1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright 2017 IBM Corp.
4 */
5
6#include <linux/hugetlb.h>
7#include <linux/sched/mm.h>
8#include <asm/opal-api.h>
9#include <asm/pnv-pci.h>
10#include <misc/cxllib.h>
11
12#include "cxl.h"
13
14#define CXL_INVALID_DRA ~0ull
15#define CXL_DUMMY_READ_SIZE 128
16#define CXL_DUMMY_READ_ALIGN 8
17#define CXL_CAPI_WINDOW_START 0x2000000000000ull
18#define CXL_CAPI_WINDOW_LOG_SIZE 48
19#define CXL_XSL_CONFIG_CURRENT_VERSION CXL_XSL_CONFIG_VERSION1
20
21
22bool cxllib_slot_is_supported(struct pci_dev *dev, unsigned long flags)
23{
24 int rc;
25 u32 phb_index;
26 u64 chip_id, capp_unit_id;
27
28 /* No flags currently supported */
29 if (flags)
30 return false;
31
32 if (!cpu_has_feature(CPU_FTR_HVMODE))
33 return false;
34
35 if (!cxl_is_power9())
36 return false;
37
38 if (cxl_slot_is_switched(dev))
39 return false;
40
41 /* on p9, some pci slots are not connected to a CAPP unit */
42 rc = cxl_calc_capp_routing(dev, chipid: &chip_id, phb_index: &phb_index, capp_unit_id: &capp_unit_id);
43 if (rc)
44 return false;
45
46 return true;
47}
48EXPORT_SYMBOL_GPL(cxllib_slot_is_supported);
49
50static DEFINE_MUTEX(dra_mutex);
51static u64 dummy_read_addr = CXL_INVALID_DRA;
52
53static int allocate_dummy_read_buf(void)
54{
55 u64 buf, vaddr;
56 size_t buf_size;
57
58 /*
59 * Dummy read buffer is 128-byte long, aligned on a
60 * 256-byte boundary and we need the physical address.
61 */
62 buf_size = CXL_DUMMY_READ_SIZE + (1ull << CXL_DUMMY_READ_ALIGN);
63 buf = (u64) kzalloc(size: buf_size, GFP_KERNEL);
64 if (!buf)
65 return -ENOMEM;
66
67 vaddr = (buf + (1ull << CXL_DUMMY_READ_ALIGN) - 1) &
68 (~0ull << CXL_DUMMY_READ_ALIGN);
69
70 WARN((vaddr + CXL_DUMMY_READ_SIZE) > (buf + buf_size),
71 "Dummy read buffer alignment issue");
72 dummy_read_addr = virt_to_phys(address: (void *) vaddr);
73 return 0;
74}
75
76int cxllib_get_xsl_config(struct pci_dev *dev, struct cxllib_xsl_config *cfg)
77{
78 int rc;
79 u32 phb_index;
80 u64 chip_id, capp_unit_id;
81
82 if (!cpu_has_feature(CPU_FTR_HVMODE))
83 return -EINVAL;
84
85 mutex_lock(&dra_mutex);
86 if (dummy_read_addr == CXL_INVALID_DRA) {
87 rc = allocate_dummy_read_buf();
88 if (rc) {
89 mutex_unlock(lock: &dra_mutex);
90 return rc;
91 }
92 }
93 mutex_unlock(lock: &dra_mutex);
94
95 rc = cxl_calc_capp_routing(dev, chipid: &chip_id, phb_index: &phb_index, capp_unit_id: &capp_unit_id);
96 if (rc)
97 return rc;
98
99 rc = cxl_get_xsl9_dsnctl(dev, capp_unit_id, reg: &cfg->dsnctl);
100 if (rc)
101 return rc;
102
103 cfg->version = CXL_XSL_CONFIG_CURRENT_VERSION;
104 cfg->log_bar_size = CXL_CAPI_WINDOW_LOG_SIZE;
105 cfg->bar_addr = CXL_CAPI_WINDOW_START;
106 cfg->dra = dummy_read_addr;
107 return 0;
108}
109EXPORT_SYMBOL_GPL(cxllib_get_xsl_config);
110
111int cxllib_switch_phb_mode(struct pci_dev *dev, enum cxllib_mode mode,
112 unsigned long flags)
113{
114 int rc = 0;
115
116 if (!cpu_has_feature(CPU_FTR_HVMODE))
117 return -EINVAL;
118
119 switch (mode) {
120 case CXL_MODE_PCI:
121 /*
122 * We currently don't support going back to PCI mode
123 * However, we'll turn the invalidations off, so that
124 * the firmware doesn't have to ack them and can do
125 * things like reset, etc.. with no worries.
126 * So always return EPERM (can't go back to PCI) or
127 * EBUSY if we couldn't even turn off snooping
128 */
129 rc = pnv_phb_to_cxl_mode(dev, OPAL_PHB_CAPI_MODE_SNOOP_OFF);
130 if (rc)
131 rc = -EBUSY;
132 else
133 rc = -EPERM;
134 break;
135 case CXL_MODE_CXL:
136 /* DMA only supported on TVT1 for the time being */
137 if (flags != CXL_MODE_DMA_TVT1)
138 return -EINVAL;
139 rc = pnv_phb_to_cxl_mode(dev, OPAL_PHB_CAPI_MODE_DMA_TVT1);
140 if (rc)
141 return rc;
142 rc = pnv_phb_to_cxl_mode(dev, OPAL_PHB_CAPI_MODE_SNOOP_ON);
143 break;
144 default:
145 rc = -EINVAL;
146 }
147 return rc;
148}
149EXPORT_SYMBOL_GPL(cxllib_switch_phb_mode);
150
151/*
152 * When switching the PHB to capi mode, the TVT#1 entry for
153 * the Partitionable Endpoint is set in bypass mode, like
154 * in PCI mode.
155 * Configure the device dma to use TVT#1, which is done
156 * by calling dma_set_mask() with a mask large enough.
157 */
158int cxllib_set_device_dma(struct pci_dev *dev, unsigned long flags)
159{
160 int rc;
161
162 if (flags)
163 return -EINVAL;
164
165 rc = dma_set_mask(dev: &dev->dev, DMA_BIT_MASK(64));
166 return rc;
167}
168EXPORT_SYMBOL_GPL(cxllib_set_device_dma);
169
170int cxllib_get_PE_attributes(struct task_struct *task,
171 unsigned long translation_mode,
172 struct cxllib_pe_attributes *attr)
173{
174 if (translation_mode != CXL_TRANSLATED_MODE &&
175 translation_mode != CXL_REAL_MODE)
176 return -EINVAL;
177
178 attr->sr = cxl_calculate_sr(master: false,
179 kernel: task == NULL,
180 real_mode: translation_mode == CXL_REAL_MODE,
181 p9: true);
182 attr->lpid = mfspr(SPRN_LPID);
183 if (task) {
184 struct mm_struct *mm = get_task_mm(task);
185 if (mm == NULL)
186 return -EINVAL;
187 /*
188 * Caller is keeping a reference on mm_users for as long
189 * as XSL uses the memory context
190 */
191 attr->pid = mm->context.id;
192 mmput(mm);
193 attr->tid = task->thread.tidr;
194 } else {
195 attr->pid = 0;
196 attr->tid = 0;
197 }
198 return 0;
199}
200EXPORT_SYMBOL_GPL(cxllib_get_PE_attributes);
201
202static int get_vma_info(struct mm_struct *mm, u64 addr,
203 u64 *vma_start, u64 *vma_end,
204 unsigned long *page_size)
205{
206 struct vm_area_struct *vma = NULL;
207 int rc = 0;
208
209 mmap_read_lock(mm);
210
211 vma = find_vma(mm, addr);
212 if (!vma) {
213 rc = -EFAULT;
214 goto out;
215 }
216 *page_size = vma_kernel_pagesize(vma);
217 *vma_start = vma->vm_start;
218 *vma_end = vma->vm_end;
219out:
220 mmap_read_unlock(mm);
221 return rc;
222}
223
224int cxllib_handle_fault(struct mm_struct *mm, u64 addr, u64 size, u64 flags)
225{
226 int rc;
227 u64 dar, vma_start, vma_end;
228 unsigned long page_size;
229
230 if (mm == NULL)
231 return -EFAULT;
232
233 /*
234 * The buffer we have to process can extend over several pages
235 * and may also cover several VMAs.
236 * We iterate over all the pages. The page size could vary
237 * between VMAs.
238 */
239 rc = get_vma_info(mm, addr, vma_start: &vma_start, vma_end: &vma_end, page_size: &page_size);
240 if (rc)
241 return rc;
242
243 for (dar = (addr & ~(page_size - 1)); dar < (addr + size);
244 dar += page_size) {
245 if (dar < vma_start || dar >= vma_end) {
246 /*
247 * We don't hold mm->mmap_lock while iterating, since
248 * the lock is required by one of the lower-level page
249 * fault processing functions and it could
250 * create a deadlock.
251 *
252 * It means the VMAs can be altered between 2
253 * loop iterations and we could theoretically
254 * miss a page (however unlikely). But that's
255 * not really a problem, as the driver will
256 * retry access, get another page fault on the
257 * missing page and call us again.
258 */
259 rc = get_vma_info(mm, addr: dar, vma_start: &vma_start, vma_end: &vma_end,
260 page_size: &page_size);
261 if (rc)
262 return rc;
263 }
264
265 rc = cxl_handle_mm_fault(mm, dsisr: flags, dar);
266 if (rc)
267 return -EFAULT;
268 }
269 return 0;
270}
271EXPORT_SYMBOL_GPL(cxllib_handle_fault);
272

source code of linux/drivers/misc/cxl/cxllib.c