drivers/pci/endpoint/pci-epc-mem.c

   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");