1 /**
2  * PCI Endpoint *Controller* Address Space Management
3  *
4  * Copyright (C) 2017 Texas Instruments
5  * Author: Kishon Vijay Abraham I <kishon@ti.com>
6  *
7  * This program is free software: you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 of
9  * the License as published by the Free Software Foundation.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #include <linux/io.h>
21 #include <linux/module.h>
22 #include <linux/slab.h>
23 
24 #include <linux/pci-epc.h>
25 
26 /**
27  * pci_epc_mem_init() - initialize the pci_epc_mem structure
28  * @epc: the EPC device that invoked pci_epc_mem_init
29  * @phys_base: the physical address of the base
30  * @size: the size of the address space
31  *
32  * Invoke to initialize the pci_epc_mem structure used by the
33  * endpoint functions to allocate mapped PCI address.
34  */
35 int pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_base, size_t size)
36 {
37 	int ret;
38 	struct pci_epc_mem *mem;
39 	unsigned long *bitmap;
40 	int pages = size >> PAGE_SHIFT;
41 	int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
42 
43 	mem = kzalloc(sizeof(*mem), GFP_KERNEL);
44 	if (!mem) {
45 		ret = -ENOMEM;
46 		goto err;
47 	}
48 
49 	bitmap = kzalloc(bitmap_size, GFP_KERNEL);
50 	if (!bitmap) {
51 		ret = -ENOMEM;
52 		goto err_mem;
53 	}
54 
55 	mem->bitmap = bitmap;
56 	mem->phys_base = phys_base;
57 	mem->pages = pages;
58 	mem->size = size;
59 
60 	epc->mem = mem;
61 
62 	return 0;
63 
64 err_mem:
65 	kfree(mem);
66 
67 err:
68 return ret;
69 }
70 EXPORT_SYMBOL_GPL(pci_epc_mem_init);
71 
72 /**
73  * pci_epc_mem_exit() - cleanup the pci_epc_mem structure
74  * @epc: the EPC device that invoked pci_epc_mem_exit
75  *
76  * Invoke to cleanup the pci_epc_mem structure allocated in
77  * pci_epc_mem_init().
78  */
79 void pci_epc_mem_exit(struct pci_epc *epc)
80 {
81 	struct pci_epc_mem *mem = epc->mem;
82 
83 	epc->mem = NULL;
84 	kfree(mem->bitmap);
85 	kfree(mem);
86 }
87 EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
88 
89 /**
90  * pci_epc_mem_alloc_addr() - allocate memory address from EPC addr space
91  * @epc: the EPC device on which memory has to be allocated
92  * @phys_addr: populate the allocated physical address here
93  * @size: the size of the address space that has to be allocated
94  *
95  * Invoke to allocate memory address from the EPC address space. This
96  * is usually done to map the remote RC address into the local system.
97  */
98 void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
99 				     phys_addr_t *phys_addr, size_t size)
100 {
101 	int pageno;
102 	void __iomem *virt_addr;
103 	struct pci_epc_mem *mem = epc->mem;
104 	int order = get_order(size);
105 
106 	pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order);
107 	if (pageno < 0)
108 		return NULL;
109 
110 	*phys_addr = mem->phys_base + (pageno << PAGE_SHIFT);
111 	virt_addr = ioremap(*phys_addr, size);
112 	if (!virt_addr)
113 		bitmap_release_region(mem->bitmap, pageno, order);
114 
115 	return virt_addr;
116 }
117 EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
118 
119 /**
120  * pci_epc_mem_free_addr() - free the allocated memory address
121  * @epc: the EPC device on which memory was allocated
122  * @phys_addr: the allocated physical address
123  * @virt_addr: virtual address of the allocated mem space
124  * @size: the size of the allocated address space
125  *
126  * Invoke to free the memory allocated using pci_epc_mem_alloc_addr.
127  */
128 void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
129 			   void __iomem *virt_addr, size_t size)
130 {
131 	int pageno;
132 	int order = get_order(size);
133 	struct pci_epc_mem *mem = epc->mem;
134 
135 	iounmap(virt_addr);
136 	pageno = (phys_addr - mem->phys_base) >> PAGE_SHIFT;
137 	bitmap_release_region(mem->bitmap, pageno, order);
138 }
139 EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);
140 
141 MODULE_DESCRIPTION("PCI EPC Address Space Management");
142 MODULE_AUTHOR("Kishon Vijay Abraham I <kishon@ti.com>");
143 MODULE_LICENSE("GPL v2");
144