| Kevin Cernekee | d666cd0 | 2014-10-20 21:28:05 -0700 | [diff] [blame^] | 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); |