1/* SPDX-License-Identifier: GPL-2.0-only */
2/* linux/drivers/spi/spi_s3c24xx_fiq.S
3 *
4 * Copyright 2009 Simtec Electronics
5 *	Ben Dooks <ben@simtec.co.uk>
6 *
7 * S3C24XX SPI - FIQ pseudo-DMA transfer code
8*/
9
10#include <linux/linkage.h>
11#include <asm/assembler.h>
12
13#include <mach/map.h>
14#include <mach/regs-irq.h>
15#include <plat/regs-spi.h>
16
17#include "spi-s3c24xx-fiq.h"
18
19	.text
20
21	@ entry to these routines is as follows, with the register names
22	@ defined in fiq.h so that they can be shared with the C files which
23	@ setup the calling registers.
24	@
25	@ fiq_rirq	The base of the IRQ registers to find S3C2410_SRCPND
26	@ fiq_rtmp	Temporary register to hold tx/rx data
27	@ fiq_rspi	The base of the SPI register block
28	@ fiq_rtx	The tx buffer pointer
29	@ fiq_rrx	The rx buffer pointer
30	@ fiq_rcount	The number of bytes to move
31
32	@ each entry starts with a word entry of how long it is
33	@ and an offset to the irq acknowledgment word
34
35ENTRY(s3c24xx_spi_fiq_rx)
36s3c24xx_spi_fix_rx:
37	.word	fiq_rx_end - fiq_rx_start
38	.word	fiq_rx_irq_ack - fiq_rx_start
39fiq_rx_start:
40	ldr	fiq_rtmp, fiq_rx_irq_ack
41	str	fiq_rtmp, [ fiq_rirq, # S3C2410_SRCPND - S3C24XX_VA_IRQ ]
42
43	ldrb	fiq_rtmp, [ fiq_rspi, #  S3C2410_SPRDAT ]
44	strb	fiq_rtmp, [ fiq_rrx ], #1
45
46	mov	fiq_rtmp, #0xff
47	strb	fiq_rtmp, [ fiq_rspi, # S3C2410_SPTDAT ]
48
49	subs	fiq_rcount, fiq_rcount, #1
50	subnes	pc, lr, #4		@@ return, still have work to do
51
52	@@ set IRQ controller so that next op will trigger IRQ
53	mov	fiq_rtmp, #0
54	str	fiq_rtmp, [ fiq_rirq, # S3C2410_INTMOD  - S3C24XX_VA_IRQ ]
55	subs	pc, lr, #4
56
57fiq_rx_irq_ack:
58	.word	0
59fiq_rx_end:
60
61ENTRY(s3c24xx_spi_fiq_txrx)
62s3c24xx_spi_fiq_txrx:
63	.word	fiq_txrx_end - fiq_txrx_start
64	.word	fiq_txrx_irq_ack - fiq_txrx_start
65fiq_txrx_start:
66
67	ldrb	fiq_rtmp, [ fiq_rspi, #  S3C2410_SPRDAT ]
68	strb	fiq_rtmp, [ fiq_rrx ], #1
69
70	ldr	fiq_rtmp, fiq_txrx_irq_ack
71	str	fiq_rtmp, [ fiq_rirq, # S3C2410_SRCPND - S3C24XX_VA_IRQ ]
72
73	ldrb	fiq_rtmp, [ fiq_rtx ], #1
74	strb	fiq_rtmp, [ fiq_rspi, # S3C2410_SPTDAT ]
75
76	subs	fiq_rcount, fiq_rcount, #1
77	subnes	pc, lr, #4		@@ return, still have work to do
78
79	mov	fiq_rtmp, #0
80	str	fiq_rtmp, [ fiq_rirq, # S3C2410_INTMOD  - S3C24XX_VA_IRQ ]
81	subs	pc, lr, #4
82
83fiq_txrx_irq_ack:
84	.word	0
85
86fiq_txrx_end:
87
88ENTRY(s3c24xx_spi_fiq_tx)
89s3c24xx_spi_fix_tx:
90	.word	fiq_tx_end - fiq_tx_start
91	.word	fiq_tx_irq_ack - fiq_tx_start
92fiq_tx_start:
93	ldrb	fiq_rtmp, [ fiq_rspi, #  S3C2410_SPRDAT ]
94
95	ldr	fiq_rtmp, fiq_tx_irq_ack
96	str	fiq_rtmp, [ fiq_rirq, # S3C2410_SRCPND - S3C24XX_VA_IRQ ]
97
98	ldrb	fiq_rtmp, [ fiq_rtx ], #1
99	strb	fiq_rtmp, [ fiq_rspi, # S3C2410_SPTDAT ]
100
101	subs	fiq_rcount, fiq_rcount, #1
102	subnes	pc, lr, #4		@@ return, still have work to do
103
104	mov	fiq_rtmp, #0
105	str	fiq_rtmp, [ fiq_rirq, # S3C2410_INTMOD  - S3C24XX_VA_IRQ ]
106	subs	pc, lr, #4
107
108fiq_tx_irq_ack:
109	.word	0
110
111fiq_tx_end:
112
113	.end
114