[PATCH v4 19/36] thunderbolt: Extend tunnel creation to more than 2 adjacent switches

Mika Westerberg
2019-04-10T13:38:04Z

Now that we can allocate hop IDs per port on a path, we can take
advantage of this and create tunnels covering longer paths than just
between two adjacent switches. PCIe actually does not need this as it
is typically a daisy chain between two adjacent switches but this way we
do not need to hard-code creation of the tunnel.

While there add name to struct tb_path to make debugging easier, and
update kernel-doc comments.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
drivers/thunderbolt/path.c | 121 ++++++++++++++++++++++++++++++-----
drivers/thunderbolt/tb.h | 54 ++++++++++++----
drivers/thunderbolt/tunnel.c | 56 ++++------------
3 files changed, 163 insertions(+), 68 deletions(-)

diff --git a/drivers/thunderbolt/path.c b/drivers/thunderbolt/path.c
index 8c2e19a6117a..a7cdac7f6808 100644
--- a/drivers/thunderbolt/path.c
+++ b/drivers/thunderbolt/path.c
@@ -31,23 +31,100 @@ static void tb_dump_hop(struct tb_port *port, struct tb_regs_hop *hop)
}

/**
- * tb_path_alloc() - allocate a thunderbolt path
+ * tb_path_alloc() - allocate a thunderbolt path between two ports
+ * @tb: Domain pointer
+ * @src: Source port of the path
+ * @src_hopid: HopID used for the first ingress port in the path
+ * @dst: Destination port of the path
+ * @dst_hopid: HopID used for the last egress port in the path
+ * @link_nr: Preferred link if there are dual links on the path
+ * @name: Name of the path
+ *
+ * Creates path between two ports starting with given @src_hopid. Reserves
+ * HopIDs for each port (they can be different from @src_hopid depending on
+ * how many HopIDs each port already have reserved). If there are dual
+ * links on the path, prioritizes using @link_nr.
*
* Return: Returns a tb_path on success or NULL on failure.
*/
-struct tb_path *tb_path_alloc(struct tb *tb, int num_hops)
+struct tb_path *tb_path_alloc(struct tb *tb, struct tb_port *src, int src_hopid,
+ struct tb_port *dst, int dst_hopid, int link_nr,
+ const char *name)
{
- struct tb_path *path = kzalloc(sizeof(*path), GFP_KERNEL);
+ struct tb_port *in_port, *out_port;
+ int in_hopid, out_hopid;
+ struct tb_path *path;
+ size_t num_hops;
+ int i, ret;
+
+ path = kzalloc(sizeof(*path), GFP_KERNEL);
if (!path)
return NULL;
+
+ /*
+ * Number of hops on a path is the distance between the two
+ * switches plus the source adapter port.
+ */
+ num_hops = abs(tb_route_length(tb_route(src->sw)) -
+ tb_route_length(tb_route(dst->sw))) + 1;
+
path->hops = kcalloc(num_hops, sizeof(*path->hops), GFP_KERNEL);
if (!path->hops) {
kfree(path);
return NULL;
}
+
+ in_hopid = src_hopid;
+ out_port = NULL;
+
+ for (i = 0; i < num_hops; i++) {
+ in_port = tb_next_port_on_path(src, dst, out_port);
+ if (!in_port)
+ goto err;
+
+ if (in_port->dual_link_port && in_port->link_nr != link_nr)
+ in_port = in_port->dual_link_port;
+
+ ret = tb_port_alloc_in_hopid(in_port, in_hopid, in_hopid);
+ if (ret < 0)
+ goto err;
+ in_hopid = ret;
+
+ out_port = tb_next_port_on_path(src, dst, in_port);
+ if (!out_port)
+ goto err;
+
+ if (out_port->dual_link_port && out_port->link_nr != link_nr)
+ out_port = out_port->dual_link_port;
+
+ if (i == num_hops - 1)
+ ret = tb_port_alloc_out_hopid(out_port, dst_hopid,
+ dst_hopid);
+ else
+ ret = tb_port_alloc_out_hopid(out_port, -1, -1);
+
+ if (ret < 0)
+ goto err;
+ out_hopid = ret;
+
+ path->hops[i].in_hop_index = in_hopid;
+ path->hops[i].in_port = in_port;
+ path->hops[i].in_counter_index = -1;
+ path->hops[i].out_port = out_port;
+ path->hops[i].next_hop_index = out_hopid;
+
+ in_hopid = out_hopid;
+ }
+
path->tb = tb;
path->path_length = num_hops;
+ path->name = name;
+
return path;
+
+err:
+ tb_path_free(path);
+ return NULL;
}

/**
@@ -55,10 +132,24 @@ struct tb_path *tb_path_alloc(struct tb *tb, int num_hops)
*/
void tb_path_free(struct tb_path *path)
{
+ int i;
+
if (path->activated) {
tb_WARN(path->tb, "trying to free an activated path\n")
return;
}
+
+ for (i = 0; i < path->path_length; i++) {
+ const struct tb_path_hop *hop = &path->hops[i];
+
+ if (hop->in_port)
+ tb_port_release_in_hopid(hop->in_port,
+ hop->in_hop_index);
+ if (hop->out_port)
+ tb_port_release_out_hopid(hop->out_port,
+ hop->next_hop_index);
+ }
+
kfree(path->hops);
kfree(path);
}
@@ -133,12 +224,12 @@ void tb_path_deactivate(struct tb_path *path)
tb_WARN(path->tb, "trying to deactivate an inactive path\n");
return;
}
- tb_info(path->tb,
- "deactivating path from %llx:%x to %llx:%x\n",
- tb_route(path->hops[0].in_port->sw),
- path->hops[0].in_port->port,
- tb_route(path->hops[path->path_length - 1].out_port->sw),
- path->hops[path->path_length - 1].out_port->port);
+ tb_dbg(path->tb,
+ "deactivating %s path from %llx:%x to %llx:%x\n",
+ path->name, tb_route(path->hops[0].in_port->sw),
+ path->hops[0].in_port->port,
+ tb_route(path->hops[path->path_length - 1].out_port->sw),
+ path->hops[path->path_length - 1].out_port->port);
__tb_path_deactivate_hops(path, 0);
__tb_path_deallocate_nfc(path, 0);
path->activated = false;
@@ -161,12 +252,12 @@ int tb_path_activate(struct tb_path *path)
return -EINVAL;
}

- tb_info(path->tb,
- "activating path from %llx:%x to %llx:%x\n",
- tb_route(path->hops[0].in_port->sw),
- path->hops[0].in_port->port,
- tb_route(path->hops[path->path_length - 1].out_port->sw),
- path->hops[path->path_length - 1].out_port->port);
+ tb_dbg(path->tb,
+ "activating %s path from %llx:%x to %llx:%x\n",
+ path->name, tb_route(path->hops[0].in_port->sw),
+ path->hops[0].in_port->port,
+ tb_route(path->hops[path->path_length - 1].out_port->sw),
+ path->hops[path->path_length - 1].out_port->port);

/* Clear counters. */
for (i = path->path_length - 1; i >= 0; i--) {
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 11d5ab53ad36..322bbdc00d95 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -147,11 +147,22 @@ struct tb_port {

/**
* struct tb_path_hop - routing information for a tb_path
+ * @in_port: Ingress port of a switch
+ * @out_port: Egress port of a switch where the packet is routed out
+ * (must be on the same switch than @in_port)
+ * @in_hop_index: HopID where the path configuration entry is placed in
+ * the path config space of @in_port.
+ * @in_counter_index: Used counter index (not used in the driver
+ * currently, %-1 to disable)
+ * @next_hop_index: HopID of the packet when it is routed out from @out_port
*
* Hop configuration is always done on the IN port of a switch.
* in_port and out_port have to be on the same switch. Packets arriving on
* in_port with "hop" = in_hop_index will get routed to through out_port. The
- * next hop to take (on out_port->remote) is determined by next_hop_index.
+ * next hop to take (on out_port->remote) is determined by
+ * next_hop_index. When routing packet to another switch (out->remote is
+ * set) the @next_hop_index must match the @in_hop_index of that next
+ * hop to make routing possible.
*
* in_counter_index is the index of a counter (in TB_CFG_COUNTERS) on the in
* port.
@@ -160,31 +171,50 @@ struct tb_path_hop {
struct tb_port *in_port;
struct tb_port *out_port;
int in_hop_index;
- int in_counter_index; /* write -1 to disable counters for this hop. */
+ int in_counter_index;
int next_hop_index;
};

/**
* enum tb_path_port - path options mask
+ * @TB_PATH_NONE: Do not activate on any hop on path
+ * @TB_PATH_SOURCE: Activate on the first hop (out of src)
+ * @TB_PATH_INTERNAL: Activate on the intermediate hops (not the first/last)
+ * @TB_PATH_DESTINATION: Activate on the last hop (into dst)
+ * @TB_PATH_ALL: Activate on all hops on the path
*/
enum tb_path_port {
TB_PATH_NONE = 0,
- TB_PATH_SOURCE = 1, /* activate on the first hop (out of src) */
- TB_PATH_INTERNAL = 2, /* activate on other hops (not the first/last) */
- TB_PATH_DESTINATION = 4, /* activate on the last hop (into dst) */
+ TB_PATH_SOURCE = 1,
+ TB_PATH_INTERNAL = 2,
+ TB_PATH_DESTINATION = 4,
TB_PATH_ALL = 7,
};

/**
* struct tb_path - a unidirectional path between two ports
+ * @tb: Pointer to the domain structure
+ * @name: Name of the path (used for debugging)
+ * @nfc_credits: Number of non flow controlled credits allocated for the path
+ * @ingress_shared_buffer: Shared buffering used for ingress ports on the path
+ * @egress_shared_buffer: Shared buffering used for egress ports on the path
+ * @ingress_fc_enable: Flow control for ingress ports on the path
+ * @egress_fc_enable: Flow control for egress ports on the path
+ * @priority: Priority group if the path
+ * @weight: Weight of the path inside the priority group
+ * @drop_packages: Drop packages from queue tail or head
+ * @activated: Is the path active
+ * @hops: Path hops
+ * @path_length: How many hops the path uses
*
- * A path consists of a number of hops (see tb_path_hop). To establish a PCIe
- * tunnel two paths have to be created between the two PCIe ports.
- *
+ * A path consists of a number of hops (see &struct tb_path_hop). To
+ * establish a PCIe tunnel two paths have to be created between the two
+ * PCIe ports.
*/
struct tb_path {
struct tb *tb;
- int nfc_credits; /* non flow controlled credits */
+ const char *name;
+ int nfc_credits;
enum tb_path_port ingress_shared_buffer;
enum tb_path_port egress_shared_buffer;
enum tb_path_port ingress_fc_enable;
@@ -195,7 +225,7 @@ struct tb_path {
bool drop_packages;
bool activated;
struct tb_path_hop *hops;
- int path_length; /* number of hops */
+ int path_length;
};

/* HopIDs 0-7 are reserved by the Thunderbolt protocol */
@@ -503,7 +533,9 @@ int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap);

int tb_pci_port_enable(struct tb_port *port, bool enable);

-struct tb_path *tb_path_alloc(struct tb *tb, int num_hops);
+struct tb_path *tb_path_alloc(struct tb *tb, struct tb_port *src, int src_hopid,
+ struct tb_port *dst, int dst_hopid, int link_nr,
+ const char *name);
void tb_path_free(struct tb_path *path);
int tb_path_activate(struct tb_path *path);
void tb_path_deactivate(struct tb_path *path);
diff --git a/drivers/thunderbolt/tunnel.c b/drivers/thunderbolt/tunnel.c
index 20ce28276f7a..91d7e00516b4 100644
--- a/drivers/thunderbolt/tunnel.c
+++ b/drivers/thunderbolt/tunnel.c
@@ -12,6 +12,9 @@
#include "tunnel.h"
#include "tb.h"

+/* PCIe adapters use always HopID of 8 for both directions */
+#define TB_PCI_HOPID 8
+
#define TB_PCI_PATH_DOWN 0
#define TB_PCI_PATH_UP 1

@@ -86,21 +89,13 @@ static void tb_pci_init_path(struct tb_path *path)
* Allocate a PCI tunnel. The ports must be of type TB_TYPE_PCIE_UP and
* TB_TYPE_PCIE_DOWN.
*
- * Currently only paths consisting of two hops are supported (that is the
- * ports must be on "adjacent" switches).
- *
- * The paths are hard-coded to use hop 8 (the only working hop id available on
- * my thunderbolt devices). Therefore at most ONE path per device may be
- * activated.
- *
* Return: Returns a tb_tunnel on success or NULL on failure.
*/
struct tb_tunnel *tb_tunnel_alloc_pci(struct tb *tb, struct tb_port *up,
struct tb_port *down)
{
- struct tb_path *path_to_up;
- struct tb_path *path_to_down;
struct tb_tunnel *tunnel;
+ struct tb_path *path;

tunnel = tb_tunnel_alloc(tb, 2);
if (!tunnel)
@@ -110,46 +105,23 @@ struct tb_tunnel *tb_tunnel_alloc_pci(struct tb *tb, struct tb_port *up,
tunnel->src_port = down;
tunnel->dst_port = up;

- path_to_up = tb_path_alloc(tb, 2);
- if (!path_to_up) {
+ path = tb_path_alloc(tb, down, TB_PCI_HOPID, up, TB_PCI_HOPID, 0,
+ "PCIe Down");
+ if (!path) {
tb_tunnel_free(tunnel);
return NULL;
}
- tunnel->paths[TB_PCI_PATH_UP] = path_to_up;
+ tb_pci_init_path(path);
+ tunnel->paths[TB_PCI_PATH_UP] = path;

- path_to_down = tb_path_alloc(tb, 2);
- if (!path_to_down) {
+ path = tb_path_alloc(tb, up, TB_PCI_HOPID, down, TB_PCI_HOPID, 0,
+ "PCIe Up");
+ if (!path) {
tb_tunnel_free(tunnel);
return NULL;
}
- tunnel->paths[TB_PCI_PATH_DOWN] = path_to_down;
-
- tb_pci_init_path(path_to_up);
- tb_pci_init_path(path_to_down);
-
- path_to_up->hops[0].in_port = down;
- path_to_up->hops[0].in_hop_index = 8;
- path_to_up->hops[0].in_counter_index = -1;
- path_to_up->hops[0].out_port = tb_upstream_port(up->sw)->remote;
- path_to_up->hops[0].next_hop_index = 8;
-
- path_to_up->hops[1].in_port = tb_upstream_port(up->sw);
- path_to_up->hops[1].in_hop_index = 8;
- path_to_up->hops[1].in_counter_index = -1;
- path_to_up->hops[1].out_port = up;
- path_to_up->hops[1].next_hop_index = 8;
-
- path_to_down->hops[0].in_port = up;
- path_to_down->hops[0].in_hop_index = 8;
- path_to_down->hops[0].in_counter_index = -1;
- path_to_down->hops[0].out_port = tb_upstream_port(up->sw);
- path_to_down->hops[0].next_hop_index = 8;
-
- path_to_down->hops[1].in_port = tb_upstream_port(up->sw)->remote;
- path_to_down->hops[1].in_hop_index = 8;
- path_to_down->hops[1].in_counter_index = -1;
- path_to_down->hops[1].out_port = down;
- path_to_down->hops[1].next_hop_index = 8;
+ tb_pci_init_path(path);
+ tunnel->paths[TB_PCI_PATH_DOWN] = path;

return tunnel;
}
--
2.20.1