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

   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  */
  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->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_mem_init() - initialize the pci_epc_mem structure
  40  * @epc: the EPC device that invoked pci_epc_mem_init
  41  * @phys_base: the physical address of the base
  42  * @size: the size of the address space
  43  * @page_size: size of each page
  44  *
  45  * Invoke to initialize the pci_epc_mem structure used by the
  46  * endpoint functions to allocate mapped PCI address.
  47  */
  48 int __pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_base, size_t size,
  49                        size_t page_size)
  50 {
  51         int ret;
  52         struct pci_epc_mem *mem;
  53         unsigned long *bitmap;
  54         unsigned int page_shift;
  55         int pages;
  56         int bitmap_size;
  57
  58         if (page_size < PAGE_SIZE)
  59                 page_size = PAGE_SIZE;
  60
  61         page_shift = ilog2(page_size);
  62         pages = size >> page_shift;
  63         bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
  64
  65         mem = kzalloc(sizeof(*mem), GFP_KERNEL);
  66         if (!mem) {
  67                 ret = -ENOMEM;
  68                 goto err;
  69         }
  70
  71         bitmap = kzalloc(bitmap_size, GFP_KERNEL);
  72         if (!bitmap) {
  73                 ret = -ENOMEM;
  74                 goto err_mem;
  75         }
  76
  77         mem->bitmap = bitmap;
  78         mem->phys_base = phys_base;
  79         mem->page_size = page_size;
  80         mem->pages = pages;
  81         mem->size = size;
  82
  83         epc->mem = mem;
  84
  85         return 0;
  86
  87 err_mem:
  88         kfree(mem);
  89
  90 err:
  91 return ret;
  92 }
  93 EXPORT_SYMBOL_GPL(__pci_epc_mem_init);
  94
  95 /**
  96  * pci_epc_mem_exit() - cleanup the pci_epc_mem structure
  97  * @epc: the EPC device that invoked pci_epc_mem_exit
  98  *
  99  * Invoke to cleanup the pci_epc_mem structure allocated in
 100  * pci_epc_mem_init().
 101  */
 102 void pci_epc_mem_exit(struct pci_epc *epc)
 103 {
 104         struct pci_epc_mem *mem = epc->mem;
 105
 106         epc->mem = NULL;
 107         kfree(mem->bitmap);
 108         kfree(mem);
 109 }
 110 EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
 111
 112 /**
 113  * pci_epc_mem_alloc_addr() - allocate memory address from EPC addr space
 114  * @epc: the EPC device on which memory has to be allocated
 115  * @phys_addr: populate the allocated physical address here
 116  * @size: the size of the address space that has to be allocated
 117  *
 118  * Invoke to allocate memory address from the EPC address space. This
 119  * is usually done to map the remote RC address into the local system.
 120  */
 121 void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
 122                                      phys_addr_t *phys_addr, size_t size)
 123 {
 124         int pageno;
 125         void __iomem *virt_addr;
 126         struct pci_epc_mem *mem = epc->mem;
 127         unsigned int page_shift = ilog2(mem->page_size);
 128         int order;
 129
 130         size = ALIGN(size, mem->page_size);
 131         order = pci_epc_mem_get_order(mem, size);
 132
 133         pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order);
 134         if (pageno < 0)
 135                 return NULL;
 136
 137         *phys_addr = mem->phys_base + ((phys_addr_t)pageno << page_shift);
 138         virt_addr = ioremap(*phys_addr, size);
 139         if (!virt_addr)
 140                 bitmap_release_region(mem->bitmap, pageno, order);
 141
 142         return virt_addr;
 143 }
 144 EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
 145
 146 /**
 147  * pci_epc_mem_free_addr() - free the allocated memory address
 148  * @epc: the EPC device on which memory was allocated
 149  * @phys_addr: the allocated physical address
 150  * @virt_addr: virtual address of the allocated mem space
 151  * @size: the size of the allocated address space
 152  *
 153  * Invoke to free the memory allocated using pci_epc_mem_alloc_addr.
 154  */
 155 void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
 156                            void __iomem *virt_addr, size_t size)
 157 {
 158         int pageno;
 159         struct pci_epc_mem *mem = epc->mem;
 160         unsigned int page_shift = ilog2(mem->page_size);
 161         int order;
 162
 163         iounmap(virt_addr);
 164         pageno = (phys_addr - mem->phys_base) >> page_shift;
 165         size = ALIGN(size, mem->page_size);
 166         order = pci_epc_mem_get_order(mem, size);
 167         bitmap_release_region(mem->bitmap, pageno, order);
 168 }
 169 EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);
 170
 171 MODULE_DESCRIPTION("PCI EPC Address Space Management");
 172 MODULE_AUTHOR("Kishon Vijay Abraham I <kishon@ti.com>");
 173 MODULE_LICENSE("GPL v2");