This adds support for the UHBR (Ultra High Bit Rate) bandwidths
introduced with DisplayPort 2.0 (and refined in 2.1). These can go up to
80 Gbit/s and their support is represent in additional bits in the DP IN
capability.
This updates the DisplayPort tunneling to support these new rates too.
Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
---
drivers/thunderbolt/tb_regs.h | 3 +
drivers/thunderbolt/tunnel.c | 100 ++++++++++++++++++++++++++++------
2 files changed, 87 insertions(+), 16 deletions(-)
diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h
index c95fc7fe7adf..cf9f2370878a 100644
--- a/drivers/thunderbolt/tb_regs.h
+++ b/drivers/thunderbolt/tb_regs.h
@@ -450,6 +450,9 @@ struct tb_regs_port_header {
#define DP_COMMON_CAP_1_LANE 0x0
#define DP_COMMON_CAP_2_LANES 0x1
#define DP_COMMON_CAP_4_LANES 0x2
+#define DP_COMMON_CAP_UHBR10 BIT(17)
+#define DP_COMMON_CAP_UHBR20 BIT(18)
+#define DP_COMMON_CAP_UHBR13_5 BIT(19)
#define DP_COMMON_CAP_LTTPR_NS BIT(27)
#define DP_COMMON_CAP_BW_MODE BIT(28)
#define DP_COMMON_CAP_DPRX_DONE BIT(31)
diff --git a/drivers/thunderbolt/tunnel.c b/drivers/thunderbolt/tunnel.c
index 64ec0cccc0df..620dc9d240f0 100644
--- a/drivers/thunderbolt/tunnel.c
+++ b/drivers/thunderbolt/tunnel.c
@@ -417,6 +417,10 @@ static int tb_dp_cm_handshake(struct tb_port *in, struct tb_port *out,
return -ETIMEDOUT;
}
+/*
+ * Returns maximum possible rate from capability supporting only DP 2.0
+ * and below. Used when DP BW allocation mode is not enabled.
+ */
static inline u32 tb_dp_cap_get_rate(u32 val)
{
u32 rate = (val & DP_COMMON_CAP_RATE_MASK) >> DP_COMMON_CAP_RATE_SHIFT;
@@ -435,6 +439,28 @@ static inline u32 tb_dp_cap_get_rate(u32 val)
}
}
+/*
+ * Returns maximum possible rate from capability supporting DP 2.1
+ * UHBR20, 13.5 and 10 rates as well. Use only when DP BW allocation
+ * mode is enabled.
+ */
+static inline u32 tb_dp_cap_get_rate_ext(u32 val)
+{
+ if (val & DP_COMMON_CAP_UHBR20)
+ return 20000;
+ else if (val & DP_COMMON_CAP_UHBR13_5)
+ return 13500;
+ else if (val & DP_COMMON_CAP_UHBR10)
+ return 10000;
+
+ return tb_dp_cap_get_rate(val);
+}
+
+static inline bool tb_dp_is_uhbr_rate(unsigned int rate)
+{
+ return rate >= 10000;
+}
+
static inline u32 tb_dp_cap_set_rate(u32 val, u32 rate)
{
val &= ~DP_COMMON_CAP_RATE_MASK;
@@ -497,7 +523,9 @@ static inline u32 tb_dp_cap_set_lanes(u32 val, u32 lanes)
static unsigned int tb_dp_bandwidth(unsigned int rate, unsigned int lanes)
{
- /* Tunneling removes the DP 8b/10b encoding */
+ /* Tunneling removes the DP 8b/10b 128/132b encoding */
+ if (tb_dp_is_uhbr_rate(rate))
+ return rate * lanes * 128 / 132;
return rate * lanes * 8 / 10;
}
@@ -690,6 +718,19 @@ static int tb_dp_bandwidth_alloc_mode_enable(struct tb_tunnel *tunnel)
if (ret)
return ret;
+ /*
+ * Pick up granularity that supports maximum possible bandwidth.
+ * For that we use the UHBR rates too.
+ */
+ in_rate = tb_dp_cap_get_rate_ext(in_dp_cap);
+ out_rate = tb_dp_cap_get_rate_ext(out_dp_cap);
+ rate = min(in_rate, out_rate);
+ tmp = tb_dp_bandwidth(rate, lanes);
+
+ tb_port_dbg(in,
+ "maximum bandwidth through allocation mode %u Mb/s x%u = %u Mb/s\n",
+ rate, lanes, tmp);
+
for (granularity = 250; tmp / granularity > 255 && granularity <= 1000;
granularity *= 2)
;
@@ -805,15 +846,42 @@ static int tb_dp_activate(struct tb_tunnel *tunnel, bool active)
}
/* max_bw is rounded up to next granularity */
-static int tb_dp_nrd_bandwidth(struct tb_tunnel *tunnel, int *max_bw)
+static int tb_dp_bandwidth_mode_maximum_bandwidth(struct tb_tunnel *tunnel,
+ int *max_bw)
{
struct tb_port *in = tunnel->src_port;
int ret, rate, lanes, nrd_bw;
+ u32 cap;
- ret = usb4_dp_port_nrd(in, &rate, &lanes);
+ /*
+ * DP IN adapter DP_LOCAL_CAP gets updated to the lowest AUX
+ * read parameter values so this so we can use this to determine
+ * the maximum possible bandwidth over this link.
+ *
+ * See USB4 v2 spec 1.0 10.4.4.5.
+ */
+ ret = tb_port_read(in, &cap, TB_CFG_PORT,
+ in->cap_adap + DP_LOCAL_CAP, 1);
if (ret)
return ret;
+ rate = tb_dp_cap_get_rate_ext(cap);
+ if (tb_dp_is_uhbr_rate(rate)) {
+ /*
+ * When UHBR is used there is no reduction in lanes so
+ * we can use this directly.
+ */
+ lanes = tb_dp_cap_get_lanes(cap);
+ } else {
+ /*
+ * If there is no UHBR supported then check the
+ * non-reduced rate and lanes.
+ */
+ ret = usb4_dp_port_nrd(in, &rate, &lanes);
+ if (ret)
+ return ret;
+ }
+
nrd_bw = tb_dp_bandwidth(rate, lanes);
if (max_bw) {
@@ -846,7 +914,7 @@ static int tb_dp_bandwidth_mode_consumed_bandwidth(struct tb_tunnel *tunnel,
return ret;
allocated_bw = ret;
- ret = tb_dp_nrd_bandwidth(tunnel, &max_bw);
+ ret = tb_dp_bandwidth_mode_maximum_bandwidth(tunnel, &max_bw);
if (ret < 0)
return ret;
if (allocated_bw == max_bw)
@@ -884,7 +952,7 @@ static int tb_dp_allocated_bandwidth(struct tb_tunnel *tunnel, int *allocated_up
return ret;
allocated_bw = ret;
- ret = tb_dp_nrd_bandwidth(tunnel, &max_bw);
+ ret = tb_dp_bandwidth_mode_maximum_bandwidth(tunnel, &max_bw);
if (ret < 0)
return ret;
if (allocated_bw == max_bw)
@@ -914,7 +982,7 @@ static int tb_dp_alloc_bandwidth(struct tb_tunnel *tunnel, int *alloc_up,
if (!usb4_dp_port_bandwidth_mode_enabled(in))
return -EOPNOTSUPP;
- ret = tb_dp_nrd_bandwidth(tunnel, &max_bw);
+ ret = tb_dp_bandwidth_mode_maximum_bandwidth(tunnel, &max_bw);
if (ret < 0)
return ret;
@@ -937,6 +1005,9 @@ static int tb_dp_alloc_bandwidth(struct tb_tunnel *tunnel, int *alloc_up,
/* Now we can use BW mode registers to figure out the bandwidth */
/* TODO: need to handle discovery too */
tunnel->bw_mode = true;
+
+ tb_port_dbg(in, "allocated bandwidth through allocation mode %d Mb/s\n",
+ tmp);
return 0;
}
@@ -1011,23 +1082,20 @@ static int tb_dp_maximum_bandwidth(struct tb_tunnel *tunnel, int *max_up,
int *max_down)
{
struct tb_port *in = tunnel->src_port;
- u32 rate, lanes;
int ret;
- /*
- * DP IN adapter DP_LOCAL_CAP gets updated to the lowest AUX read
- * parameter values so this so we can use this to determine the
- * maximum possible bandwidth over this link.
- */
- ret = tb_dp_read_cap(tunnel, DP_LOCAL_CAP, &rate, &lanes);
- if (ret)
+ if (!usb4_dp_port_bandwidth_mode_enabled(in))
+ return -EOPNOTSUPP;
+
+ ret = tb_dp_bandwidth_mode_maximum_bandwidth(tunnel, NULL);
+ if (ret < 0)
return ret;
if (in->sw->config.depth < tunnel->dst_port->sw->config.depth) {
*max_up = 0;
- *max_down = tb_dp_bandwidth(rate, lanes);
+ *max_down = ret;
} else {
- *max_up = tb_dp_bandwidth(rate, lanes);
+ *max_up = ret;
*max_down = 0;
}
--
2.39.2
