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Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -04001/*
2 * Copyright 2010
3 * by Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
4 *
5 * This code provides a IOMMU for Xen PV guests with PCI passthrough.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License v2.0 as published by
9 * the Free Software Foundation
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * PV guests under Xen are running in an non-contiguous memory architecture.
17 *
18 * When PCI pass-through is utilized, this necessitates an IOMMU for
19 * translating bus (DMA) to virtual and vice-versa and also providing a
20 * mechanism to have contiguous pages for device drivers operations (say DMA
21 * operations).
22 *
23 * Specifically, under Xen the Linux idea of pages is an illusion. It
24 * assumes that pages start at zero and go up to the available memory. To
25 * help with that, the Linux Xen MMU provides a lookup mechanism to
26 * translate the page frame numbers (PFN) to machine frame numbers (MFN)
27 * and vice-versa. The MFN are the "real" frame numbers. Furthermore
28 * memory is not contiguous. Xen hypervisor stitches memory for guests
29 * from different pools, which means there is no guarantee that PFN==MFN
30 * and PFN+1==MFN+1. Lastly with Xen 4.0, pages (in debug mode) are
31 * allocated in descending order (high to low), meaning the guest might
32 * never get any MFN's under the 4GB mark.
33 *
34 */
35
Joe Perches283c0972013-06-28 03:21:41 -070036#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
37
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -040038#include <linux/bootmem.h>
39#include <linux/dma-mapping.h>
Paul Gortmaker63c97442011-07-10 13:22:07 -040040#include <linux/export.h>
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -040041#include <xen/swiotlb-xen.h>
42#include <xen/page.h>
43#include <xen/xen-ops.h>
Konrad Rzeszutek Wilkf4b2f072011-07-22 12:46:43 -040044#include <xen/hvc-console.h>
Stefano Stabellini83862cc2013-10-10 13:40:44 +000045#include <asm/dma-mapping.h>
Stefano Stabellini1b65c4e2013-10-10 13:41:10 +000046#include <asm/xen/page-coherent.h>
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -040047/*
48 * Used to do a quick range check in swiotlb_tbl_unmap_single and
49 * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
50 * API.
51 */
52
Stefano Stabellini83862cc2013-10-10 13:40:44 +000053#ifndef CONFIG_X86
54static unsigned long dma_alloc_coherent_mask(struct device *dev,
55 gfp_t gfp)
56{
57 unsigned long dma_mask = 0;
58
59 dma_mask = dev->coherent_dma_mask;
60 if (!dma_mask)
61 dma_mask = (gfp & GFP_DMA) ? DMA_BIT_MASK(24) : DMA_BIT_MASK(32);
62
63 return dma_mask;
64}
65#endif
66
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -040067static char *xen_io_tlb_start, *xen_io_tlb_end;
68static unsigned long xen_io_tlb_nslabs;
69/*
70 * Quick lookup value of the bus address of the IOTLB.
71 */
72
Konrad Rzeszutek Wilkb8b0f552012-08-21 14:49:34 -040073static u64 start_dma_addr;
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -040074
Stefano Stabellini6b42a7e2013-10-25 10:33:27 +000075static inline dma_addr_t xen_phys_to_bus(phys_addr_t paddr)
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -040076{
Justin P. Mattock6eab04a2011-04-08 19:49:08 -070077 return phys_to_machine(XPADDR(paddr)).maddr;
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -040078}
79
Stefano Stabellini6b42a7e2013-10-25 10:33:27 +000080static inline phys_addr_t xen_bus_to_phys(dma_addr_t baddr)
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -040081{
82 return machine_to_phys(XMADDR(baddr)).paddr;
83}
84
Stefano Stabellini6b42a7e2013-10-25 10:33:27 +000085static inline dma_addr_t xen_virt_to_bus(void *address)
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -040086{
87 return xen_phys_to_bus(virt_to_phys(address));
88}
89
90static int check_pages_physically_contiguous(unsigned long pfn,
91 unsigned int offset,
92 size_t length)
93{
94 unsigned long next_mfn;
95 int i;
96 int nr_pages;
97
98 next_mfn = pfn_to_mfn(pfn);
99 nr_pages = (offset + length + PAGE_SIZE-1) >> PAGE_SHIFT;
100
101 for (i = 1; i < nr_pages; i++) {
102 if (pfn_to_mfn(++pfn) != ++next_mfn)
103 return 0;
104 }
105 return 1;
106}
107
Stefano Stabellini6b42a7e2013-10-25 10:33:27 +0000108static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400109{
110 unsigned long pfn = PFN_DOWN(p);
111 unsigned int offset = p & ~PAGE_MASK;
112
113 if (offset + size <= PAGE_SIZE)
114 return 0;
115 if (check_pages_physically_contiguous(pfn, offset, size))
116 return 0;
117 return 1;
118}
119
120static int is_xen_swiotlb_buffer(dma_addr_t dma_addr)
121{
122 unsigned long mfn = PFN_DOWN(dma_addr);
123 unsigned long pfn = mfn_to_local_pfn(mfn);
124 phys_addr_t paddr;
125
126 /* If the address is outside our domain, it CAN
127 * have the same virtual address as another address
128 * in our domain. Therefore _only_ check address within our domain.
129 */
130 if (pfn_valid(pfn)) {
131 paddr = PFN_PHYS(pfn);
132 return paddr >= virt_to_phys(xen_io_tlb_start) &&
133 paddr < virt_to_phys(xen_io_tlb_end);
134 }
135 return 0;
136}
137
138static int max_dma_bits = 32;
139
140static int
141xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
142{
143 int i, rc;
144 int dma_bits;
Stefano Stabellini69908902013-10-09 16:56:32 +0000145 dma_addr_t dma_handle;
Stefano Stabellini1b65c4e2013-10-10 13:41:10 +0000146 phys_addr_t p = virt_to_phys(buf);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400147
148 dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
149
150 i = 0;
151 do {
152 int slabs = min(nslabs - i, (unsigned long)IO_TLB_SEGSIZE);
153
154 do {
155 rc = xen_create_contiguous_region(
Stefano Stabellini1b65c4e2013-10-10 13:41:10 +0000156 p + (i << IO_TLB_SHIFT),
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400157 get_order(slabs << IO_TLB_SHIFT),
Stefano Stabellini69908902013-10-09 16:56:32 +0000158 dma_bits, &dma_handle);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400159 } while (rc && dma_bits++ < max_dma_bits);
160 if (rc)
161 return rc;
162
163 i += slabs;
164 } while (i < nslabs);
165 return 0;
166}
Konrad Rzeszutek Wilk1cef36a2012-08-23 13:55:26 -0400167static unsigned long xen_set_nslabs(unsigned long nr_tbl)
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400168{
Konrad Rzeszutek Wilk1cef36a2012-08-23 13:55:26 -0400169 if (!nr_tbl) {
FUJITA Tomonori5f98ecd2011-06-05 11:47:29 +0900170 xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
171 xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
Konrad Rzeszutek Wilk1cef36a2012-08-23 13:55:26 -0400172 } else
173 xen_io_tlb_nslabs = nr_tbl;
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400174
Konrad Rzeszutek Wilk1cef36a2012-08-23 13:55:26 -0400175 return xen_io_tlb_nslabs << IO_TLB_SHIFT;
176}
Konrad Rzeszutek Wilk5bab7862012-08-23 14:03:55 -0400177
178enum xen_swiotlb_err {
179 XEN_SWIOTLB_UNKNOWN = 0,
180 XEN_SWIOTLB_ENOMEM,
181 XEN_SWIOTLB_EFIXUP
182};
183
184static const char *xen_swiotlb_error(enum xen_swiotlb_err err)
185{
186 switch (err) {
187 case XEN_SWIOTLB_ENOMEM:
188 return "Cannot allocate Xen-SWIOTLB buffer\n";
189 case XEN_SWIOTLB_EFIXUP:
190 return "Failed to get contiguous memory for DMA from Xen!\n"\
191 "You either: don't have the permissions, do not have"\
192 " enough free memory under 4GB, or the hypervisor memory"\
193 " is too fragmented!";
194 default:
195 break;
196 }
197 return "";
198}
Konrad Rzeszutek Wilkb8277602012-08-23 14:36:15 -0400199int __ref xen_swiotlb_init(int verbose, bool early)
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400200{
Konrad Rzeszutek Wilkb8277602012-08-23 14:36:15 -0400201 unsigned long bytes, order;
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400202 int rc = -ENOMEM;
Konrad Rzeszutek Wilk5bab7862012-08-23 14:03:55 -0400203 enum xen_swiotlb_err m_ret = XEN_SWIOTLB_UNKNOWN;
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400204 unsigned int repeat = 3;
205
Konrad Rzeszutek Wilk1cef36a2012-08-23 13:55:26 -0400206 xen_io_tlb_nslabs = swiotlb_nr_tbl();
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400207retry:
Konrad Rzeszutek Wilk1cef36a2012-08-23 13:55:26 -0400208 bytes = xen_set_nslabs(xen_io_tlb_nslabs);
Konrad Rzeszutek Wilkb8277602012-08-23 14:36:15 -0400209 order = get_order(xen_io_tlb_nslabs << IO_TLB_SHIFT);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400210 /*
211 * Get IO TLB memory from any location.
212 */
Konrad Rzeszutek Wilkb8277602012-08-23 14:36:15 -0400213 if (early)
214 xen_io_tlb_start = alloc_bootmem_pages(PAGE_ALIGN(bytes));
215 else {
216#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
217#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
218 while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
219 xen_io_tlb_start = (void *)__get_free_pages(__GFP_NOWARN, order);
220 if (xen_io_tlb_start)
221 break;
222 order--;
223 }
224 if (order != get_order(bytes)) {
Joe Perches283c0972013-06-28 03:21:41 -0700225 pr_warn("Warning: only able to allocate %ld MB for software IO TLB\n",
226 (PAGE_SIZE << order) >> 20);
Konrad Rzeszutek Wilkb8277602012-08-23 14:36:15 -0400227 xen_io_tlb_nslabs = SLABS_PER_PAGE << order;
228 bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
229 }
230 }
Konrad Rzeszutek Wilkf4b2f072011-07-22 12:46:43 -0400231 if (!xen_io_tlb_start) {
Konrad Rzeszutek Wilk5bab7862012-08-23 14:03:55 -0400232 m_ret = XEN_SWIOTLB_ENOMEM;
Konrad Rzeszutek Wilkf4b2f072011-07-22 12:46:43 -0400233 goto error;
234 }
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400235 xen_io_tlb_end = xen_io_tlb_start + bytes;
236 /*
237 * And replace that memory with pages under 4GB.
238 */
239 rc = xen_swiotlb_fixup(xen_io_tlb_start,
240 bytes,
241 xen_io_tlb_nslabs);
Konrad Rzeszutek Wilkf4b2f072011-07-22 12:46:43 -0400242 if (rc) {
Konrad Rzeszutek Wilkb8277602012-08-23 14:36:15 -0400243 if (early)
244 free_bootmem(__pa(xen_io_tlb_start), PAGE_ALIGN(bytes));
245 else {
246 free_pages((unsigned long)xen_io_tlb_start, order);
247 xen_io_tlb_start = NULL;
248 }
Konrad Rzeszutek Wilk5bab7862012-08-23 14:03:55 -0400249 m_ret = XEN_SWIOTLB_EFIXUP;
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400250 goto error;
Konrad Rzeszutek Wilkf4b2f072011-07-22 12:46:43 -0400251 }
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400252 start_dma_addr = xen_virt_to_bus(xen_io_tlb_start);
Konrad Rzeszutek Wilkc468bde2012-09-17 10:20:09 -0400253 if (early) {
Yinghai Luac2cbab2013-01-24 12:20:16 -0800254 if (swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs,
255 verbose))
256 panic("Cannot allocate SWIOTLB buffer");
Konrad Rzeszutek Wilkc468bde2012-09-17 10:20:09 -0400257 rc = 0;
258 } else
Konrad Rzeszutek Wilkb8277602012-08-23 14:36:15 -0400259 rc = swiotlb_late_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs);
260 return rc;
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400261error:
Konrad Rzeszutek Wilkf4b2f072011-07-22 12:46:43 -0400262 if (repeat--) {
263 xen_io_tlb_nslabs = max(1024UL, /* Min is 2MB */
264 (xen_io_tlb_nslabs >> 1));
Joe Perches283c0972013-06-28 03:21:41 -0700265 pr_info("Lowering to %luMB\n",
266 (xen_io_tlb_nslabs << IO_TLB_SHIFT) >> 20);
Konrad Rzeszutek Wilkf4b2f072011-07-22 12:46:43 -0400267 goto retry;
268 }
Joe Perches283c0972013-06-28 03:21:41 -0700269 pr_err("%s (rc:%d)\n", xen_swiotlb_error(m_ret), rc);
Konrad Rzeszutek Wilkb8277602012-08-23 14:36:15 -0400270 if (early)
271 panic("%s (rc:%d)", xen_swiotlb_error(m_ret), rc);
272 else
273 free_pages((unsigned long)xen_io_tlb_start, order);
274 return rc;
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400275}
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400276void *
277xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
Andrzej Pietrasiewiczbaa676f2012-03-27 14:28:18 +0200278 dma_addr_t *dma_handle, gfp_t flags,
279 struct dma_attrs *attrs)
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400280{
281 void *ret;
282 int order = get_order(size);
283 u64 dma_mask = DMA_BIT_MASK(32);
Konrad Rzeszutek Wilk6810df82011-08-25 16:13:54 -0400284 phys_addr_t phys;
285 dma_addr_t dev_addr;
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400286
287 /*
288 * Ignore region specifiers - the kernel's ideas of
289 * pseudo-phys memory layout has nothing to do with the
290 * machine physical layout. We can't allocate highmem
291 * because we can't return a pointer to it.
292 */
293 flags &= ~(__GFP_DMA | __GFP_HIGHMEM);
294
295 if (dma_alloc_from_coherent(hwdev, size, dma_handle, &ret))
296 return ret;
297
Stefano Stabellini1b65c4e2013-10-10 13:41:10 +0000298 /* On ARM this function returns an ioremap'ped virtual address for
299 * which virt_to_phys doesn't return the corresponding physical
300 * address. In fact on ARM virt_to_phys only works for kernel direct
301 * mapped RAM memory. Also see comment below.
302 */
303 ret = xen_alloc_coherent_pages(hwdev, size, dma_handle, flags, attrs);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400304
Konrad Rzeszutek Wilk6810df82011-08-25 16:13:54 -0400305 if (!ret)
306 return ret;
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400307
Konrad Rzeszutek Wilk6810df82011-08-25 16:13:54 -0400308 if (hwdev && hwdev->coherent_dma_mask)
Ronny Hegewaldb5031ed2012-08-31 09:57:52 +0000309 dma_mask = dma_alloc_coherent_mask(hwdev, flags);
Konrad Rzeszutek Wilk6810df82011-08-25 16:13:54 -0400310
Stefano Stabellini1b65c4e2013-10-10 13:41:10 +0000311 /* At this point dma_handle is the physical address, next we are
312 * going to set it to the machine address.
313 * Do not use virt_to_phys(ret) because on ARM it doesn't correspond
314 * to *dma_handle. */
315 phys = *dma_handle;
Konrad Rzeszutek Wilk6810df82011-08-25 16:13:54 -0400316 dev_addr = xen_phys_to_bus(phys);
317 if (((dev_addr + size - 1 <= dma_mask)) &&
318 !range_straddles_page_boundary(phys, size))
319 *dma_handle = dev_addr;
320 else {
Stefano Stabellini1b65c4e2013-10-10 13:41:10 +0000321 if (xen_create_contiguous_region(phys, order,
Stefano Stabellini69908902013-10-09 16:56:32 +0000322 fls64(dma_mask), dma_handle) != 0) {
Stefano Stabellini1b65c4e2013-10-10 13:41:10 +0000323 xen_free_coherent_pages(hwdev, size, ret, (dma_addr_t)phys, attrs);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400324 return NULL;
325 }
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400326 }
Konrad Rzeszutek Wilk6810df82011-08-25 16:13:54 -0400327 memset(ret, 0, size);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400328 return ret;
329}
330EXPORT_SYMBOL_GPL(xen_swiotlb_alloc_coherent);
331
332void
333xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
Andrzej Pietrasiewiczbaa676f2012-03-27 14:28:18 +0200334 dma_addr_t dev_addr, struct dma_attrs *attrs)
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400335{
336 int order = get_order(size);
Konrad Rzeszutek Wilk6810df82011-08-25 16:13:54 -0400337 phys_addr_t phys;
338 u64 dma_mask = DMA_BIT_MASK(32);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400339
340 if (dma_release_from_coherent(hwdev, order, vaddr))
341 return;
342
Konrad Rzeszutek Wilk6810df82011-08-25 16:13:54 -0400343 if (hwdev && hwdev->coherent_dma_mask)
344 dma_mask = hwdev->coherent_dma_mask;
345
Stefano Stabellini1b65c4e2013-10-10 13:41:10 +0000346 /* do not use virt_to_phys because on ARM it doesn't return you the
347 * physical address */
348 phys = xen_bus_to_phys(dev_addr);
Konrad Rzeszutek Wilk6810df82011-08-25 16:13:54 -0400349
350 if (((dev_addr + size - 1 > dma_mask)) ||
351 range_straddles_page_boundary(phys, size))
Stefano Stabellini1b65c4e2013-10-10 13:41:10 +0000352 xen_destroy_contiguous_region(phys, order);
Konrad Rzeszutek Wilk6810df82011-08-25 16:13:54 -0400353
Stefano Stabellini1b65c4e2013-10-10 13:41:10 +0000354 xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400355}
356EXPORT_SYMBOL_GPL(xen_swiotlb_free_coherent);
357
358
359/*
360 * Map a single buffer of the indicated size for DMA in streaming mode. The
361 * physical address to use is returned.
362 *
363 * Once the device is given the dma address, the device owns this memory until
364 * either xen_swiotlb_unmap_page or xen_swiotlb_dma_sync_single is performed.
365 */
366dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
367 unsigned long offset, size_t size,
368 enum dma_data_direction dir,
369 struct dma_attrs *attrs)
370{
Alexander Duycke05ed4d2012-10-15 10:19:39 -0700371 phys_addr_t map, phys = page_to_phys(page) + offset;
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400372 dma_addr_t dev_addr = xen_phys_to_bus(phys);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400373
374 BUG_ON(dir == DMA_NONE);
375 /*
376 * If the address happens to be in the device's DMA window,
377 * we can safely return the device addr and not worry about bounce
378 * buffering it.
379 */
380 if (dma_capable(dev, dev_addr, size) &&
Stefano Stabellini6cf05462013-10-25 10:33:25 +0000381 !range_straddles_page_boundary(phys, size) && !swiotlb_force) {
382 /* we are not interested in the dma_addr returned by
383 * xen_dma_map_page, only in the potential cache flushes executed
384 * by the function. */
385 xen_dma_map_page(dev, page, offset, size, dir, attrs);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400386 return dev_addr;
Stefano Stabellini6cf05462013-10-25 10:33:25 +0000387 }
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400388
389 /*
390 * Oh well, have to allocate and map a bounce buffer.
391 */
392 map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir);
Alexander Duycke05ed4d2012-10-15 10:19:39 -0700393 if (map == SWIOTLB_MAP_ERROR)
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400394 return DMA_ERROR_CODE;
395
Stefano Stabellini6cf05462013-10-25 10:33:25 +0000396 xen_dma_map_page(dev, pfn_to_page(map >> PAGE_SHIFT),
397 map & ~PAGE_MASK, size, dir, attrs);
Alexander Duycke05ed4d2012-10-15 10:19:39 -0700398 dev_addr = xen_phys_to_bus(map);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400399
400 /*
401 * Ensure that the address returned is DMA'ble
402 */
Konrad Rzeszutek Wilkab2a47b2011-07-22 12:51:48 -0400403 if (!dma_capable(dev, dev_addr, size)) {
Alexander Duyck61ca08c2012-10-15 10:19:44 -0700404 swiotlb_tbl_unmap_single(dev, map, size, dir);
Konrad Rzeszutek Wilkab2a47b2011-07-22 12:51:48 -0400405 dev_addr = 0;
406 }
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400407 return dev_addr;
408}
409EXPORT_SYMBOL_GPL(xen_swiotlb_map_page);
410
411/*
412 * Unmap a single streaming mode DMA translation. The dma_addr and size must
413 * match what was provided for in a previous xen_swiotlb_map_page call. All
414 * other usages are undefined.
415 *
416 * After this call, reads by the cpu to the buffer are guaranteed to see
417 * whatever the device wrote there.
418 */
419static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
Stefano Stabellini6cf05462013-10-25 10:33:25 +0000420 size_t size, enum dma_data_direction dir,
421 struct dma_attrs *attrs)
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400422{
423 phys_addr_t paddr = xen_bus_to_phys(dev_addr);
424
425 BUG_ON(dir == DMA_NONE);
426
Stefano Stabellini6cf05462013-10-25 10:33:25 +0000427 xen_dma_unmap_page(hwdev, paddr, size, dir, attrs);
428
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400429 /* NOTE: We use dev_addr here, not paddr! */
430 if (is_xen_swiotlb_buffer(dev_addr)) {
Alexander Duyck61ca08c2012-10-15 10:19:44 -0700431 swiotlb_tbl_unmap_single(hwdev, paddr, size, dir);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400432 return;
433 }
434
435 if (dir != DMA_FROM_DEVICE)
436 return;
437
438 /*
439 * phys_to_virt doesn't work with hihgmem page but we could
440 * call dma_mark_clean() with hihgmem page here. However, we
441 * are fine since dma_mark_clean() is null on POWERPC. We can
442 * make dma_mark_clean() take a physical address if necessary.
443 */
444 dma_mark_clean(phys_to_virt(paddr), size);
445}
446
447void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
448 size_t size, enum dma_data_direction dir,
449 struct dma_attrs *attrs)
450{
Stefano Stabellini6cf05462013-10-25 10:33:25 +0000451 xen_unmap_single(hwdev, dev_addr, size, dir, attrs);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400452}
453EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_page);
454
455/*
456 * Make physical memory consistent for a single streaming mode DMA translation
457 * after a transfer.
458 *
459 * If you perform a xen_swiotlb_map_page() but wish to interrogate the buffer
460 * using the cpu, yet do not wish to teardown the dma mapping, you must
461 * call this function before doing so. At the next point you give the dma
462 * address back to the card, you must first perform a
463 * xen_swiotlb_dma_sync_for_device, and then the device again owns the buffer
464 */
465static void
466xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
467 size_t size, enum dma_data_direction dir,
468 enum dma_sync_target target)
469{
470 phys_addr_t paddr = xen_bus_to_phys(dev_addr);
471
472 BUG_ON(dir == DMA_NONE);
473
Stefano Stabellini6cf05462013-10-25 10:33:25 +0000474 if (target == SYNC_FOR_CPU)
475 xen_dma_sync_single_for_cpu(hwdev, paddr, size, dir);
476
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400477 /* NOTE: We use dev_addr here, not paddr! */
Stefano Stabellini6cf05462013-10-25 10:33:25 +0000478 if (is_xen_swiotlb_buffer(dev_addr))
Alexander Duyckfbfda892012-10-15 10:19:49 -0700479 swiotlb_tbl_sync_single(hwdev, paddr, size, dir, target);
Stefano Stabellini6cf05462013-10-25 10:33:25 +0000480
481 if (target == SYNC_FOR_DEVICE)
482 xen_dma_sync_single_for_cpu(hwdev, paddr, size, dir);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400483
484 if (dir != DMA_FROM_DEVICE)
485 return;
486
487 dma_mark_clean(phys_to_virt(paddr), size);
488}
489
490void
491xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
492 size_t size, enum dma_data_direction dir)
493{
494 xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);
495}
496EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_cpu);
497
498void
499xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
500 size_t size, enum dma_data_direction dir)
501{
502 xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);
503}
504EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_device);
505
506/*
507 * Map a set of buffers described by scatterlist in streaming mode for DMA.
508 * This is the scatter-gather version of the above xen_swiotlb_map_page
509 * interface. Here the scatter gather list elements are each tagged with the
510 * appropriate dma address and length. They are obtained via
511 * sg_dma_{address,length}(SG).
512 *
513 * NOTE: An implementation may be able to use a smaller number of
514 * DMA address/length pairs than there are SG table elements.
515 * (for example via virtual mapping capabilities)
516 * The routine returns the number of addr/length pairs actually
517 * used, at most nents.
518 *
519 * Device ownership issues as mentioned above for xen_swiotlb_map_page are the
520 * same here.
521 */
522int
523xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
524 int nelems, enum dma_data_direction dir,
525 struct dma_attrs *attrs)
526{
527 struct scatterlist *sg;
528 int i;
529
530 BUG_ON(dir == DMA_NONE);
531
532 for_each_sg(sgl, sg, nelems, i) {
533 phys_addr_t paddr = sg_phys(sg);
534 dma_addr_t dev_addr = xen_phys_to_bus(paddr);
535
536 if (swiotlb_force ||
537 !dma_capable(hwdev, dev_addr, sg->length) ||
538 range_straddles_page_boundary(paddr, sg->length)) {
Alexander Duycke05ed4d2012-10-15 10:19:39 -0700539 phys_addr_t map = swiotlb_tbl_map_single(hwdev,
540 start_dma_addr,
541 sg_phys(sg),
542 sg->length,
543 dir);
544 if (map == SWIOTLB_MAP_ERROR) {
Stefano Stabellini783d0282013-10-25 10:33:26 +0000545 dev_warn(hwdev, "swiotlb buffer is full\n");
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400546 /* Don't panic here, we expect map_sg users
547 to do proper error handling. */
548 xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
549 attrs);
Stefano Stabellini781575c2013-08-05 17:30:48 +0100550 sg_dma_len(sgl) = 0;
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400551 return DMA_ERROR_CODE;
552 }
Alexander Duycke05ed4d2012-10-15 10:19:39 -0700553 sg->dma_address = xen_phys_to_bus(map);
Stefano Stabellini6cf05462013-10-25 10:33:25 +0000554 } else {
555 /* we are not interested in the dma_addr returned by
556 * xen_dma_map_page, only in the potential cache flushes executed
557 * by the function. */
558 xen_dma_map_page(hwdev, pfn_to_page(paddr >> PAGE_SHIFT),
559 paddr & ~PAGE_MASK,
560 sg->length,
561 dir,
562 attrs);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400563 sg->dma_address = dev_addr;
Stefano Stabellini6cf05462013-10-25 10:33:25 +0000564 }
Stefano Stabellini781575c2013-08-05 17:30:48 +0100565 sg_dma_len(sg) = sg->length;
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400566 }
567 return nelems;
568}
569EXPORT_SYMBOL_GPL(xen_swiotlb_map_sg_attrs);
570
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400571/*
572 * Unmap a set of streaming mode DMA translations. Again, cpu read rules
573 * concerning calls here are the same as for swiotlb_unmap_page() above.
574 */
575void
576xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
577 int nelems, enum dma_data_direction dir,
578 struct dma_attrs *attrs)
579{
580 struct scatterlist *sg;
581 int i;
582
583 BUG_ON(dir == DMA_NONE);
584
585 for_each_sg(sgl, sg, nelems, i)
Stefano Stabellini6cf05462013-10-25 10:33:25 +0000586 xen_unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir, attrs);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400587
588}
589EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_sg_attrs);
590
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400591/*
592 * Make physical memory consistent for a set of streaming mode DMA translations
593 * after a transfer.
594 *
595 * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
596 * and usage.
597 */
598static void
599xen_swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
600 int nelems, enum dma_data_direction dir,
601 enum dma_sync_target target)
602{
603 struct scatterlist *sg;
604 int i;
605
606 for_each_sg(sgl, sg, nelems, i)
607 xen_swiotlb_sync_single(hwdev, sg->dma_address,
Stefano Stabellini781575c2013-08-05 17:30:48 +0100608 sg_dma_len(sg), dir, target);
Konrad Rzeszutek Wilkb0971862010-05-11 10:05:49 -0400609}
610
611void
612xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
613 int nelems, enum dma_data_direction dir)
614{
615 xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);
616}
617EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_cpu);
618
619void
620xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
621 int nelems, enum dma_data_direction dir)
622{
623 xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);
624}
625EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_device);
626
627int
628xen_swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
629{
630 return !dma_addr;
631}
632EXPORT_SYMBOL_GPL(xen_swiotlb_dma_mapping_error);
633
634/*
635 * Return whether the given device DMA address mask can be supported
636 * properly. For example, if your device can only drive the low 24-bits
637 * during bus mastering, then you would pass 0x00ffffff as the mask to
638 * this function.
639 */
640int
641xen_swiotlb_dma_supported(struct device *hwdev, u64 mask)
642{
643 return xen_virt_to_bus(xen_io_tlb_end - 1) <= mask;
644}
645EXPORT_SYMBOL_GPL(xen_swiotlb_dma_supported);
Stefano Stabellinieb1ddc02013-10-09 16:56:33 +0000646
647int
648xen_swiotlb_set_dma_mask(struct device *dev, u64 dma_mask)
649{
650 if (!dev->dma_mask || !xen_swiotlb_dma_supported(dev, dma_mask))
651 return -EIO;
652
653 *dev->dma_mask = dma_mask;
654
655 return 0;
656}
657EXPORT_SYMBOL_GPL(xen_swiotlb_set_dma_mask);