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   1 /*
   2  * arch/sh/drivers/dma/dma-g2.c
   3  *
   4  * G2 bus DMA support
   5  *
   6  * Copyright (C) 2003, 2004  Paul Mundt
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License.  See the file "COPYING" in the main directory of this archive
  10  * for more details.
  11  */
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/interrupt.h>
  16
  17 #include <asm/mach/sysasic.h>
  18 #include <asm/mach/dma.h>
  19 #include <asm/dma.h>
  20
  21 struct g2_channel {
  22         unsigned long g2_addr;          /* G2 bus address */
  23         unsigned long root_addr;        /* Root bus (SH-4) address */
  24         unsigned long size;             /* Size (in bytes), 32-byte aligned */
  25         unsigned long direction;        /* Transfer direction */
  26         unsigned long ctrl;             /* Transfer control */
  27         unsigned long chan_enable;      /* Channel enable */
  28         unsigned long xfer_enable;      /* Transfer enable */
  29         unsigned long xfer_stat;        /* Transfer status */
  30 } __attribute__ ((aligned(32)));
  31
  32 struct g2_status {
  33         unsigned long g2_addr;
  34         unsigned long root_addr;
  35         unsigned long size;
  36         unsigned long status;
  37 } __attribute__ ((aligned(16)));
  38
  39 struct g2_dma_info {
  40         struct g2_channel channel[G2_NR_DMA_CHANNELS];
  41         unsigned long pad1[G2_NR_DMA_CHANNELS];
  42         unsigned long wait_state;
  43         unsigned long pad2[10];
  44         unsigned long magic;
  45         struct g2_status status[G2_NR_DMA_CHANNELS];
  46 } __attribute__ ((aligned(256)));
  47
  48 static volatile struct g2_dma_info *g2_dma = (volatile struct g2_dma_info *)0xa05f7800;
  49
  50 static irqreturn_t g2_dma_interrupt(int irq, void *dev_id, struct pt_regs *regs)
  51 {
  52         /* FIXME: Do some meaningful completion work here.. */
  53         return IRQ_HANDLED;
  54 }
  55
  56 static struct irqaction g2_dma_irq = {
  57         .name           = "g2 DMA handler",
  58         .handler        = g2_dma_interrupt,
  59         .flags          = IRQF_DISABLED,
  60 };
  61
  62 static int g2_enable_dma(struct dma_channel *chan)
  63 {
  64         unsigned int chan_nr = chan->chan;
  65
  66         g2_dma->channel[chan_nr].chan_enable = 1;
  67         g2_dma->channel[chan_nr].xfer_enable = 1;
  68
  69         return 0;
  70 }
  71
  72 static int g2_disable_dma(struct dma_channel *chan)
  73 {
  74         unsigned int chan_nr = chan->chan;
  75
  76         g2_dma->channel[chan_nr].chan_enable = 0;
  77         g2_dma->channel[chan_nr].xfer_enable = 0;
  78
  79         return 0;
  80 }
  81
  82 static int g2_xfer_dma(struct dma_channel *chan)
  83 {
  84         unsigned int chan_nr = chan->chan;
  85
  86         if (chan->sar & 31) {
  87                 printk("g2dma: unaligned source 0x%lx\n", chan->sar);
  88                 return -EINVAL;
  89         }
  90
  91         if (chan->dar & 31) {
  92                 printk("g2dma: unaligned dest 0x%lx\n", chan->dar);
  93                 return -EINVAL;
  94         }
  95
  96         /* Align the count */
  97         if (chan->count & 31)
  98                 chan->count = (chan->count + (32 - 1)) & ~(32 - 1);
  99
 100         /* Fixup destination */
 101         chan->dar += 0xa0800000;
 102
 103         /* Fixup direction */
 104         chan->mode = !chan->mode;
 105
 106         flush_icache_range((unsigned long)chan->sar, chan->count);
 107
 108         g2_disable_dma(chan);
 109
 110         g2_dma->channel[chan_nr].g2_addr   = chan->dar & 0x1fffffe0;
 111         g2_dma->channel[chan_nr].root_addr = chan->sar & 0x1fffffe0;
 112         g2_dma->channel[chan_nr].size      = (chan->count & ~31) | 0x80000000;
 113         g2_dma->channel[chan_nr].direction = chan->mode;
 114
 115         /*
 116          * bit 0 - ???
 117          * bit 1 - if set, generate a hardware event on transfer completion
 118          * bit 2 - ??? something to do with suspend?
 119          */
 120         g2_dma->channel[chan_nr].ctrl   = 5; /* ?? */
 121
 122         g2_enable_dma(chan);
 123
 124         /* debug cruft */
 125         pr_debug("count, sar, dar, mode, ctrl, chan, xfer: %ld, 0x%08lx, "
 126                  "0x%08lx, %ld, %ld, %ld, %ld\n",
 127                  g2_dma->channel[chan_nr].size,
 128                  g2_dma->channel[chan_nr].root_addr,
 129                  g2_dma->channel[chan_nr].g2_addr,
 130                  g2_dma->channel[chan_nr].direction,
 131                  g2_dma->channel[chan_nr].ctrl,
 132                  g2_dma->channel[chan_nr].chan_enable,
 133                  g2_dma->channel[chan_nr].xfer_enable);
 134
 135         return 0;
 136 }
 137
 138 static struct dma_ops g2_dma_ops = {
 139         .xfer           = g2_xfer_dma,
 140 };
 141
 142 static struct dma_info g2_dma_info = {
 143         .name           = "g2_dmac",
 144         .nr_channels    = 4,
 145         .ops            = &g2_dma_ops,
 146         .flags          = DMAC_CHANNELS_TEI_CAPABLE,
 147 };
 148
 149 static int __init g2_dma_init(void)
 150 {
 151         setup_irq(HW_EVENT_G2_DMA, &g2_dma_irq);
 152
 153         /* Magic */
 154         g2_dma->wait_state      = 27;
 155         g2_dma->magic           = 0x4659404f;
 156
 157         return register_dmac(&g2_dma_info);
 158 }
 159
 160 static void __exit g2_dma_exit(void)
 161 {
 162         free_irq(HW_EVENT_G2_DMA, 0);
 163         unregister_dmac(&g2_dma_info);
 164 }
 165
 166 subsys_initcall(g2_dma_init);
 167 module_exit(g2_dma_exit);
 168
 169 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
 170 MODULE_DESCRIPTION("G2 bus DMA driver");
 171 MODULE_LICENSE("GPL");
 172