arch/sh/drivers/dma/dma-pvr2.c

   1 /*
   2  * arch/sh/boards/dreamcast/dma-pvr2.c
   3  *
   4  * NEC PowerVR 2 (Dreamcast) 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 #include <asm/mach/sysasic.h>
  17 #include <asm/mach/dma.h>
  18 #include <asm/dma.h>
  19 #include <asm/io.h>
  20
  21 static unsigned int xfer_complete = 0;
  22 static int count = 0;
  23
  24 static irqreturn_t pvr2_dma_interrupt(int irq, void *dev_id, struct pt_regs *regs)
  25 {
  26         if (get_dma_residue(PVR2_CASCADE_CHAN)) {
  27                 printk(KERN_WARNING "DMA: SH DMAC did not complete transfer "
  28                        "on channel %d, waiting..\n", PVR2_CASCADE_CHAN);
  29                 dma_wait_for_completion(PVR2_CASCADE_CHAN);
  30         }
  31
  32         if (count++ < 10)
  33                 pr_debug("Got a pvr2 dma interrupt for channel %d\n",
  34                          irq - HW_EVENT_PVR2_DMA);
  35
  36         xfer_complete = 1;
  37
  38         return IRQ_HANDLED;
  39 }
  40
  41 static int pvr2_request_dma(struct dma_channel *chan)
  42 {
  43         if (ctrl_inl(PVR2_DMA_MODE) != 0)
  44                 return -EBUSY;
  45
  46         ctrl_outl(0, PVR2_DMA_LMMODE0);
  47
  48         return 0;
  49 }
  50
  51 static int pvr2_get_dma_residue(struct dma_channel *chan)
  52 {
  53         return xfer_complete == 0;
  54 }
  55
  56 static int pvr2_xfer_dma(struct dma_channel *chan)
  57 {
  58         if (chan->sar || !chan->dar)
  59                 return -EINVAL;
  60
  61         xfer_complete = 0;
  62
  63         ctrl_outl(chan->dar, PVR2_DMA_ADDR);
  64         ctrl_outl(chan->count, PVR2_DMA_COUNT);
  65         ctrl_outl(chan->mode & DMA_MODE_MASK, PVR2_DMA_MODE);
  66
  67         return 0;
  68 }
  69
  70 static struct irqaction pvr2_dma_irq = {
  71         .name           = "pvr2 DMA handler",
  72         .handler        = pvr2_dma_interrupt,
  73         .flags          = SA_INTERRUPT,
  74 };
  75
  76 static struct dma_ops pvr2_dma_ops = {
  77         .request        = pvr2_request_dma,
  78         .get_residue    = pvr2_get_dma_residue,
  79         .xfer           = pvr2_xfer_dma,
  80 };
  81
  82 static struct dma_info pvr2_dma_info = {
  83         .name           = "PowerVR 2 DMA",
  84         .nr_channels    = 1,
  85         .ops            = &pvr2_dma_ops,
  86         .flags          = DMAC_CHANNELS_TEI_CAPABLE,
  87 };
  88
  89 static int __init pvr2_dma_init(void)
  90 {
  91         setup_irq(HW_EVENT_PVR2_DMA, &pvr2_dma_irq);
  92         request_dma(PVR2_CASCADE_CHAN, "pvr2 cascade");
  93
  94         return register_dmac(&pvr2_dma_info);
  95 }
  96
  97 static void __exit pvr2_dma_exit(void)
  98 {
  99         free_dma(PVR2_CASCADE_CHAN);
 100         free_irq(HW_EVENT_PVR2_DMA, 0);
 101 }
 102
 103 subsys_initcall(pvr2_dma_init);
 104 module_exit(pvr2_dma_exit);
 105
 106 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
 107 MODULE_DESCRIPTION("NEC PowerVR 2 DMA driver");
 108 MODULE_LICENSE("GPL");
 109