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Message-Id: <20241001173109.1513-9-alexandru.gagniuc@hp.com>
Date: Tue, 1 Oct 2024 17:31:03 +0000
From: Alexandru Gagniuc <alexandru.gagniuc@...com>
To: gregkh@...uxfoundation.org,
stable@...r.kernel.org
Cc: qin.wan@...com,
andreas.noever@...il.com,
michael.jamet@...el.com,
mika.westerberg@...ux.intel.com,
YehezkelShB@...il.com,
linux-usb@...r.kernel.org,
linux-kernel@...r.kernel.org,
Gil Fine <gil.fine@...ux.intel.com>,
Alexandru Gagniuc <alexandru.gagniuc@...com>
Subject: [PATCH 6.6 08/14] thunderbolt: Change bandwidth reservations to comply USB4 v2
From: Gil Fine <gil.fine@...ux.intel.com>
[ Upstream commit 582e70b0d3a412d15389a3c9c07a44791b311715 ]
USB4 v2 Connection Manager guide (section 6.1.2.3) suggests to reserve
bandwidth in a sligthly different manner. It suggests to keep minimum of
1500 Mb/s for each path that carry a bulk traffic. Here we change the
bandwidth reservations to comply to the above for USB 3.x and PCIe
protocols over Gen 4 link, taking weights into account (that's 1500 Mb/s
for PCIe and 3000 Mb/s for USB 3.x).
For Gen 3 and below we use the existing reservation.
Signed-off-by: Gil Fine <gil.fine@...ux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
Signed-off-by: Qin Wan <qin.wan@...com>
Signed-off-by: Alexandru Gagniuc <alexandru.gagniuc@...com>
---
drivers/thunderbolt/tb.c | 11 ++++++
drivers/thunderbolt/tunnel.c | 66 ++++++++++++++++++++++++++++++++++--
drivers/thunderbolt/tunnel.h | 2 ++
3 files changed, 76 insertions(+), 3 deletions(-)
diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index e37fb1081420..183225bdbbf5 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -602,6 +602,7 @@ static int tb_available_bandwidth(struct tb *tb, struct tb_port *src_port,
/* Find the minimum available bandwidth over all links */
tb_for_each_port_on_path(src_port, dst_port, port) {
int link_speed, link_width, up_bw, down_bw;
+ int pci_reserved_up, pci_reserved_down;
if (!tb_port_is_null(port))
continue;
@@ -695,6 +696,16 @@ static int tb_available_bandwidth(struct tb *tb, struct tb_port *src_port,
up_bw -= usb3_consumed_up;
down_bw -= usb3_consumed_down;
+ /*
+ * If there is anything reserved for PCIe bulk traffic
+ * take it into account here too.
+ */
+ if (tb_tunnel_reserved_pci(port, &pci_reserved_up,
+ &pci_reserved_down)) {
+ up_bw -= pci_reserved_up;
+ down_bw -= pci_reserved_down;
+ }
+
if (up_bw < *available_up)
*available_up = up_bw;
if (down_bw < *available_down)
diff --git a/drivers/thunderbolt/tunnel.c b/drivers/thunderbolt/tunnel.c
index b81344c6c06a..e296ab5d657b 100644
--- a/drivers/thunderbolt/tunnel.c
+++ b/drivers/thunderbolt/tunnel.c
@@ -31,7 +31,7 @@
#define TB_USB3_PATH_UP 1
#define TB_USB3_PRIORITY 3
-#define TB_USB3_WEIGHT 3
+#define TB_USB3_WEIGHT 2
/* DP adapters use HopID 8 for AUX and 9 for Video */
#define TB_DP_AUX_TX_HOPID 8
@@ -61,6 +61,15 @@
#define TB_DMA_PRIORITY 5
#define TB_DMA_WEIGHT 1
+/*
+ * Reserve additional bandwidth for USB 3.x and PCIe bulk traffic
+ * according to USB4 v2 Connection Manager guide. This ends up reserving
+ * 1500 Mb/s for PCIe and 3000 Mb/s for USB 3.x taking weights into
+ * account.
+ */
+#define USB4_V2_PCI_MIN_BANDWIDTH (1500 * TB_PCI_WEIGHT)
+#define USB4_V2_USB3_MIN_BANDWIDTH (1500 * TB_USB3_WEIGHT)
+
static unsigned int dma_credits = TB_DMA_CREDITS;
module_param(dma_credits, uint, 0444);
MODULE_PARM_DESC(dma_credits, "specify custom credits for DMA tunnels (default: "
@@ -150,11 +159,11 @@ static struct tb_tunnel *tb_tunnel_alloc(struct tb *tb, size_t npaths,
static int tb_pci_set_ext_encapsulation(struct tb_tunnel *tunnel, bool enable)
{
+ struct tb_port *port = tb_upstream_port(tunnel->dst_port->sw);
int ret;
/* Only supported of both routers are at least USB4 v2 */
- if (usb4_switch_version(tunnel->src_port->sw) < 2 ||
- usb4_switch_version(tunnel->dst_port->sw) < 2)
+ if (tb_port_get_link_generation(port) < 4)
return 0;
ret = usb4_pci_port_set_ext_encapsulation(tunnel->src_port, enable);
@@ -370,6 +379,51 @@ struct tb_tunnel *tb_tunnel_alloc_pci(struct tb *tb, struct tb_port *up,
return NULL;
}
+/**
+ * tb_tunnel_reserved_pci() - Amount of bandwidth to reserve for PCIe
+ * @port: Lane 0 adapter
+ * @reserved_up: Upstream bandwidth in Mb/s to reserve
+ * @reserved_down: Downstream bandwidth in Mb/s to reserve
+ *
+ * Can be called to any connected lane 0 adapter to find out how much
+ * bandwidth needs to be left in reserve for possible PCIe bulk traffic.
+ * Returns true if there is something to be reserved and writes the
+ * amount to @reserved_down/@...erved_up. Otherwise returns false and
+ * does not touch the parameters.
+ */
+bool tb_tunnel_reserved_pci(struct tb_port *port, int *reserved_up,
+ int *reserved_down)
+{
+ if (WARN_ON_ONCE(!port->remote))
+ return false;
+
+ if (!tb_acpi_may_tunnel_pcie())
+ return false;
+
+ if (tb_port_get_link_generation(port) < 4)
+ return false;
+
+ /* Must have PCIe adapters */
+ if (tb_is_upstream_port(port)) {
+ if (!tb_switch_find_port(port->sw, TB_TYPE_PCIE_UP))
+ return false;
+ if (!tb_switch_find_port(port->remote->sw, TB_TYPE_PCIE_DOWN))
+ return false;
+ } else {
+ if (!tb_switch_find_port(port->sw, TB_TYPE_PCIE_DOWN))
+ return false;
+ if (!tb_switch_find_port(port->remote->sw, TB_TYPE_PCIE_UP))
+ return false;
+ }
+
+ *reserved_up = USB4_V2_PCI_MIN_BANDWIDTH;
+ *reserved_down = USB4_V2_PCI_MIN_BANDWIDTH;
+
+ tb_port_dbg(port, "reserving %u/%u Mb/s for PCIe\n", *reserved_up,
+ *reserved_down);
+ return true;
+}
+
static bool tb_dp_is_usb4(const struct tb_switch *sw)
{
/* Titan Ridge DP adapters need the same treatment as USB4 */
@@ -1747,6 +1801,7 @@ static int tb_usb3_activate(struct tb_tunnel *tunnel, bool activate)
static int tb_usb3_consumed_bandwidth(struct tb_tunnel *tunnel,
int *consumed_up, int *consumed_down)
{
+ struct tb_port *port = tb_upstream_port(tunnel->dst_port->sw);
int pcie_weight = tb_acpi_may_tunnel_pcie() ? TB_PCI_WEIGHT : 0;
/*
@@ -1758,6 +1813,11 @@ static int tb_usb3_consumed_bandwidth(struct tb_tunnel *tunnel,
*consumed_down = tunnel->allocated_down *
(TB_USB3_WEIGHT + pcie_weight) / TB_USB3_WEIGHT;
+ if (tb_port_get_link_generation(port) >= 4) {
+ *consumed_up = max(*consumed_up, USB4_V2_USB3_MIN_BANDWIDTH);
+ *consumed_down = max(*consumed_down, USB4_V2_USB3_MIN_BANDWIDTH);
+ }
+
return 0;
}
diff --git a/drivers/thunderbolt/tunnel.h b/drivers/thunderbolt/tunnel.h
index 750ebb570d99..b4cff5482112 100644
--- a/drivers/thunderbolt/tunnel.h
+++ b/drivers/thunderbolt/tunnel.h
@@ -80,6 +80,8 @@ struct tb_tunnel *tb_tunnel_discover_pci(struct tb *tb, struct tb_port *down,
bool alloc_hopid);
struct tb_tunnel *tb_tunnel_alloc_pci(struct tb *tb, struct tb_port *up,
struct tb_port *down);
+bool tb_tunnel_reserved_pci(struct tb_port *port, int *reserved_up,
+ int *reserved_down);
struct tb_tunnel *tb_tunnel_discover_dp(struct tb *tb, struct tb_port *in,
bool alloc_hopid);
struct tb_tunnel *tb_tunnel_alloc_dp(struct tb *tb, struct tb_port *in,
--
2.45.1
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