thunderbolt: Introduce thunderbolt bus and connection manager

Thunderbolt fabric consists of one or more switches. This fabric is
called domain and it is controlled by an entity called connection
manager. The connection manager can be either internal (driven by a
firmware running on the host controller) or external (software driver).
This driver currently implements support for the latter.

In order to manage switches and their properties more easily we model
this domain structure as a Linux bus. Each host controller adds a domain
device to this bus, and these devices are named as domainN where N
stands for index or id of the current domain.

We then abstract connection manager specific operations into a new
structure tb_cm_ops and convert the existing tb.c to fill those
accordingly. This makes it easier to add support for the internal
connection manager in subsequent patches.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 230 insertions, 0 deletions

diff --git a/drivers/thunderbolt/domain.c b/drivers/thunderbolt/domain.c
new file mode 100644
index 000000000000..3302f4c59638
--- /dev/null
+++ b/drivers/thunderbolt/domain.c
@@ -0,0 +1,230 @@
+/*
+ * Thunderbolt bus support
+ *
+ * Copyright (C) 2017, Intel Corporation
+ * Author:  Mika Westerberg <mika.westerberg@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/device.h>
+#include <linux/idr.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "tb.h"
+
+static DEFINE_IDA(tb_domain_ida);
+
+struct bus_type tb_bus_type = {
+	.name = "thunderbolt",
+};
+
+static void tb_domain_release(struct device *dev)
+{
+	struct tb *tb = container_of(dev, struct tb, dev);
+
+	tb_ctl_free(tb->ctl);
+	destroy_workqueue(tb->wq);
+	ida_simple_remove(&tb_domain_ida, tb->index);
+	mutex_destroy(&tb->lock);
+	kfree(tb);
+}
+
+struct device_type tb_domain_type = {
+	.name = "thunderbolt_domain",
+	.release = tb_domain_release,
+};
+
+/**
+ * tb_domain_alloc() - Allocate a domain
+ * @nhi: Pointer to the host controller
+ * @privsize: Size of the connection manager private data
+ *
+ * Allocates and initializes a new Thunderbolt domain. Connection
+ * managers are expected to call this and then fill in @cm_ops
+ * accordingly.
+ *
+ * Call tb_domain_put() to release the domain before it has been added
+ * to the system.
+ *
+ * Return: allocated domain structure on %NULL in case of error
+ */
+struct tb *tb_domain_alloc(struct tb_nhi *nhi, size_t privsize)
+{
+	struct tb *tb;
+
+	/*
+	 * Make sure the structure sizes map with that the hardware
+	 * expects because bit-fields are being used.
+	 */
+	BUILD_BUG_ON(sizeof(struct tb_regs_switch_header) != 5 * 4);
+	BUILD_BUG_ON(sizeof(struct tb_regs_port_header) != 8 * 4);
+	BUILD_BUG_ON(sizeof(struct tb_regs_hop) != 2 * 4);
+
+	tb = kzalloc(sizeof(*tb) + privsize, GFP_KERNEL);
+	if (!tb)
+		return NULL;
+
+	tb->nhi = nhi;
+	mutex_init(&tb->lock);
+
+	tb->index = ida_simple_get(&tb_domain_ida, 0, 0, GFP_KERNEL);
+	if (tb->index < 0)
+		goto err_free;
+
+	tb->wq = alloc_ordered_workqueue("thunderbolt%d", 0, tb->index);
+	if (!tb->wq)
+		goto err_remove_ida;
+
+	tb->dev.parent = &nhi->pdev->dev;
+	tb->dev.bus = &tb_bus_type;
+	tb->dev.type = &tb_domain_type;
+	dev_set_name(&tb->dev, "domain%d", tb->index);
+	device_initialize(&tb->dev);
+
+	return tb;
+
+err_remove_ida:
+	ida_simple_remove(&tb_domain_ida, tb->index);
+err_free:
+	kfree(tb);
+
+	return NULL;
+}
+
+/**
+ * tb_domain_add() - Add domain to the system
+ * @tb: Domain to add
+ *
+ * Starts the domain and adds it to the system. Hotplugging devices will
+ * work after this has been returned successfully. In order to remove
+ * and release the domain after this function has been called, call
+ * tb_domain_remove().
+ *
+ * Return: %0 in case of success and negative errno in case of error
+ */
+int tb_domain_add(struct tb *tb)
+{
+	int ret;
+
+	if (WARN_ON(!tb->cm_ops))
+		return -EINVAL;
+
+	mutex_lock(&tb->lock);
+
+	tb->ctl = tb_ctl_alloc(tb->nhi, tb->cm_ops->hotplug, tb);
+	if (!tb->ctl) {
+		ret = -ENOMEM;
+		goto err_unlock;
+	}
+
+	/*
+	 * tb_schedule_hotplug_handler may be called as soon as the config
+	 * channel is started. Thats why we have to hold the lock here.
+	 */
+	tb_ctl_start(tb->ctl);
+
+	ret = device_add(&tb->dev);
+	if (ret)
+		goto err_ctl_stop;
+
+	/* Start the domain */
+	if (tb->cm_ops->start) {
+		ret = tb->cm_ops->start(tb);
+		if (ret)
+			goto err_domain_del;
+	}
+
+	/* This starts event processing */
+	mutex_unlock(&tb->lock);
+
+	return 0;
+
+err_domain_del:
+	device_del(&tb->dev);
+err_ctl_stop:
+	tb_ctl_stop(tb->ctl);
+err_unlock:
+	mutex_unlock(&tb->lock);
+
+	return ret;
+}
+
+/**
+ * tb_domain_remove() - Removes and releases a domain
+ * @tb: Domain to remove
+ *
+ * Stops the domain, removes it from the system and releases all
+ * resources once the last reference has been released.
+ */
+void tb_domain_remove(struct tb *tb)
+{
+	mutex_lock(&tb->lock);
+	if (tb->cm_ops->stop)
+		tb->cm_ops->stop(tb);
+	/* Stop the domain control traffic */
+	tb_ctl_stop(tb->ctl);
+	mutex_unlock(&tb->lock);
+
+	flush_workqueue(tb->wq);
+	device_unregister(&tb->dev);
+}
+
+/**
+ * tb_domain_suspend_noirq() - Suspend a domain
+ * @tb: Domain to suspend
+ *
+ * Suspends all devices in the domain and stops the control channel.
+ */
+int tb_domain_suspend_noirq(struct tb *tb)
+{
+	int ret = 0;
+
+	/*
+	 * The control channel interrupt is left enabled during suspend
+	 * and taking the lock here prevents any events happening before
+	 * we actually have stopped the domain and the control channel.
+	 */
+	mutex_lock(&tb->lock);
+	if (tb->cm_ops->suspend_noirq)
+		ret = tb->cm_ops->suspend_noirq(tb);
+	if (!ret)
+		tb_ctl_stop(tb->ctl);
+	mutex_unlock(&tb->lock);
+
+	return ret;
+}
+
+/**
+ * tb_domain_resume_noirq() - Resume a domain
+ * @tb: Domain to resume
+ *
+ * Re-starts the control channel, and resumes all devices connected to
+ * the domain.
+ */
+int tb_domain_resume_noirq(struct tb *tb)
+{
+	int ret = 0;
+
+	mutex_lock(&tb->lock);
+	tb_ctl_start(tb->ctl);
+	if (tb->cm_ops->resume_noirq)
+		ret = tb->cm_ops->resume_noirq(tb);
+	mutex_unlock(&tb->lock);
+
+	return ret;
+}
+
+int tb_domain_init(void)
+{
+	return bus_register(&tb_bus_type);
+}
+
+void tb_domain_exit(void)
+{
+	bus_unregister(&tb_bus_type);
+	ida_destroy(&tb_domain_ida);
+}