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Diffstat (limited to 'arch/mips/mm/dma-noncoherent.c')
| -rw-r--r-- | arch/mips/mm/dma-noncoherent.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/arch/mips/mm/dma-noncoherent.c b/arch/mips/mm/dma-noncoherent.c new file mode 100644 index 000000000000..e6c9485cadcf --- /dev/null +++ b/arch/mips/mm/dma-noncoherent.c @@ -0,0 +1,161 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2000 Ani Joshi <ajoshi@unixbox.com> + * Copyright (C) 2000, 2001, 06 Ralf Baechle <ralf@linux-mips.org> + * swiped from i386, and cloned for MIPS by Geert, polished by Ralf. + */ +#include <linux/dma-direct.h> +#include <linux/dma-noncoherent.h> +#include <linux/dma-contiguous.h> +#include <linux/highmem.h> + +#include <asm/cache.h> +#include <asm/cpu-type.h> +#include <asm/dma-coherence.h> +#include <asm/io.h> + +/* + * The affected CPUs below in 'cpu_needs_post_dma_flush()' can speculatively + * fill random cachelines with stale data at any time, requiring an extra + * flush post-DMA. + * + * Warning on the terminology - Linux calls an uncached area coherent; MIPS + * terminology calls memory areas with hardware maintained coherency coherent. + * + * Note that the R14000 and R16000 should also be checked for in this condition. + * However this function is only called on non-I/O-coherent systems and only the + * R10000 and R12000 are used in such systems, the SGI IP28 Indigo² rsp. + * SGI IP32 aka O2. + */ +static inline bool cpu_needs_post_dma_flush(struct device *dev) +{ + switch (boot_cpu_type()) { + case CPU_R10000: + case CPU_R12000: + case CPU_BMIPS5000: + return true; + default: + /* + * Presence of MAARs suggests that the CPU supports + * speculatively prefetching data, and therefore requires + * the post-DMA flush/invalidate. + */ + return cpu_has_maar; + } +} + +void *arch_dma_alloc(struct device *dev, size_t size, + dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) +{ + void *ret; + + ret = dma_direct_alloc_pages(dev, size, dma_handle, gfp, attrs); + if (!ret && !(attrs & DMA_ATTR_NON_CONSISTENT)) { + dma_cache_wback_inv((unsigned long) ret, size); + ret = (void *)UNCAC_ADDR(ret); + } + + return ret; +} + +void arch_dma_free(struct device *dev, size_t size, void *cpu_addr, + dma_addr_t dma_addr, unsigned long attrs) +{ + if (!(attrs & DMA_ATTR_NON_CONSISTENT)) + cpu_addr = (void *)CAC_ADDR((unsigned long)cpu_addr); + dma_direct_free_pages(dev, size, cpu_addr, dma_addr, attrs); +} + +long arch_dma_coherent_to_pfn(struct device *dev, void *cpu_addr, + dma_addr_t dma_addr) +{ + unsigned long addr = CAC_ADDR((unsigned long)cpu_addr); + return page_to_pfn(virt_to_page((void *)addr)); +} + +pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot, + unsigned long attrs) +{ + if (attrs & DMA_ATTR_WRITE_COMBINE) + return pgprot_writecombine(prot); + return pgprot_noncached(prot); +} + +static inline void dma_sync_virt(void *addr, size_t size, + enum dma_data_direction dir) +{ + switch (dir) { + case DMA_TO_DEVICE: + dma_cache_wback((unsigned long)addr, size); + break; + + case DMA_FROM_DEVICE: + dma_cache_inv((unsigned long)addr, size); + break; + + case DMA_BIDIRECTIONAL: + dma_cache_wback_inv((unsigned long)addr, size); + break; + + default: + BUG(); + } +} + +/* + * A single sg entry may refer to multiple physically contiguous pages. But + * we still need to process highmem pages individually. If highmem is not + * configured then the bulk of this loop gets optimized out. + */ +static inline void dma_sync_phys(phys_addr_t paddr, size_t size, + enum dma_data_direction dir) +{ + struct page *page = pfn_to_page(paddr >> PAGE_SHIFT); + unsigned long offset = paddr & ~PAGE_MASK; + size_t left = size; + + do { + size_t len = left; + + if (PageHighMem(page)) { + void *addr; + + if (offset + len > PAGE_SIZE) { + if (offset >= PAGE_SIZE) { + page += offset >> PAGE_SHIFT; + offset &= ~PAGE_MASK; + } + len = PAGE_SIZE - offset; + } + + addr = kmap_atomic(page); + dma_sync_virt(addr + offset, len, dir); + kunmap_atomic(addr); + } else + dma_sync_virt(page_address(page) + offset, size, dir); + offset = 0; + page++; + left -= len; + } while (left); +} + +void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr, + size_t size, enum dma_data_direction dir) +{ + dma_sync_phys(paddr, size, dir); +} + +void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr, + size_t size, enum dma_data_direction dir) +{ + if (cpu_needs_post_dma_flush(dev)) + dma_sync_phys(paddr, size, dir); +} + +void arch_dma_cache_sync(struct device *dev, void *vaddr, size_t size, + enum dma_data_direction direction) +{ + BUG_ON(direction == DMA_NONE); + + dma_sync_virt(vaddr, size, direction); +} |