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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Intel I/OAT DMA Linux driver4 * 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_SMP15#include <asm/smp.h>16#undef cpu_physical_id17#define cpu_physical_id(cpu) (cpuid_ebx(1) >> 24)18#endif19 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 0:625 * contain the bit number of the APIC ID to map into the DCA tag. If the valid26 * 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 0x8029 30#define DCA3_TAG_MAP_BIT_TO_INV 0x8031#define DCA3_TAG_MAP_BIT_TO_SEL 0x4032#define DCA3_TAG_MAP_LITERAL_VAL 0x133 34#define DCA_TAG_MAP_MASK 0xDF35 36/* expected tag map bytes for I/OAT ver.2 */37#define DCA2_TAG_MAP_BYTE0 0x8038#define DCA2_TAG_MAP_BYTE1 0x039#define DCA2_TAG_MAP_BYTE2 0x8140#define DCA2_TAG_MAP_BYTE3 0x8241#define DCA2_TAG_MAP_BYTE4 0x8242 43/*44 * "Legacy" DCA systems do not implement the DCA register set in the45 * 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 850 51/* pack PCI B/D/F into a u16 */52static inline u16 dcaid_from_pcidev(struct pci_dev *pci)53{54 return pci_dev_id(pci);55}56 57static 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 72int 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 81struct 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 687#define IOAT3_DCA_MAX_REQ 288 89struct 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 98static 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 113static 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 147static 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 174static 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 205static 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 212static 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 230static 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 0x00235 *236 * This an invalid map and will result in only 2 possible tags237 * 0x1F and 0x00. 0x00 is an invalid DCA tag so we know that238 * 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 247struct 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