arch/sh/drivers/dma/dma-g2.c

   1 /*
   2  * arch/sh/drivers/dma/dma-g2.c
   3  *
   4  * G2 bus DMA support
   5  *
   6  * Copyright (C) 2003 - 2006  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 #include <asm/cacheflush.h>
  17 #include <mach/sysasic.h>
  18 #include <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 #define g2_bytes_remaining(i) \
  51         ((g2_dma->channel[i].size - \
  52           g2_dma->status[i].size) & 0x0fffffff)
  53
  54 static irqreturn_t g2_dma_interrupt(int irq, void *dev_id)
  55 {
  56         int i;
  57
  58         for (i = 0; i < G2_NR_DMA_CHANNELS; i++) {
  59                 if (g2_dma->status[i].status & 0x20000000) {
  60                         unsigned int bytes = g2_bytes_remaining(i);
  61
  62                         if (likely(bytes == 0)) {
  63                                 struct dma_info *info = dev_id;
  64                                 struct dma_channel *chan = info->channels + i;
  65
  66                                 wake_up(&chan->wait_queue);
  67
  68                                 return IRQ_HANDLED;
  69                         }
  70                 }
  71         }
  72
  73         return IRQ_NONE;
  74 }
  75
  76 static int g2_enable_dma(struct dma_channel *chan)
  77 {
  78         unsigned int chan_nr = chan->chan;
  79
  80         g2_dma->channel[chan_nr].chan_enable = 1;
  81         g2_dma->channel[chan_nr].xfer_enable = 1;
  82
  83         return 0;
  84 }
  85
  86 static int g2_disable_dma(struct dma_channel *chan)
  87 {
  88         unsigned int chan_nr = chan->chan;
  89
  90         g2_dma->channel[chan_nr].chan_enable = 0;
  91         g2_dma->channel[chan_nr].xfer_enable = 0;
  92
  93         return 0;
  94 }
  95
  96 static int g2_xfer_dma(struct dma_channel *chan)
  97 {
  98         unsigned int chan_nr = chan->chan;
  99
 100         if (chan->sar & 31) {
 101                 printk("g2dma: unaligned source 0x%lx\n", chan->sar);
 102                 return -EINVAL;
 103         }
 104
 105         if (chan->dar & 31) {
 106                 printk("g2dma: unaligned dest 0x%lx\n", chan->dar);
 107                 return -EINVAL;
 108         }
 109
 110         /* Align the count */
 111         if (chan->count & 31)
 112                 chan->count = (chan->count + (32 - 1)) & ~(32 - 1);
 113
 114         /* Fixup destination */
 115         chan->dar += 0xa0800000;
 116
 117         /* Fixup direction */
 118         chan->mode = !chan->mode;
 119
 120         flush_icache_range((unsigned long)chan->sar, chan->count);
 121
 122         g2_disable_dma(chan);
 123
 124         g2_dma->channel[chan_nr].g2_addr   = chan->dar & 0x1fffffe0;
 125         g2_dma->channel[chan_nr].root_addr = chan->sar & 0x1fffffe0;
 126         g2_dma->channel[chan_nr].size      = (chan->count & ~31) | 0x80000000;
 127         g2_dma->channel[chan_nr].direction = chan->mode;
 128
 129         /*
 130          * bit 0 - ???
 131          * bit 1 - if set, generate a hardware event on transfer completion
 132          * bit 2 - ??? something to do with suspend?
 133          */
 134         g2_dma->channel[chan_nr].ctrl   = 5; /* ?? */
 135
 136         g2_enable_dma(chan);
 137
 138         /* debug cruft */
 139         pr_debug("count, sar, dar, mode, ctrl, chan, xfer: %ld, 0x%08lx, "
 140                  "0x%08lx, %ld, %ld, %ld, %ld\n",
 141                  g2_dma->channel[chan_nr].size,
 142                  g2_dma->channel[chan_nr].root_addr,
 143                  g2_dma->channel[chan_nr].g2_addr,
 144                  g2_dma->channel[chan_nr].direction,
 145                  g2_dma->channel[chan_nr].ctrl,
 146                  g2_dma->channel[chan_nr].chan_enable,
 147                  g2_dma->channel[chan_nr].xfer_enable);
 148
 149         return 0;
 150 }
 151
 152 static int g2_get_residue(struct dma_channel *chan)
 153 {
 154         return g2_bytes_remaining(chan->chan);
 155 }
 156
 157 static struct dma_ops g2_dma_ops = {
 158         .xfer           = g2_xfer_dma,
 159         .get_residue    = g2_get_residue,
 160 };
 161
 162 static struct dma_info g2_dma_info = {
 163         .name           = "g2_dmac",
 164         .nr_channels    = 4,
 165         .ops            = &g2_dma_ops,
 166         .flags          = DMAC_CHANNELS_TEI_CAPABLE,
 167 };
 168
 169 static int __init g2_dma_init(void)
 170 {
 171         int ret;
 172
 173         ret = request_irq(HW_EVENT_G2_DMA, g2_dma_interrupt, IRQF_DISABLED,
 174                           "g2 DMA handler", &g2_dma_info);
 175         if (unlikely(ret))
 176                 return -EINVAL;
 177
 178         /* Magic */
 179         g2_dma->wait_state      = 27;
 180         g2_dma->magic           = 0x4659404f;
 181
 182         ret = register_dmac(&g2_dma_info);
 183         if (unlikely(ret != 0))
 184                 free_irq(HW_EVENT_G2_DMA, 0);
 185
 186         return ret;
 187 }
 188
 189 static void __exit g2_dma_exit(void)
 190 {
 191         free_irq(HW_EVENT_G2_DMA, 0);
 192         unregister_dmac(&g2_dma_info);
 193 }
 194
 195 subsys_initcall(g2_dma_init);
 196 module_exit(g2_dma_exit);
 197
 198 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
 199 MODULE_DESCRIPTION("G2 bus DMA driver");
 200 MODULE_LICENSE("GPL");