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d666cd02 KC |
1 | /* |
2 | * This file is subject to the terms and conditions of the GNU General Public | |
3 | * License. See the file "COPYING" in the main directory of this archive | |
4 | * for more details. | |
5 | * | |
6 | * Copyright (C) 2014 Kevin Cernekee <cernekee@gmail.com> | |
7 | */ | |
8 | ||
9 | #include <linux/device.h> | |
10 | #include <linux/dma-direction.h> | |
11 | #include <linux/dma-mapping.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/mm.h> | |
14 | #include <linux/of.h> | |
15 | #include <linux/pci.h> | |
16 | #include <linux/types.h> | |
17 | #include <dma-coherence.h> | |
18 | ||
19 | /* | |
20 | * BCM3384 has configurable address translation windows which allow the | |
21 | * peripherals' DMA addresses to be different from the Zephyr-visible | |
22 | * physical addresses. e.g. usb_dma_addr = zephyr_pa ^ 0x08000000 | |
23 | * | |
24 | * If our DT "memory" node has a "dma-xor-mask" property we will enable this | |
25 | * translation using the provided offset. | |
26 | */ | |
27 | static u32 bcm3384_dma_xor_mask; | |
28 | static u32 bcm3384_dma_xor_limit = 0xffffffff; | |
29 | ||
30 | /* | |
31 | * PCI collapses the memory hole at 0x10000000 - 0x1fffffff. | |
32 | * On systems with a dma-xor-mask, this range is guaranteed to live above | |
33 | * the dma-xor-limit. | |
34 | */ | |
35 | #define BCM3384_MEM_HOLE_PA 0x10000000 | |
36 | #define BCM3384_MEM_HOLE_SIZE 0x10000000 | |
37 | ||
38 | static dma_addr_t bcm3384_phys_to_dma(struct device *dev, phys_addr_t pa) | |
39 | { | |
40 | if (dev && dev_is_pci(dev) && | |
41 | pa >= (BCM3384_MEM_HOLE_PA + BCM3384_MEM_HOLE_SIZE)) | |
42 | return pa - BCM3384_MEM_HOLE_SIZE; | |
43 | if (pa <= bcm3384_dma_xor_limit) | |
44 | return pa ^ bcm3384_dma_xor_mask; | |
45 | return pa; | |
46 | } | |
47 | ||
48 | dma_addr_t plat_map_dma_mem(struct device *dev, void *addr, size_t size) | |
49 | { | |
50 | return bcm3384_phys_to_dma(dev, virt_to_phys(addr)); | |
51 | } | |
52 | ||
53 | dma_addr_t plat_map_dma_mem_page(struct device *dev, struct page *page) | |
54 | { | |
55 | return bcm3384_phys_to_dma(dev, page_to_phys(page)); | |
56 | } | |
57 | ||
58 | unsigned long plat_dma_addr_to_phys(struct device *dev, dma_addr_t dma_addr) | |
59 | { | |
60 | if (dev && dev_is_pci(dev) && | |
61 | dma_addr >= BCM3384_MEM_HOLE_PA) | |
62 | return dma_addr + BCM3384_MEM_HOLE_SIZE; | |
63 | if ((dma_addr ^ bcm3384_dma_xor_mask) <= bcm3384_dma_xor_limit) | |
64 | return dma_addr ^ bcm3384_dma_xor_mask; | |
65 | return dma_addr; | |
66 | } | |
67 | ||
68 | static int __init bcm3384_init_dma_xor(void) | |
69 | { | |
70 | struct device_node *np = of_find_node_by_type(NULL, "memory"); | |
71 | ||
72 | if (!np) | |
73 | return 0; | |
74 | ||
75 | of_property_read_u32(np, "dma-xor-mask", &bcm3384_dma_xor_mask); | |
76 | of_property_read_u32(np, "dma-xor-limit", &bcm3384_dma_xor_limit); | |
77 | ||
78 | of_node_put(np); | |
79 | return 0; | |
80 | } | |
81 | arch_initcall(bcm3384_init_dma_xor); |