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 */
23static 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 */
47int 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
106err_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}
116EXPORT_SYMBOL_GPL(pci_epc_multi_mem_init);
117
118int 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}
129EXPORT_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 */
138void 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}
157EXPORT_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 */
168void __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}
206EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
207
208static 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 */
234void 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}
259EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);
260
261MODULE_DESCRIPTION("PCI EPC Address Space Management");
262MODULE_AUTHOR("Kishon Vijay Abraham I <kishon@ti.com>");
263MODULE_LICENSE("GPL v2");
264