LXR linux/arch/mips/sgi-ip32/ip32-dma.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) 2006  Ralf Baechle <ralf@linux-mips.org>
   4 */
   5#include <linux/dma-direct.h>
   6#include <asm/ip32/crime.h>
   7
   8/*
   9 * Few notes.
  10 * 1. CPU sees memory as two chunks: 0-256M@0x0, and the rest @0x40000000+256M
  11 * 2. PCI sees memory as one big chunk @0x0 (or we could use 0x40000000 for
  12 *    native-endian)
  13 * 3. All other devices see memory as one big chunk at 0x40000000
  14 * 4. Non-PCI devices will pass NULL as struct device*
  15 *
  16 * Thus we translate differently, depending on device.
  17 */
  18
  19#define RAM_OFFSET_MASK 0x3fffffffUL
  20
  21dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
  22{
  23        dma_addr_t dma_addr = paddr & RAM_OFFSET_MASK;
  24
  25        if (!dev)
  26                dma_addr += CRIME_HI_MEM_BASE;
  27        return dma_addr;
  28}
  29
  30phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr)
  31{
  32        phys_addr_t paddr = dma_addr & RAM_OFFSET_MASK;
  33
  34        if (dma_addr >= 256*1024*1024)
  35                paddr += CRIME_HI_MEM_BASE;
  36        return paddr;
  37}
  38