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 #include <asm/cpuid.h>
14
15 /* either a kernel change is needed, or we need something like this in kernel */
16 #ifndef CONFIG_SMP
17 #include <asm/smp.h>
18 #undef cpu_physical_id
19 #define cpu_physical_id(cpu) (cpuid_ebx(1) >> 24)
20 #endif
21
22 #include "dma.h"
23 #include "registers.h"
24
25 /*
26 * Bit 7 of a tag map entry is the "valid" bit, if it is set then bits 0:6
27 * contain the bit number of the APIC ID to map into the DCA tag. If the valid
28 * bit is not set, then the value must be 0 or 1 and defines the bit in the tag.
29 */
30 #define DCA_TAG_MAP_VALID 0x80
31
32 #define DCA3_TAG_MAP_BIT_TO_INV 0x80
33 #define DCA3_TAG_MAP_BIT_TO_SEL 0x40
34 #define DCA3_TAG_MAP_LITERAL_VAL 0x1
35
36 #define DCA_TAG_MAP_MASK 0xDF
37
38 /* expected tag map bytes for I/OAT ver.2 */
39 #define DCA2_TAG_MAP_BYTE0 0x80
40 #define DCA2_TAG_MAP_BYTE1 0x0
41 #define DCA2_TAG_MAP_BYTE2 0x81
42 #define DCA2_TAG_MAP_BYTE3 0x82
43 #define DCA2_TAG_MAP_BYTE4 0x82
44
45 /*
46 * "Legacy" DCA systems do not implement the DCA register set in the
47 * I/OAT device. Software needs direct support for their tag mappings.
48 */
49
50 #define APICID_BIT(x) (DCA_TAG_MAP_VALID | (x))
51 #define IOAT_TAG_MAP_LEN 8
52
53 /* pack PCI B/D/F into a u16 */
dcaid_from_pcidev(struct pci_dev * pci)54 static inline u16 dcaid_from_pcidev(struct pci_dev *pci)
55 {
56 return pci_dev_id(pci);
57 }
58
dca_enabled_in_bios(struct pci_dev * pdev)59 static int dca_enabled_in_bios(struct pci_dev *pdev)
60 {
61 /* CPUID level 9 returns DCA configuration */
62 /* Bit 0 indicates DCA enabled by the BIOS */
63 u32 eax;
64 int res;
65
66 eax = cpuid_eax(CPUID_LEAF_DCA);
67 res = eax & BIT(0);
68 if (!res)
69 dev_dbg(&pdev->dev, "DCA is disabled in BIOS\n");
70
71 return res;
72 }
73
system_has_dca_enabled(struct pci_dev * pdev)74 int system_has_dca_enabled(struct pci_dev *pdev)
75 {
76 if (boot_cpu_has(X86_FEATURE_DCA))
77 return dca_enabled_in_bios(pdev);
78
79 dev_dbg(&pdev->dev, "boot cpu doesn't have X86_FEATURE_DCA\n");
80 return 0;
81 }
82
83 struct ioat_dca_slot {
84 struct pci_dev *pdev; /* requester device */
85 u16 rid; /* requester id, as used by IOAT */
86 };
87
88 #define IOAT_DCA_MAX_REQ 6
89 #define IOAT3_DCA_MAX_REQ 2
90
91 struct ioat_dca_priv {
92 void __iomem *iobase;
93 void __iomem *dca_base;
94 int max_requesters;
95 int requester_count;
96 u8 tag_map[IOAT_TAG_MAP_LEN];
97 struct ioat_dca_slot req_slots[];
98 };
99
ioat_dca_dev_managed(struct dca_provider * dca,struct device * dev)100 static int ioat_dca_dev_managed(struct dca_provider *dca,
101 struct device *dev)
102 {
103 struct ioat_dca_priv *ioatdca = dca_priv(dca);
104 struct pci_dev *pdev;
105 int i;
106
107 pdev = to_pci_dev(dev);
108 for (i = 0; i < ioatdca->max_requesters; i++) {
109 if (ioatdca->req_slots[i].pdev == pdev)
110 return 1;
111 }
112 return 0;
113 }
114
ioat_dca_add_requester(struct dca_provider * dca,struct device * dev)115 static int ioat_dca_add_requester(struct dca_provider *dca, struct device *dev)
116 {
117 struct ioat_dca_priv *ioatdca = dca_priv(dca);
118 struct pci_dev *pdev;
119 int i;
120 u16 id;
121 u16 global_req_table;
122
123 /* This implementation only supports PCI-Express */
124 if (!dev_is_pci(dev))
125 return -ENODEV;
126 pdev = to_pci_dev(dev);
127 id = dcaid_from_pcidev(pdev);
128
129 if (ioatdca->requester_count == ioatdca->max_requesters)
130 return -ENODEV;
131
132 for (i = 0; i < ioatdca->max_requesters; i++) {
133 if (ioatdca->req_slots[i].pdev == NULL) {
134 /* found an empty slot */
135 ioatdca->requester_count++;
136 ioatdca->req_slots[i].pdev = pdev;
137 ioatdca->req_slots[i].rid = id;
138 global_req_table =
139 readw(ioatdca->dca_base + IOAT3_DCA_GREQID_OFFSET);
140 writel(id | IOAT_DCA_GREQID_VALID,
141 ioatdca->iobase + global_req_table + (i * 4));
142 return i;
143 }
144 }
145 /* Error, ioatdma->requester_count is out of whack */
146 return -EFAULT;
147 }
148
ioat_dca_remove_requester(struct dca_provider * dca,struct device * dev)149 static int ioat_dca_remove_requester(struct dca_provider *dca,
150 struct device *dev)
151 {
152 struct ioat_dca_priv *ioatdca = dca_priv(dca);
153 struct pci_dev *pdev;
154 int i;
155 u16 global_req_table;
156
157 /* This implementation only supports PCI-Express */
158 if (!dev_is_pci(dev))
159 return -ENODEV;
160 pdev = to_pci_dev(dev);
161
162 for (i = 0; i < ioatdca->max_requesters; i++) {
163 if (ioatdca->req_slots[i].pdev == pdev) {
164 global_req_table =
165 readw(ioatdca->dca_base + IOAT3_DCA_GREQID_OFFSET);
166 writel(0, ioatdca->iobase + global_req_table + (i * 4));
167 ioatdca->req_slots[i].pdev = NULL;
168 ioatdca->req_slots[i].rid = 0;
169 ioatdca->requester_count--;
170 return i;
171 }
172 }
173 return -ENODEV;
174 }
175
ioat_dca_get_tag(struct dca_provider * dca,struct device * dev,int cpu)176 static u8 ioat_dca_get_tag(struct dca_provider *dca,
177 struct device *dev,
178 int cpu)
179 {
180 u8 tag;
181
182 struct ioat_dca_priv *ioatdca = dca_priv(dca);
183 int i, apic_id, bit, value;
184 u8 entry;
185
186 tag = 0;
187 apic_id = cpu_physical_id(cpu);
188
189 for (i = 0; i < IOAT_TAG_MAP_LEN; i++) {
190 entry = ioatdca->tag_map[i];
191 if (entry & DCA3_TAG_MAP_BIT_TO_SEL) {
192 bit = entry &
193 ~(DCA3_TAG_MAP_BIT_TO_SEL | DCA3_TAG_MAP_BIT_TO_INV);
194 value = (apic_id & (1 << bit)) ? 1 : 0;
195 } else if (entry & DCA3_TAG_MAP_BIT_TO_INV) {
196 bit = entry & ~DCA3_TAG_MAP_BIT_TO_INV;
197 value = (apic_id & (1 << bit)) ? 0 : 1;
198 } else {
199 value = (entry & DCA3_TAG_MAP_LITERAL_VAL) ? 1 : 0;
200 }
201 tag |= (value << i);
202 }
203
204 return tag;
205 }
206
207 static const struct dca_ops ioat_dca_ops = {
208 .add_requester = ioat_dca_add_requester,
209 .remove_requester = ioat_dca_remove_requester,
210 .get_tag = ioat_dca_get_tag,
211 .dev_managed = ioat_dca_dev_managed,
212 };
213
ioat_dca_count_dca_slots(void * iobase,u16 dca_offset)214 static int ioat_dca_count_dca_slots(void *iobase, u16 dca_offset)
215 {
216 int slots = 0;
217 u32 req;
218 u16 global_req_table;
219
220 global_req_table = readw(iobase + dca_offset + IOAT3_DCA_GREQID_OFFSET);
221 if (global_req_table == 0)
222 return 0;
223
224 do {
225 req = readl(iobase + global_req_table + (slots * sizeof(u32)));
226 slots++;
227 } while ((req & IOAT_DCA_GREQID_LASTID) == 0);
228
229 return slots;
230 }
231
dca3_tag_map_invalid(u8 * tag_map)232 static inline int dca3_tag_map_invalid(u8 *tag_map)
233 {
234 /*
235 * If the tag map is not programmed by the BIOS the default is:
236 * 0x80 0x80 0x80 0x80 0x80 0x00 0x00 0x00
237 *
238 * This an invalid map and will result in only 2 possible tags
239 * 0x1F and 0x00. 0x00 is an invalid DCA tag so we know that
240 * this entire definition is invalid.
241 */
242 return ((tag_map[0] == DCA_TAG_MAP_VALID) &&
243 (tag_map[1] == DCA_TAG_MAP_VALID) &&
244 (tag_map[2] == DCA_TAG_MAP_VALID) &&
245 (tag_map[3] == DCA_TAG_MAP_VALID) &&
246 (tag_map[4] == DCA_TAG_MAP_VALID));
247 }
248
ioat_dca_init(struct pci_dev * pdev,void __iomem * iobase)249 struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase)
250 {
251 struct dca_provider *dca;
252 struct ioat_dca_priv *ioatdca;
253 int slots;
254 int i;
255 int err;
256 u16 dca_offset;
257 u16 csi_fsb_control;
258 u16 pcie_control;
259 u8 bit;
260
261 union {
262 u64 full;
263 struct {
264 u32 low;
265 u32 high;
266 };
267 } tag_map;
268
269 if (!system_has_dca_enabled(pdev))
270 return NULL;
271
272 dca_offset = readw(iobase + IOAT_DCAOFFSET_OFFSET);
273 if (dca_offset == 0)
274 return NULL;
275
276 slots = ioat_dca_count_dca_slots(iobase, dca_offset);
277 if (slots == 0)
278 return NULL;
279
280 dca = alloc_dca_provider(&ioat_dca_ops,
281 struct_size(ioatdca, req_slots, slots));
282 if (!dca)
283 return NULL;
284
285 ioatdca = dca_priv(dca);
286 ioatdca->iobase = iobase;
287 ioatdca->dca_base = iobase + dca_offset;
288 ioatdca->max_requesters = slots;
289
290 /* some bios might not know to turn these on */
291 csi_fsb_control = readw(ioatdca->dca_base + IOAT3_CSI_CONTROL_OFFSET);
292 if ((csi_fsb_control & IOAT3_CSI_CONTROL_PREFETCH) == 0) {
293 csi_fsb_control |= IOAT3_CSI_CONTROL_PREFETCH;
294 writew(csi_fsb_control,
295 ioatdca->dca_base + IOAT3_CSI_CONTROL_OFFSET);
296 }
297 pcie_control = readw(ioatdca->dca_base + IOAT3_PCI_CONTROL_OFFSET);
298 if ((pcie_control & IOAT3_PCI_CONTROL_MEMWR) == 0) {
299 pcie_control |= IOAT3_PCI_CONTROL_MEMWR;
300 writew(pcie_control,
301 ioatdca->dca_base + IOAT3_PCI_CONTROL_OFFSET);
302 }
303
304
305 /* TODO version, compatibility and configuration checks */
306
307 /* copy out the APIC to DCA tag map */
308 tag_map.low =
309 readl(ioatdca->dca_base + IOAT3_APICID_TAG_MAP_OFFSET_LOW);
310 tag_map.high =
311 readl(ioatdca->dca_base + IOAT3_APICID_TAG_MAP_OFFSET_HIGH);
312 for (i = 0; i < 8; i++) {
313 bit = tag_map.full >> (8 * i);
314 ioatdca->tag_map[i] = bit & DCA_TAG_MAP_MASK;
315 }
316
317 if (dca3_tag_map_invalid(ioatdca->tag_map)) {
318 add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
319 pr_warn_once("%s %s: APICID_TAG_MAP set incorrectly by BIOS, disabling DCA\n",
320 dev_driver_string(&pdev->dev),
321 dev_name(&pdev->dev));
322 free_dca_provider(dca);
323 return NULL;
324 }
325
326 err = register_dca_provider(dca, &pdev->dev);
327 if (err) {
328 free_dca_provider(dca);
329 return NULL;
330 }
331
332 return dca;
333 }
334