arch/sh/drivers/pci/dma-dreamcast.c

   1 /*
   2  * arch/sh/pci/dma-dreamcast.c
   3  *
   4  * PCI DMA support for the Sega Dreamcast
   5  *
   6  * Copyright (C) 2001, 2002  M. R. Brown
   7  * Copyright (C) 2002, 2003  Paul Mundt
   8  *
   9  * This file originally bore the message (with enclosed-$):
  10  *      Id: pci.c,v 1.3 2003/05/04 19:29:46 lethal Exp
  11  *      Dreamcast PCI: Supports SEGA Broadband Adaptor only.
  12  *
  13  * This file is subject to the terms and conditions of the GNU General Public
  14  * License.  See the file "COPYING" in the main directory of this archive
  15  * for more details.
  16  */
  17
  18 #include <linux/config.h>
  19 #include <linux/sched.h>
  20 #include <linux/kernel.h>
  21 #include <linux/param.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/init.h>
  24 #include <linux/irq.h>
  25 #include <linux/pci.h>
  26 #include <linux/dma-mapping.h>
  27 #include <linux/device.h>
  28
  29 #include <asm/io.h>
  30 #include <asm/irq.h>
  31 #include <asm/mach/pci.h>
  32
  33 static int gapspci_dma_used = 0;
  34
  35 void *dreamcast_consistent_alloc(struct device *dev, size_t size,
  36                                  dma_addr_t *dma_handle, int flag)
  37 {
  38         unsigned long buf;
  39
  40         if (dev && dev->bus != &pci_bus_type)
  41                 return NULL;
  42
  43         if (gapspci_dma_used + size > GAPSPCI_DMA_SIZE)
  44                 return ERR_PTR(-EINVAL);
  45
  46         buf = GAPSPCI_DMA_BASE + gapspci_dma_used;
  47
  48         gapspci_dma_used = PAGE_ALIGN(gapspci_dma_used+size);
  49
  50         *dma_handle = (dma_addr_t)buf;
  51
  52         buf = P2SEGADDR(buf);
  53
  54         /* Flush the dcache before we hand off the buffer */
  55         dma_cache_wback_inv((void *)buf, size);
  56
  57         return (void *)buf;
  58 }
  59
  60 int dreamcast_consistent_free(struct device *dev, size_t size,
  61                          void *vaddr, dma_addr_t dma_handle)
  62 {
  63         if (dev && dev->bus != &pci_bus_type)
  64                 return -EINVAL;
  65
  66         /* XXX */
  67         gapspci_dma_used = 0;
  68
  69         return 0;
  70 }
  71