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Commit 37134cd5 authored by Kevin Hilman's avatar Kevin Hilman Committed by Russell King
Browse files

[ARM] 3209/1: Configurable DMA-consistent memory region 



Patch from Kevin Hilman

This patch increase available DMA-consistent memory allocated by dma_coherent_alloc(). The default remains at 2M (defined in asm/memory.h) and each platform has the ability to override in asm/arch-foo/memory.h.

Signed-off-by: default avatarKevin Hilman <kevin@hilman.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent a3e49436

arch/arm/mm/consistent.c

+41 −12
Original line number Diff line number Diff line
@@ -20,15 +20,25 @@ 


#include <asm/cacheflush.h>

#include <asm/tlbflush.h>

#include <asm/sizes.h>



/* Sanity check size */

#if (CONSISTENT_DMA_SIZE % SZ_2M)

#error "CONSISTENT_DMA_SIZE must be multiple of 2MiB"

#endif



#define CONSISTENT_BASE	(0xffc00000)

#define CONSISTENT_END	(0xffe00000)

#define CONSISTENT_BASE	(CONSISTENT_END - CONSISTENT_DMA_SIZE)



#define CONSISTENT_OFFSET(x)	(((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)

#define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PGDIR_SHIFT)

#define NUM_CONSISTENT_PTES (CONSISTENT_DMA_SIZE >> PGDIR_SHIFT)





/*

 * This is the page table (2MB) covering uncached, DMA consistent allocations

 * These are the page tables (2MB each) covering uncached, DMA consistent allocations

 */

static pte_t *consistent_pte;

static pte_t *consistent_pte[NUM_CONSISTENT_PTES];

static DEFINE_SPINLOCK(consistent_lock);



/*
@@ -142,7 +152,7 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, 
	unsigned long order;

	u64 mask = ISA_DMA_THRESHOLD, limit;



	if (!consistent_pte) {

	if (!consistent_pte[0]) {

		printk(KERN_ERR "%s: not initialised\n", __func__);

		dump_stack();

		return NULL;
@@ -205,9 +215,12 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, 
	c = vm_region_alloc(&consistent_head, size,

			    gfp & ~(__GFP_DMA | __GFP_HIGHMEM));

	if (c) {

		pte_t *pte = consistent_pte + CONSISTENT_OFFSET(c->vm_start);

		pte_t *pte;

		struct page *end = page + (1 << order);

		int idx = CONSISTENT_PTE_INDEX(c->vm_start);

		u32 off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);



		pte = consistent_pte[idx] + off;

		c->vm_pages = page;



		/*
@@ -226,6 +239,11 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp, 
			set_pte(pte, mk_pte(page, prot));

			page++;

			pte++;

			off++;

			if (off >= PTRS_PER_PTE) {

				off = 0;

				pte = consistent_pte[++idx];

			}

		} while (size -= PAGE_SIZE);



		/*
@@ -327,6 +345,8 @@ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr 
	struct vm_region *c;

	unsigned long flags, addr;

	pte_t *ptep;

	int idx;

	u32 off;



	WARN_ON(irqs_disabled());
@@ -347,7 +367,9 @@ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr 
		size = c->vm_end - c->vm_start;

	}



	ptep = consistent_pte + CONSISTENT_OFFSET(c->vm_start);

	idx = CONSISTENT_PTE_INDEX(c->vm_start);

	off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);

	ptep = consistent_pte[idx] + off;

	addr = c->vm_start;

	do {

		pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);
@@ -355,6 +377,11 @@ void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr 


		ptep++;

		addr += PAGE_SIZE;

		off++;

		if (off >= PTRS_PER_PTE) {

			off = 0;

			ptep = consistent_pte[++idx];

		}



		if (!pte_none(pte) && pte_present(pte)) {

			pfn = pte_pfn(pte);
@@ -401,11 +428,12 @@ static int __init consistent_init(void) 
	pgd_t *pgd;

	pmd_t *pmd;

	pte_t *pte;

	int ret = 0;

	int ret = 0, i = 0;

	u32 base = CONSISTENT_BASE;



	do {

		pgd = pgd_offset(&init_mm, CONSISTENT_BASE);

		pmd = pmd_alloc(&init_mm, pgd, CONSISTENT_BASE);

		pgd = pgd_offset(&init_mm, base);

		pmd = pmd_alloc(&init_mm, pgd, base);

		if (!pmd) {

			printk(KERN_ERR "%s: no pmd tables\n", __func__);

			ret = -ENOMEM;
@@ -413,15 +441,16 @@ static int __init consistent_init(void) 
		}

		WARN_ON(!pmd_none(*pmd));



		pte = pte_alloc_kernel(pmd, CONSISTENT_BASE);

		pte = pte_alloc_kernel(pmd, base);

		if (!pte) {

			printk(KERN_ERR "%s: no pte tables\n", __func__);

			ret = -ENOMEM;

			break;

		}



		consistent_pte = pte;

	} while (0);

		consistent_pte[i++] = pte;

		base += (1 << PGDIR_SHIFT);

	} while (base < CONSISTENT_END);



	return ret;

}

include/asm-arm/memory.h

+9 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <linux/config.h>

#include <linux/compiler.h>

#include <asm/arch/memory.h>

#include <asm/sizes.h>



#ifndef TASK_SIZE

/*
@@ -47,6 +48,14 @@ 
#define PAGE_OFFSET		UL(0xc0000000)

#endif



/*

 * Size of DMA-consistent memory region.  Must be multiple of 2M,

 * between 2MB and 14MB inclusive.

 */

#ifndef CONSISTENT_DMA_SIZE

#define CONSISTENT_DMA_SIZE SZ_2M

#endif



/*

 * Physical vs virtual RAM address space conversion.  These are

 * private definitions which should NOT be used outside memory.h