diff options
Diffstat (limited to 'drivers/infiniband/hw/mlx5/mem.c')
| -rw-r--r-- | drivers/infiniband/hw/mlx5/mem.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/drivers/infiniband/hw/mlx5/mem.c b/drivers/infiniband/hw/mlx5/mem.c index 92e7621ec858..fd9778113d26 100644 --- a/drivers/infiniband/hw/mlx5/mem.c +++ b/drivers/infiniband/hw/mlx5/mem.c @@ -107,6 +107,51 @@ void mlx5_ib_populate_pas(struct ib_umem *umem, size_t page_size, __be64 *pas, } } +/* + * Compute the page shift and page_offset for mailboxes that use a quantized + * page_offset. The granulatity of the page offset scales according to page + * size. + */ +unsigned long __mlx5_umem_find_best_quantized_pgoff( + struct ib_umem *umem, unsigned long pgsz_bitmap, + unsigned int page_offset_bits, u64 pgoff_bitmask, unsigned int scale, + unsigned int *page_offset_quantized) +{ + const u64 page_offset_mask = (1 << page_offset_bits) - 1; + unsigned long page_size; + u64 page_offset; + + page_size = ib_umem_find_best_pgoff(umem, pgsz_bitmap, pgoff_bitmask); + if (!page_size) + return 0; + + /* + * page size is the largest possible page size. + * + * Reduce the page_size, and thus the page_offset and quanta, until the + * page_offset fits into the mailbox field. Once page_size < scale this + * loop is guaranteed to terminate. + */ + page_offset = ib_umem_dma_offset(umem, page_size); + while (page_offset & ~(u64)(page_offset_mask * (page_size / scale))) { + page_size /= 2; + page_offset = ib_umem_dma_offset(umem, page_size); + } + + /* + * The address is not aligned, or otherwise cannot be represented by the + * page_offset. + */ + if (!(pgsz_bitmap & page_size)) + return 0; + + *page_offset_quantized = + (unsigned long)page_offset / (page_size / scale); + if (WARN_ON(*page_offset_quantized > page_offset_mask)) + return 0; + return page_size; +} + int mlx5_ib_get_buf_offset(u64 addr, int page_shift, u32 *offset) { u64 page_size; |