diff options
Diffstat (limited to 'drivers/parisc/iommu-helpers.h')
| -rw-r--r-- | drivers/parisc/iommu-helpers.h | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/drivers/parisc/iommu-helpers.h b/drivers/parisc/iommu-helpers.h new file mode 100644 index 0000000000..c43f1a212a --- /dev/null +++ b/drivers/parisc/iommu-helpers.h @@ -0,0 +1,182 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include <linux/prefetch.h> + +/** + * iommu_fill_pdir - Insert coalesced scatter/gather chunks into the I/O Pdir. + * @ioc: The I/O Controller. + * @startsg: The scatter/gather list of coalesced chunks. + * @nents: The number of entries in the scatter/gather list. + * @hint: The DMA Hint. + * + * This function inserts the coalesced scatter/gather list chunks into the + * I/O Controller's I/O Pdir. + */ +static inline unsigned int +iommu_fill_pdir(struct ioc *ioc, struct scatterlist *startsg, int nents, + unsigned long hint, + void (*iommu_io_pdir_entry)(__le64 *, space_t, unsigned long, + unsigned long)) +{ + struct scatterlist *dma_sg = startsg; /* pointer to current DMA */ + unsigned int n_mappings = 0; + unsigned long dma_offset = 0, dma_len = 0; + __le64 *pdirp = NULL; + + /* Horrible hack. For efficiency's sake, dma_sg starts one + * entry below the true start (it is immediately incremented + * in the loop) */ + dma_sg--; + + while (nents-- > 0) { + unsigned long vaddr; + long size; + + DBG_RUN_SG(" %d : %08lx %p/%05x\n", nents, + (unsigned long)sg_dma_address(startsg), + sg_virt(startsg), startsg->length + ); + + + /* + ** Look for the start of a new DMA stream + */ + + if (sg_dma_address(startsg) & PIDE_FLAG) { + u32 pide = sg_dma_address(startsg) & ~PIDE_FLAG; + + BUG_ON(pdirp && (dma_len != sg_dma_len(dma_sg))); + + dma_sg++; + + dma_len = sg_dma_len(startsg); + sg_dma_len(startsg) = 0; + dma_offset = (unsigned long) pide & ~IOVP_MASK; + n_mappings++; +#if defined(ZX1_SUPPORT) + /* Pluto IOMMU IO Virt Address is not zero based */ + sg_dma_address(dma_sg) = pide | ioc->ibase; +#else + /* SBA, ccio, and dino are zero based. + * Trying to save a few CPU cycles for most users. + */ + sg_dma_address(dma_sg) = pide; +#endif + pdirp = &(ioc->pdir_base[pide >> IOVP_SHIFT]); + prefetchw(pdirp); + } + + BUG_ON(pdirp == NULL); + + vaddr = (unsigned long)sg_virt(startsg); + sg_dma_len(dma_sg) += startsg->length; + size = startsg->length + dma_offset; + dma_offset = 0; +#ifdef IOMMU_MAP_STATS + ioc->msg_pages += startsg->length >> IOVP_SHIFT; +#endif + do { + iommu_io_pdir_entry(pdirp, KERNEL_SPACE, + vaddr, hint); + vaddr += IOVP_SIZE; + size -= IOVP_SIZE; + pdirp++; + } while(unlikely(size > 0)); + startsg++; + } + return(n_mappings); +} + + +/* +** First pass is to walk the SG list and determine where the breaks are +** in the DMA stream. Allocates PDIR entries but does not fill them. +** Returns the number of DMA chunks. +** +** Doing the fill separate from the coalescing/allocation keeps the +** code simpler. Future enhancement could make one pass through +** the sglist do both. +*/ + +static inline unsigned int +iommu_coalesce_chunks(struct ioc *ioc, struct device *dev, + struct scatterlist *startsg, int nents, + int (*iommu_alloc_range)(struct ioc *, struct device *, size_t)) +{ + struct scatterlist *contig_sg; /* contig chunk head */ + unsigned long dma_offset, dma_len; /* start/len of DMA stream */ + unsigned int n_mappings = 0; + unsigned int max_seg_size = min(dma_get_max_seg_size(dev), + (unsigned)DMA_CHUNK_SIZE); + unsigned int max_seg_boundary = dma_get_seg_boundary(dev) + 1; + if (max_seg_boundary) /* check if the addition above didn't overflow */ + max_seg_size = min(max_seg_size, max_seg_boundary); + + while (nents > 0) { + + /* + ** Prepare for first/next DMA stream + */ + contig_sg = startsg; + dma_len = startsg->length; + dma_offset = startsg->offset; + + /* PARANOID: clear entries */ + sg_dma_address(startsg) = 0; + sg_dma_len(startsg) = 0; + + /* + ** This loop terminates one iteration "early" since + ** it's always looking one "ahead". + */ + while(--nents > 0) { + unsigned long prev_end, sg_start; + + prev_end = (unsigned long)sg_virt(startsg) + + startsg->length; + + startsg++; + sg_start = (unsigned long)sg_virt(startsg); + + /* PARANOID: clear entries */ + sg_dma_address(startsg) = 0; + sg_dma_len(startsg) = 0; + + /* + ** First make sure current dma stream won't + ** exceed max_seg_size if we coalesce the + ** next entry. + */ + if (unlikely(ALIGN(dma_len + dma_offset + startsg->length, IOVP_SIZE) > + max_seg_size)) + break; + + /* + * Next see if we can append the next chunk (i.e. + * it must end on one page and begin on another, or + * it must start on the same address as the previous + * entry ended. + */ + if (unlikely((prev_end != sg_start) || + ((prev_end | sg_start) & ~PAGE_MASK))) + break; + + dma_len += startsg->length; + } + + /* + ** End of DMA Stream + ** Terminate last VCONTIG block. + ** Allocate space for DMA stream. + */ + sg_dma_len(contig_sg) = dma_len; + dma_len = ALIGN(dma_len + dma_offset, IOVP_SIZE); + sg_dma_address(contig_sg) = + PIDE_FLAG + | (iommu_alloc_range(ioc, dev, dma_len) << IOVP_SHIFT) + | dma_offset; + n_mappings++; + } + + return n_mappings; +} + |