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Shannon Nelson2ed6dc32007-10-16 01:27:42 -07001/*
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
54static u8 ioat_tag_map_BNB[IOAT_TAG_MAP_LEN] = {
55 1, APICID_BIT(1), APICID_BIT(2), APICID_BIT(2), };
56static u8 ioat_tag_map_SCNB[IOAT_TAG_MAP_LEN] = {
57 1, APICID_BIT(1), APICID_BIT(2), APICID_BIT(2), };
58static u8 ioat_tag_map_CNB[IOAT_TAG_MAP_LEN] = {
59 1, APICID_BIT(1), APICID_BIT(3), APICID_BIT(4), APICID_BIT(2), };
60static u8 ioat_tag_map_UNISYS[IOAT_TAG_MAP_LEN] = { 0 };
61
62/* pack PCI B/D/F into a u16 */
63static inline u16 dcaid_from_pcidev(struct pci_dev *pci)
64{
65 return (pci->bus->number << 8) | pci->devfn;
66}
67
Shannon Nelson5149fd02007-10-18 03:07:13 -070068static int dca_enabled_in_bios(struct pci_dev *pdev)
Shannon Nelson2ed6dc32007-10-16 01:27:42 -070069{
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)
Shannon Nelson5149fd02007-10-18 03:07:13 -070078 dev_err(&pdev->dev, "DCA is disabled in BIOS\n");
Shannon Nelson2ed6dc32007-10-16 01:27:42 -070079
80 return res;
81}
82
Shannon Nelson5149fd02007-10-18 03:07:13 -070083static int system_has_dca_enabled(struct pci_dev *pdev)
Shannon Nelson2ed6dc32007-10-16 01:27:42 -070084{
85 if (boot_cpu_has(X86_FEATURE_DCA))
Shannon Nelson5149fd02007-10-18 03:07:13 -070086 return dca_enabled_in_bios(pdev);
Shannon Nelson2ed6dc32007-10-16 01:27:42 -070087
Shannon Nelson5149fd02007-10-18 03:07:13 -070088 dev_err(&pdev->dev, "boot cpu doesn't have X86_FEATURE_DCA\n");
Shannon Nelson2ed6dc32007-10-16 01:27:42 -070089 return 0;
90}
91
92struct 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
99struct 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
118static 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
150static 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
174static 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
196static 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
203struct 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
Shannon Nelson5149fd02007-10-18 03:07:13 -0700211 if (!system_has_dca_enabled(pdev))
Shannon Nelson2ed6dc32007-10-16 01:27:42 -0700212 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