/* * SPDX-License-Identifier: MIT * * Copyright © 2016 Intel Corporation */ #ifndef I915_SCATTERLIST_H #define I915_SCATTERLIST_H #include #include #include #include "i915_gem.h" /* * Optimised SGL iterator for GEM objects */ static __always_inline struct sgt_iter { struct scatterlist *sgp; union { unsigned long pfn; dma_addr_t dma; }; unsigned int curr; unsigned int max; } __sgt_iter(struct scatterlist *sgl, bool dma) { struct sgt_iter s = { .sgp = sgl }; if (s.sgp) { s.max = s.curr = s.sgp->offset; s.max += s.sgp->length; if (dma) s.dma = sg_dma_address(s.sgp); else s.pfn = page_to_pfn(sg_page(s.sgp)); } return s; } static inline int __sg_page_count(const struct scatterlist *sg) { return sg->length >> PAGE_SHIFT; } static inline struct scatterlist *____sg_next(struct scatterlist *sg) { ++sg; if (unlikely(sg_is_chain(sg))) sg = sg_chain_ptr(sg); return sg; } /** * __sg_next - return the next scatterlist entry in a list * @sg: The current sg entry * * Description: * If the entry is the last, return NULL; otherwise, step to the next * element in the array (@sg@+1). If that's a chain pointer, follow it; * otherwise just return the pointer to the current element. **/ static inline struct scatterlist *__sg_next(struct scatterlist *sg) { return sg_is_last(sg) ? NULL : ____sg_next(sg); } /** * __for_each_sgt_daddr - iterate over the device addresses of the given sg_table * @__dp: Device address (output) * @__iter: 'struct sgt_iter' (iterator state, internal) * @__sgt: sg_table to iterate over (input) * @__step: step size */ #define __for_each_sgt_daddr(__dp, __iter, __sgt, __step) \ for ((__iter) = __sgt_iter((__sgt)->sgl, true); \ ((__dp) = (__iter).dma + (__iter).curr), (__iter).sgp; \ (((__iter).curr += (__step)) >= (__iter).max) ? \ (__iter) = __sgt_iter(__sg_next((__iter).sgp), true), 0 : 0) /** * for_each_sgt_page - iterate over the pages of the given sg_table * @__pp: page pointer (output) * @__iter: 'struct sgt_iter' (iterator state, internal) * @__sgt: sg_table to iterate over (input) */ #define for_each_sgt_page(__pp, __iter, __sgt) \ for ((__iter) = __sgt_iter((__sgt)->sgl, false); \ ((__pp) = (__iter).pfn == 0 ? NULL : \ pfn_to_page((__iter).pfn + ((__iter).curr >> PAGE_SHIFT))); \ (((__iter).curr += PAGE_SIZE) >= (__iter).max) ? \ (__iter) = __sgt_iter(__sg_next((__iter).sgp), false), 0 : 0) static inline unsigned int i915_sg_page_sizes(struct scatterlist *sg) { unsigned int page_sizes; page_sizes = 0; while (sg) { GEM_BUG_ON(sg->offset); GEM_BUG_ON(!IS_ALIGNED(sg->length, PAGE_SIZE)); page_sizes |= sg->length; sg = __sg_next(sg); } return page_sizes; } #ifdef __linux__ static inline unsigned int i915_sg_segment_size(void) { unsigned int size = swiotlb_max_segment(); if (size == 0) return SCATTERLIST_MAX_SEGMENT; size = rounddown(size, PAGE_SIZE); /* swiotlb_max_segment_size can return 1 byte when it means one page. */ if (size < PAGE_SIZE) size = PAGE_SIZE; return size; } #else static inline unsigned int i915_sg_segment_size(void) { return PAGE_SIZE; } #endif bool i915_sg_trim(struct sg_table *orig_st); #endif