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author | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-08-05 17:04:01 -0300 |
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committer | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-08-05 17:04:01 -0300 |
commit | 57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch) | |
tree | 5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/c6x/mm/dma-coherent.c |
Initial import
Diffstat (limited to 'arch/c6x/mm/dma-coherent.c')
-rw-r--r-- | arch/c6x/mm/dma-coherent.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/arch/c6x/mm/dma-coherent.c b/arch/c6x/mm/dma-coherent.c new file mode 100644 index 000000000..4187e5180 --- /dev/null +++ b/arch/c6x/mm/dma-coherent.c @@ -0,0 +1,143 @@ +/* + * Port on Texas Instruments TMS320C6x architecture + * + * Copyright (C) 2004, 2009, 2010, 2011 Texas Instruments Incorporated + * Author: Aurelien Jacquiot <aurelien.jacquiot@ti.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * DMA uncached mapping support. + * + * Using code pulled from ARM + * Copyright (C) 2000-2004 Russell King + * + */ +#include <linux/slab.h> +#include <linux/bitmap.h> +#include <linux/bitops.h> +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/dma-mapping.h> +#include <linux/memblock.h> + +#include <asm/page.h> + +/* + * DMA coherent memory management, can be redefined using the memdma= + * kernel command line + */ + +/* none by default */ +static phys_addr_t dma_base; +static u32 dma_size; +static u32 dma_pages; + +static unsigned long *dma_bitmap; + +/* bitmap lock */ +static DEFINE_SPINLOCK(dma_lock); + +/* + * Return a DMA coherent and contiguous memory chunk from the DMA memory + */ +static inline u32 __alloc_dma_pages(int order) +{ + unsigned long flags; + u32 pos; + + spin_lock_irqsave(&dma_lock, flags); + pos = bitmap_find_free_region(dma_bitmap, dma_pages, order); + spin_unlock_irqrestore(&dma_lock, flags); + + return dma_base + (pos << PAGE_SHIFT); +} + +static void __free_dma_pages(u32 addr, int order) +{ + unsigned long flags; + u32 pos = (addr - dma_base) >> PAGE_SHIFT; + + if (addr < dma_base || (pos + (1 << order)) >= dma_pages) { + printk(KERN_ERR "%s: freeing outside range.\n", __func__); + BUG(); + } + + spin_lock_irqsave(&dma_lock, flags); + bitmap_release_region(dma_bitmap, pos, order); + spin_unlock_irqrestore(&dma_lock, flags); +} + +/* + * Allocate DMA coherent memory space and return both the kernel + * virtual and DMA address for that space. + */ +void *dma_alloc_coherent(struct device *dev, size_t size, + dma_addr_t *handle, gfp_t gfp) +{ + u32 paddr; + int order; + + if (!dma_size || !size) + return NULL; + + order = get_count_order(((size - 1) >> PAGE_SHIFT) + 1); + + paddr = __alloc_dma_pages(order); + + if (handle) + *handle = paddr; + + if (!paddr) + return NULL; + + return phys_to_virt(paddr); +} +EXPORT_SYMBOL(dma_alloc_coherent); + +/* + * Free DMA coherent memory as defined by the above mapping. + */ +void dma_free_coherent(struct device *dev, size_t size, void *vaddr, + dma_addr_t dma_handle) +{ + int order; + + if (!dma_size || !size) + return; + + order = get_count_order(((size - 1) >> PAGE_SHIFT) + 1); + + __free_dma_pages(virt_to_phys(vaddr), order); +} +EXPORT_SYMBOL(dma_free_coherent); + +/* + * Initialise the coherent DMA memory allocator using the given uncached region. + */ +void __init coherent_mem_init(phys_addr_t start, u32 size) +{ + phys_addr_t bitmap_phys; + + if (!size) + return; + + printk(KERN_INFO + "Coherent memory (DMA) region start=0x%x size=0x%x\n", + start, size); + + dma_base = start; + dma_size = size; + + /* allocate bitmap */ + dma_pages = dma_size >> PAGE_SHIFT; + if (dma_size & (PAGE_SIZE - 1)) + ++dma_pages; + + bitmap_phys = memblock_alloc(BITS_TO_LONGS(dma_pages) * sizeof(long), + sizeof(long)); + + dma_bitmap = phys_to_virt(bitmap_phys); + memset(dma_bitmap, 0, dma_pages * PAGE_SIZE); +} |