drivers/dma/ioat_dca.c

   1 /*
   2  * Intel I/OAT DMA Linux driver
   3  * Copyright(c) 2007 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  * You should have received a copy of the GNU General Public License along with
  15  * this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  17  *
  18  * The full GNU General Public License is included in this distribution in
  19  * the file called "COPYING".
  20  *
  21  */
  22
  23 #include <linux/kernel.h>
  24 #include <linux/pci.h>
  25 #include <linux/smp.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/dca.h>
  28
  29 /* either a kernel change is needed, or we need something like this in kernel */
  30 #ifndef CONFIG_SMP
  31 #include <asm/smp.h>
  32 #undef cpu_physical_id
  33 #define cpu_physical_id(cpu) (cpuid_ebx(1) >> 24)
  34 #endif
  35
  36 #include "ioatdma.h"
  37 #include "ioatdma_registers.h"
  38
  39 /*
  40  * Bit 16 of a tag map entry is the "valid" bit, if it is set then bits 0:15
  41  * contain the bit number of the APIC ID to map into the DCA tag.  If the valid
  42  * bit is not set, then the value must be 0 or 1 and defines the bit in the tag.
  43  */
  44 #define DCA_TAG_MAP_VALID 0x80
  45
  46 /*
  47  * "Legacy" DCA systems do not implement the DCA register set in the
  48  * I/OAT device.  Software needs direct support for their tag mappings.
  49  */
  50
  51 #define APICID_BIT(x)           (DCA_TAG_MAP_VALID | (x))
  52 #define IOAT_TAG_MAP_LEN        8
  53
  54 static u8 ioat_tag_map_BNB[IOAT_TAG_MAP_LEN] = {
  55         1, APICID_BIT(1), APICID_BIT(2), APICID_BIT(2), };
  56 static u8 ioat_tag_map_SCNB[IOAT_TAG_MAP_LEN] = {
  57         1, APICID_BIT(1), APICID_BIT(2), APICID_BIT(2), };
  58 static u8 ioat_tag_map_CNB[IOAT_TAG_MAP_LEN] = {
  59         1, APICID_BIT(1), APICID_BIT(3), APICID_BIT(4), APICID_BIT(2), };
  60 static u8 ioat_tag_map_UNISYS[IOAT_TAG_MAP_LEN] = { 0 };
  61
  62 /* pack PCI B/D/F into a u16 */
  63 static inline u16 dcaid_from_pcidev(struct pci_dev *pci)
  64 {
  65         return (pci->bus->number << 8) | pci->devfn;
  66 }
  67
  68 static int dca_enabled_in_bios(struct pci_dev *pdev)
  69 {
  70         /* CPUID level 9 returns DCA configuration */
  71         /* Bit 0 indicates DCA enabled by the BIOS */
  72         unsigned long cpuid_level_9;
  73         int res;
  74
  75         cpuid_level_9 = cpuid_eax(9);
  76         res = test_bit(0, &cpuid_level_9);
  77         if (!res)
  78                 dev_err(&pdev->dev, "DCA is disabled in BIOS\n");
  79
  80         return res;
  81 }
  82
  83 static int system_has_dca_enabled(struct pci_dev *pdev)
  84 {
  85         if (boot_cpu_has(X86_FEATURE_DCA))
  86                 return dca_enabled_in_bios(pdev);
  87
  88         dev_err(&pdev->dev, "boot cpu doesn't have X86_FEATURE_DCA\n");
  89         return 0;
  90 }
  91
  92 struct ioat_dca_slot {
  93         struct pci_dev *pdev;   /* requester device */
  94         u16 rid;                /* requester id, as used by IOAT */
  95 };
  96
  97 #define IOAT_DCA_MAX_REQ 6
  98
  99 struct ioat_dca_priv {
 100         void __iomem            *iobase;
 101         void                    *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[0];
 106 };
 107
 108 /* 5000 series chipset DCA Port Requester ID Table Entry Format
 109  * [15:8]       PCI-Express Bus Number
 110  * [7:3]        PCI-Express Device Number
 111  * [2:0]        PCI-Express Function Number
 112  *
 113  * 5000 series chipset DCA control register format
 114  * [7:1]        Reserved (0)
 115  * [0]          Ignore Function Number
 116  */
 117
 118 static int ioat_dca_add_requester(struct dca_provider *dca, struct device *dev)
 119 {
 120         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 121         struct pci_dev *pdev;
 122         int i;
 123         u16 id;
 124
 125         /* This implementation only supports PCI-Express */
 126         if (dev->bus != &pci_bus_type)
 127                 return -ENODEV;
 128         pdev = to_pci_dev(dev);
 129         id = dcaid_from_pcidev(pdev);
 130
 131         if (ioatdca->requester_count == ioatdca->max_requesters)
 132                 return -ENODEV;
 133
 134         for (i = 0; i < ioatdca->max_requesters; i++) {
 135                 if (ioatdca->req_slots[i].pdev == NULL) {
 136                         /* found an empty slot */
 137                         ioatdca->requester_count++;
 138                         ioatdca->req_slots[i].pdev = pdev;
 139                         ioatdca->req_slots[i].rid = id;
 140                         writew(id, ioatdca->dca_base + (i * 4));
 141                         /* make sure the ignore function bit is off */
 142                         writeb(0, ioatdca->dca_base + (i * 4) + 2);
 143                         return i;
 144                 }
 145         }
 146         /* Error, ioatdma->requester_count is out of whack */
 147         return -EFAULT;
 148 }
 149
 150 static int ioat_dca_remove_requester(struct dca_provider *dca,
 151                                      struct device *dev)
 152 {
 153         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 154         struct pci_dev *pdev;
 155         int i;
 156
 157         /* This implementation only supports PCI-Express */
 158         if (dev->bus != &pci_bus_type)
 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                         writew(0, ioatdca->dca_base + (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, int cpu)
 175 {
 176         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 177         int i, apic_id, bit, value;
 178         u8 entry, tag;
 179
 180         tag = 0;
 181         apic_id = cpu_physical_id(cpu);
 182
 183         for (i = 0; i < IOAT_TAG_MAP_LEN; i++) {
 184                 entry = ioatdca->tag_map[i];
 185                 if (entry & DCA_TAG_MAP_VALID) {
 186                         bit = entry & ~DCA_TAG_MAP_VALID;
 187                         value = (apic_id & (1 << bit)) ? 1 : 0;
 188                 } else {
 189                         value = entry ? 1 : 0;
 190                 }
 191                 tag |= (value << i);
 192         }
 193         return tag;
 194 }
 195
 196 static struct dca_ops ioat_dca_ops = {
 197         .add_requester          = ioat_dca_add_requester,
 198         .remove_requester       = ioat_dca_remove_requester,
 199         .get_tag                = ioat_dca_get_tag,
 200 };
 201
 202
 203 struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase)
 204 {
 205         struct dca_provider *dca;
 206         struct ioat_dca_priv *ioatdca;
 207         u8 *tag_map = NULL;
 208         int i;
 209         int err;
 210
 211         if (!system_has_dca_enabled(pdev))
 212                 return NULL;
 213
 214         /* I/OAT v1 systems must have a known tag_map to support DCA */
 215         switch (pdev->vendor) {
 216         case PCI_VENDOR_ID_INTEL:
 217                 switch (pdev->device) {
 218                 case PCI_DEVICE_ID_INTEL_IOAT:
 219                         tag_map = ioat_tag_map_BNB;
 220                         break;
 221                 case PCI_DEVICE_ID_INTEL_IOAT_CNB:
 222                         tag_map = ioat_tag_map_CNB;
 223                         break;
 224                 case PCI_DEVICE_ID_INTEL_IOAT_SCNB:
 225                         tag_map = ioat_tag_map_SCNB;
 226                         break;
 227                 }
 228                 break;
 229         case PCI_VENDOR_ID_UNISYS:
 230                 switch (pdev->device) {
 231                 case PCI_DEVICE_ID_UNISYS_DMA_DIRECTOR:
 232                         tag_map = ioat_tag_map_UNISYS;
 233                         break;
 234                 }
 235                 break;
 236         }
 237         if (tag_map == NULL)
 238                 return NULL;
 239
 240         dca = alloc_dca_provider(&ioat_dca_ops,
 241                         sizeof(*ioatdca) +
 242                         (sizeof(struct ioat_dca_slot) * IOAT_DCA_MAX_REQ));
 243         if (!dca)
 244                 return NULL;
 245
 246         ioatdca = dca_priv(dca);
 247         ioatdca->max_requesters = IOAT_DCA_MAX_REQ;
 248
 249         ioatdca->dca_base = iobase + 0x54;
 250
 251         /* copy over the APIC ID to DCA tag mapping */
 252         for (i = 0; i < IOAT_TAG_MAP_LEN; i++)
 253                 ioatdca->tag_map[i] = tag_map[i];
 254
 255         err = register_dca_provider(dca, &pdev->dev);
 256         if (err) {
 257                 free_dca_provider(dca);
 258                 return NULL;
 259         }
 260
 261         return dca;
 262 }
 263