1 /*
2  * Copyright 2014 Advanced Micro Devices, Inc.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20  * OTHER DEALINGS IN THE SOFTWARE.
21  */
22 #include "kfd_priv.h"
23 #include <linux/mm.h>
24 #include <linux/mman.h>
25 #include <linux/slab.h>
26 #include <linux/io.h>
27 #include <linux/idr.h>
28 
29 /*
30  * This extension supports a kernel level doorbells management for the
31  * kernel queues using the first doorbell page reserved for the kernel.
32  */
33 
34 static DEFINE_IDA(doorbell_ida);
35 static unsigned int max_doorbell_slices;
36 
37 /*
38  * Each device exposes a doorbell aperture, a PCI MMIO aperture that
39  * receives 32-bit writes that are passed to queues as wptr values.
40  * The doorbells are intended to be written by applications as part
41  * of queueing work on user-mode queues.
42  * We assign doorbells to applications in PAGE_SIZE-sized and aligned chunks.
43  * We map the doorbell address space into user-mode when a process creates
44  * its first queue on each device.
45  * Although the mapping is done by KFD, it is equivalent to an mmap of
46  * the /dev/kfd with the particular device encoded in the mmap offset.
47  * There will be other uses for mmap of /dev/kfd, so only a range of
48  * offsets (KFD_MMAP_DOORBELL_START-END) is used for doorbells.
49  */
50 
51 /* # of doorbell bytes allocated for each process. */
52 size_t kfd_doorbell_process_slice(struct kfd_dev *kfd)
53 {
54 	return roundup(kfd->device_info->doorbell_size *
55 			KFD_MAX_NUM_OF_QUEUES_PER_PROCESS,
56 			PAGE_SIZE);
57 }
58 
59 /* Doorbell calculations for device init. */
60 int kfd_doorbell_init(struct kfd_dev *kfd)
61 {
62 	size_t doorbell_start_offset;
63 	size_t doorbell_aperture_size;
64 	size_t doorbell_process_limit;
65 
66 	/*
67 	 * We start with calculations in bytes because the input data might
68 	 * only be byte-aligned.
69 	 * Only after we have done the rounding can we assume any alignment.
70 	 */
71 
72 	doorbell_start_offset =
73 			roundup(kfd->shared_resources.doorbell_start_offset,
74 					kfd_doorbell_process_slice(kfd));
75 
76 	doorbell_aperture_size =
77 			rounddown(kfd->shared_resources.doorbell_aperture_size,
78 					kfd_doorbell_process_slice(kfd));
79 
80 	if (doorbell_aperture_size > doorbell_start_offset)
81 		doorbell_process_limit =
82 			(doorbell_aperture_size - doorbell_start_offset) /
83 						kfd_doorbell_process_slice(kfd);
84 	else
85 		return -ENOSPC;
86 
87 	if (!max_doorbell_slices ||
88 	    doorbell_process_limit < max_doorbell_slices)
89 		max_doorbell_slices = doorbell_process_limit;
90 
91 	kfd->doorbell_base = kfd->shared_resources.doorbell_physical_address +
92 				doorbell_start_offset;
93 
94 	kfd->doorbell_id_offset = doorbell_start_offset / sizeof(u32);
95 
96 	kfd->doorbell_kernel_ptr = ioremap(kfd->doorbell_base,
97 					   kfd_doorbell_process_slice(kfd));
98 
99 	if (!kfd->doorbell_kernel_ptr)
100 		return -ENOMEM;
101 
102 	pr_debug("Doorbell initialization:\n");
103 	pr_debug("doorbell base           == 0x%08lX\n",
104 			(uintptr_t)kfd->doorbell_base);
105 
106 	pr_debug("doorbell_id_offset      == 0x%08lX\n",
107 			kfd->doorbell_id_offset);
108 
109 	pr_debug("doorbell_process_limit  == 0x%08lX\n",
110 			doorbell_process_limit);
111 
112 	pr_debug("doorbell_kernel_offset  == 0x%08lX\n",
113 			(uintptr_t)kfd->doorbell_base);
114 
115 	pr_debug("doorbell aperture size  == 0x%08lX\n",
116 			kfd->shared_resources.doorbell_aperture_size);
117 
118 	pr_debug("doorbell kernel address == %p\n", kfd->doorbell_kernel_ptr);
119 
120 	return 0;
121 }
122 
123 void kfd_doorbell_fini(struct kfd_dev *kfd)
124 {
125 	if (kfd->doorbell_kernel_ptr)
126 		iounmap(kfd->doorbell_kernel_ptr);
127 }
128 
129 int kfd_doorbell_mmap(struct kfd_dev *dev, struct kfd_process *process,
130 		      struct vm_area_struct *vma)
131 {
132 	phys_addr_t address;
133 
134 	/*
135 	 * For simplicitly we only allow mapping of the entire doorbell
136 	 * allocation of a single device & process.
137 	 */
138 	if (vma->vm_end - vma->vm_start != kfd_doorbell_process_slice(dev))
139 		return -EINVAL;
140 
141 	/* Calculate physical address of doorbell */
142 	address = kfd_get_process_doorbells(dev, process);
143 
144 	vma->vm_flags |= VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_NORESERVE |
145 				VM_DONTDUMP | VM_PFNMAP;
146 
147 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
148 
149 	pr_debug("Mapping doorbell page\n"
150 		 "     target user address == 0x%08llX\n"
151 		 "     physical address    == 0x%08llX\n"
152 		 "     vm_flags            == 0x%04lX\n"
153 		 "     size                == 0x%04lX\n",
154 		 (unsigned long long) vma->vm_start, address, vma->vm_flags,
155 		 kfd_doorbell_process_slice(dev));
156 
157 
158 	return io_remap_pfn_range(vma,
159 				vma->vm_start,
160 				address >> PAGE_SHIFT,
161 				kfd_doorbell_process_slice(dev),
162 				vma->vm_page_prot);
163 }
164 
165 
166 /* get kernel iomem pointer for a doorbell */
167 void __iomem *kfd_get_kernel_doorbell(struct kfd_dev *kfd,
168 					unsigned int *doorbell_off)
169 {
170 	u32 inx;
171 
172 	mutex_lock(&kfd->doorbell_mutex);
173 	inx = find_first_zero_bit(kfd->doorbell_available_index,
174 					KFD_MAX_NUM_OF_QUEUES_PER_PROCESS);
175 
176 	__set_bit(inx, kfd->doorbell_available_index);
177 	mutex_unlock(&kfd->doorbell_mutex);
178 
179 	if (inx >= KFD_MAX_NUM_OF_QUEUES_PER_PROCESS)
180 		return NULL;
181 
182 	inx *= kfd->device_info->doorbell_size / sizeof(u32);
183 
184 	/*
185 	 * Calculating the kernel doorbell offset using the first
186 	 * doorbell page.
187 	 */
188 	*doorbell_off = kfd->doorbell_id_offset + inx;
189 
190 	pr_debug("Get kernel queue doorbell\n"
191 			"     doorbell offset   == 0x%08X\n"
192 			"     doorbell index    == 0x%x\n",
193 		*doorbell_off, inx);
194 
195 	return kfd->doorbell_kernel_ptr + inx;
196 }
197 
198 void kfd_release_kernel_doorbell(struct kfd_dev *kfd, u32 __iomem *db_addr)
199 {
200 	unsigned int inx;
201 
202 	inx = (unsigned int)(db_addr - kfd->doorbell_kernel_ptr)
203 		* sizeof(u32) / kfd->device_info->doorbell_size;
204 
205 	mutex_lock(&kfd->doorbell_mutex);
206 	__clear_bit(inx, kfd->doorbell_available_index);
207 	mutex_unlock(&kfd->doorbell_mutex);
208 }
209 
210 void write_kernel_doorbell(void __iomem *db, u32 value)
211 {
212 	if (db) {
213 		writel(value, db);
214 		pr_debug("Writing %d to doorbell address %p\n", value, db);
215 	}
216 }
217 
218 void write_kernel_doorbell64(void __iomem *db, u64 value)
219 {
220 	if (db) {
221 		WARN(((unsigned long)db & 7) != 0,
222 		     "Unaligned 64-bit doorbell");
223 		writeq(value, (u64 __iomem *)db);
224 		pr_debug("writing %llu to doorbell address %p\n", value, db);
225 	}
226 }
227 
228 unsigned int kfd_doorbell_id_to_offset(struct kfd_dev *kfd,
229 					struct kfd_process *process,
230 					unsigned int doorbell_id)
231 {
232 	/*
233 	 * doorbell_id_offset accounts for doorbells taken by KGD.
234 	 * index * kfd_doorbell_process_slice/sizeof(u32) adjusts to
235 	 * the process's doorbells. The offset returned is in dword
236 	 * units regardless of the ASIC-dependent doorbell size.
237 	 */
238 	return kfd->doorbell_id_offset +
239 		process->doorbell_index
240 		* kfd_doorbell_process_slice(kfd) / sizeof(u32) +
241 		doorbell_id * kfd->device_info->doorbell_size / sizeof(u32);
242 }
243 
244 uint64_t kfd_get_number_elems(struct kfd_dev *kfd)
245 {
246 	uint64_t num_of_elems = (kfd->shared_resources.doorbell_aperture_size -
247 				kfd->shared_resources.doorbell_start_offset) /
248 					kfd_doorbell_process_slice(kfd) + 1;
249 
250 	return num_of_elems;
251 
252 }
253 
254 phys_addr_t kfd_get_process_doorbells(struct kfd_dev *dev,
255 					struct kfd_process *process)
256 {
257 	return dev->doorbell_base +
258 		process->doorbell_index * kfd_doorbell_process_slice(dev);
259 }
260 
261 int kfd_alloc_process_doorbells(struct kfd_process *process)
262 {
263 	int r = ida_simple_get(&doorbell_ida, 1, max_doorbell_slices,
264 				GFP_KERNEL);
265 	if (r > 0)
266 		process->doorbell_index = r;
267 
268 	return r;
269 }
270 
271 void kfd_free_process_doorbells(struct kfd_process *process)
272 {
273 	if (process->doorbell_index)
274 		ida_simple_remove(&doorbell_ida, process->doorbell_index);
275 }
276