// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2005-2017 Andes Technology Corporation
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/dma-noncoherent.h>
#include <linux/io.h>
#include <linux/cache.h>
#include <linux/highmem.h>
#include <linux/slab.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/proc-fns.h>
/*
* This is the page table (2MB) covering uncached, DMA consistent allocations
*/
static pte_t *consistent_pte;
static DEFINE_RAW_SPINLOCK(consistent_lock);
/*
* VM region handling support.
*
* This should become something generic, handling VM region allocations for
* vmalloc and similar (ioremap, module space, etc).
*
* I envisage vmalloc()'s supporting vm_struct becoming:
*
* struct vm_struct {
* struct vm_region region;
* unsigned long flags;
* struct page **pages;
* unsigned int nr_pages;
* unsigned long phys_addr;
* };
*
* get_vm_area() would then call vm_region_alloc with an appropriate
* struct vm_region head (eg):
*
* struct vm_region vmalloc_head = {
* .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list),
* .vm_start = VMALLOC_START,
* .vm_end = VMALLOC_END,
* };
*
* However, vmalloc_head.vm_start is variable (typically, it is dependent on
* the amount of RAM found at boot time.) I would imagine that get_vm_area()
* would have to initialise this each time prior to calling vm_region_alloc().
*/
struct arch_vm_region {
struct list_head vm_list;
unsigned long vm_start;
unsigned long vm_end;
struct page *vm_pages;
};
static struct arch_vm_region consistent_head = {
.vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
.vm_start = CONSISTENT_BASE,
.vm_end = CONSISTENT_END,
};
static struct arch_vm_region *vm_region_alloc(struct arch_vm_region *head,
size_t size, int gfp)
{
unsigned long addr = head->vm_start, end = head->vm_end - size;
unsigned long flags;
struct arch_vm_region *c, *new;
new = kmalloc(sizeof(struct arch_vm_region), gfp);
if (!new)
goto out;
raw_spin_lock_irqsave(&consistent_lock, flags);
list_for_each_entry(c, &head->vm_list, vm_list) {
if ((addr + size) < addr)
goto nospc;
if ((addr + size) <= c->vm_start)
goto found;
addr = c->vm_end;
if (addr > end)
goto nospc;
}
found:
/*
* Insert this entry _before_ the one we found.
*/
list_add_tail(&new->vm_list, &c->vm_list);
new->vm_start = addr;
new->vm_end = addr + size;
raw_spin_unlock_irqrestore(&consistent_lock, flags);
return new;
nospc:
raw_spin_unlock_irqrestore(&consistent_lock, flags);
kfree(new);
out:
return NULL;
}
static struct arch_vm_region *vm_region_find(struct arch_vm_region *head,
unsigned long addr)
{
struct arch_vm_region *c;
list_for_each_entry(c, &head->vm_list, vm_list) {
if (c->vm_start == addr)
goto out;
}
c = NULL;
out:
return c;
}
void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
gfp_t gfp, unsigned long attrs)
{
struct page *page;
struct arch_vm_region *c;
unsigned long order;
u64 mask = ~0ULL, limit;
pgprot_t prot = pgprot_noncached(PAGE_KERNEL);
if (!consistent_pte) {
pr_err("%s: not initialized\n", __func__);
dump_stack();
return NULL;
}
if (dev) {
mask = dev->coherent_dma_mask;
/*
* Sanity check the DMA mask - it must be non-zero, and
* must be able to be satisfied by a DMA allocation.
*/
if (mask == 0) {
dev_warn(dev, "coherent DMA mask is unset\n");
goto no_page;
}
}
/*
* Sanity check the allocation size.
*/
size = PAGE_ALIGN(size);
limit = (mask + 1) & ~mask;
if ((limit && size >= limit) ||
size >= (CONSISTENT_END - CONSISTENT_BASE)) {
pr_warn("coherent allocation too big "
"(requested %#x mask %#llx)\n", size, mask);
goto no_page;
}
order = get_order(size);
if (mask != 0xffffffff)
gfp |= GFP_DMA;
page = alloc_pages(gfp, order);
if (!page)
goto no_page;
/*
* Invalidate any data that might be lurking in the
* kernel direct-mapped region for device DMA.
*/
{
unsigned long kaddr = (unsigned long)page_address(page);
memset(page_address(page), 0, size);
cpu_dma_wbinval_range(kaddr, kaddr + size);
}
/*
* Allocate a virtual address in the consistent mapping region.
*/
c = vm_region_alloc(&consistent_head, size,
gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
if (c) {
pte_t *pte = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
struct page *end = page + (1 << order);
c->vm_pages = page;
/*
* Set the "dma handle"
*/
*handle = page_to_phys(page);
do {
BUG_ON(!pte_none(*pte));
/*
* x86 does not mark the pages reserved...
*/
SetPageReserved(page);
set_pte(pte, mk_pte(page, prot));
page++;
pte++;
} while (size -= PAGE_SIZE);
/*
* Free the otherwise unused pages.
*/
while (page < end) {
__free_page(page);
page++;
}
return (void *)c->vm_start;
}
if (page)
__free_pages(page, order);
no_page:
*handle = ~0;
return NULL;
}
void arch_dma_free(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t handle, unsigned long attrs)
{
struct arch_vm_region *c;
unsigned long flags, addr;
pte_t *ptep;
size = PAGE_ALIGN(size);
raw_spin_lock_irqsave(&consistent_lock, flags);
c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
if (!c)
goto no_area;
if ((c->vm_end - c->vm_start) != size) {
pr_err("%s: freeing wrong coherent size (%ld != %d)\n",
__func__, c->vm_end - c->vm_start, size);
dump_stack();
size = c->vm_end - c->vm_start;
}
ptep = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
addr = c->vm_start;
do {
pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);
unsigned long pfn;
ptep++;
addr += PAGE_SIZE;
if (!pte_none(pte) && pte_present(pte)) {
pfn = pte_pfn(pte);
if (pfn_valid(pfn)) {
struct page *page = pfn_to_page(pfn);
/*
* x86 does not mark the pages reserved...
*/
ClearPageReserved(page);
__free_page(page);
continue;
}
}
pr_crit("%s: bad page in kernel page table\n", __func__);
} while (size -= PAGE_SIZE);
flush_tlb_kernel_range(c->vm_start, c->vm_end);
list_del(&c->vm_list);
raw_spin_unlock_irqrestore(&consistent_lock, flags);
kfree(c);
return;
no_area:
raw_spin_unlock_irqrestore(&consistent_lock, flags);
pr_err("%s: trying to free invalid coherent area: %p\n",
__func__, cpu_addr);
dump_stack();
}
/*
* Initialise the consistent memory allocation.
*/
static int __init consistent_init(void)
{
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
int ret = 0;
do {
pgd = pgd_offset(&init_mm, CONSISTENT_BASE);
pmd = pmd_alloc(&init_mm, pgd, CONSISTENT_BASE);
if (!pmd) {
pr_err("%s: no pmd tables\n", __func__);
ret = -ENOMEM;
break;
}
/* The first level mapping may be created in somewhere.
* It's not necessary to warn here. */
/* WARN_ON(!pmd_none(*pmd)); */
pte = pte_alloc_kernel(pmd, CONSISTENT_BASE);
if (!pte) {
ret = -ENOMEM;
break;
}
consistent_pte = pte;
} while (0);
return ret;
}
core_initcall(consistent_init);
static inline void cache_op(phys_addr_t paddr, size_t size,
void (*fn)(unsigned long start, unsigned long end))
{
struct page *page = pfn_to_page(paddr >> PAGE_SHIFT);
unsigned offset = paddr & ~PAGE_MASK;
size_t left = size;
unsigned long start;
do {
size_t len = left;
if (PageHighMem(page)) {
void *addr;
if (offset + len > PAGE_SIZE) {
if (offset >= PAGE_SIZE) {
page += offset >> PAGE_SHIFT;
offset &= ~PAGE_MASK;
}
len = PAGE_SIZE - offset;
}
addr = kmap_atomic(page);
start = (unsigned long)(addr + offset);
fn(start, start + len);
kunmap_atomic(addr);
} else {
start = (unsigned long)phys_to_virt(paddr);
fn(start, start + size);
}
offset = 0;
page++;
left -= len;
} while (left);
}
void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,
size_t size, enum dma_data_direction dir)
{
switch (dir) {
case DMA_FROM_DEVICE:
break;
case DMA_TO_DEVICE:
case DMA_BIDIRECTIONAL:
cache_op(paddr, size, cpu_dma_wb_range);
break;
default:
BUG();
}
}
void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
size_t size, enum dma_data_direction dir)
{
switch (dir) {
case DMA_TO_DEVICE:
break;
case DMA_FROM_DEVICE:
case DMA_BIDIRECTIONAL:
cache_op(paddr, size, cpu_dma_inval_range);
break;
default:
BUG();
}
}
