ip32-dma.c 949 B

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  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. * Few notes.
  9. * 1. CPU sees memory as two chunks: 0-256M@0x0, and the rest @0x40000000+256M
  10. * 2. PCI sees memory as one big chunk @0x0 (or we could use 0x40000000 for
  11. * native-endian)
  12. * 3. All other devices see memory as one big chunk at 0x40000000
  13. * 4. Non-PCI devices will pass NULL as struct device*
  14. *
  15. * Thus we translate differently, depending on device.
  16. */
  17. #define RAM_OFFSET_MASK 0x3fffffffUL
  18. dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
  19. {
  20. dma_addr_t dma_addr = paddr & RAM_OFFSET_MASK;
  21. if (!dev)
  22. dma_addr += CRIME_HI_MEM_BASE;
  23. return dma_addr;
  24. }
  25. phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr)
  26. {
  27. phys_addr_t paddr = dma_addr & RAM_OFFSET_MASK;
  28. if (dma_addr >= 256*1024*1024)
  29. paddr += CRIME_HI_MEM_BASE;
  30. return paddr;
  31. }