usb: Add driver for UCSI

USB Type-C Connector System Software Interface (UCSI) is
specification that defines the registers and data structures
that can be used to control USB Type-C ports on a system.
UCSI is used on several Intel Broxton SoC based platforms.
Things that UCSI can be used to control include at least USB
Data Role swapping, Power Role swapping and controlling of
Alternate Modes on top of providing general details about
the port and the partners that are attached to it.

The initial purpose of the UCSI driver is to make sure USB
is in host mode on desktop and server systems that are USB
dual role capable, and provide UCSI interface.

The goal is to integrate the driver later to an USB Type-C
framework for Linux kernel, and at the same time add support
for more extensive USB Type-C port control that UCSI offers,
for example data role swapping, power role swapping,
Alternate Mode control etc.

The UCSI specification is public can be obtained from here:
http://www.intel.com/content/www/us/en/io/universal-serial-bus/usb-type-c-ucsi-spec.html

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 478 insertions, 0 deletions

diff --git a/drivers/usb/misc/ucsi.c b/drivers/usb/misc/ucsi.c
new file mode 100644
index 000000000000..07397bddefa3
--- /dev/null
+++ b/drivers/usb/misc/ucsi.c
@@ -0,0 +1,478 @@
+/*
+ * USB Type-C Connector System Software Interface driver
+ *
+ * Copyright (C) 2016, Intel Corporation
+ * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/acpi.h>
+
+#include "ucsi.h"
+
+/* Double the time defined by MIN_TIME_TO_RESPOND_WITH_BUSY */
+#define UCSI_TIMEOUT_MS 20
+
+enum ucsi_status {
+	UCSI_IDLE = 0,
+	UCSI_BUSY,
+	UCSI_ERROR,
+};
+
+struct ucsi_connector {
+	int num;
+	struct ucsi *ucsi;
+	struct work_struct work;
+	struct ucsi_connector_capability cap;
+};
+
+struct ucsi {
+	struct device *dev;
+	struct ucsi_data __iomem *data;
+
+	enum ucsi_status status;
+	struct completion complete;
+	struct ucsi_capability cap;
+	struct ucsi_connector *connector;
+
+	/* device lock */
+	spinlock_t dev_lock;
+
+	/* PPM Communication lock */
+	struct mutex ppm_lock;
+
+	/* PPM communication flags */
+	unsigned long flags;
+#define EVENT_PENDING	0
+#define COMMAND_PENDING	1
+};
+
+static int ucsi_acpi_cmd(struct ucsi *ucsi, struct ucsi_control *ctrl)
+{
+	uuid_le uuid = UUID_LE(0x6f8398c2, 0x7ca4, 0x11e4,
+			       0xad, 0x36, 0x63, 0x10, 0x42, 0xb5, 0x00, 0x8f);
+	union acpi_object *obj;
+
+	ucsi->data->ctrl.raw_cmd = ctrl->raw_cmd;
+
+	obj = acpi_evaluate_dsm(ACPI_HANDLE(ucsi->dev), uuid.b, 1, 1, NULL);
+	if (!obj) {
+		dev_err(ucsi->dev, "%s: failed to evaluate _DSM\n", __func__);
+		return -EIO;
+	}
+
+	ACPI_FREE(obj);
+	return 0;
+}
+
+static void ucsi_acpi_notify(acpi_handle handle, u32 event, void *data)
+{
+	struct ucsi *ucsi = data;
+	struct ucsi_cci *cci;
+
+	spin_lock(&ucsi->dev_lock);
+
+	ucsi->status = UCSI_IDLE;
+	cci = &ucsi->data->cci;
+
+	/*
+	 * REVISIT: This is not documented behavior, but all known PPMs ACK
+	 * asynchronous events by sending notification with cleared CCI.
+	 */
+	if (!ucsi->data->raw_cci) {
+		if (test_bit(EVENT_PENDING, &ucsi->flags))
+			complete(&ucsi->complete);
+		else
+			dev_WARN(ucsi->dev, "spurious notification\n");
+		goto out_unlock;
+	}
+
+	if (test_bit(COMMAND_PENDING, &ucsi->flags)) {
+		if (cci->busy) {
+			ucsi->status = UCSI_BUSY;
+			complete(&ucsi->complete);
+
+			goto out_unlock;
+		} else if (cci->ack_complete || cci->cmd_complete) {
+			/* Error Indication is only valid with commands */
+			if (cci->error && cci->cmd_complete)
+				ucsi->status = UCSI_ERROR;
+
+			ucsi->data->ctrl.raw_cmd = 0;
+			complete(&ucsi->complete);
+		}
+	}
+
+	if (cci->connector_change) {
+		struct ucsi_connector *con;
+
+		/*
+		 * This is workaround for buggy PPMs that create asynchronous
+		 * event notifications before OPM has enabled them.
+		 */
+		if (!ucsi->connector)
+			goto out_unlock;
+
+		con = ucsi->connector + (cci->connector_change - 1);
+
+		/*
+		 * PPM will not clear the connector specific bit in Connector
+		 * Change Indication field of CCI until the driver has ACK it,
+		 * and the driver can not ACK it before it has been processed.
+		 * The PPM will not generate new events before the first has
+		 * been acknowledged, even if they are for an other connector.
+		 * So only one event at a time.
+		 */
+		if (!test_and_set_bit(EVENT_PENDING, &ucsi->flags))
+			schedule_work(&con->work);
+	}
+out_unlock:
+	spin_unlock(&ucsi->dev_lock);
+}
+
+static int ucsi_ack(struct ucsi *ucsi, u8 cmd)
+{
+	struct ucsi_control ctrl;
+	int ret;
+
+	ctrl.cmd.cmd = UCSI_ACK_CC_CI;
+	ctrl.cmd.length = 0;
+	ctrl.cmd.data = cmd;
+	ret = ucsi_acpi_cmd(ucsi, &ctrl);
+	if (ret)
+		return ret;
+
+	/* Waiting for ACK also with ACK CMD for now */
+	ret = wait_for_completion_timeout(&ucsi->complete,
+					  msecs_to_jiffies(UCSI_TIMEOUT_MS));
+	if (!ret)
+		return -ETIMEDOUT;
+	return 0;
+}
+
+static int ucsi_run_cmd(struct ucsi *ucsi, struct ucsi_control *ctrl,
+			void *data, size_t size)
+{
+	u16 err_value = 0;
+	int ret;
+
+	set_bit(COMMAND_PENDING, &ucsi->flags);
+
+	ret = ucsi_acpi_cmd(ucsi, ctrl);
+	if (ret)
+		goto err_clear_flag;
+
+	ret = wait_for_completion_timeout(&ucsi->complete,
+					  msecs_to_jiffies(UCSI_TIMEOUT_MS));
+	if (!ret) {
+		ret = -ETIMEDOUT;
+		goto err_clear_flag;
+	}
+
+	switch (ucsi->status) {
+	case UCSI_IDLE:
+		if (data)
+			memcpy(data, ucsi->data->message_in, size);
+
+		ret = ucsi_ack(ucsi, UCSI_ACK_CMD);
+		break;
+	case UCSI_BUSY:
+		/* The caller decides whether to cancel or not */
+		ret = -EBUSY;
+		goto err_clear_flag;
+	case UCSI_ERROR:
+		ret = ucsi_ack(ucsi, UCSI_ACK_CMD);
+		if (ret)
+			goto err_clear_flag;
+
+		ctrl->cmd.cmd = UCSI_GET_ERROR_STATUS;
+		ctrl->cmd.length = 0;
+		ctrl->cmd.data = 0;
+		ret = ucsi_acpi_cmd(ucsi, ctrl);
+		if (ret)
+			goto err_clear_flag;
+
+		ret = wait_for_completion_timeout(&ucsi->complete,
+					msecs_to_jiffies(UCSI_TIMEOUT_MS));
+		if (!ret) {
+			ret = -ETIMEDOUT;
+			goto err_clear_flag;
+		}
+
+		memcpy(&err_value, ucsi->data->message_in, sizeof(err_value));
+
+		/* Something has really gone wrong */
+		if (WARN_ON(ucsi->status == UCSI_ERROR)) {
+			ret = -ENODEV;
+			goto err_clear_flag;
+		}
+
+		ret = ucsi_ack(ucsi, UCSI_ACK_CMD);
+		if (ret)
+			goto err_clear_flag;
+
+		switch (err_value) {
+		case UCSI_ERROR_INCOMPATIBLE_PARTNER:
+			ret = -EOPNOTSUPP;
+			break;
+		case UCSI_ERROR_CC_COMMUNICATION_ERR:
+			ret = -ECOMM;
+			break;
+		case UCSI_ERROR_CONTRACT_NEGOTIATION_FAIL:
+			ret = -EIO;
+			break;
+		case UCSI_ERROR_DEAD_BATTERY:
+			dev_warn(ucsi->dev, "Dead battery condition!\n");
+			ret = -EPERM;
+			break;
+		/* The following mean a bug in this driver */
+		case UCSI_ERROR_INVALID_CON_NUM:
+		case UCSI_ERROR_UNREGONIZED_CMD:
+		case UCSI_ERROR_INVALID_CMD_ARGUMENT:
+		default:
+			dev_warn(ucsi->dev,
+				 "%s: possible UCSI driver bug - error %hu\n",
+				 __func__, err_value);
+			ret = -EINVAL;
+			break;
+		}
+		break;
+	}
+	ctrl->raw_cmd = 0;
+err_clear_flag:
+	clear_bit(COMMAND_PENDING, &ucsi->flags);
+	return ret;
+}
+
+static void ucsi_connector_change(struct work_struct *work)
+{
+	struct ucsi_connector *con = container_of(work, struct ucsi_connector,
+						  work);
+	struct ucsi_connector_status constat;
+	struct ucsi *ucsi = con->ucsi;
+	struct ucsi_control ctrl;
+	int ret;
+
+	mutex_lock(&ucsi->ppm_lock);
+
+	ctrl.cmd.cmd = UCSI_GET_CONNECTOR_STATUS;
+	ctrl.cmd.length = 0;
+	ctrl.cmd.data = con->num;
+	ret = ucsi_run_cmd(con->ucsi, &ctrl, &constat, sizeof(constat));
+	if (ret) {
+		dev_err(ucsi->dev, "%s: failed to read connector status (%d)\n",
+			__func__, ret);
+		goto out_ack_event;
+	}
+
+	/* Ignoring disconnections and Alternate Modes */
+	if (!constat.connected || !(constat.change &
+	    (UCSI_CONSTAT_PARTNER_CHANGE | UCSI_CONSTAT_CONNECT_CHANGE)) ||
+	    constat.partner_flags & UCSI_CONSTAT_PARTNER_FLAG_ALT_MODE)
+		goto out_ack_event;
+
+	/* If the partner got USB Host role, attempting swap */
+	if (constat.partner_type & UCSI_CONSTAT_PARTNER_TYPE_DFP) {
+		ctrl.uor.cmd = UCSI_SET_UOR;
+		ctrl.uor.con_num = con->num;
+		ctrl.uor.role = UCSI_UOR_ROLE_DFP;
+
+		ret = ucsi_run_cmd(con->ucsi, &ctrl, NULL, 0);
+		if (ret)
+			dev_err(ucsi->dev, "%s: failed to swap role (%d)\n",
+				__func__, ret);
+	}
+out_ack_event:
+	ucsi_ack(ucsi, UCSI_ACK_EVENT);
+	clear_bit(EVENT_PENDING, &ucsi->flags);
+	mutex_unlock(&ucsi->ppm_lock);
+}
+
+static int ucsi_reset_ppm(struct ucsi *ucsi)
+{
+	int timeout = UCSI_TIMEOUT_MS;
+	struct ucsi_control ctrl;
+	int ret;
+
+	memset(&ctrl, 0, sizeof(ctrl));
+	ctrl.cmd.cmd = UCSI_PPM_RESET;
+	ret = ucsi_acpi_cmd(ucsi, &ctrl);
+	if (ret)
+		return ret;
+
+	/* There is no quarantee the PPM will ever set the RESET_COMPLETE bit */
+	while (!ucsi->data->cci.reset_complete && timeout--)
+		usleep_range(1000, 2000);
+	return 0;
+}
+
+static int ucsi_init(struct ucsi *ucsi)
+{
+	struct ucsi_connector *con;
+	struct ucsi_control ctrl;
+	int ret;
+	int i;
+
+	init_completion(&ucsi->complete);
+	spin_lock_init(&ucsi->dev_lock);
+	mutex_init(&ucsi->ppm_lock);
+
+	/* Reset the PPM */
+	ret = ucsi_reset_ppm(ucsi);
+	if (ret)
+		return ret;
+
+	/*
+	 * REVISIT: Executing second reset to WA an issue seen on some of the
+	 * Broxton based platforms, where the first reset puts the PPM into a
+	 * state where it's unable to recognise some of the commands.
+	 */
+	ret = ucsi_reset_ppm(ucsi);
+	if (ret)
+		return ret;
+
+	mutex_lock(&ucsi->ppm_lock);
+
+	/* Enable basic notifications */
+	ctrl.cmd.cmd = UCSI_SET_NOTIFICATION_ENABLE;
+	ctrl.cmd.length = 0;
+	ctrl.cmd.data = UCSI_ENABLE_NTFY_CMD_COMPLETE | UCSI_ENABLE_NTFY_ERROR;
+	ret = ucsi_run_cmd(ucsi, &ctrl, NULL, 0);
+	if (ret)
+		goto err_reset;
+
+	/* Get PPM capabilities */
+	ctrl.cmd.cmd = UCSI_GET_CAPABILITY;
+	ret = ucsi_run_cmd(ucsi, &ctrl, &ucsi->cap, sizeof(ucsi->cap));
+	if (ret)
+		goto err_reset;
+
+	if (!ucsi->cap.num_connectors) {
+		ret = -ENODEV;
+		goto err_reset;
+	}
+
+	ucsi->connector = devm_kcalloc(ucsi->dev, ucsi->cap.num_connectors,
+				       sizeof(*ucsi->connector), GFP_KERNEL);
+	if (!ucsi->connector) {
+		ret = -ENOMEM;
+		goto err_reset;
+	}
+
+	for (i = 1, con = ucsi->connector; i < ucsi->cap.num_connectors + 1;
+	     i++, con++) {
+		/* Get connector capability */
+		ctrl.cmd.cmd = UCSI_GET_CONNECTOR_CAPABILITY;
+		ctrl.cmd.data = i;
+		ret = ucsi_run_cmd(ucsi, &ctrl, &con->cap, sizeof(con->cap));
+		if (ret)
+			goto err_reset;
+
+		con->num = i;
+		con->ucsi = ucsi;
+		INIT_WORK(&con->work, ucsi_connector_change);
+	}
+
+	/* Enable all notifications */
+	ctrl.cmd.cmd = UCSI_SET_NOTIFICATION_ENABLE;
+	ctrl.cmd.data = UCSI_ENABLE_NTFY_ALL;
+	ret = ucsi_run_cmd(ucsi, &ctrl, NULL, 0);
+	if (ret < 0)
+		goto err_reset;
+
+	mutex_unlock(&ucsi->ppm_lock);
+	return 0;
+err_reset:
+	ucsi_reset_ppm(ucsi);
+	mutex_unlock(&ucsi->ppm_lock);
+	return ret;
+}
+
+static int ucsi_acpi_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	acpi_status status;
+	struct ucsi *ucsi;
+	int ret;
+
+	ucsi = devm_kzalloc(&pdev->dev, sizeof(*ucsi), GFP_KERNEL);
+	if (!ucsi)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "missing memory resource\n");
+		return -ENODEV;
+	}
+
+	/*
+	 * NOTE: ACPI has claimed the memory region as it's also an Operation
+	 * Region. It's not possible to request it in the driver.
+	 */
+	ucsi->data = devm_ioremap(&pdev->dev, res->start, resource_size(res));
+	if (!ucsi->data)
+		return -ENOMEM;
+
+	ucsi->dev = &pdev->dev;
+
+	status = acpi_install_notify_handler(ACPI_HANDLE(&pdev->dev),
+					     ACPI_ALL_NOTIFY,
+					     ucsi_acpi_notify, ucsi);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	ret = ucsi_init(ucsi);
+	if (ret) {
+		acpi_remove_notify_handler(ACPI_HANDLE(&pdev->dev),
+					   ACPI_ALL_NOTIFY,
+					   ucsi_acpi_notify);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, ucsi);
+	return 0;
+}
+
+static int ucsi_acpi_remove(struct platform_device *pdev)
+{
+	struct ucsi *ucsi = platform_get_drvdata(pdev);
+
+	acpi_remove_notify_handler(ACPI_HANDLE(&pdev->dev),
+				   ACPI_ALL_NOTIFY, ucsi_acpi_notify);
+
+	/* Make sure there are no events in the middle of being processed */
+	if (wait_on_bit_timeout(&ucsi->flags, EVENT_PENDING,
+				TASK_UNINTERRUPTIBLE,
+				msecs_to_jiffies(UCSI_TIMEOUT_MS)))
+		dev_WARN(ucsi->dev, "%s: Events still pending\n", __func__);
+
+	ucsi_reset_ppm(ucsi);
+	return 0;
+}
+
+static const struct acpi_device_id ucsi_acpi_match[] = {
+	{ "PNP0CA0", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, ucsi_acpi_match);
+
+static struct platform_driver ucsi_acpi_platform_driver = {
+	.driver = {
+		.name = "ucsi_acpi",
+		.acpi_match_table = ACPI_PTR(ucsi_acpi_match),
+	},
+	.probe = ucsi_acpi_probe,
+	.remove = ucsi_acpi_remove,
+};
+
+module_platform_driver(ucsi_acpi_platform_driver);
+
+MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("USB Type-C System Software Interface (UCSI) driver");