At the BAR level, multiple MWs may be packed into a single BAR. In addition, a single MW may itself be subdivided into multiple address subranges, each of which can be mapped independently by the underlying NTB hardware.
Introduce an optional ntb_dev_ops callback, .mw_set_trans_ranges(), to describe and program such layouts explicitly. The helper allows an NTB driver to provide, for each MW, a list of contiguous subranges that together cover the MW address space. Signed-off-by: Koichiro Den <[email protected]> --- include/linux/ntb.h | 46 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) diff --git a/include/linux/ntb.h b/include/linux/ntb.h index 8ff9d663096b..84908753f446 100644 --- a/include/linux/ntb.h +++ b/include/linux/ntb.h @@ -206,6 +206,11 @@ static inline int ntb_ctx_ops_is_valid(const struct ntb_ctx_ops *ops) 1; } +struct ntb_mw_subrange { + dma_addr_t addr; + resource_size_t size; +}; + /** * struct ntb_dev_ops - ntb device operations * @port_number: See ntb_port_number(). @@ -218,6 +223,7 @@ static inline int ntb_ctx_ops_is_valid(const struct ntb_ctx_ops *ops) * @mw_count: See ntb_mw_count(). * @mw_get_align: See ntb_mw_get_align(). * @mw_set_trans: See ntb_mw_set_trans(). + * @mw_set_trans_ranges:See ntb_mw_set_trans_ranges(). * @mw_clear_trans: See ntb_mw_clear_trans(). * @peer_mw_count: See ntb_peer_mw_count(). * @peer_mw_get_addr: See ntb_peer_mw_get_addr(). @@ -276,6 +282,9 @@ struct ntb_dev_ops { resource_size_t *size_max); int (*mw_set_trans)(struct ntb_dev *ntb, int pidx, int widx, dma_addr_t addr, resource_size_t size); + int (*mw_set_trans_ranges)(struct ntb_dev *ntb, int pidx, int widx, + unsigned int num_ranges, + const struct ntb_mw_subrange *ranges); int (*mw_clear_trans)(struct ntb_dev *ntb, int pidx, int widx); int (*peer_mw_count)(struct ntb_dev *ntb); int (*peer_mw_get_addr)(struct ntb_dev *ntb, int widx, @@ -350,6 +359,7 @@ static inline int ntb_dev_ops_is_valid(const struct ntb_dev_ops *ops) ops->mw_get_align && (ops->mw_set_trans || ops->peer_mw_set_trans) && + /* ops->mw_set_trans_ranges && */ /* ops->mw_clear_trans && */ ops->peer_mw_count && ops->peer_mw_get_addr && @@ -860,6 +870,42 @@ static inline int ntb_mw_set_trans(struct ntb_dev *ntb, int pidx, int widx, return ntb->ops->mw_set_trans(ntb, pidx, widx, addr, size); } +/** + * ntb_mw_set_trans_ranges() - set the translations of an inbound memory + * window, composed of multiple subranges. + * @ntb: NTB device context. + * @pidx: Port index of peer device. + * @widx: Memory window index. + * @num_ranges: The number of ranges described by @ranges array. + * @ranges: Array of subranges. The subranges are interpreted in ascending + * window offset order (i.e. ranges[0] maps the first part of the MW, + * ranges[1] the next part, ...). + * + * Return: Zero on success, otherwise an error number. If the driver does + * not implement the callback, return -EOPNOTSUPP. + */ +static inline int ntb_mw_set_trans_ranges(struct ntb_dev *ntb, int pidx, int widx, + unsigned int num_ranges, + const struct ntb_mw_subrange *ranges) +{ + if (!num_ranges || !ranges) + return -EINVAL; + + if (ntb->ops->mw_set_trans_ranges) + return ntb->ops->mw_set_trans_ranges(ntb, pidx, widx, + num_ranges, ranges); + + /* + * Fallback for drivers that only support the legacy single-range + * translation API. + */ + if (num_ranges == 1) + return ntb_mw_set_trans(ntb, pidx, widx, + ranges[0].addr, ranges[0].size); + + return -EOPNOTSUPP; +} + /** * ntb_mw_clear_trans() - clear the translation address of an inbound memory * window -- 2.51.0
