* [PATCH] nds32: use the generic remapping allocator for coherent DMA allocations
2019-06-14 10:09 [RFC] switch nds32 to use the generic remapping DMA allocator Christoph Hellwig
@ 2019-06-14 10:09 ` Christoph Hellwig
2019-06-14 11:35 ` [RFC] switch nds32 to use the generic remapping DMA allocator Greentime Hu
1 sibling, 0 replies; 6+ messages in thread
From: Christoph Hellwig @ 2019-06-14 10:09 UTC (permalink / raw)
To: Greentime Hu, Vincent Chen; +Cc: iommu, linux-kernel
Replace the code that sets up uncached PTEs with the generic vmap based
remapping code. It also provides an atomic pool for allocations from
non-blocking context, which we not properly supported by the existing
nds32 code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
arch/nds32/Kconfig | 2 +
arch/nds32/kernel/dma.c | 325 ++--------------------------------------
2 files changed, 13 insertions(+), 314 deletions(-)
diff --git a/arch/nds32/Kconfig b/arch/nds32/Kconfig
index 3299e287a477..643ea6b4bfa2 100644
--- a/arch/nds32/Kconfig
+++ b/arch/nds32/Kconfig
@@ -7,12 +7,14 @@
config NDS32
def_bool y
select ARCH_32BIT_OFF_T
+ select ARCH_HAS_DMA_PREP_COHERENT
select ARCH_HAS_SYNC_DMA_FOR_CPU
select ARCH_HAS_SYNC_DMA_FOR_DEVICE
select ARCH_WANT_FRAME_POINTERS if FTRACE
select CLKSRC_MMIO
select CLONE_BACKWARDS
select COMMON_CLK
+ select DMA_DIRECT_REMAP
select GENERIC_ATOMIC64
select GENERIC_CPU_DEVICES
select GENERIC_CLOCKEVENTS
diff --git a/arch/nds32/kernel/dma.c b/arch/nds32/kernel/dma.c
index d0dbd4fe9645..490e3720d694 100644
--- a/arch/nds32/kernel/dma.c
+++ b/arch/nds32/kernel/dma.c
@@ -3,327 +3,13 @@
#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))
{
@@ -389,3 +75,14 @@ void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
BUG();
}
}
+
+void arch_dma_prep_coherent(struct page *page, size_t size)
+{
+ cache_op(page_to_phys(page), size, cpu_dma_wbinval_range);
+}
+
+static int __init atomic_pool_init(void)
+{
+ return dma_atomic_pool_init(GFP_KERNEL, pgprot_noncached(PAGE_KERNEL));
+}
+postcore_initcall(atomic_pool_init);
--
2.20.1
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