microblaze: use the generic dma coherent remap allocator

This switches to using common code for the DMA allocations, including
potential use of the CMA allocator if configured.

Switching to the generic code enables DMA allocations from atomic
context, which is required by the DMA API documentation, and also
adds various other minor features drivers start relying upon.  It
also makes sure we have on tested code base for all architectures
that require uncached pte bits for coherent DMA allocations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/microblaze/Kconfig

@@ -17,6 +17,7 @@ config MICROBLAZE
 	select TIMER_OF
 	select CLONE_BACKWARDS3
 	select COMMON_CLK
+	select DMA_DIRECT_REMAP if MMU
 	select GENERIC_ATOMIC64
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_CPU_DEVICES

arch/microblaze/mm/consistent.c

@@ -4,43 +4,16 @@
  * Copyright (C) 2010 Michal Simek <monstr@monstr.eu>
  * Copyright (C) 2010 PetaLogix
  * Copyright (C) 2005 John Williams <jwilliams@itee.uq.edu.au>
- *
- * Based on PowerPC version derived from arch/arm/mm/consistent.c
- * Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
- * Copyright (C) 2000 Russell King
  */
 
-#include <linux/export.h>
-#include <linux/signal.h>
-#include <linux/sched.h>
 #include <linux/kernel.h>
-#include <linux/errno.h>
 #include <linux/string.h>
 #include <linux/types.h>
-#include <linux/ptrace.h>
-#include <linux/mman.h>
 #include <linux/mm.h>
-#include <linux/swap.h>
-#include <linux/stddef.h>
-#include <linux/vmalloc.h>
 #include <linux/init.h>
-#include <linux/delay.h>
-#include <linux/memblock.h>
-#include <linux/highmem.h>
-#include <linux/pci.h>
-#include <linux/interrupt.h>
-#include <linux/gfp.h>
 #include <linux/dma-noncoherent.h>
-
-#include <asm/pgalloc.h>
-#include <linux/io.h>
-#include <linux/hardirq.h>
-#include <linux/mmu_context.h>
-#include <asm/mmu.h>
-#include <linux/uaccess.h>
-#include <asm/pgtable.h>
 #include <asm/cpuinfo.h>
-#include <asm/tlbflush.h>
+#include <asm/cacheflush.h>
 
 void arch_dma_prep_coherent(struct page *page, size_t size)
 {
@@ -84,126 +57,9 @@ void *cached_kernel_address(void *ptr)
 	return (void *)(addr & ~UNCACHED_SHADOW_MASK);
 }
 #else /* CONFIG_MMU */
-void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
-		gfp_t gfp, unsigned long attrs)
+static int __init atomic_pool_init(void)
 {
-	unsigned long order, vaddr;
-	void *ret;
-	unsigned int i, err = 0;
-	struct page *page, *end;
-	phys_addr_t pa;
-	struct vm_struct *area;
-	unsigned long va;
-
-	if (in_interrupt())
-		BUG();
-
-	/* Only allocate page size areas. */
-	size = PAGE_ALIGN(size);
-	order = get_order(size);
-
-	vaddr = __get_free_pages(gfp | __GFP_ZERO, order);
-	if (!vaddr)
-		return NULL;
-
-	/*
-	 * we need to ensure that there are no cachelines in use,
-	 * or worse dirty in this area.
-	 */
-	arch_dma_prep_coherent(virt_to_page((unsigned long)vaddr), size);
-
-	/* Allocate some common virtual space to map the new pages. */
-	area = get_vm_area(size, VM_ALLOC);
-	if (!area) {
-		free_pages(vaddr, order);
-		return NULL;
-	}
-	va = (unsigned long) area->addr;
-	ret = (void *)va;
-
-	/* This gives us the real physical address of the first page. */
-	*dma_handle = pa = __virt_to_phys(vaddr);
-
-	/*
-	 * free wasted pages.  We skip the first page since we know
-	 * that it will have count = 1 and won't require freeing.
-	 * We also mark the pages in use as reserved so that
-	 * remap_page_range works.
-	 */
-	page = virt_to_page(vaddr);
-	end = page + (1 << order);
-
-	split_page(page, order);
-
-	for (i = 0; i < size && err == 0; i += PAGE_SIZE) {
-		/* MS: This is the whole magic - use cache inhibit pages */
-		err = map_page(va + i, pa + i, _PAGE_KERNEL | _PAGE_NO_CACHE);
-
-		SetPageReserved(page);
-		page++;
-	}
-
-	/* Free the otherwise unused pages. */
-	while (page < end) {
-		__free_page(page);
-		page++;
-	}
-
-	if (err) {
-		free_pages(vaddr, order);
-		return NULL;
-	}
-
-	return ret;
-}
-
-static pte_t *consistent_virt_to_pte(void *vaddr)
-{
-	unsigned long addr = (unsigned long)vaddr;
-
-	return pte_offset_kernel(pmd_offset(pgd_offset_k(addr), addr), addr);
-}
-
-long arch_dma_coherent_to_pfn(struct device *dev, void *vaddr,
-		dma_addr_t dma_addr)
-{
-	pte_t *ptep = consistent_virt_to_pte(vaddr);
-
-	if (pte_none(*ptep) || !pte_present(*ptep))
-		return 0;
-
-	return pte_pfn(*ptep);
-}
-
-/*
- * free page(s) as defined by the above mapping.
- */
-void arch_dma_free(struct device *dev, size_t size, void *vaddr,
-		dma_addr_t dma_addr, unsigned long attrs)
-{
-	struct page *page;
-
-	if (in_interrupt())
-		BUG();
-
-	size = PAGE_ALIGN(size);
-
-	do {
-		pte_t *ptep = consistent_virt_to_pte(vaddr);
-		unsigned long pfn;
-
-		if (!pte_none(*ptep) && pte_present(*ptep)) {
-			pfn = pte_pfn(*ptep);
-			pte_clear(&init_mm, (unsigned int)vaddr, ptep);
-			if (pfn_valid(pfn)) {
-				page = pfn_to_page(pfn);
-				__free_reserved_page(page);
-			}
-		}
-		vaddr += PAGE_SIZE;
-	} while (size -= PAGE_SIZE);
-
-	/* flush tlb */
-	flush_tlb_all();
+	return dma_atomic_pool_init(GFP_KERNEL, pgprot_noncached(PAGE_KERNEL));
 }
+postcore_initcall(atomic_pool_init);
 #endif /* CONFIG_MMU */