drivers/dma/ioat/dca.c

   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 /* verify if tag map matches expected values */
  44 static inline int dca2_tag_map_valid(u8 *tag_map)
  45 {
  46         return ((tag_map[0] == DCA2_TAG_MAP_BYTE0) &&
  47                 (tag_map[1] == DCA2_TAG_MAP_BYTE1) &&
  48                 (tag_map[2] == DCA2_TAG_MAP_BYTE2) &&
  49                 (tag_map[3] == DCA2_TAG_MAP_BYTE3) &&
  50                 (tag_map[4] == DCA2_TAG_MAP_BYTE4));
  51 }
  52
  53 /*
  54  * "Legacy" DCA systems do not implement the DCA register set in the
  55  * I/OAT device.  Software needs direct support for their tag mappings.
  56  */
  57
  58 #define APICID_BIT(x)           (DCA_TAG_MAP_VALID | (x))
  59 #define IOAT_TAG_MAP_LEN        8
  60
  61 /* pack PCI B/D/F into a u16 */
  62 static inline u16 dcaid_from_pcidev(struct pci_dev *pci)
  63 {
  64         return (pci->bus->number << 8) | pci->devfn;
  65 }
  66
  67 static int dca_enabled_in_bios(struct pci_dev *pdev)
  68 {
  69         /* CPUID level 9 returns DCA configuration */
  70         /* Bit 0 indicates DCA enabled by the BIOS */
  71         unsigned long cpuid_level_9;
  72         int res;
  73
  74         cpuid_level_9 = cpuid_eax(9);
  75         res = test_bit(0, &cpuid_level_9);
  76         if (!res)
  77                 dev_dbg(&pdev->dev, "DCA is disabled in BIOS\n");
  78
  79         return res;
  80 }
  81
  82 int system_has_dca_enabled(struct pci_dev *pdev)
  83 {
  84         if (boot_cpu_has(X86_FEATURE_DCA))
  85                 return dca_enabled_in_bios(pdev);
  86
  87         dev_dbg(&pdev->dev, "boot cpu doesn't have X86_FEATURE_DCA\n");
  88         return 0;
  89 }
  90
  91 struct ioat_dca_slot {
  92         struct pci_dev *pdev;   /* requester device */
  93         u16 rid;                /* requester id, as used by IOAT */
  94 };
  95
  96 #define IOAT_DCA_MAX_REQ 6
  97 #define IOAT3_DCA_MAX_REQ 2
  98
  99 struct ioat_dca_priv {
 100         void __iomem            *iobase;
 101         void __iomem            *dca_base;
 102         int                      max_requesters;
 103         int                      requester_count;
 104         u8                       tag_map[IOAT_TAG_MAP_LEN];
 105         struct ioat_dca_slot     req_slots[];
 106 };
 107
 108 static int ioat_dca_dev_managed(struct dca_provider *dca,
 109                                 struct device *dev)
 110 {
 111         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 112         struct pci_dev *pdev;
 113         int i;
 114
 115         pdev = to_pci_dev(dev);
 116         for (i = 0; i < ioatdca->max_requesters; i++) {
 117                 if (ioatdca->req_slots[i].pdev == pdev)
 118                         return 1;
 119         }
 120         return 0;
 121 }
 122
 123 static int ioat_dca_add_requester(struct dca_provider *dca, struct device *dev)
 124 {
 125         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 126         struct pci_dev *pdev;
 127         int i;
 128         u16 id;
 129         u16 global_req_table;
 130
 131         /* This implementation only supports PCI-Express */
 132         if (!dev_is_pci(dev))
 133                 return -ENODEV;
 134         pdev = to_pci_dev(dev);
 135         id = dcaid_from_pcidev(pdev);
 136
 137         if (ioatdca->requester_count == ioatdca->max_requesters)
 138                 return -ENODEV;
 139
 140         for (i = 0; i < ioatdca->max_requesters; i++) {
 141                 if (ioatdca->req_slots[i].pdev == NULL) {
 142                         /* found an empty slot */
 143                         ioatdca->requester_count++;
 144                         ioatdca->req_slots[i].pdev = pdev;
 145                         ioatdca->req_slots[i].rid = id;
 146                         global_req_table =
 147                               readw(ioatdca->dca_base + IOAT3_DCA_GREQID_OFFSET);
 148                         writel(id | IOAT_DCA_GREQID_VALID,
 149                                ioatdca->iobase + global_req_table + (i * 4));
 150                         return i;
 151                 }
 152         }
 153         /* Error, ioatdma->requester_count is out of whack */
 154         return -EFAULT;
 155 }
 156
 157 static int ioat_dca_remove_requester(struct dca_provider *dca,
 158                                       struct device *dev)
 159 {
 160         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 161         struct pci_dev *pdev;
 162         int i;
 163         u16 global_req_table;
 164
 165         /* This implementation only supports PCI-Express */
 166         if (!dev_is_pci(dev))
 167                 return -ENODEV;
 168         pdev = to_pci_dev(dev);
 169
 170         for (i = 0; i < ioatdca->max_requesters; i++) {
 171                 if (ioatdca->req_slots[i].pdev == pdev) {
 172                         global_req_table =
 173                               readw(ioatdca->dca_base + IOAT3_DCA_GREQID_OFFSET);
 174                         writel(0, ioatdca->iobase + global_req_table + (i * 4));
 175                         ioatdca->req_slots[i].pdev = NULL;
 176                         ioatdca->req_slots[i].rid = 0;
 177                         ioatdca->requester_count--;
 178                         return i;
 179                 }
 180         }
 181         return -ENODEV;
 182 }
 183
 184 static u8 ioat_dca_get_tag(struct dca_provider *dca,
 185                             struct device *dev,
 186                             int cpu)
 187 {
 188         u8 tag;
 189
 190         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 191         int i, apic_id, bit, value;
 192         u8 entry;
 193
 194         tag = 0;
 195         apic_id = cpu_physical_id(cpu);
 196
 197         for (i = 0; i < IOAT_TAG_MAP_LEN; i++) {
 198                 entry = ioatdca->tag_map[i];
 199                 if (entry & DCA3_TAG_MAP_BIT_TO_SEL) {
 200                         bit = entry &
 201                                 ~(DCA3_TAG_MAP_BIT_TO_SEL | DCA3_TAG_MAP_BIT_TO_INV);
 202                         value = (apic_id & (1 << bit)) ? 1 : 0;
 203                 } else if (entry & DCA3_TAG_MAP_BIT_TO_INV) {
 204                         bit = entry & ~DCA3_TAG_MAP_BIT_TO_INV;
 205                         value = (apic_id & (1 << bit)) ? 0 : 1;
 206                 } else {
 207                         value = (entry & DCA3_TAG_MAP_LITERAL_VAL) ? 1 : 0;
 208                 }
 209                 tag |= (value << i);
 210         }
 211
 212         return tag;
 213 }
 214
 215 static const struct dca_ops ioat_dca_ops = {
 216         .add_requester          = ioat_dca_add_requester,
 217         .remove_requester       = ioat_dca_remove_requester,
 218         .get_tag                = ioat_dca_get_tag,
 219         .dev_managed            = ioat_dca_dev_managed,
 220 };
 221
 222 static int ioat_dca_count_dca_slots(void *iobase, u16 dca_offset)
 223 {
 224         int slots = 0;
 225         u32 req;
 226         u16 global_req_table;
 227
 228         global_req_table = readw(iobase + dca_offset + IOAT3_DCA_GREQID_OFFSET);
 229         if (global_req_table == 0)
 230                 return 0;
 231
 232         do {
 233                 req = readl(iobase + global_req_table + (slots * sizeof(u32)));
 234                 slots++;
 235         } while ((req & IOAT_DCA_GREQID_LASTID) == 0);
 236
 237         return slots;
 238 }
 239
 240 static inline int dca3_tag_map_invalid(u8 *tag_map)
 241 {
 242         /*
 243          * If the tag map is not programmed by the BIOS the default is:
 244          * 0x80 0x80 0x80 0x80 0x80 0x00 0x00 0x00
 245          *
 246          * This an invalid map and will result in only 2 possible tags
 247          * 0x1F and 0x00.  0x00 is an invalid DCA tag so we know that
 248          * this entire definition is invalid.
 249          */
 250         return ((tag_map[0] == DCA_TAG_MAP_VALID) &&
 251                 (tag_map[1] == DCA_TAG_MAP_VALID) &&
 252                 (tag_map[2] == DCA_TAG_MAP_VALID) &&
 253                 (tag_map[3] == DCA_TAG_MAP_VALID) &&
 254                 (tag_map[4] == DCA_TAG_MAP_VALID));
 255 }
 256
 257 struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase)
 258 {
 259         struct dca_provider *dca;
 260         struct ioat_dca_priv *ioatdca;
 261         int slots;
 262         int i;
 263         int err;
 264         u16 dca_offset;
 265         u16 csi_fsb_control;
 266         u16 pcie_control;
 267         u8 bit;
 268
 269         union {
 270                 u64 full;
 271                 struct {
 272                         u32 low;
 273                         u32 high;
 274                 };
 275         } tag_map;
 276
 277         if (!system_has_dca_enabled(pdev))
 278                 return NULL;
 279
 280         dca_offset = readw(iobase + IOAT_DCAOFFSET_OFFSET);
 281         if (dca_offset == 0)
 282                 return NULL;
 283
 284         slots = ioat_dca_count_dca_slots(iobase, dca_offset);
 285         if (slots == 0)
 286                 return NULL;
 287
 288         dca = alloc_dca_provider(&ioat_dca_ops,
 289                                  struct_size(ioatdca, req_slots, slots));
 290         if (!dca)
 291                 return NULL;
 292
 293         ioatdca = dca_priv(dca);
 294         ioatdca->iobase = iobase;
 295         ioatdca->dca_base = iobase + dca_offset;
 296         ioatdca->max_requesters = slots;
 297
 298         /* some bios might not know to turn these on */
 299         csi_fsb_control = readw(ioatdca->dca_base + IOAT3_CSI_CONTROL_OFFSET);
 300         if ((csi_fsb_control & IOAT3_CSI_CONTROL_PREFETCH) == 0) {
 301                 csi_fsb_control |= IOAT3_CSI_CONTROL_PREFETCH;
 302                 writew(csi_fsb_control,
 303                        ioatdca->dca_base + IOAT3_CSI_CONTROL_OFFSET);
 304         }
 305         pcie_control = readw(ioatdca->dca_base + IOAT3_PCI_CONTROL_OFFSET);
 306         if ((pcie_control & IOAT3_PCI_CONTROL_MEMWR) == 0) {
 307                 pcie_control |= IOAT3_PCI_CONTROL_MEMWR;
 308                 writew(pcie_control,
 309                        ioatdca->dca_base + IOAT3_PCI_CONTROL_OFFSET);
 310         }
 311
 312
 313         /* TODO version, compatibility and configuration checks */
 314
 315         /* copy out the APIC to DCA tag map */
 316         tag_map.low =
 317                 readl(ioatdca->dca_base + IOAT3_APICID_TAG_MAP_OFFSET_LOW);
 318         tag_map.high =
 319                 readl(ioatdca->dca_base + IOAT3_APICID_TAG_MAP_OFFSET_HIGH);
 320         for (i = 0; i < 8; i++) {
 321                 bit = tag_map.full >> (8 * i);
 322                 ioatdca->tag_map[i] = bit & DCA_TAG_MAP_MASK;
 323         }
 324
 325         if (dca3_tag_map_invalid(ioatdca->tag_map)) {
 326                 add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
 327                 pr_warn_once("%s %s: APICID_TAG_MAP set incorrectly by BIOS, disabling DCA\n",
 328                              dev_driver_string(&pdev->dev),
 329                              dev_name(&pdev->dev));
 330                 free_dca_provider(dca);
 331                 return NULL;
 332         }
 333
 334         err = register_dca_provider(dca, &pdev->dev);
 335         if (err) {
 336                 free_dca_provider(dca);
 337                 return NULL;
 338         }
 339
 340         return dca;
 341 }