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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * arch/sh/drivers/dma/dma-pvr2.c
   4  *
   5  * NEC PowerVR 2 (Dreamcast) DMA support
   6  *
   7  * Copyright (C) 2003, 2004  Paul Mundt
   8  */
   9 #include <linux/init.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/interrupt.h>
  13 #include <mach/sysasic.h>
  14 #include <mach/dma.h>
  15 #include <asm/dma.h>
  16 #include <asm/io.h>
  17
  18 static unsigned int xfer_complete;
  19 static int count;
  20
  21 static irqreturn_t pvr2_dma_interrupt(int irq, void *dev_id)
  22 {
  23         if (get_dma_residue(PVR2_CASCADE_CHAN)) {
  24                 printk(KERN_WARNING "DMA: SH DMAC did not complete transfer "
  25                        "on channel %d, waiting..\n", PVR2_CASCADE_CHAN);
  26                 dma_wait_for_completion(PVR2_CASCADE_CHAN);
  27         }
  28
  29         if (count++ < 10)
  30                 pr_debug("Got a pvr2 dma interrupt for channel %d\n",
  31                          irq - HW_EVENT_PVR2_DMA);
  32
  33         xfer_complete = 1;
  34
  35         return IRQ_HANDLED;
  36 }
  37
  38 static int pvr2_request_dma(struct dma_channel *chan)
  39 {
  40         if (__raw_readl(PVR2_DMA_MODE) != 0)
  41                 return -EBUSY;
  42
  43         __raw_writel(0, PVR2_DMA_LMMODE0);
  44
  45         return 0;
  46 }
  47
  48 static int pvr2_get_dma_residue(struct dma_channel *chan)
  49 {
  50         return xfer_complete == 0;
  51 }
  52
  53 static int pvr2_xfer_dma(struct dma_channel *chan)
  54 {
  55         if (chan->sar || !chan->dar)
  56                 return -EINVAL;
  57
  58         xfer_complete = 0;
  59
  60         __raw_writel(chan->dar, PVR2_DMA_ADDR);
  61         __raw_writel(chan->count, PVR2_DMA_COUNT);
  62         __raw_writel(chan->mode & DMA_MODE_MASK, PVR2_DMA_MODE);
  63
  64         return 0;
  65 }
  66
  67 static struct dma_ops pvr2_dma_ops = {
  68         .request        = pvr2_request_dma,
  69         .get_residue    = pvr2_get_dma_residue,
  70         .xfer           = pvr2_xfer_dma,
  71 };
  72
  73 static struct dma_info pvr2_dma_info = {
  74         .name           = "pvr2_dmac",
  75         .nr_channels    = 1,
  76         .ops            = &pvr2_dma_ops,
  77         .flags          = DMAC_CHANNELS_TEI_CAPABLE,
  78 };
  79
  80 static int __init pvr2_dma_init(void)
  81 {
  82         if (request_irq(HW_EVENT_PVR2_DMA, pvr2_dma_interrupt, 0,
  83                         "pvr2 DMA handler", NULL))
  84                 pr_err("Failed to register pvr2 DMA handler interrupt\n");
  85         request_dma(PVR2_CASCADE_CHAN, "pvr2 cascade");
  86
  87         return register_dmac(&pvr2_dma_info);
  88 }
  89
  90 static void __exit pvr2_dma_exit(void)
  91 {
  92         free_dma(PVR2_CASCADE_CHAN);
  93         free_irq(HW_EVENT_PVR2_DMA, 0);
  94         unregister_dmac(&pvr2_dma_info);
  95 }
  96
  97 subsys_initcall(pvr2_dma_init);
  98 module_exit(pvr2_dma_exit);
  99
 100 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
 101 MODULE_DESCRIPTION("NEC PowerVR 2 DMA driver");
 102 MODULE_LICENSE("GPL v2");