Commit c8c08fd9 authored by Aapo Vienamo's avatar Aapo Vienamo Committed by Mika Westerberg
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thunderbolt: debugfs: Implement Gen 4 margining eye selection 



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: default avatarAapo Vienamo <aapo.vienamo@iki.fi>
Signed-off-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
parent c9077d59

drivers/thunderbolt/debugfs.c

+58 −0
Original line number Diff line number Diff line
@@ -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;

}

drivers/thunderbolt/sb_regs.h

+2 −1
Original line number Diff line number Diff line
@@ -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)

drivers/thunderbolt/tb.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

};

drivers/thunderbolt/usb4.c

+4 −2
Original line number Diff line number Diff line
@@ -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);