drivers/dma/ioat/dca.c

   1 /*
   2  * Intel I/OAT DMA Linux driver
   3  * Copyright(c) 2007 - 2009 Intel Corporation.
   4  *
   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  *
  14  * 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
  32 #include "dma.h"
  33 #include "registers.h"
  34
  35 /*
  36  * Bit 7 of a tag map entry is the "valid" bit, if it is set then bits 0:6
  37  * 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
  42 #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
  48 /* 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 */
  56 static 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
  65 /*
  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
  73 /* pack PCI B/D/F into a u16 */
  74 static inline u16 dcaid_from_pcidev(struct pci_dev *pci)
  75 {
  76         return (pci->bus->number << 8) | pci->devfn;
  77 }
  78
  79 static int dca_enabled_in_bios(struct pci_dev *pdev)
  80 {
  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)
  89                 dev_dbg(&pdev->dev, "DCA is disabled in BIOS\n");
  90
  91         return res;
  92 }
  93
  94 int system_has_dca_enabled(struct pci_dev *pdev)
  95 {
  96         if (boot_cpu_has(X86_FEATURE_DCA))
  97                 return dca_enabled_in_bios(pdev);
  98
  99         dev_dbg(&pdev->dev, "boot cpu doesn't have X86_FEATURE_DCA\n");
 100         return 0;
 101 }
 102
 103 struct 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
 109 #define IOAT3_DCA_MAX_REQ 2
 110
 111 struct ioat_dca_priv {
 112         void __iomem            *iobase;
 113         void __iomem            *dca_base;
 114         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
 120 static 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
 135 static int ioat_dca_add_requester(struct dca_provider *dca, struct device *dev)
 136 {
 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 */
 144         if (!dev_is_pci(dev))
 145                 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
 169 static int ioat_dca_remove_requester(struct dca_provider *dca,
 170                                       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 */
 178         if (!dev_is_pci(dev))
 179                 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
 196 static u8 ioat_dca_get_tag(struct dca_provider *dca,
 197                             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
 227 static const struct dca_ops ioat_dca_ops = {
 228         .add_requester          = ioat_dca_add_requester,
 229         .remove_requester       = ioat_dca_remove_requester,
 230         .get_tag                = ioat_dca_get_tag,
 231         .dev_managed            = ioat_dca_dev_managed,
 232 };
 233
 234 static int ioat_dca_count_dca_slots(void *iobase, u16 dca_offset)
 235 {
 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
 252 static 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
 269 struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase)
 270 {
 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
 296         slots = ioat_dca_count_dca_slots(iobase, dca_offset);
 297         if (slots == 0)
 298                 return NULL;
 299
 300         dca = alloc_dca_provider(&ioat_dca_ops,
 301                                  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
 338         if (dca3_tag_map_invalid(ioatdca->tag_map)) {
 339                 WARN_TAINT_ONCE(1, TAINT_FIRMWARE_WORKAROUND,
 340                                 "%s %s: APICID_TAG_MAP set incorrectly by BIOS, disabling DCA\n",
 341                                 dev_driver_string(&pdev->dev),
 342                                 dev_name(&pdev->dev));
 343                 free_dca_provider(dca);
 344                 return NULL;
 345         }
 346
 347         err = register_dca_provider(dca, &pdev->dev);
 348         if (err) {
 349                 free_dca_provider(dca);
 350                 return NULL;
 351         }
 352
 353         return dca;
 354 }