From: Aapo Vienamo <aapo.vienamo@xxxxxx>
Add a debugfs knob for USB4 Gen 4 margining eye selection. Gen 4 uses
3-level pulse amplitude modulation (PAM3) which changes how margining
measurements are made because PAM3 has two eyes per lane from which
the margins can be measured.
Signed-off-by: Aapo Vienamo <aapo.vienamo@xxxxxx>
Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
---
drivers/thunderbolt/debugfs.c | 58 +++++++++++++++++++++++++++++++++++
drivers/thunderbolt/sb_regs.h | 3 +-
drivers/thunderbolt/tb.h | 1 +
drivers/thunderbolt/usb4.c | 6 ++--
4 files changed, 65 insertions(+), 3 deletions(-)
diff --git a/drivers/thunderbolt/debugfs.c b/drivers/thunderbolt/debugfs.c
index 83721ca069a5..699e1632e3f5 100644
--- a/drivers/thunderbolt/debugfs.c
+++ b/drivers/thunderbolt/debugfs.c
@@ -436,6 +436,8 @@ static ssize_t retimer_sb_regs_write(struct file *file,
* @time: %true if time margining is used instead of voltage
* @right_high: %false if left/low margin test is performed, %true if
* right/high
+ * @upper_eye: %false if the lower PAM3 eye is used, %true if the upper
+ * eye is used
*/
struct tb_margining {
struct tb_port *port;
@@ -462,6 +464,7 @@ struct tb_margining {
bool software;
bool time;
bool right_high;
+ bool upper_eye;
};
static int margining_modify_error_counter(struct tb_margining *margining,
@@ -1162,6 +1165,7 @@ static int margining_run_write(void *data, u64 val)
.time = margining->time,
.voltage_time_offset = margining->voltage_time_offset,
.right_high = margining->right_high,
+ .upper_eye = margining->upper_eye,
.optional_voltage_offset_range = margining->optional_voltage_offset_range,
};
@@ -1177,6 +1181,7 @@ static int margining_run_write(void *data, u64 val)
.lanes = margining->lanes,
.time = margining->time,
.right_high = margining->right_high,
+ .upper_eye = margining->upper_eye,
.optional_voltage_offset_range = margining->optional_voltage_offset_range,
};
@@ -1464,6 +1469,55 @@ static int margining_margin_show(struct seq_file *s, void *not_used)
}
DEBUGFS_ATTR_RW(margining_margin);
+static ssize_t margining_eye_write(struct file *file,
+ const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ struct seq_file *s = file->private_data;
+ struct tb_port *port = s->private;
+ struct usb4_port *usb4 = port->usb4;
+ struct tb *tb = port->sw->tb;
+ int ret = 0;
+ char *buf;
+
+ buf = validate_and_copy_from_user(user_buf, &count);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ buf[count - 1] = '\0';
+
+ scoped_cond_guard(mutex_intr, ret = -ERESTARTSYS, &tb->lock) {
+ if (!strcmp(buf, "lower"))
+ usb4->margining->upper_eye = false;
+ else if (!strcmp(buf, "upper"))
+ usb4->margining->upper_eye = true;
+ else
+ ret = -EINVAL;
+ }
+
+ free_page((unsigned long)buf);
+ return ret ? ret : count;
+}
+
+static int margining_eye_show(struct seq_file *s, void *not_used)
+{
+ struct tb_port *port = s->private;
+ struct usb4_port *usb4 = port->usb4;
+ struct tb *tb = port->sw->tb;
+
+ scoped_guard(mutex_intr, &tb->lock) {
+ if (usb4->margining->upper_eye)
+ seq_puts(s, "lower [upper]\n");
+ else
+ seq_puts(s, "[lower] upper\n");
+
+ return 0;
+ }
+
+ return -ERESTARTSYS;
+}
+DEBUGFS_ATTR_RW(margining_eye);
+
static struct tb_margining *margining_alloc(struct tb_port *port,
struct device *dev,
enum usb4_sb_target target,
@@ -1573,6 +1627,10 @@ static struct tb_margining *margining_alloc(struct tb_port *port,
debugfs_create_file("dwell_time", DEBUGFS_MODE, dir, margining,
&margining_dwell_time_fops);
}
+
+ if (margining->gen >= 4)
+ debugfs_create_file("eye", 0600, dir, port, &margining_eye_fops);
+
return margining;
}
diff --git a/drivers/thunderbolt/sb_regs.h b/drivers/thunderbolt/sb_regs.h
index f60b8d90a71a..b7e91b99fefe 100644
--- a/drivers/thunderbolt/sb_regs.h
+++ b/drivers/thunderbolt/sb_regs.h
@@ -83,7 +83,7 @@ enum usb4_sb_opcode {
/* USB4_SB_OPCODE_RUN_HW_LANE_MARGINING */
#define USB4_MARGIN_HW_TIME BIT(3)
-#define USB4_MARGIN_HW_RH BIT(4)
+#define USB4_MARGIN_HW_RHU BIT(4)
#define USB4_MARGIN_HW_BER_MASK GENMASK(9, 5)
#define USB4_MARGIN_HW_BER_SHIFT 5
#define USB4_MARGIN_HW_OPT_VOLTAGE BIT(10)
@@ -106,6 +106,7 @@ enum usb4_sb_opcode {
#define USB4_MARGIN_SW_OPT_VOLTAGE BIT(5)
#define USB4_MARGIN_SW_VT_MASK GENMASK(12, 6)
#define USB4_MARGIN_SW_COUNTER_MASK GENMASK(14, 13)
+#define USB4_MARGIN_SW_UPPER_EYE BIT(15)
#define USB4_MARGIN_SW_ERR_COUNTER_LANE_0_MASK GENMASK(3, 0)
#define USB4_MARGIN_SW_ERR_COUNTER_LANE_1_MASK GENMASK(7, 4)
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index fa7fc9bba70f..ced9be271620 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -1384,6 +1384,7 @@ struct usb4_port_margining_params {
u32 voltage_time_offset;
bool optional_voltage_offset_range;
bool right_high;
+ bool upper_eye;
bool time;
};
diff --git a/drivers/thunderbolt/usb4.c b/drivers/thunderbolt/usb4.c
index 1fb72ff1268e..985f24b044b3 100644
--- a/drivers/thunderbolt/usb4.c
+++ b/drivers/thunderbolt/usb4.c
@@ -1673,8 +1673,8 @@ int usb4_port_hw_margin(struct tb_port *port, enum usb4_sb_target target,
val = params->lanes;
if (params->time)
val |= USB4_MARGIN_HW_TIME;
- if (params->right_high)
- val |= USB4_MARGIN_HW_RH;
+ if (params->right_high || params->upper_eye)
+ val |= USB4_MARGIN_HW_RHU;
if (params->ber_level)
val |= FIELD_PREP(USB4_MARGIN_HW_BER_MASK, params->ber_level);
if (params->optional_voltage_offset_range)
@@ -1723,6 +1723,8 @@ int usb4_port_sw_margin(struct tb_port *port, enum usb4_sb_target target,
val |= USB4_MARGIN_SW_OPT_VOLTAGE;
if (params->right_high)
val |= USB4_MARGIN_SW_RH;
+ if (params->upper_eye)
+ val |= USB4_MARGIN_SW_UPPER_EYE;
val |= FIELD_PREP(USB4_MARGIN_SW_COUNTER_MASK, params->error_counter);
val |= FIELD_PREP(USB4_MARGIN_SW_VT_MASK, params->voltage_time_offset);
--
2.45.2
