pci-epc-mem.c
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/**
* PCI Endpoint *Controller* Address Space Management
*
* Copyright (C) 2017 Texas Instruments
* Author: Kishon Vijay Abraham I <kishon@ti.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 of
* the License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/io.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/pci-epc.h>
/**
* pci_epc_mem_get_order() - determine the allocation order of a memory size
* @mem: address space of the endpoint controller
* @size: the size for which to get the order
*
* Reimplement get_order() for mem->page_size since the generic get_order
* always gets order with a constant PAGE_SIZE.
*/
static int pci_epc_mem_get_order(struct pci_epc_mem *mem, size_t size)
{
int order;
unsigned int page_shift = ilog2(mem->page_size);
size--;
size >>= page_shift;
#if BITS_PER_LONG == 32
order = fls(size);
#else
order = fls64(size);
#endif
return order;
}
/**
* __pci_epc_mem_init() - initialize the pci_epc_mem structure
* @epc: the EPC device that invoked pci_epc_mem_init
* @phys_base: the physical address of the base
* @size: the size of the address space
* @page_size: size of each page
*
* Invoke to initialize the pci_epc_mem structure used by the
* endpoint functions to allocate mapped PCI address.
*/
int __pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_base, size_t size,
size_t page_size)
{
int ret;
struct pci_epc_mem *mem;
unsigned long *bitmap;
unsigned int page_shift;
int pages;
int bitmap_size;
if (page_size < PAGE_SIZE)
page_size = PAGE_SIZE;
page_shift = ilog2(page_size);
pages = size >> page_shift;
bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
mem = kzalloc(sizeof(*mem), GFP_KERNEL);
if (!mem) {
ret = -ENOMEM;
goto err;
}
bitmap = kzalloc(bitmap_size, GFP_KERNEL);
if (!bitmap) {
ret = -ENOMEM;
goto err_mem;
}
mem->bitmap = bitmap;
mem->phys_base = phys_base;
mem->page_size = page_size;
mem->pages = pages;
mem->size = size;
epc->mem = mem;
return 0;
err_mem:
kfree(mem);
err:
return ret;
}
EXPORT_SYMBOL_GPL(__pci_epc_mem_init);
/**
* pci_epc_mem_exit() - cleanup the pci_epc_mem structure
* @epc: the EPC device that invoked pci_epc_mem_exit
*
* Invoke to cleanup the pci_epc_mem structure allocated in
* pci_epc_mem_init().
*/
void pci_epc_mem_exit(struct pci_epc *epc)
{
struct pci_epc_mem *mem = epc->mem;
epc->mem = NULL;
kfree(mem->bitmap);
kfree(mem);
}
EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
/**
* pci_epc_mem_alloc_addr() - allocate memory address from EPC addr space
* @epc: the EPC device on which memory has to be allocated
* @phys_addr: populate the allocated physical address here
* @size: the size of the address space that has to be allocated
*
* Invoke to allocate memory address from the EPC address space. This
* is usually done to map the remote RC address into the local system.
*/
void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
phys_addr_t *phys_addr, size_t size)
{
int pageno;
void __iomem *virt_addr;
struct pci_epc_mem *mem = epc->mem;
unsigned int page_shift = ilog2(mem->page_size);
int order;
size = ALIGN(size, mem->page_size);
order = pci_epc_mem_get_order(mem, size);
pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order);
if (pageno < 0)
return NULL;
*phys_addr = mem->phys_base + (pageno << page_shift);
virt_addr = ioremap(*phys_addr, size);
if (!virt_addr)
bitmap_release_region(mem->bitmap, pageno, order);
return virt_addr;
}
EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
/**
* pci_epc_mem_free_addr() - free the allocated memory address
* @epc: the EPC device on which memory was allocated
* @phys_addr: the allocated physical address
* @virt_addr: virtual address of the allocated mem space
* @size: the size of the allocated address space
*
* Invoke to free the memory allocated using pci_epc_mem_alloc_addr.
*/
void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
void __iomem *virt_addr, size_t size)
{
int pageno;
struct pci_epc_mem *mem = epc->mem;
unsigned int page_shift = ilog2(mem->page_size);
int order;
iounmap(virt_addr);
pageno = (phys_addr - mem->phys_base) >> page_shift;
size = ALIGN(size, mem->page_size);
order = pci_epc_mem_get_order(mem, size);
bitmap_release_region(mem->bitmap, pageno, order);
}
EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);
MODULE_DESCRIPTION("PCI EPC Address Space Management");
MODULE_AUTHOR("Kishon Vijay Abraham I <kishon@ti.com>");
MODULE_LICENSE("GPL v2");