1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * PCI Endpoint *Controller* Address Space Management
4 *
5 * Copyright (C) 2017 Texas Instruments
6 * Author: Kishon Vijay Abraham I <kishon@ti.com>
7 */
8
9 #include <linux/io.h>
10 #include <linux/module.h>
11 #include <linux/slab.h>
12
13 #include <linux/pci-epc.h>
14
15 /**
16 * pci_epc_mem_get_order() - determine the allocation order of a memory size
17 * @mem: address space of the endpoint controller
18 * @size: the size for which to get the order
19 *
20 * Reimplement get_order() for mem->page_size since the generic get_order
21 * always gets order with a constant PAGE_SIZE.
22 */
pci_epc_mem_get_order(struct pci_epc_mem * mem,size_t size)23 static int pci_epc_mem_get_order(struct pci_epc_mem *mem, size_t size)
24 {
25 int order;
26 unsigned int page_shift = ilog2(mem->window.page_size);
27
28 size--;
29 size >>= page_shift;
30 #if BITS_PER_LONG == 32
31 order = fls(size);
32 #else
33 order = fls64(size);
34 #endif
35 return order;
36 }
37
38 /**
39 * pci_epc_multi_mem_init() - initialize the pci_epc_mem structure
40 * @epc: the EPC device that invoked pci_epc_mem_init
41 * @windows: pointer to windows supported by the device
42 * @num_windows: number of windows device supports
43 *
44 * Invoke to initialize the pci_epc_mem structure used by the
45 * endpoint functions to allocate mapped PCI address.
46 */
pci_epc_multi_mem_init(struct pci_epc * epc,struct pci_epc_mem_window * windows,unsigned int num_windows)47 int pci_epc_multi_mem_init(struct pci_epc *epc,
48 struct pci_epc_mem_window *windows,
49 unsigned int num_windows)
50 {
51 struct pci_epc_mem *mem = NULL;
52 unsigned long *bitmap = NULL;
53 unsigned int page_shift;
54 size_t page_size;
55 int bitmap_size;
56 int pages;
57 int ret;
58 int i;
59
60 epc->num_windows = 0;
61
62 if (!windows || !num_windows)
63 return -EINVAL;
64
65 epc->windows = kcalloc(num_windows, sizeof(*epc->windows), GFP_KERNEL);
66 if (!epc->windows)
67 return -ENOMEM;
68
69 for (i = 0; i < num_windows; i++) {
70 page_size = windows[i].page_size;
71 if (page_size < PAGE_SIZE)
72 page_size = PAGE_SIZE;
73 page_shift = ilog2(page_size);
74 pages = windows[i].size >> page_shift;
75 bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
76
77 mem = kzalloc(sizeof(*mem), GFP_KERNEL);
78 if (!mem) {
79 ret = -ENOMEM;
80 i--;
81 goto err_mem;
82 }
83
84 bitmap = kzalloc(bitmap_size, GFP_KERNEL);
85 if (!bitmap) {
86 ret = -ENOMEM;
87 kfree(mem);
88 i--;
89 goto err_mem;
90 }
91
92 mem->window.phys_base = windows[i].phys_base;
93 mem->window.size = windows[i].size;
94 mem->window.page_size = page_size;
95 mem->bitmap = bitmap;
96 mem->pages = pages;
97 mutex_init(&mem->lock);
98 epc->windows[i] = mem;
99 }
100
101 epc->mem = epc->windows[0];
102 epc->num_windows = num_windows;
103
104 return 0;
105
106 err_mem:
107 for (; i >= 0; i--) {
108 mem = epc->windows[i];
109 kfree(mem->bitmap);
110 kfree(mem);
111 }
112 kfree(epc->windows);
113
114 return ret;
115 }
116 EXPORT_SYMBOL_GPL(pci_epc_multi_mem_init);
117
pci_epc_mem_init(struct pci_epc * epc,phys_addr_t base,size_t size,size_t page_size)118 int pci_epc_mem_init(struct pci_epc *epc, phys_addr_t base,
119 size_t size, size_t page_size)
120 {
121 struct pci_epc_mem_window mem_window;
122
123 mem_window.phys_base = base;
124 mem_window.size = size;
125 mem_window.page_size = page_size;
126
127 return pci_epc_multi_mem_init(epc, &mem_window, 1);
128 }
129 EXPORT_SYMBOL_GPL(pci_epc_mem_init);
130
131 /**
132 * pci_epc_mem_exit() - cleanup the pci_epc_mem structure
133 * @epc: the EPC device that invoked pci_epc_mem_exit
134 *
135 * Invoke to cleanup the pci_epc_mem structure allocated in
136 * pci_epc_mem_init().
137 */
pci_epc_mem_exit(struct pci_epc * epc)138 void pci_epc_mem_exit(struct pci_epc *epc)
139 {
140 struct pci_epc_mem *mem;
141 int i;
142
143 if (!epc->num_windows)
144 return;
145
146 for (i = 0; i < epc->num_windows; i++) {
147 mem = epc->windows[i];
148 kfree(mem->bitmap);
149 kfree(mem);
150 }
151 kfree(epc->windows);
152
153 epc->windows = NULL;
154 epc->mem = NULL;
155 epc->num_windows = 0;
156 }
157 EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
158
159 /**
160 * pci_epc_mem_alloc_addr() - allocate memory address from EPC addr space
161 * @epc: the EPC device on which memory has to be allocated
162 * @phys_addr: populate the allocated physical address here
163 * @size: the size of the address space that has to be allocated
164 *
165 * Invoke to allocate memory address from the EPC address space. This
166 * is usually done to map the remote RC address into the local system.
167 */
pci_epc_mem_alloc_addr(struct pci_epc * epc,phys_addr_t * phys_addr,size_t size)168 void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
169 phys_addr_t *phys_addr, size_t size)
170 {
171 void __iomem *virt_addr = NULL;
172 struct pci_epc_mem *mem;
173 unsigned int page_shift;
174 size_t align_size;
175 int pageno;
176 int order;
177 int i;
178
179 for (i = 0; i < epc->num_windows; i++) {
180 mem = epc->windows[i];
181 mutex_lock(&mem->lock);
182 align_size = ALIGN(size, mem->window.page_size);
183 order = pci_epc_mem_get_order(mem, align_size);
184
185 pageno = bitmap_find_free_region(mem->bitmap, mem->pages,
186 order);
187 if (pageno >= 0) {
188 page_shift = ilog2(mem->window.page_size);
189 *phys_addr = mem->window.phys_base +
190 ((phys_addr_t)pageno << page_shift);
191 virt_addr = ioremap(*phys_addr, align_size);
192 if (!virt_addr) {
193 bitmap_release_region(mem->bitmap,
194 pageno, order);
195 mutex_unlock(&mem->lock);
196 continue;
197 }
198 mutex_unlock(&mem->lock);
199 return virt_addr;
200 }
201 mutex_unlock(&mem->lock);
202 }
203
204 return virt_addr;
205 }
206 EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
207
pci_epc_get_matching_window(struct pci_epc * epc,phys_addr_t phys_addr)208 static struct pci_epc_mem *pci_epc_get_matching_window(struct pci_epc *epc,
209 phys_addr_t phys_addr)
210 {
211 struct pci_epc_mem *mem;
212 int i;
213
214 for (i = 0; i < epc->num_windows; i++) {
215 mem = epc->windows[i];
216
217 if (phys_addr >= mem->window.phys_base &&
218 phys_addr < (mem->window.phys_base + mem->window.size))
219 return mem;
220 }
221
222 return NULL;
223 }
224
225 /**
226 * pci_epc_mem_free_addr() - free the allocated memory address
227 * @epc: the EPC device on which memory was allocated
228 * @phys_addr: the allocated physical address
229 * @virt_addr: virtual address of the allocated mem space
230 * @size: the size of the allocated address space
231 *
232 * Invoke to free the memory allocated using pci_epc_mem_alloc_addr.
233 */
pci_epc_mem_free_addr(struct pci_epc * epc,phys_addr_t phys_addr,void __iomem * virt_addr,size_t size)234 void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
235 void __iomem *virt_addr, size_t size)
236 {
237 struct pci_epc_mem *mem;
238 unsigned int page_shift;
239 size_t page_size;
240 int pageno;
241 int order;
242
243 mem = pci_epc_get_matching_window(epc, phys_addr);
244 if (!mem) {
245 pr_err("failed to get matching window\n");
246 return;
247 }
248
249 page_size = mem->window.page_size;
250 page_shift = ilog2(page_size);
251 iounmap(virt_addr);
252 pageno = (phys_addr - mem->window.phys_base) >> page_shift;
253 size = ALIGN(size, page_size);
254 order = pci_epc_mem_get_order(mem, size);
255 mutex_lock(&mem->lock);
256 bitmap_release_region(mem->bitmap, pageno, order);
257 mutex_unlock(&mem->lock);
258 }
259 EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);
260
261 MODULE_DESCRIPTION("PCI EPC Address Space Management");
262 MODULE_AUTHOR("Kishon Vijay Abraham I <kishon@ti.com>");
263 MODULE_LICENSE("GPL v2");
264