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 "map.h"
14#include "regs-irq.h"
15
16#include <linux/spi/s3c24xx-fiq.h>
17
18#define S3C2410_SPTDAT           (0x10)
19#define S3C2410_SPRDAT           (0x14)
20
21	.text
22
23	@ entry to these routines is as follows, with the register names
24	@ defined in fiq.h so that they can be shared with the C files which
25	@ setup the calling registers.
26	@
27	@ fiq_rirq	The base of the IRQ registers to find S3C2410_SRCPND
28	@ fiq_rtmp	Temporary register to hold tx/rx data
29	@ fiq_rspi	The base of the SPI register block
30	@ fiq_rtx	The tx buffer pointer
31	@ fiq_rrx	The rx buffer pointer
32	@ fiq_rcount	The number of bytes to move
33
34	@ each entry starts with a word entry of how long it is
35	@ and an offset to the irq acknowledgment word
36
37ENTRY(s3c24xx_spi_fiq_rx)
38	.word	fiq_rx_end - fiq_rx_start
39	.word	fiq_rx_irq_ack - fiq_rx_start
40fiq_rx_start:
41	ldr	fiq_rtmp, fiq_rx_irq_ack
42	str	fiq_rtmp, [ fiq_rirq, # S3C2410_SRCPND - S3C24XX_VA_IRQ ]
43
44	ldrb	fiq_rtmp, [ fiq_rspi, #  S3C2410_SPRDAT ]
45	strb	fiq_rtmp, [ fiq_rrx ], #1
46
47	mov	fiq_rtmp, #0xff
48	strb	fiq_rtmp, [ fiq_rspi, # S3C2410_SPTDAT ]
49
50	subs	fiq_rcount, fiq_rcount, #1
51	subsne	pc, lr, #4		@@ return, still have work to do
52
53	@@ set IRQ controller so that next op will trigger IRQ
54	mov	fiq_rtmp, #0
55	str	fiq_rtmp, [ fiq_rirq, # S3C2410_INTMOD  - S3C24XX_VA_IRQ ]
56	subs	pc, lr, #4
57
58fiq_rx_irq_ack:
59	.word	0
60fiq_rx_end:
61
62ENTRY(s3c24xx_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	subsne	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)
89	.word	fiq_tx_end - fiq_tx_start
90	.word	fiq_tx_irq_ack - fiq_tx_start
91fiq_tx_start:
92	ldrb	fiq_rtmp, [ fiq_rspi, #  S3C2410_SPRDAT ]
93
94	ldr	fiq_rtmp, fiq_tx_irq_ack
95	str	fiq_rtmp, [ fiq_rirq, # S3C2410_SRCPND - S3C24XX_VA_IRQ ]
96
97	ldrb	fiq_rtmp, [ fiq_rtx ], #1
98	strb	fiq_rtmp, [ fiq_rspi, # S3C2410_SPTDAT ]
99
100	subs	fiq_rcount, fiq_rcount, #1
101	subsne	pc, lr, #4		@@ return, still have work to do
102
103	mov	fiq_rtmp, #0
104	str	fiq_rtmp, [ fiq_rirq, # S3C2410_INTMOD  - S3C24XX_VA_IRQ ]
105	subs	pc, lr, #4
106
107fiq_tx_irq_ack:
108	.word	0
109
110fiq_tx_end:
111
112	.end
113