1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Intel I/OAT DMA Linux driver
4 * Copyright(c) 2007 - 2009 Intel Corporation.
5 */
6
7 #include <linux/kernel.h>
8 #include <linux/pci.h>
9 #include <linux/smp.h>
10 #include <linux/interrupt.h>
11 #include <linux/dca.h>
12
13 /* either a kernel change is needed, or we need something like this in kernel */
14 #ifndef CONFIG_SMP
15 #include <asm/smp.h>
16 #undef cpu_physical_id
17 #define cpu_physical_id(cpu) (cpuid_ebx(1) >> 24)
18 #endif
19
20 #include "dma.h"
21 #include "registers.h"
22
23 /*
24 * Bit 7 of a tag map entry is the "valid" bit, if it is set then bits 0:6
25 * contain the bit number of the APIC ID to map into the DCA tag. If the valid
26 * bit is not set, then the value must be 0 or 1 and defines the bit in the tag.
27 */
28 #define DCA_TAG_MAP_VALID 0x80
29
30 #define DCA3_TAG_MAP_BIT_TO_INV 0x80
31 #define DCA3_TAG_MAP_BIT_TO_SEL 0x40
32 #define DCA3_TAG_MAP_LITERAL_VAL 0x1
33
34 #define DCA_TAG_MAP_MASK 0xDF
35
36 /* expected tag map bytes for I/OAT ver.2 */
37 #define DCA2_TAG_MAP_BYTE0 0x80
38 #define DCA2_TAG_MAP_BYTE1 0x0
39 #define DCA2_TAG_MAP_BYTE2 0x81
40 #define DCA2_TAG_MAP_BYTE3 0x82
41 #define DCA2_TAG_MAP_BYTE4 0x82
42
43 /*
44 * "Legacy" DCA systems do not implement the DCA register set in the
45 * I/OAT device. Software needs direct support for their tag mappings.
46 */
47
48 #define APICID_BIT(x) (DCA_TAG_MAP_VALID | (x))
49 #define IOAT_TAG_MAP_LEN 8
50
51 /* pack PCI B/D/F into a u16 */
dcaid_from_pcidev(struct pci_dev * pci)52 static inline u16 dcaid_from_pcidev(struct pci_dev *pci)
53 {
54 return pci_dev_id(pci);
55 }
56
dca_enabled_in_bios(struct pci_dev * pdev)57 static int dca_enabled_in_bios(struct pci_dev *pdev)
58 {
59 /* CPUID level 9 returns DCA configuration */
60 /* Bit 0 indicates DCA enabled by the BIOS */
61 unsigned long cpuid_level_9;
62 int res;
63
64 cpuid_level_9 = cpuid_eax(9);
65 res = test_bit(0, &cpuid_level_9);
66 if (!res)
67 dev_dbg(&pdev->dev, "DCA is disabled in BIOS\n");
68
69 return res;
70 }
71
system_has_dca_enabled(struct pci_dev * pdev)72 int system_has_dca_enabled(struct pci_dev *pdev)
73 {
74 if (boot_cpu_has(X86_FEATURE_DCA))
75 return dca_enabled_in_bios(pdev);
76
77 dev_dbg(&pdev->dev, "boot cpu doesn't have X86_FEATURE_DCA\n");
78 return 0;
79 }
80
81 struct ioat_dca_slot {
82 struct pci_dev *pdev; /* requester device */
83 u16 rid; /* requester id, as used by IOAT */
84 };
85
86 #define IOAT_DCA_MAX_REQ 6
87 #define IOAT3_DCA_MAX_REQ 2
88
89 struct ioat_dca_priv {
90 void __iomem *iobase;
91 void __iomem *dca_base;
92 int max_requesters;
93 int requester_count;
94 u8 tag_map[IOAT_TAG_MAP_LEN];
95 struct ioat_dca_slot req_slots[];
96 };
97
ioat_dca_dev_managed(struct dca_provider * dca,struct device * dev)98 static int ioat_dca_dev_managed(struct dca_provider *dca,
99 struct device *dev)
100 {
101 struct ioat_dca_priv *ioatdca = dca_priv(dca);
102 struct pci_dev *pdev;
103 int i;
104
105 pdev = to_pci_dev(dev);
106 for (i = 0; i < ioatdca->max_requesters; i++) {
107 if (ioatdca->req_slots[i].pdev == pdev)
108 return 1;
109 }
110 return 0;
111 }
112
ioat_dca_add_requester(struct dca_provider * dca,struct device * dev)113 static int ioat_dca_add_requester(struct dca_provider *dca, struct device *dev)
114 {
115 struct ioat_dca_priv *ioatdca = dca_priv(dca);
116 struct pci_dev *pdev;
117 int i;
118 u16 id;
119 u16 global_req_table;
120
121 /* This implementation only supports PCI-Express */
122 if (!dev_is_pci(dev))
123 return -ENODEV;
124 pdev = to_pci_dev(dev);
125 id = dcaid_from_pcidev(pdev);
126
127 if (ioatdca->requester_count == ioatdca->max_requesters)
128 return -ENODEV;
129
130 for (i = 0; i < ioatdca->max_requesters; i++) {
131 if (ioatdca->req_slots[i].pdev == NULL) {
132 /* found an empty slot */
133 ioatdca->requester_count++;
134 ioatdca->req_slots[i].pdev = pdev;
135 ioatdca->req_slots[i].rid = id;
136 global_req_table =
137 readw(ioatdca->dca_base + IOAT3_DCA_GREQID_OFFSET);
138 writel(id | IOAT_DCA_GREQID_VALID,
139 ioatdca->iobase + global_req_table + (i * 4));
140 return i;
141 }
142 }
143 /* Error, ioatdma->requester_count is out of whack */
144 return -EFAULT;
145 }
146
ioat_dca_remove_requester(struct dca_provider * dca,struct device * dev)147 static int ioat_dca_remove_requester(struct dca_provider *dca,
148 struct device *dev)
149 {
150 struct ioat_dca_priv *ioatdca = dca_priv(dca);
151 struct pci_dev *pdev;
152 int i;
153 u16 global_req_table;
154
155 /* This implementation only supports PCI-Express */
156 if (!dev_is_pci(dev))
157 return -ENODEV;
158 pdev = to_pci_dev(dev);
159
160 for (i = 0; i < ioatdca->max_requesters; i++) {
161 if (ioatdca->req_slots[i].pdev == pdev) {
162 global_req_table =
163 readw(ioatdca->dca_base + IOAT3_DCA_GREQID_OFFSET);
164 writel(0, ioatdca->iobase + global_req_table + (i * 4));
165 ioatdca->req_slots[i].pdev = NULL;
166 ioatdca->req_slots[i].rid = 0;
167 ioatdca->requester_count--;
168 return i;
169 }
170 }
171 return -ENODEV;
172 }
173
ioat_dca_get_tag(struct dca_provider * dca,struct device * dev,int cpu)174 static u8 ioat_dca_get_tag(struct dca_provider *dca,
175 struct device *dev,
176 int cpu)
177 {
178 u8 tag;
179
180 struct ioat_dca_priv *ioatdca = dca_priv(dca);
181 int i, apic_id, bit, value;
182 u8 entry;
183
184 tag = 0;
185 apic_id = cpu_physical_id(cpu);
186
187 for (i = 0; i < IOAT_TAG_MAP_LEN; i++) {
188 entry = ioatdca->tag_map[i];
189 if (entry & DCA3_TAG_MAP_BIT_TO_SEL) {
190 bit = entry &
191 ~(DCA3_TAG_MAP_BIT_TO_SEL | DCA3_TAG_MAP_BIT_TO_INV);
192 value = (apic_id & (1 << bit)) ? 1 : 0;
193 } else if (entry & DCA3_TAG_MAP_BIT_TO_INV) {
194 bit = entry & ~DCA3_TAG_MAP_BIT_TO_INV;
195 value = (apic_id & (1 << bit)) ? 0 : 1;
196 } else {
197 value = (entry & DCA3_TAG_MAP_LITERAL_VAL) ? 1 : 0;
198 }
199 tag |= (value << i);
200 }
201
202 return tag;
203 }
204
205 static const struct dca_ops ioat_dca_ops = {
206 .add_requester = ioat_dca_add_requester,
207 .remove_requester = ioat_dca_remove_requester,
208 .get_tag = ioat_dca_get_tag,
209 .dev_managed = ioat_dca_dev_managed,
210 };
211
ioat_dca_count_dca_slots(void * iobase,u16 dca_offset)212 static int ioat_dca_count_dca_slots(void *iobase, u16 dca_offset)
213 {
214 int slots = 0;
215 u32 req;
216 u16 global_req_table;
217
218 global_req_table = readw(iobase + dca_offset + IOAT3_DCA_GREQID_OFFSET);
219 if (global_req_table == 0)
220 return 0;
221
222 do {
223 req = readl(iobase + global_req_table + (slots * sizeof(u32)));
224 slots++;
225 } while ((req & IOAT_DCA_GREQID_LASTID) == 0);
226
227 return slots;
228 }
229
dca3_tag_map_invalid(u8 * tag_map)230 static inline int dca3_tag_map_invalid(u8 *tag_map)
231 {
232 /*
233 * If the tag map is not programmed by the BIOS the default is:
234 * 0x80 0x80 0x80 0x80 0x80 0x00 0x00 0x00
235 *
236 * This an invalid map and will result in only 2 possible tags
237 * 0x1F and 0x00. 0x00 is an invalid DCA tag so we know that
238 * this entire definition is invalid.
239 */
240 return ((tag_map[0] == DCA_TAG_MAP_VALID) &&
241 (tag_map[1] == DCA_TAG_MAP_VALID) &&
242 (tag_map[2] == DCA_TAG_MAP_VALID) &&
243 (tag_map[3] == DCA_TAG_MAP_VALID) &&
244 (tag_map[4] == DCA_TAG_MAP_VALID));
245 }
246
ioat_dca_init(struct pci_dev * pdev,void __iomem * iobase)247 struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase)
248 {
249 struct dca_provider *dca;
250 struct ioat_dca_priv *ioatdca;
251 int slots;
252 int i;
253 int err;
254 u16 dca_offset;
255 u16 csi_fsb_control;
256 u16 pcie_control;
257 u8 bit;
258
259 union {
260 u64 full;
261 struct {
262 u32 low;
263 u32 high;
264 };
265 } tag_map;
266
267 if (!system_has_dca_enabled(pdev))
268 return NULL;
269
270 dca_offset = readw(iobase + IOAT_DCAOFFSET_OFFSET);
271 if (dca_offset == 0)
272 return NULL;
273
274 slots = ioat_dca_count_dca_slots(iobase, dca_offset);
275 if (slots == 0)
276 return NULL;
277
278 dca = alloc_dca_provider(&ioat_dca_ops,
279 struct_size(ioatdca, req_slots, slots));
280 if (!dca)
281 return NULL;
282
283 ioatdca = dca_priv(dca);
284 ioatdca->iobase = iobase;
285 ioatdca->dca_base = iobase + dca_offset;
286 ioatdca->max_requesters = slots;
287
288 /* some bios might not know to turn these on */
289 csi_fsb_control = readw(ioatdca->dca_base + IOAT3_CSI_CONTROL_OFFSET);
290 if ((csi_fsb_control & IOAT3_CSI_CONTROL_PREFETCH) == 0) {
291 csi_fsb_control |= IOAT3_CSI_CONTROL_PREFETCH;
292 writew(csi_fsb_control,
293 ioatdca->dca_base + IOAT3_CSI_CONTROL_OFFSET);
294 }
295 pcie_control = readw(ioatdca->dca_base + IOAT3_PCI_CONTROL_OFFSET);
296 if ((pcie_control & IOAT3_PCI_CONTROL_MEMWR) == 0) {
297 pcie_control |= IOAT3_PCI_CONTROL_MEMWR;
298 writew(pcie_control,
299 ioatdca->dca_base + IOAT3_PCI_CONTROL_OFFSET);
300 }
301
302
303 /* TODO version, compatibility and configuration checks */
304
305 /* copy out the APIC to DCA tag map */
306 tag_map.low =
307 readl(ioatdca->dca_base + IOAT3_APICID_TAG_MAP_OFFSET_LOW);
308 tag_map.high =
309 readl(ioatdca->dca_base + IOAT3_APICID_TAG_MAP_OFFSET_HIGH);
310 for (i = 0; i < 8; i++) {
311 bit = tag_map.full >> (8 * i);
312 ioatdca->tag_map[i] = bit & DCA_TAG_MAP_MASK;
313 }
314
315 if (dca3_tag_map_invalid(ioatdca->tag_map)) {
316 add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
317 pr_warn_once("%s %s: APICID_TAG_MAP set incorrectly by BIOS, disabling DCA\n",
318 dev_driver_string(&pdev->dev),
319 dev_name(&pdev->dev));
320 free_dca_provider(dca);
321 return NULL;
322 }
323
324 err = register_dca_provider(dca, &pdev->dev);
325 if (err) {
326 free_dca_provider(dca);
327 return NULL;
328 }
329
330 return dca;
331 }
332
