csky: use the generic remapping dma alloc implementation

The csky code was largely copied from arm/arm64, so switch to the
generic arm64-based implementation instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Guo Ren <ren_guo@c-sky.com>

arch/csky/Kconfig

@@ -8,7 +8,7 @@ config CSKY
 	select CLKSRC_MMIO
 	select CLKSRC_OF
 	select DMA_DIRECT_OPS
-	select DMA_REMAP
+	select DMA_DIRECT_REMAP
 	select IRQ_DOMAIN
 	select HANDLE_DOMAIN_IRQ
 	select DW_APB_TIMER_OF

arch/csky/mm/dma-mapping.c

@@ -14,73 +14,13 @@
 #include <linux/version.h>
 #include <asm/cache.h>
 
-static struct gen_pool *atomic_pool;
-static size_t atomic_pool_size __initdata = SZ_256K;
-
-static int __init early_coherent_pool(char *p)
-{
-	atomic_pool_size = memparse(p, &p);
-	return 0;
-}
-early_param("coherent_pool", early_coherent_pool);
-
 static int __init atomic_pool_init(void)
 {
-	struct page *page;
-	size_t size = atomic_pool_size;
-	void *ptr;
-	int ret;
-
-	atomic_pool = gen_pool_create(PAGE_SHIFT, -1);
-	if (!atomic_pool)
-		BUG();
-
-	page = alloc_pages(GFP_KERNEL, get_order(size));
-	if (!page)
-		BUG();
-
-	ptr = dma_common_contiguous_remap(page, size, VM_ALLOC,
-					  pgprot_noncached(PAGE_KERNEL),
-					  __builtin_return_address(0));
-	if (!ptr)
-		BUG();
-
-	ret = gen_pool_add_virt(atomic_pool, (unsigned long)ptr,
-				page_to_phys(page), atomic_pool_size, -1);
-	if (ret)
-		BUG();
-
-	gen_pool_set_algo(atomic_pool, gen_pool_first_fit_order_align, NULL);
-
-	pr_info("DMA: preallocated %zu KiB pool for atomic coherent pool\n",
-		atomic_pool_size / 1024);
-
-	pr_info("DMA: vaddr: 0x%x phy: 0x%lx,\n", (unsigned int)ptr,
-		page_to_phys(page));
-
-	return 0;
+	return dma_atomic_pool_init(GFP_KERNEL, pgprot_noncached(PAGE_KERNEL));
 }
 postcore_initcall(atomic_pool_init);
 
-static void *csky_dma_alloc_atomic(struct device *dev, size_t size,
-				   dma_addr_t *dma_handle)
-{
-	unsigned long addr;
-
-	addr = gen_pool_alloc(atomic_pool, size);
-	if (addr)
-		*dma_handle = gen_pool_virt_to_phys(atomic_pool, addr);
-
-	return (void *)addr;
-}
-
-static void csky_dma_free_atomic(struct device *dev, size_t size, void *vaddr,
-				 dma_addr_t dma_handle, unsigned long attrs)
-{
-	gen_pool_free(atomic_pool, (unsigned long)vaddr, size);
-}
-
-static void __dma_clear_buffer(struct page *page, size_t size)
+void arch_dma_prep_coherent(struct page *page, size_t size)
 {
 	if (PageHighMem(page)) {
 		unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
@@ -107,84 +47,6 @@ static void __dma_clear_buffer(struct page *page, size_t size)
 	}
 }
 
-static void *csky_dma_alloc_nonatomic(struct device *dev, size_t size,
-				      dma_addr_t *dma_handle, gfp_t gfp,
-				      unsigned long attrs)
-{
-	void  *vaddr;
-	struct page *page;
-	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
-
-	if (DMA_ATTR_NON_CONSISTENT & attrs) {
-		pr_err("csky %s can't support DMA_ATTR_NON_CONSISTENT.\n", __func__);
-		return NULL;
-	}
-
-	if (IS_ENABLED(CONFIG_DMA_CMA))
-		page = dma_alloc_from_contiguous(dev, count, get_order(size),
-						 gfp);
-	else
-		page = alloc_pages(gfp, get_order(size));
-
-	if (!page) {
-		pr_err("csky %s no more free pages.\n", __func__);
-		return NULL;
-	}
-
-	*dma_handle = page_to_phys(page);
-
-	__dma_clear_buffer(page, size);
-
-	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING)
-		return page;
-
-	vaddr = dma_common_contiguous_remap(page, PAGE_ALIGN(size), VM_USERMAP,
-		pgprot_noncached(PAGE_KERNEL), __builtin_return_address(0));
-	if (!vaddr)
-		BUG();
-
-	return vaddr;
-}
-
-static void csky_dma_free_nonatomic(
-	struct device *dev,
-	size_t size,
-	void *vaddr,
-	dma_addr_t dma_handle,
-	unsigned long attrs
-	)
-{
-	struct page *page = phys_to_page(dma_handle);
-	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
-
-	if ((unsigned int)vaddr >= VMALLOC_START)
-		dma_common_free_remap(vaddr, size, VM_USERMAP);
-
-	if (IS_ENABLED(CONFIG_DMA_CMA))
-		dma_release_from_contiguous(dev, page, count);
-	else
-		__free_pages(page, get_order(size));
-}
-
-void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
-		     gfp_t gfp, unsigned long attrs)
-{
-	if (gfpflags_allow_blocking(gfp))
-		return csky_dma_alloc_nonatomic(dev, size, dma_handle, gfp,
-						attrs);
-	else
-		return csky_dma_alloc_atomic(dev, size, dma_handle);
-}
-
-void arch_dma_free(struct device *dev, size_t size, void *vaddr,
-		   dma_addr_t dma_handle, unsigned long attrs)
-{
-	if (!addr_in_gen_pool(atomic_pool, (unsigned int) vaddr, size))
-		csky_dma_free_nonatomic(dev, size, vaddr, dma_handle, attrs);
-	else
-		csky_dma_free_atomic(dev, size, vaddr, dma_handle, attrs);
-}
-
 static inline void cache_op(phys_addr_t paddr, size_t size,
 			    void (*fn)(unsigned long start, unsigned long end))
 {