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Shannon Nelson2ed6dc32007-10-16 01:27:42 -07001/*
2 * Intel I/OAT DMA Linux driver
Maciej Sosnowski211a22c2009-02-26 11:05:43 +01003 * Copyright(c) 2007 - 2009 Intel Corporation.
Shannon Nelson2ed6dc32007-10-16 01:27:42 -07004 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms and conditions of the GNU General Public License,
7 * version 2, as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
12 * more details.
13 *
Shannon Nelson2ed6dc32007-10-16 01:27:42 -070014 * The full GNU General Public License is included in this distribution in
15 * the file called "COPYING".
16 *
17 */
18
19#include <linux/kernel.h>
20#include <linux/pci.h>
21#include <linux/smp.h>
22#include <linux/interrupt.h>
23#include <linux/dca.h>
24
25/* either a kernel change is needed, or we need something like this in kernel */
26#ifndef CONFIG_SMP
27#include <asm/smp.h>
28#undef cpu_physical_id
29#define cpu_physical_id(cpu) (cpuid_ebx(1) >> 24)
30#endif
31
Dan Williams584ec222009-07-28 14:32:12 -070032#include "dma.h"
33#include "registers.h"
Shannon Nelson2ed6dc32007-10-16 01:27:42 -070034
35/*
Maciej Sosnowski7f1b3582008-07-22 17:30:57 -070036 * Bit 7 of a tag map entry is the "valid" bit, if it is set then bits 0:6
Shannon Nelson2ed6dc32007-10-16 01:27:42 -070037 * contain the bit number of the APIC ID to map into the DCA tag. If the valid
38 * bit is not set, then the value must be 0 or 1 and defines the bit in the tag.
39 */
40#define DCA_TAG_MAP_VALID 0x80
41
Maciej Sosnowski7f1b3582008-07-22 17:30:57 -070042#define DCA3_TAG_MAP_BIT_TO_INV 0x80
43#define DCA3_TAG_MAP_BIT_TO_SEL 0x40
44#define DCA3_TAG_MAP_LITERAL_VAL 0x1
45
46#define DCA_TAG_MAP_MASK 0xDF
47
Maciej Sosnowski49bc4632009-02-26 11:04:23 +010048/* expected tag map bytes for I/OAT ver.2 */
49#define DCA2_TAG_MAP_BYTE0 0x80
50#define DCA2_TAG_MAP_BYTE1 0x0
51#define DCA2_TAG_MAP_BYTE2 0x81
52#define DCA2_TAG_MAP_BYTE3 0x82
53#define DCA2_TAG_MAP_BYTE4 0x82
54
55/* verify if tag map matches expected values */
56static inline int dca2_tag_map_valid(u8 *tag_map)
57{
58 return ((tag_map[0] == DCA2_TAG_MAP_BYTE0) &&
59 (tag_map[1] == DCA2_TAG_MAP_BYTE1) &&
60 (tag_map[2] == DCA2_TAG_MAP_BYTE2) &&
61 (tag_map[3] == DCA2_TAG_MAP_BYTE3) &&
62 (tag_map[4] == DCA2_TAG_MAP_BYTE4));
63}
64
Shannon Nelson2ed6dc32007-10-16 01:27:42 -070065/*
66 * "Legacy" DCA systems do not implement the DCA register set in the
67 * I/OAT device. Software needs direct support for their tag mappings.
68 */
69
70#define APICID_BIT(x) (DCA_TAG_MAP_VALID | (x))
71#define IOAT_TAG_MAP_LEN 8
72
Shannon Nelson2ed6dc32007-10-16 01:27:42 -070073/* pack PCI B/D/F into a u16 */
74static inline u16 dcaid_from_pcidev(struct pci_dev *pci)
75{
76 return (pci->bus->number << 8) | pci->devfn;
77}
78
Shannon Nelson5149fd02007-10-18 03:07:13 -070079static int dca_enabled_in_bios(struct pci_dev *pdev)
Shannon Nelson2ed6dc32007-10-16 01:27:42 -070080{
81 /* CPUID level 9 returns DCA configuration */
82 /* Bit 0 indicates DCA enabled by the BIOS */
83 unsigned long cpuid_level_9;
84 int res;
85
86 cpuid_level_9 = cpuid_eax(9);
87 res = test_bit(0, &cpuid_level_9);
88 if (!res)
Dan Williamse22dde92009-11-17 11:34:31 -070089 dev_dbg(&pdev->dev, "DCA is disabled in BIOS\n");
Shannon Nelson2ed6dc32007-10-16 01:27:42 -070090
91 return res;
92}
93
Dan Williams228c4f52009-11-19 17:07:10 -070094int system_has_dca_enabled(struct pci_dev *pdev)
Shannon Nelson2ed6dc32007-10-16 01:27:42 -070095{
96 if (boot_cpu_has(X86_FEATURE_DCA))
Shannon Nelson5149fd02007-10-18 03:07:13 -070097 return dca_enabled_in_bios(pdev);
Shannon Nelson2ed6dc32007-10-16 01:27:42 -070098
Dan Williamse22dde92009-11-17 11:34:31 -070099 dev_dbg(&pdev->dev, "boot cpu doesn't have X86_FEATURE_DCA\n");
Shannon Nelson2ed6dc32007-10-16 01:27:42 -0700100 return 0;
101}
102
103struct ioat_dca_slot {
104 struct pci_dev *pdev; /* requester device */
105 u16 rid; /* requester id, as used by IOAT */
106};
107
108#define IOAT_DCA_MAX_REQ 6
Maciej Sosnowski7f1b3582008-07-22 17:30:57 -0700109#define IOAT3_DCA_MAX_REQ 2
Shannon Nelson2ed6dc32007-10-16 01:27:42 -0700110
111struct ioat_dca_priv {
112 void __iomem *iobase;
Al Viro53a0c982008-03-29 03:08:08 +0000113 void __iomem *dca_base;
Shannon Nelson2ed6dc32007-10-16 01:27:42 -0700114 int max_requesters;
115 int requester_count;
116 u8 tag_map[IOAT_TAG_MAP_LEN];
117 struct ioat_dca_slot req_slots[0];
118};
119
Maciej Sosnowski7f1b3582008-07-22 17:30:57 -0700120static int ioat_dca_dev_managed(struct dca_provider *dca,
121 struct device *dev)
122{
123 struct ioat_dca_priv *ioatdca = dca_priv(dca);
124 struct pci_dev *pdev;
125 int i;
126
127 pdev = to_pci_dev(dev);
128 for (i = 0; i < ioatdca->max_requesters; i++) {
129 if (ioatdca->req_slots[i].pdev == pdev)
130 return 1;
131 }
132 return 0;
133}
134
Dave Jiang3372de52015-08-11 08:48:55 -0700135static int ioat_dca_add_requester(struct dca_provider *dca, struct device *dev)
Maciej Sosnowski7f1b3582008-07-22 17:30:57 -0700136{
137 struct ioat_dca_priv *ioatdca = dca_priv(dca);
138 struct pci_dev *pdev;
139 int i;
140 u16 id;
141 u16 global_req_table;
142
143 /* This implementation only supports PCI-Express */
Yijing Wang1fde2542013-12-05 19:31:18 +0800144 if (!dev_is_pci(dev))
Maciej Sosnowski7f1b3582008-07-22 17:30:57 -0700145 return -ENODEV;
146 pdev = to_pci_dev(dev);
147 id = dcaid_from_pcidev(pdev);
148
149 if (ioatdca->requester_count == ioatdca->max_requesters)
150 return -ENODEV;
151
152 for (i = 0; i < ioatdca->max_requesters; i++) {
153 if (ioatdca->req_slots[i].pdev == NULL) {
154 /* found an empty slot */
155 ioatdca->requester_count++;
156 ioatdca->req_slots[i].pdev = pdev;
157 ioatdca->req_slots[i].rid = id;
158 global_req_table =
159 readw(ioatdca->dca_base + IOAT3_DCA_GREQID_OFFSET);
160 writel(id | IOAT_DCA_GREQID_VALID,
161 ioatdca->iobase + global_req_table + (i * 4));
162 return i;
163 }
164 }
165 /* Error, ioatdma->requester_count is out of whack */
166 return -EFAULT;
167}
168
Dave Jiang3372de52015-08-11 08:48:55 -0700169static int ioat_dca_remove_requester(struct dca_provider *dca,
Maciej Sosnowski7f1b3582008-07-22 17:30:57 -0700170 struct device *dev)
171{
172 struct ioat_dca_priv *ioatdca = dca_priv(dca);
173 struct pci_dev *pdev;
174 int i;
175 u16 global_req_table;
176
177 /* This implementation only supports PCI-Express */
Yijing Wang1fde2542013-12-05 19:31:18 +0800178 if (!dev_is_pci(dev))
Maciej Sosnowski7f1b3582008-07-22 17:30:57 -0700179 return -ENODEV;
180 pdev = to_pci_dev(dev);
181
182 for (i = 0; i < ioatdca->max_requesters; i++) {
183 if (ioatdca->req_slots[i].pdev == pdev) {
184 global_req_table =
185 readw(ioatdca->dca_base + IOAT3_DCA_GREQID_OFFSET);
186 writel(0, ioatdca->iobase + global_req_table + (i * 4));
187 ioatdca->req_slots[i].pdev = NULL;
188 ioatdca->req_slots[i].rid = 0;
189 ioatdca->requester_count--;
190 return i;
191 }
192 }
193 return -ENODEV;
194}
195
Dave Jiang3372de52015-08-11 08:48:55 -0700196static u8 ioat_dca_get_tag(struct dca_provider *dca,
Maciej Sosnowski7f1b3582008-07-22 17:30:57 -0700197 struct device *dev,
198 int cpu)
199{
200 u8 tag;
201
202 struct ioat_dca_priv *ioatdca = dca_priv(dca);
203 int i, apic_id, bit, value;
204 u8 entry;
205
206 tag = 0;
207 apic_id = cpu_physical_id(cpu);
208
209 for (i = 0; i < IOAT_TAG_MAP_LEN; i++) {
210 entry = ioatdca->tag_map[i];
211 if (entry & DCA3_TAG_MAP_BIT_TO_SEL) {
212 bit = entry &
213 ~(DCA3_TAG_MAP_BIT_TO_SEL | DCA3_TAG_MAP_BIT_TO_INV);
214 value = (apic_id & (1 << bit)) ? 1 : 0;
215 } else if (entry & DCA3_TAG_MAP_BIT_TO_INV) {
216 bit = entry & ~DCA3_TAG_MAP_BIT_TO_INV;
217 value = (apic_id & (1 << bit)) ? 0 : 1;
218 } else {
219 value = (entry & DCA3_TAG_MAP_LITERAL_VAL) ? 1 : 0;
220 }
221 tag |= (value << i);
222 }
223
224 return tag;
225}
226
Julia Lawall2bb129e2015-11-13 12:46:00 +0100227static const struct dca_ops ioat_dca_ops = {
Dave Jiang3372de52015-08-11 08:48:55 -0700228 .add_requester = ioat_dca_add_requester,
229 .remove_requester = ioat_dca_remove_requester,
230 .get_tag = ioat_dca_get_tag,
Maciej Sosnowski7f1b3582008-07-22 17:30:57 -0700231 .dev_managed = ioat_dca_dev_managed,
232};
233
Dave Jiang3372de52015-08-11 08:48:55 -0700234static int ioat_dca_count_dca_slots(void *iobase, u16 dca_offset)
Maciej Sosnowski7f1b3582008-07-22 17:30:57 -0700235{
236 int slots = 0;
237 u32 req;
238 u16 global_req_table;
239
240 global_req_table = readw(iobase + dca_offset + IOAT3_DCA_GREQID_OFFSET);
241 if (global_req_table == 0)
242 return 0;
243
244 do {
245 req = readl(iobase + global_req_table + (slots * sizeof(u32)));
246 slots++;
247 } while ((req & IOAT_DCA_GREQID_LASTID) == 0);
248
249 return slots;
250}
251
Alexander Duyck07bd34d2012-09-15 04:08:39 +0000252static inline int dca3_tag_map_invalid(u8 *tag_map)
253{
254 /*
255 * If the tag map is not programmed by the BIOS the default is:
256 * 0x80 0x80 0x80 0x80 0x80 0x00 0x00 0x00
257 *
258 * This an invalid map and will result in only 2 possible tags
259 * 0x1F and 0x00. 0x00 is an invalid DCA tag so we know that
260 * this entire definition is invalid.
261 */
262 return ((tag_map[0] == DCA_TAG_MAP_VALID) &&
263 (tag_map[1] == DCA_TAG_MAP_VALID) &&
264 (tag_map[2] == DCA_TAG_MAP_VALID) &&
265 (tag_map[3] == DCA_TAG_MAP_VALID) &&
266 (tag_map[4] == DCA_TAG_MAP_VALID));
267}
268
Dave Jiang3372de52015-08-11 08:48:55 -0700269struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase)
Maciej Sosnowski7f1b3582008-07-22 17:30:57 -0700270{
271 struct dca_provider *dca;
272 struct ioat_dca_priv *ioatdca;
273 int slots;
274 int i;
275 int err;
276 u16 dca_offset;
277 u16 csi_fsb_control;
278 u16 pcie_control;
279 u8 bit;
280
281 union {
282 u64 full;
283 struct {
284 u32 low;
285 u32 high;
286 };
287 } tag_map;
288
289 if (!system_has_dca_enabled(pdev))
290 return NULL;
291
292 dca_offset = readw(iobase + IOAT_DCAOFFSET_OFFSET);
293 if (dca_offset == 0)
294 return NULL;
295
Dave Jiang3372de52015-08-11 08:48:55 -0700296 slots = ioat_dca_count_dca_slots(iobase, dca_offset);
Maciej Sosnowski7f1b3582008-07-22 17:30:57 -0700297 if (slots == 0)
298 return NULL;
299
Dave Jiang3372de52015-08-11 08:48:55 -0700300 dca = alloc_dca_provider(&ioat_dca_ops,
Maciej Sosnowski7f1b3582008-07-22 17:30:57 -0700301 sizeof(*ioatdca)
302 + (sizeof(struct ioat_dca_slot) * slots));
303 if (!dca)
304 return NULL;
305
306 ioatdca = dca_priv(dca);
307 ioatdca->iobase = iobase;
308 ioatdca->dca_base = iobase + dca_offset;
309 ioatdca->max_requesters = slots;
310
311 /* some bios might not know to turn these on */
312 csi_fsb_control = readw(ioatdca->dca_base + IOAT3_CSI_CONTROL_OFFSET);
313 if ((csi_fsb_control & IOAT3_CSI_CONTROL_PREFETCH) == 0) {
314 csi_fsb_control |= IOAT3_CSI_CONTROL_PREFETCH;
315 writew(csi_fsb_control,
316 ioatdca->dca_base + IOAT3_CSI_CONTROL_OFFSET);
317 }
318 pcie_control = readw(ioatdca->dca_base + IOAT3_PCI_CONTROL_OFFSET);
319 if ((pcie_control & IOAT3_PCI_CONTROL_MEMWR) == 0) {
320 pcie_control |= IOAT3_PCI_CONTROL_MEMWR;
321 writew(pcie_control,
322 ioatdca->dca_base + IOAT3_PCI_CONTROL_OFFSET);
323 }
324
325
326 /* TODO version, compatibility and configuration checks */
327
328 /* copy out the APIC to DCA tag map */
329 tag_map.low =
330 readl(ioatdca->dca_base + IOAT3_APICID_TAG_MAP_OFFSET_LOW);
331 tag_map.high =
332 readl(ioatdca->dca_base + IOAT3_APICID_TAG_MAP_OFFSET_HIGH);
333 for (i = 0; i < 8; i++) {
334 bit = tag_map.full >> (8 * i);
335 ioatdca->tag_map[i] = bit & DCA_TAG_MAP_MASK;
336 }
337
Alexander Duyck07bd34d2012-09-15 04:08:39 +0000338 if (dca3_tag_map_invalid(ioatdca->tag_map)) {
Prarit Bhargava036e9ef2017-06-13 12:56:34 -0400339 add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
340 pr_warn_once("%s %s: APICID_TAG_MAP set incorrectly by BIOS, disabling DCA\n",
341 dev_driver_string(&pdev->dev),
342 dev_name(&pdev->dev));
Alexander Duyck07bd34d2012-09-15 04:08:39 +0000343 free_dca_provider(dca);
344 return NULL;
345 }
346
Maciej Sosnowski7f1b3582008-07-22 17:30:57 -0700347 err = register_dca_provider(dca, &pdev->dev);
348 if (err) {
349 free_dca_provider(dca);
350 return NULL;
351 }
352
353 return dca;
354}