drivers/spi/spi-s3c24xx-fiq.S

   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
  38 ENTRY(s3c24xx_spi_fiq_rx)
  39 s3c24xx_spi_fix_rx:
  40         .word   fiq_rx_end - fiq_rx_start
  41         .word   fiq_rx_irq_ack - fiq_rx_start
  42 fiq_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
  60 fiq_rx_irq_ack:
  61         .word   0
  62 fiq_rx_end:
  63
  64 ENTRY(s3c24xx_spi_fiq_txrx)
  65 s3c24xx_spi_fiq_txrx:
  66         .word   fiq_txrx_end - fiq_txrx_start
  67         .word   fiq_txrx_irq_ack - fiq_txrx_start
  68 fiq_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
  86 fiq_txrx_irq_ack:
  87         .word   0
  88
  89 fiq_txrx_end:
  90
  91 ENTRY(s3c24xx_spi_fiq_tx)
  92 s3c24xx_spi_fix_tx:
  93         .word   fiq_tx_end - fiq_tx_start
  94         .word   fiq_tx_irq_ack - fiq_tx_start
  95 fiq_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
 111 fiq_tx_irq_ack:
 112         .word   0
 113
 114 fiq_tx_end:
 115
 116         .end