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 */ 52 static inline u16 dcaid_from_pcidev(struct pci_dev *pci) 53 { 54 return pci_dev_id(pci); 55 } 56 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 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 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 } 112 113 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 } 146 147 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 } 173 174 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 }; 211 212 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 } 229 230 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 } 246 247 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