diff options
Diffstat (limited to 'kernel/dma')
| -rw-r--r-- | kernel/dma/Kconfig | 5 | ||||
| -rw-r--r-- | kernel/dma/remap.c | 158 |
2 files changed, 162 insertions, 1 deletions
diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig index c92e08173ed8..41c3b1df70eb 100644 --- a/kernel/dma/Kconfig +++ b/kernel/dma/Kconfig @@ -55,3 +55,8 @@ config SWIOTLB config DMA_REMAP depends on MMU bool + +config DMA_DIRECT_REMAP + bool + depends on DMA_DIRECT_OPS + select DMA_REMAP diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c index a15c393ea4e5..b32bb08f96ae 100644 --- a/kernel/dma/remap.c +++ b/kernel/dma/remap.c @@ -1,8 +1,13 @@ // SPDX-License-Identifier: GPL-2.0 /* + * Copyright (C) 2012 ARM Ltd. * Copyright (c) 2014 The Linux Foundation */ -#include <linux/dma-mapping.h> +#include <linux/dma-direct.h> +#include <linux/dma-noncoherent.h> +#include <linux/dma-contiguous.h> +#include <linux/init.h> +#include <linux/genalloc.h> #include <linux/slab.h> #include <linux/vmalloc.h> @@ -86,3 +91,154 @@ void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags) unmap_kernel_range((unsigned long)cpu_addr, PAGE_ALIGN(size)); vunmap(cpu_addr); } + +#ifdef CONFIG_DMA_DIRECT_REMAP +static struct gen_pool *atomic_pool __ro_after_init; + +#define DEFAULT_DMA_COHERENT_POOL_SIZE SZ_256K +static size_t atomic_pool_size __initdata = DEFAULT_DMA_COHERENT_POOL_SIZE; + +static int __init early_coherent_pool(char *p) +{ + atomic_pool_size = memparse(p, &p); + return 0; +} +early_param("coherent_pool", early_coherent_pool); + +int __init dma_atomic_pool_init(gfp_t gfp, pgprot_t prot) +{ + unsigned int pool_size_order = get_order(atomic_pool_size); + unsigned long nr_pages = atomic_pool_size >> PAGE_SHIFT; + struct page *page; + void *addr; + int ret; + + if (dev_get_cma_area(NULL)) + page = dma_alloc_from_contiguous(NULL, nr_pages, + pool_size_order, false); + else + page = alloc_pages(gfp, pool_size_order); + if (!page) + goto out; + + memset(page_address(page), 0, atomic_pool_size); + arch_dma_prep_coherent(page, atomic_pool_size); + + atomic_pool = gen_pool_create(PAGE_SHIFT, -1); + if (!atomic_pool) + goto free_page; + + addr = dma_common_contiguous_remap(page, atomic_pool_size, VM_USERMAP, + prot, __builtin_return_address(0)); + if (!addr) + goto destroy_genpool; + + ret = gen_pool_add_virt(atomic_pool, (unsigned long)addr, + page_to_phys(page), atomic_pool_size, -1); + if (ret) + goto remove_mapping; + gen_pool_set_algo(atomic_pool, gen_pool_first_fit_order_align, NULL); + + pr_info("DMA: preallocated %zu KiB pool for atomic allocations\n", + atomic_pool_size / 1024); + return 0; + +remove_mapping: + dma_common_free_remap(addr, atomic_pool_size, VM_USERMAP); +destroy_genpool: + gen_pool_destroy(atomic_pool); + atomic_pool = NULL; +free_page: + if (!dma_release_from_contiguous(NULL, page, nr_pages)) + __free_pages(page, pool_size_order); +out: + pr_err("DMA: failed to allocate %zu KiB pool for atomic coherent allocation\n", + atomic_pool_size / 1024); + return -ENOMEM; +} + +bool dma_in_atomic_pool(void *start, size_t size) +{ + return addr_in_gen_pool(atomic_pool, (unsigned long)start, size); +} + +void *dma_alloc_from_pool(size_t size, struct page **ret_page, gfp_t flags) +{ + unsigned long val; + void *ptr = NULL; + + if (!atomic_pool) { + WARN(1, "coherent pool not initialised!\n"); + return NULL; + } + + val = gen_pool_alloc(atomic_pool, size); + if (val) { + phys_addr_t phys = gen_pool_virt_to_phys(atomic_pool, val); + + *ret_page = pfn_to_page(__phys_to_pfn(phys)); + ptr = (void *)val; + memset(ptr, 0, size); + } + + return ptr; +} + +bool dma_free_from_pool(void *start, size_t size) +{ + if (!dma_in_atomic_pool(start, size)) + return false; + gen_pool_free(atomic_pool, (unsigned long)start, size); + return true; +} + +void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, + gfp_t flags, unsigned long attrs) +{ + struct page *page = NULL; + void *ret, *kaddr; + + size = PAGE_ALIGN(size); + + if (!gfpflags_allow_blocking(flags)) { + ret = dma_alloc_from_pool(size, &page, flags); + if (!ret) + return NULL; + *dma_handle = phys_to_dma(dev, page_to_phys(page)); + return ret; + } + + kaddr = dma_direct_alloc_pages(dev, size, dma_handle, flags, attrs); + if (!kaddr) + return NULL; + page = virt_to_page(kaddr); + + /* remove any dirty cache lines on the kernel alias */ + arch_dma_prep_coherent(page, size); + + /* create a coherent mapping */ + ret = dma_common_contiguous_remap(page, size, VM_USERMAP, + arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs), + __builtin_return_address(0)); + if (!ret) + dma_direct_free_pages(dev, size, kaddr, *dma_handle, attrs); + return ret; +} + +void arch_dma_free(struct device *dev, size_t size, void *vaddr, + dma_addr_t dma_handle, unsigned long attrs) +{ + if (!dma_free_from_pool(vaddr, PAGE_ALIGN(size))) { + void *kaddr = phys_to_virt(dma_to_phys(dev, dma_handle)); + + vunmap(vaddr); + dma_direct_free_pages(dev, size, kaddr, dma_handle, attrs); + } +} + +long arch_dma_coherent_to_pfn(struct device *dev, void *cpu_addr, + dma_addr_t dma_addr) +{ + return __phys_to_pfn(dma_to_phys(dev, dma_addr)); +} +#endif /* CONFIG_DMA_DIRECT_REMAP */ |