1/*
2 * Contains routines needed to support swiotlb for ppc.
3 *
4 * Copyright (C) 2009-2010 Freescale Semiconductor, Inc.
5 * Author: Becky Bruce
6 *
7 * This program is free software; you can redistribute  it and/or modify it
8 * under  the terms of  the GNU General  Public License as published by the
9 * Free Software Foundation;  either version 2 of the  License, or (at your
10 * option) any later version.
11 *
12 */
13
14#include <linux/dma-mapping.h>
15#include <linux/memblock.h>
16#include <linux/pfn.h>
17#include <linux/of_platform.h>
18#include <linux/platform_device.h>
19#include <linux/pci.h>
20
21#include <asm/machdep.h>
22#include <asm/swiotlb.h>
23#include <asm/dma.h>
24
25unsigned int ppc_swiotlb_enable;
26
27static u64 swiotlb_powerpc_get_required(struct device *dev)
28{
29	u64 end, mask, max_direct_dma_addr = dev->archdata.max_direct_dma_addr;
30
31	end = memblock_end_of_DRAM();
32	if (max_direct_dma_addr && end > max_direct_dma_addr)
33		end = max_direct_dma_addr;
34	end += get_dma_offset(dev);
35
36	mask = 1ULL << (fls64(end) - 1);
37	mask += mask - 1;
38
39	return mask;
40}
41
42/*
43 * At the moment, all platforms that use this code only require
44 * swiotlb to be used if we're operating on HIGHMEM.  Since
45 * we don't ever call anything other than map_sg, unmap_sg,
46 * map_page, and unmap_page on highmem, use normal dma_ops
47 * for everything else.
48 */
49struct dma_map_ops swiotlb_dma_ops = {
50	.alloc = __dma_direct_alloc_coherent,
51	.free = __dma_direct_free_coherent,
52	.mmap = dma_direct_mmap_coherent,
53	.map_sg = swiotlb_map_sg_attrs,
54	.unmap_sg = swiotlb_unmap_sg_attrs,
55	.dma_supported = swiotlb_dma_supported,
56	.map_page = swiotlb_map_page,
57	.unmap_page = swiotlb_unmap_page,
58	.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
59	.sync_single_for_device = swiotlb_sync_single_for_device,
60	.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
61	.sync_sg_for_device = swiotlb_sync_sg_for_device,
62	.mapping_error = swiotlb_dma_mapping_error,
63	.get_required_mask = swiotlb_powerpc_get_required,
64};
65
66void pci_dma_dev_setup_swiotlb(struct pci_dev *pdev)
67{
68	struct pci_controller *hose;
69	struct dev_archdata *sd;
70
71	hose = pci_bus_to_host(pdev->bus);
72	sd = &pdev->dev.archdata;
73	sd->max_direct_dma_addr =
74		hose->dma_window_base_cur + hose->dma_window_size;
75}
76
77static int ppc_swiotlb_bus_notify(struct notifier_block *nb,
78				  unsigned long action, void *data)
79{
80	struct device *dev = data;
81	struct dev_archdata *sd;
82
83	/* We are only intereted in device addition */
84	if (action != BUS_NOTIFY_ADD_DEVICE)
85		return 0;
86
87	sd = &dev->archdata;
88	sd->max_direct_dma_addr = 0;
89
90	/* May need to bounce if the device can't address all of DRAM */
91	if ((dma_get_mask(dev) + 1) < memblock_end_of_DRAM())
92		set_dma_ops(dev, &swiotlb_dma_ops);
93
94	return NOTIFY_DONE;
95}
96
97static struct notifier_block ppc_swiotlb_plat_bus_notifier = {
98	.notifier_call = ppc_swiotlb_bus_notify,
99	.priority = 0,
100};
101
102int __init swiotlb_setup_bus_notifier(void)
103{
104	bus_register_notifier(&platform_bus_type,
105			      &ppc_swiotlb_plat_bus_notifier);
106	return 0;
107}
108
109void __init swiotlb_detect_4g(void)
110{
111	if ((memblock_end_of_DRAM() - 1) > 0xffffffff) {
112		ppc_swiotlb_enable = 1;
113#ifdef CONFIG_ZONE_DMA32
114		limit_zone_pfn(ZONE_DMA32, (1ULL << 32) >> PAGE_SHIFT);
115#endif
116	}
117}
118
119static int __init check_swiotlb_enabled(void)
120{
121	if (ppc_swiotlb_enable)
122		swiotlb_print_info();
123	else
124		swiotlb_free();
125
126	return 0;
127}
128subsys_initcall(check_swiotlb_enabled);
129