rcount, #1
80	subnes	pc, lr, #4		@@ return, still have work to do
81
82	mov	fiq_rtmp, #0
83	str	fiq_rtmp, [ fiq_rirq, # S3C2410_INTMOD  - S3C24XX_VA_IRQ ]
84	subs	pc, lr, #4
85
86fiq_txrx_irq_ack:
87	.word	0
88
89fiq_txrx_end:
90
91ENTRY(s3c24xx_spi_fiq_tx)
92s3c24xx_spi_fix_tx:
93	.word	fiq_tx_end - fiq_tx_start
94	.word	fiq_tx_irq_ack - fiq_tx_start
95fiq_tx_start:
96	ldrb	fiq_rtmp, [ fiq_rspi, #  S3C2410_SPRDAT ]
97
98	ldr	fiq_rtmp, fiq_tx_irq_ack
99	str	fiq_rtmp, [ fiq_rirq, # S3C2410_SRCPND - S3C24XX_VA_IRQ ]
100
101	ldrb	fiq_rtmp, [ fiq_rtx ], #1
102	strb	fiq_rtmp, [ fiq_rspi, # S3C2410_SPTDAT ]
103
104	subs	fiq_rcount, fiq_rcount, #1
105	subnes	pc, lr, #4		@@ return, still have work to do
106
107	mov	fiq_rtmp, #0
108	str	fiq_rtmp, [ fiq_rirq, # S3C2410_INTMOD  - S3C24XX_VA_IRQ ]
109	subs	pc, lr, #4
110
111fiq_tx_irq_ack:
112	.word	0
113
114fiq_tx_end:
115
116	.end
117