1 files changed, 565 insertions, 0 deletions
diff --git a/drivers/thunderbolt/retimer.c b/drivers/thunderbolt/retimer.c
new file mode 100644
index 0000000000..47becb363a
--- /dev/null
+++ b/drivers/thunderbolt/retimer.c
@@ -0,0 +1,565 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Thunderbolt/USB4 retimer support.
+ *
+ * Copyright (C) 2020, Intel Corporation
+ * Authors: Kranthi Kuntala <kranthi.kuntala@intel.com>
+ *	    Mika Westerberg <mika.westerberg@linux.intel.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/pm_runtime.h>
+#include <linux/sched/signal.h>
+
+#include "sb_regs.h"
+#include "tb.h"
+
+#define TB_MAX_RETIMER_INDEX	6
+
+/**
+ * tb_retimer_nvm_read() - Read contents of retimer NVM
+ * @rt: Retimer device
+ * @address: NVM address (in bytes) to start reading
+ * @buf: Data read from NVM is stored here
+ * @size: Number of bytes to read
+ *
+ * Reads retimer NVM and copies the contents to @buf. Returns %0 if the
+ * read was successful and negative errno in case of failure.
+ */
+int tb_retimer_nvm_read(struct tb_retimer *rt, unsigned int address, void *buf,
+			size_t size)
+{
+	return usb4_port_retimer_nvm_read(rt->port, rt->index, address, buf, size);
+}
+
+static int nvm_read(void *priv, unsigned int offset, void *val, size_t bytes)
+{
+	struct tb_nvm *nvm = priv;
+	struct tb_retimer *rt = tb_to_retimer(nvm->dev);
+	int ret;
+
+	pm_runtime_get_sync(&rt->dev);
+
+	if (!mutex_trylock(&rt->tb->lock)) {
+		ret = restart_syscall();
+		goto out;
+	}
+
+	ret = tb_retimer_nvm_read(rt, offset, val, bytes);
+	mutex_unlock(&rt->tb->lock);
+
+out:
+	pm_runtime_mark_last_busy(&rt->dev);
+	pm_runtime_put_autosuspend(&rt->dev);
+
+	return ret;
+}
+
+static int nvm_write(void *priv, unsigned int offset, void *val, size_t bytes)
+{
+	struct tb_nvm *nvm = priv;
+	struct tb_retimer *rt = tb_to_retimer(nvm->dev);
+	int ret = 0;
+
+	if (!mutex_trylock(&rt->tb->lock))
+		return restart_syscall();
+
+	ret = tb_nvm_write_buf(nvm, offset, val, bytes);
+	mutex_unlock(&rt->tb->lock);
+
+	return ret;
+}
+
+static int tb_retimer_nvm_add(struct tb_retimer *rt)
+{
+	struct tb_nvm *nvm;
+	int ret;
+
+	nvm = tb_nvm_alloc(&rt->dev);
+	if (IS_ERR(nvm)) {
+		ret = PTR_ERR(nvm) == -EOPNOTSUPP ? 0 : PTR_ERR(nvm);
+		goto err_nvm;
+	}
+
+	ret = tb_nvm_read_version(nvm);
+	if (ret)
+		goto err_nvm;
+
+	ret = tb_nvm_add_active(nvm, nvm_read);
+	if (ret)
+		goto err_nvm;
+
+	ret = tb_nvm_add_non_active(nvm, nvm_write);
+	if (ret)
+		goto err_nvm;
+
+	rt->nvm = nvm;
+	return 0;
+
+err_nvm:
+	dev_dbg(&rt->dev, "NVM upgrade disabled\n");
+	if (!IS_ERR(nvm))
+		tb_nvm_free(nvm);
+
+	return ret;
+}
+
+static int tb_retimer_nvm_validate_and_write(struct tb_retimer *rt)
+{
+	unsigned int image_size;
+	const u8 *buf;
+	int ret;
+
+	ret = tb_nvm_validate(rt->nvm);
+	if (ret)
+		return ret;
+
+	buf = rt->nvm->buf_data_start;
+	image_size = rt->nvm->buf_data_size;
+
+	ret = usb4_port_retimer_nvm_write(rt->port, rt->index, 0, buf,
+					 image_size);
+	if (ret)
+		return ret;
+
+	rt->nvm->flushed = true;
+	return 0;
+}
+
+static int tb_retimer_nvm_authenticate(struct tb_retimer *rt, bool auth_only)
+{
+	u32 status;
+	int ret;
+
+	if (auth_only) {
+		ret = usb4_port_retimer_nvm_set_offset(rt->port, rt->index, 0);
+		if (ret)
+			return ret;
+	}
+
+	ret = usb4_port_retimer_nvm_authenticate(rt->port, rt->index);
+	if (ret)
+		return ret;
+
+	usleep_range(100, 150);
+
+	/*
+	 * Check the status now if we still can access the retimer. It
+	 * is expected that the below fails.
+	 */
+	ret = usb4_port_retimer_nvm_authenticate_status(rt->port, rt->index,
+							&status);
+	if (!ret) {
+		rt->auth_status = status;
+		return status ? -EINVAL : 0;
+	}
+
+	return 0;
+}
+
+static ssize_t device_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct tb_retimer *rt = tb_to_retimer(dev);
+
+	return sysfs_emit(buf, "%#x\n", rt->device);
+}
+static DEVICE_ATTR_RO(device);
+
+static ssize_t nvm_authenticate_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct tb_retimer *rt = tb_to_retimer(dev);
+	int ret;
+
+	if (!mutex_trylock(&rt->tb->lock))
+		return restart_syscall();
+
+	if (!rt->nvm)
+		ret = -EAGAIN;
+	else if (rt->no_nvm_upgrade)
+		ret = -EOPNOTSUPP;
+	else
+		ret = sysfs_emit(buf, "%#x\n", rt->auth_status);
+
+	mutex_unlock(&rt->tb->lock);
+
+	return ret;
+}
+
+static void tb_retimer_nvm_authenticate_status(struct tb_port *port, u32 *status)
+{
+	int i;
+
+	tb_port_dbg(port, "reading NVM authentication status of retimers\n");
+
+	/*
+	 * Before doing anything else, read the authentication status.
+	 * If the retimer has it set, store it for the new retimer
+	 * device instance.
+	 */
+	for (i = 1; i <= TB_MAX_RETIMER_INDEX; i++)
+		usb4_port_retimer_nvm_authenticate_status(port, i, &status[i]);
+}
+
+static void tb_retimer_set_inbound_sbtx(struct tb_port *port)
+{
+	int i;
+
+	/*
+	 * When USB4 port is online sideband communications are
+	 * already up.
+	 */
+	if (!usb4_port_device_is_offline(port->usb4))
+		return;
+
+	tb_port_dbg(port, "enabling sideband transactions\n");
+
+	for (i = 1; i <= TB_MAX_RETIMER_INDEX; i++)
+		usb4_port_retimer_set_inbound_sbtx(port, i);
+}
+
+static void tb_retimer_unset_inbound_sbtx(struct tb_port *port)
+{
+	int i;
+
+	/*
+	 * When USB4 port is offline we need to keep the sideband
+	 * communications up to make it possible to communicate with
+	 * the connected retimers.
+	 */
+	if (usb4_port_device_is_offline(port->usb4))
+		return;
+
+	tb_port_dbg(port, "disabling sideband transactions\n");
+
+	for (i = TB_MAX_RETIMER_INDEX; i >= 1; i--)
+		usb4_port_retimer_unset_inbound_sbtx(port, i);
+}
+
+static ssize_t nvm_authenticate_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct tb_retimer *rt = tb_to_retimer(dev);
+	int val, ret;
+
+	pm_runtime_get_sync(&rt->dev);
+
+	if (!mutex_trylock(&rt->tb->lock)) {
+		ret = restart_syscall();
+		goto exit_rpm;
+	}
+
+	if (!rt->nvm) {
+		ret = -EAGAIN;
+		goto exit_unlock;
+	}
+
+	ret = kstrtoint(buf, 10, &val);
+	if (ret)
+		goto exit_unlock;
+
+	/* Always clear status */
+	rt->auth_status = 0;
+
+	if (val) {
+		/*
+		 * When NVM authentication starts the retimer is not
+		 * accessible so calling tb_retimer_unset_inbound_sbtx()
+		 * will fail and therefore we do not call it. Exception
+		 * is when the validation fails or we only write the new
+		 * NVM image without authentication.
+		 */
+		tb_retimer_set_inbound_sbtx(rt->port);
+		if (val == AUTHENTICATE_ONLY) {
+			ret = tb_retimer_nvm_authenticate(rt, true);
+		} else {
+			if (!rt->nvm->flushed) {
+				if (!rt->nvm->buf) {
+					ret = -EINVAL;
+					goto exit_unlock;
+				}
+
+				ret = tb_retimer_nvm_validate_and_write(rt);
+				if (ret || val == WRITE_ONLY)
+					goto exit_unlock;
+			}
+			if (val == WRITE_AND_AUTHENTICATE)
+				ret = tb_retimer_nvm_authenticate(rt, false);
+		}
+	}
+
+exit_unlock:
+	if (ret || val == WRITE_ONLY)
+		tb_retimer_unset_inbound_sbtx(rt->port);
+	mutex_unlock(&rt->tb->lock);
+exit_rpm:
+	pm_runtime_mark_last_busy(&rt->dev);
+	pm_runtime_put_autosuspend(&rt->dev);
+
+	if (ret)
+		return ret;
+	return count;
+}
+static DEVICE_ATTR_RW(nvm_authenticate);
+
+static ssize_t nvm_version_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct tb_retimer *rt = tb_to_retimer(dev);
+	int ret;
+
+	if (!mutex_trylock(&rt->tb->lock))
+		return restart_syscall();
+
+	if (!rt->nvm)
+		ret = -EAGAIN;
+	else
+		ret = sysfs_emit(buf, "%x.%x\n", rt->nvm->major, rt->nvm->minor);
+
+	mutex_unlock(&rt->tb->lock);
+	return ret;
+}
+static DEVICE_ATTR_RO(nvm_version);
+
+static ssize_t vendor_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct tb_retimer *rt = tb_to_retimer(dev);
+
+	return sysfs_emit(buf, "%#x\n", rt->vendor);
+}
+static DEVICE_ATTR_RO(vendor);
+
+static struct attribute *retimer_attrs[] = {
+	&dev_attr_device.attr,
+	&dev_attr_nvm_authenticate.attr,
+	&dev_attr_nvm_version.attr,
+	&dev_attr_vendor.attr,
+	NULL
+};
+
+static const struct attribute_group retimer_group = {
+	.attrs = retimer_attrs,
+};
+
+static const struct attribute_group *retimer_groups[] = {
+	&retimer_group,
+	NULL
+};
+
+static void tb_retimer_release(struct device *dev)
+{
+	struct tb_retimer *rt = tb_to_retimer(dev);
+
+	kfree(rt);
+}
+
+struct device_type tb_retimer_type = {
+	.name = "thunderbolt_retimer",
+	.groups = retimer_groups,
+	.release = tb_retimer_release,
+};
+
+static int tb_retimer_add(struct tb_port *port, u8 index, u32 auth_status)
+{
+	struct tb_retimer *rt;
+	u32 vendor, device;
+	int ret;
+
+	ret = usb4_port_retimer_read(port, index, USB4_SB_VENDOR_ID, &vendor,
+				     sizeof(vendor));
+	if (ret) {
+		if (ret != -ENODEV)
+			tb_port_warn(port, "failed read retimer VendorId: %d\n", ret);
+		return ret;
+	}
+
+	ret = usb4_port_retimer_read(port, index, USB4_SB_PRODUCT_ID, &device,
+				     sizeof(device));
+	if (ret) {
+		if (ret != -ENODEV)
+			tb_port_warn(port, "failed read retimer ProductId: %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * Check that it supports NVM operations. If not then don't add
+	 * the device at all.
+	 */
+	ret = usb4_port_retimer_nvm_sector_size(port, index);
+	if (ret < 0)
+		return ret;
+
+	rt = kzalloc(sizeof(*rt), GFP_KERNEL);
+	if (!rt)
+		return -ENOMEM;
+
+	rt->index = index;
+	rt->vendor = vendor;
+	rt->device = device;
+	rt->auth_status = auth_status;
+	rt->port = port;
+	rt->tb = port->sw->tb;
+
+	rt->dev.parent = &port->usb4->dev;
+	rt->dev.bus = &tb_bus_type;
+	rt->dev.type = &tb_retimer_type;
+	dev_set_name(&rt->dev, "%s:%u.%u", dev_name(&port->sw->dev),
+		     port->port, index);
+
+	ret = device_register(&rt->dev);
+	if (ret) {
+		dev_err(&rt->dev, "failed to register retimer: %d\n", ret);
+		put_device(&rt->dev);
+		return ret;
+	}
+
+	ret = tb_retimer_nvm_add(rt);
+	if (ret) {
+		dev_err(&rt->dev, "failed to add NVM devices: %d\n", ret);
+		device_unregister(&rt->dev);
+		return ret;
+	}
+
+	dev_info(&rt->dev, "new retimer found, vendor=%#x device=%#x\n",
+		 rt->vendor, rt->device);
+
+	pm_runtime_no_callbacks(&rt->dev);
+	pm_runtime_set_active(&rt->dev);
+	pm_runtime_enable(&rt->dev);
+	pm_runtime_set_autosuspend_delay(&rt->dev, TB_AUTOSUSPEND_DELAY);
+	pm_runtime_mark_last_busy(&rt->dev);
+	pm_runtime_use_autosuspend(&rt->dev);
+
+	return 0;
+}
+
+static void tb_retimer_remove(struct tb_retimer *rt)
+{
+	dev_info(&rt->dev, "retimer disconnected\n");
+	tb_nvm_free(rt->nvm);
+	device_unregister(&rt->dev);
+}
+
+struct tb_retimer_lookup {
+	const struct tb_port *port;
+	u8 index;
+};
+
+static int retimer_match(struct device *dev, void *data)
+{
+	const struct tb_retimer_lookup *lookup = data;
+	struct tb_retimer *rt = tb_to_retimer(dev);
+
+	return rt && rt->port == lookup->port && rt->index == lookup->index;
+}
+
+static struct tb_retimer *tb_port_find_retimer(struct tb_port *port, u8 index)
+{
+	struct tb_retimer_lookup lookup = { .port = port, .index = index };
+	struct device *dev;
+
+	dev = device_find_child(&port->usb4->dev, &lookup, retimer_match);
+	if (dev)
+		return tb_to_retimer(dev);
+
+	return NULL;
+}
+
+/**
+ * tb_retimer_scan() - Scan for on-board retimers under port
+ * @port: USB4 port to scan
+ * @add: If true also registers found retimers
+ *
+ * Brings the sideband into a state where retimers can be accessed.
+ * Then Tries to enumerate on-board retimers connected to @port. Found
+ * retimers are registered as children of @port if @add is set.  Does
+ * not scan for cable retimers for now.
+ */
+int tb_retimer_scan(struct tb_port *port, bool add)
+{
+	u32 status[TB_MAX_RETIMER_INDEX + 1] = {};
+	int ret, i, last_idx = 0;
+
+	/*
+	 * Send broadcast RT to make sure retimer indices facing this
+	 * port are set.
+	 */
+	ret = usb4_port_enumerate_retimers(port);
+	if (ret)
+		return ret;
+
+	/*
+	 * Immediately after sending enumerate retimers read the
+	 * authentication status of each retimer.
+	 */
+	tb_retimer_nvm_authenticate_status(port, status);
+
+	/*
+	 * Enable sideband channel for each retimer. We can do this
+	 * regardless whether there is device connected or not.
+	 */
+	tb_retimer_set_inbound_sbtx(port);
+
+	for (i = 1; i <= TB_MAX_RETIMER_INDEX; i++) {
+		/*
+		 * Last retimer is true only for the last on-board
+		 * retimer (the one connected directly to the Type-C
+		 * port).
+		 */
+		ret = usb4_port_retimer_is_last(port, i);
+		if (ret > 0)
+			last_idx = i;
+		else if (ret < 0)
+			break;
+	}
+
+	tb_retimer_unset_inbound_sbtx(port);
+
+	if (!last_idx)
+		return 0;
+
+	/* Add on-board retimers if they do not exist already */
+	ret = 0;
+	for (i = 1; i <= last_idx; i++) {
+		struct tb_retimer *rt;
+
+		rt = tb_port_find_retimer(port, i);
+		if (rt) {
+			put_device(&rt->dev);
+		} else if (add) {
+			ret = tb_retimer_add(port, i, status[i]);
+			if (ret && ret != -EOPNOTSUPP)
+				break;
+		}
+	}
+
+	return ret;
+}
+
+static int remove_retimer(struct device *dev, void *data)
+{
+	struct tb_retimer *rt = tb_to_retimer(dev);
+	struct tb_port *port = data;
+
+	if (rt && rt->port == port)
+		tb_retimer_remove(rt);
+	return 0;
+}
+
+/**
+ * tb_retimer_remove_all() - Remove all retimers under port
+ * @port: USB4 port whose retimers to remove
+ *
+ * This removes all previously added retimers under @port.
+ */
+void tb_retimer_remove_all(struct tb_port *port)
+{
+	struct usb4_port *usb4;
+
+	usb4 = port->usb4;
+	if (usb4)
+		device_for_each_child_reverse(&usb4->dev, port,
+					      remove_retimer);
+}