diff options
Diffstat (limited to 'kernel/dma')
| -rw-r--r-- | kernel/dma/swiotlb.c | 61 |
1 files changed, 55 insertions, 6 deletions
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 0840bc15fb53..66793b59c290 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -62,6 +62,13 @@ #define INVALID_PHYS_ADDR (~(phys_addr_t)0) +/** + * struct io_tlb_slot - IO TLB slot descriptor + * @orig_addr: The original address corresponding to a mapped entry. + * @alloc_size: Size of the allocated buffer. + * @list: The free list describing the number of free entries available + * from each index. + */ struct io_tlb_slot { phys_addr_t orig_addr; size_t alloc_size; @@ -635,11 +642,22 @@ static void dec_used(struct io_tlb_mem *mem, unsigned int nslots) } #endif /* CONFIG_DEBUG_FS */ -/* - * Find a suitable number of IO TLB entries size that will fit this request and - * allocate a buffer from that IO TLB pool. +/** + * swiotlb_area_find_slots() - search for slots in one IO TLB memory area + * @dev: Device which maps the buffer. + * @area_index: Index of the IO TLB memory area to be searched. + * @orig_addr: Original (non-bounced) IO buffer address. + * @alloc_size: Total requested size of the bounce buffer, + * including initial alignment padding. + * @alloc_align_mask: Required alignment of the allocated buffer. + * + * Find a suitable sequence of IO TLB entries for the request and allocate + * a buffer from the given IO TLB memory area. + * This function takes care of locking. + * + * Return: Index of the first allocated slot, or -1 on error. */ -static int swiotlb_do_find_slots(struct device *dev, int area_index, +static int swiotlb_area_find_slots(struct device *dev, int area_index, phys_addr_t orig_addr, size_t alloc_size, unsigned int alloc_align_mask) { @@ -734,6 +752,19 @@ found: return slot_index; } +/** + * swiotlb_find_slots() - search for slots in the whole swiotlb + * @dev: Device which maps the buffer. + * @orig_addr: Original (non-bounced) IO buffer address. + * @alloc_size: Total requested size of the bounce buffer, + * including initial alignment padding. + * @alloc_align_mask: Required alignment of the allocated buffer. + * + * Search through the whole software IO TLB to find a sequence of slots that + * match the allocation constraints. + * + * Return: Index of the first allocated slot, or -1 on error. + */ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr, size_t alloc_size, unsigned int alloc_align_mask) { @@ -742,8 +773,8 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr, int i = start, index; do { - index = swiotlb_do_find_slots(dev, i, orig_addr, alloc_size, - alloc_align_mask); + index = swiotlb_area_find_slots(dev, i, orig_addr, alloc_size, + alloc_align_mask); if (index >= 0) return index; if (++i >= mem->nareas) @@ -755,6 +786,15 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr, #ifdef CONFIG_DEBUG_FS +/** + * mem_used() - get number of used slots in an allocator + * @mem: Software IO TLB allocator. + * + * The result is accurate in this version of the function, because an atomic + * counter is available if CONFIG_DEBUG_FS is set. + * + * Return: Number of used slots. + */ static unsigned long mem_used(struct io_tlb_mem *mem) { return atomic_long_read(&mem->total_used); @@ -762,6 +802,15 @@ static unsigned long mem_used(struct io_tlb_mem *mem) #else /* !CONFIG_DEBUG_FS */ +/** + * mem_used() - get number of used slots in an allocator + * @mem: Software IO TLB allocator. + * + * The result is not accurate, because there is no locking of individual + * areas. + * + * Return: Approximate number of used slots. + */ static unsigned long mem_used(struct io_tlb_mem *mem) { int i; |