linux/drivers/spi/spi-s3c24xx-fiq.S
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   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
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