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// SPDX-License-Identifier: GPL-2.0
/*
* PCI Endpoint *Controller* Address Space Management
*
* Copyright (C) 2017 Texas Instruments
* Author: Kishon Vijay Abraham I <kishon@ti.com>
*/
#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->window.page_size);
size--;
size >>= page_shift;
#if BITS_PER_LONG == 32
order = fls(size);
#else
order = fls64(size);
#endif
return order;
}
/**
* pci_epc_multi_mem_init() - initialize the pci_epc_mem structure
* @epc: the EPC device that invoked pci_epc_mem_init
* @windows: pointer to windows supported by the device
* @num_windows: number of windows device supports
*
* Invoke to initialize the pci_epc_mem structure used by the
* endpoint functions to allocate mapped PCI address.
*/
int pci_epc_multi_mem_init(struct pci_epc *epc,
struct pci_epc_mem_window *windows,
unsigned int num_windows)
{
struct pci_epc_mem *mem = NULL;
unsigned long *bitmap = NULL;
unsigned int page_shift;
size_t page_size;
int bitmap_size;
int pages;
int ret;
int i;
epc->num_windows = 0;
if (!windows || !num_windows)
return -EINVAL;
epc->windows = kcalloc(num_windows, sizeof(*epc->windows), GFP_KERNEL);
if (!epc->windows)
return -ENOMEM;
for (i = 0; i < num_windows; i++) {
page_size = windows[i].page_size;
if (page_size < PAGE_SIZE)
page_size = PAGE_SIZE;
page_shift = ilog2(page_size);
pages = windows[i].size >> page_shift;
bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
mem = kzalloc(sizeof(*mem), GFP_KERNEL);
if (!mem) {
ret = -ENOMEM;
i--;
goto err_mem;
}
bitmap = kzalloc(bitmap_size, GFP_KERNEL);
if (!bitmap) {
ret = -ENOMEM;
kfree(mem);
i--;
goto err_mem;
}
mem->window.phys_base = windows[i].phys_base;
mem->window.size = windows[i].size;
mem->window.page_size = page_size;
mem->bitmap = bitmap;
mem->pages = pages;
mutex_init(&mem->lock);
epc->windows[i] = mem;
}
epc->mem = epc->windows[0];
epc->num_windows = num_windows;
return 0;
err_mem:
for (; i >= 0; i--) {
mem = epc->windows[i];
kfree(mem->bitmap);
kfree(mem);
}
kfree(epc->windows);
return ret;
}
EXPORT_SYMBOL_GPL(pci_epc_multi_mem_init);
/**
* pci_epc_mem_init() - Initialize the pci_epc_mem structure
* @epc: the EPC device that invoked pci_epc_mem_init
* @base: Physical address of the window region
* @size: Total Size of the window region
* @page_size: Page size of the window region
*
* Invoke to initialize a single pci_epc_mem structure used by the
* endpoint functions to allocate memory for mapping the PCI host memory
*/
int pci_epc_mem_init(struct pci_epc *epc, phys_addr_t base,
size_t size, size_t page_size)
{
struct pci_epc_mem_window mem_window;
mem_window.phys_base = base;
mem_window.size = size;
mem_window.page_size = page_size;
return pci_epc_multi_mem_init(epc, &mem_window, 1);
}
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;
int i;
if (!epc->num_windows)
return;
for (i = 0; i < epc->num_windows; i++) {
mem = epc->windows[i];
kfree(mem->bitmap);
kfree(mem);
}
kfree(epc->windows);
epc->windows = NULL;
epc->mem = NULL;
epc->num_windows = 0;
}
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)
{
void __iomem *virt_addr;
struct pci_epc_mem *mem;
unsigned int page_shift;
size_t align_size;
int pageno;
int order;
int i;
for (i = 0; i < epc->num_windows; i++) {
mem = epc->windows[i];
if (size > mem->window.size)
continue;
align_size = ALIGN(size, mem->window.page_size);
order = pci_epc_mem_get_order(mem, align_size);
mutex_lock(&mem->lock);
pageno = bitmap_find_free_region(mem->bitmap, mem->pages,
order);
if (pageno >= 0) {
page_shift = ilog2(mem->window.page_size);
*phys_addr = mem->window.phys_base +
((phys_addr_t)pageno << page_shift);
virt_addr = ioremap(*phys_addr, align_size);
if (!virt_addr) {
bitmap_release_region(mem->bitmap,
pageno, order);
mutex_unlock(&mem->lock);
continue;
}
mutex_unlock(&mem->lock);
return virt_addr;
}
mutex_unlock(&mem->lock);
}
return NULL;
}
EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
static struct pci_epc_mem *pci_epc_get_matching_window(struct pci_epc *epc,
phys_addr_t phys_addr)
{
struct pci_epc_mem *mem;
int i;
for (i = 0; i < epc->num_windows; i++) {
mem = epc->windows[i];
if (phys_addr >= mem->window.phys_base &&
phys_addr < (mem->window.phys_base + mem->window.size))
return mem;
}
return NULL;
}
/**
* 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)
{
struct pci_epc_mem *mem;
unsigned int page_shift;
size_t page_size;
int pageno;
int order;
mem = pci_epc_get_matching_window(epc, phys_addr);
if (!mem) {
pr_err("failed to get matching window\n");
return;
}
page_size = mem->window.page_size;
page_shift = ilog2(page_size);
iounmap(virt_addr);
pageno = (phys_addr - mem->window.phys_base) >> page_shift;
size = ALIGN(size, page_size);
order = pci_epc_mem_get_order(mem, size);
mutex_lock(&mem->lock);
bitmap_release_region(mem->bitmap, pageno, order);
mutex_unlock(&mem->lock);
}
EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);
MODULE_DESCRIPTION("PCI EPC Address Space Management");
MODULE_AUTHOR("Kishon Vijay Abraham I <kishon@ti.com>");