NTB: Alter link-state API to support multi-port devices
Multi-port devices permit the NTB connections between multiple domains,
so a local device can have NTB link being up with one peer and being
down with another. NTB link-state API is appropriately altered to return
a bitfield of the link-states between the local device and possible peers.
Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Acked-by: Allen Hubbe <Allen.Hubbe@dell.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
diff --git a/include/linux/ntb.h b/include/linux/ntb.h
index d23483b..b2b2924 100644
--- a/include/linux/ntb.h
+++ b/include/linux/ntb.h
@@ -235,7 +235,7 @@ struct ntb_dev_ops {
int (*peer_port_number)(struct ntb_dev *ntb, int pidx);
int (*peer_port_idx)(struct ntb_dev *ntb, int port);
- int (*link_is_up)(struct ntb_dev *ntb,
+ u64 (*link_is_up)(struct ntb_dev *ntb,
enum ntb_speed *speed, enum ntb_width *width);
int (*link_enable)(struct ntb_dev *ntb,
enum ntb_speed max_speed, enum ntb_width max_width);
@@ -607,25 +607,26 @@ static inline int ntb_peer_port_idx(struct ntb_dev *ntb, int port)
* state once after every link event. It is safe to query the link state in
* the context of the link event callback.
*
- * Return: One if the link is up, zero if the link is down, otherwise a
- * negative value indicating the error number.
+ * Return: bitfield of indexed ports link state: bit is set/cleared if the
+ * link is up/down respectively.
*/
-static inline int ntb_link_is_up(struct ntb_dev *ntb,
+static inline u64 ntb_link_is_up(struct ntb_dev *ntb,
enum ntb_speed *speed, enum ntb_width *width)
{
return ntb->ops->link_is_up(ntb, speed, width);
}
/**
- * ntb_link_enable() - enable the link on the secondary side of the ntb
+ * ntb_link_enable() - enable the local port ntb connection
* @ntb: NTB device context.
* @max_speed: The maximum link speed expressed as PCIe generation number.
* @max_width: The maximum link width expressed as the number of PCIe lanes.
*
- * Enable the link on the secondary side of the ntb. This can only be done
- * from the primary side of the ntb in primary or b2b topology. The ntb device
- * should train the link to its maximum speed and width, or the requested speed
- * and width, whichever is smaller, if supported.
+ * Enable the NTB/PCIe link on the local or remote (for bridge-to-bridge
+ * topology) side of the bridge. If it's supported the ntb device should train
+ * the link to its maximum speed and width, or the requested speed and width,
+ * whichever is smaller. Some hardware doesn't support PCIe link training, so
+ * the last two arguments will be ignored then.
*
* Return: Zero on success, otherwise an error number.
*/
@@ -637,14 +638,14 @@ static inline int ntb_link_enable(struct ntb_dev *ntb,
}
/**
- * ntb_link_disable() - disable the link on the secondary side of the ntb
+ * ntb_link_disable() - disable the local port ntb connection
* @ntb: NTB device context.
*
- * Disable the link on the secondary side of the ntb. This can only be
- * done from the primary side of the ntb in primary or b2b topology. The ntb
- * device should disable the link. Returning from this call must indicate that
- * a barrier has passed, though with no more writes may pass in either
- * direction across the link, except if this call returns an error number.
+ * Disable the link on the local or remote (for b2b topology) of the ntb.
+ * The ntb device should disable the link. Returning from this call must
+ * indicate that a barrier has passed, though with no more writes may pass in
+ * either direction across the link, except if this call returns an error
+ * number.
*
* Return: Zero on success, otherwise an error number.
*/