xref: /OK3568_Linux_fs/kernel/arch/mips/sgi-ip32/ip32-dma.c (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun  * Copyright (C) 2006  Ralf Baechle <ralf@linux-mips.org>
4*4882a593Smuzhiyun  */
5*4882a593Smuzhiyun #include <linux/dma-direct.h>
6*4882a593Smuzhiyun #include <asm/ip32/crime.h>
7*4882a593Smuzhiyun 
8*4882a593Smuzhiyun /*
9*4882a593Smuzhiyun  * Few notes.
10*4882a593Smuzhiyun  * 1. CPU sees memory as two chunks: 0-256M@0x0, and the rest @0x40000000+256M
11*4882a593Smuzhiyun  * 2. PCI sees memory as one big chunk @0x0 (or we could use 0x40000000 for
12*4882a593Smuzhiyun  *    native-endian)
13*4882a593Smuzhiyun  * 3. All other devices see memory as one big chunk at 0x40000000
14*4882a593Smuzhiyun  * 4. Non-PCI devices will pass NULL as struct device*
15*4882a593Smuzhiyun  *
16*4882a593Smuzhiyun  * Thus we translate differently, depending on device.
17*4882a593Smuzhiyun  */
18*4882a593Smuzhiyun 
19*4882a593Smuzhiyun #define RAM_OFFSET_MASK 0x3fffffffUL
20*4882a593Smuzhiyun 
phys_to_dma(struct device * dev,phys_addr_t paddr)21*4882a593Smuzhiyun dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
22*4882a593Smuzhiyun {
23*4882a593Smuzhiyun 	dma_addr_t dma_addr = paddr & RAM_OFFSET_MASK;
24*4882a593Smuzhiyun 
25*4882a593Smuzhiyun 	if (!dev)
26*4882a593Smuzhiyun 		dma_addr += CRIME_HI_MEM_BASE;
27*4882a593Smuzhiyun 	return dma_addr;
28*4882a593Smuzhiyun }
29*4882a593Smuzhiyun 
dma_to_phys(struct device * dev,dma_addr_t dma_addr)30*4882a593Smuzhiyun phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr)
31*4882a593Smuzhiyun {
32*4882a593Smuzhiyun 	phys_addr_t paddr = dma_addr & RAM_OFFSET_MASK;
33*4882a593Smuzhiyun 
34*4882a593Smuzhiyun 	if (dma_addr >= 256*1024*1024)
35*4882a593Smuzhiyun 		paddr += CRIME_HI_MEM_BASE;
36*4882a593Smuzhiyun 	return paddr;
37*4882a593Smuzhiyun }
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