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