intel_th: Add driver infrastructure for Intel(R) Trace Hub devices

Intel(R) Trace Hub (TH) is a set of hardware blocks (subdevices) that
produce, switch and output trace data from multiple hardware and
software sources over several types of trace output ports encoded
in System Trace Protocol (MIPI STPv2) and is intended to perform
full system debugging.

For these subdevices, we create a bus, where they can be discovered
and configured by userspace software.

This patch creates this bus infrastructure, three types of devices
(source, output, switch), resource allocation, some callback mechanisms
to facilitate communication between the subdevices' drivers and some
common sysfs attributes.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 692 insertions, 0 deletions

diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c
new file mode 100644
index 000000000000..165d3001c301
--- /dev/null
+++ b/drivers/hwtracing/intel_th/core.c
@@ -0,0 +1,692 @@
+/*
+ * Intel(R) Trace Hub driver core
+ *
+ * Copyright (C) 2014-2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/sysfs.h>
+#include <linux/kdev_t.h>
+#include <linux/debugfs.h>
+#include <linux/idr.h>
+#include <linux/pci.h>
+#include <linux/dma-mapping.h>
+
+#include "intel_th.h"
+#include "debug.h"
+
+static DEFINE_IDA(intel_th_ida);
+
+static int intel_th_match(struct device *dev, struct device_driver *driver)
+{
+	struct intel_th_driver *thdrv = to_intel_th_driver(driver);
+	struct intel_th_device *thdev = to_intel_th_device(dev);
+
+	if (thdev->type == INTEL_TH_SWITCH &&
+	    (!thdrv->enable || !thdrv->disable))
+		return 0;
+
+	return !strcmp(thdev->name, driver->name);
+}
+
+static int intel_th_child_remove(struct device *dev, void *data)
+{
+	device_release_driver(dev);
+
+	return 0;
+}
+
+static int intel_th_probe(struct device *dev)
+{
+	struct intel_th_driver *thdrv = to_intel_th_driver(dev->driver);
+	struct intel_th_device *thdev = to_intel_th_device(dev);
+	struct intel_th_driver *hubdrv;
+	struct intel_th_device *hub = NULL;
+	int ret;
+
+	if (thdev->type == INTEL_TH_SWITCH)
+		hub = thdev;
+	else if (dev->parent)
+		hub = to_intel_th_device(dev->parent);
+
+	if (!hub || !hub->dev.driver)
+		return -EPROBE_DEFER;
+
+	hubdrv = to_intel_th_driver(hub->dev.driver);
+
+	ret = thdrv->probe(to_intel_th_device(dev));
+	if (ret)
+		return ret;
+
+	if (thdev->type == INTEL_TH_OUTPUT &&
+	    !intel_th_output_assigned(thdev))
+		ret = hubdrv->assign(hub, thdev);
+
+	return ret;
+}
+
+static int intel_th_remove(struct device *dev)
+{
+	struct intel_th_driver *thdrv = to_intel_th_driver(dev->driver);
+	struct intel_th_device *thdev = to_intel_th_device(dev);
+	struct intel_th_device *hub = to_intel_th_device(dev->parent);
+	int err;
+
+	if (thdev->type == INTEL_TH_SWITCH) {
+		err = device_for_each_child(dev, thdev, intel_th_child_remove);
+		if (err)
+			return err;
+	}
+
+	thdrv->remove(thdev);
+
+	if (intel_th_output_assigned(thdev)) {
+		struct intel_th_driver *hubdrv =
+			to_intel_th_driver(dev->parent->driver);
+
+		if (hub->dev.driver)
+			hubdrv->unassign(hub, thdev);
+	}
+
+	return 0;
+}
+
+static struct bus_type intel_th_bus = {
+	.name		= "intel_th",
+	.dev_attrs	= NULL,
+	.match		= intel_th_match,
+	.probe		= intel_th_probe,
+	.remove		= intel_th_remove,
+};
+
+static void intel_th_device_free(struct intel_th_device *thdev);
+
+static void intel_th_device_release(struct device *dev)
+{
+	intel_th_device_free(to_intel_th_device(dev));
+}
+
+static struct device_type intel_th_source_device_type = {
+	.name		= "intel_th_source_device",
+	.release	= intel_th_device_release,
+};
+
+static char *intel_th_output_devnode(struct device *dev, umode_t *mode,
+				     kuid_t *uid, kgid_t *gid)
+{
+	struct intel_th_device *thdev = to_intel_th_device(dev);
+	char *node;
+
+	if (thdev->id >= 0)
+		node = kasprintf(GFP_KERNEL, "intel_th%d/%s%d", 0, thdev->name,
+				 thdev->id);
+	else
+		node = kasprintf(GFP_KERNEL, "intel_th%d/%s", 0, thdev->name);
+
+	return node;
+}
+
+static ssize_t port_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct intel_th_device *thdev = to_intel_th_device(dev);
+
+	if (thdev->output.port >= 0)
+		return scnprintf(buf, PAGE_SIZE, "%u\n", thdev->output.port);
+
+	return scnprintf(buf, PAGE_SIZE, "unassigned\n");
+}
+
+static DEVICE_ATTR_RO(port);
+
+static int intel_th_output_activate(struct intel_th_device *thdev)
+{
+	struct intel_th_driver *thdrv = to_intel_th_driver(thdev->dev.driver);
+
+	if (thdrv->activate)
+		return thdrv->activate(thdev);
+
+	intel_th_trace_enable(thdev);
+
+	return 0;
+}
+
+static void intel_th_output_deactivate(struct intel_th_device *thdev)
+{
+	struct intel_th_driver *thdrv = to_intel_th_driver(thdev->dev.driver);
+
+	if (thdrv->deactivate)
+		thdrv->deactivate(thdev);
+	else
+		intel_th_trace_disable(thdev);
+}
+
+static ssize_t active_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct intel_th_device *thdev = to_intel_th_device(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", thdev->output.active);
+}
+
+static ssize_t active_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t size)
+{
+	struct intel_th_device *thdev = to_intel_th_device(dev);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	if (!!val != thdev->output.active) {
+		if (val)
+			ret = intel_th_output_activate(thdev);
+		else
+			intel_th_output_deactivate(thdev);
+	}
+
+	return ret ? ret : size;
+}
+
+static DEVICE_ATTR_RW(active);
+
+static struct attribute *intel_th_output_attrs[] = {
+	&dev_attr_port.attr,
+	&dev_attr_active.attr,
+	NULL,
+};
+
+ATTRIBUTE_GROUPS(intel_th_output);
+
+static struct device_type intel_th_output_device_type = {
+	.name		= "intel_th_output_device",
+	.groups		= intel_th_output_groups,
+	.release	= intel_th_device_release,
+	.devnode	= intel_th_output_devnode,
+};
+
+static struct device_type intel_th_switch_device_type = {
+	.name		= "intel_th_switch_device",
+	.release	= intel_th_device_release,
+};
+
+static struct device_type *intel_th_device_type[] = {
+	[INTEL_TH_SOURCE]	= &intel_th_source_device_type,
+	[INTEL_TH_OUTPUT]	= &intel_th_output_device_type,
+	[INTEL_TH_SWITCH]	= &intel_th_switch_device_type,
+};
+
+int intel_th_driver_register(struct intel_th_driver *thdrv)
+{
+	if (!thdrv->probe || !thdrv->remove)
+		return -EINVAL;
+
+	thdrv->driver.bus = &intel_th_bus;
+
+	return driver_register(&thdrv->driver);
+}
+EXPORT_SYMBOL_GPL(intel_th_driver_register);
+
+void intel_th_driver_unregister(struct intel_th_driver *thdrv)
+{
+	driver_unregister(&thdrv->driver);
+}
+EXPORT_SYMBOL_GPL(intel_th_driver_unregister);
+
+static struct intel_th_device *
+intel_th_device_alloc(struct intel_th *th, unsigned int type, const char *name,
+		      int id)
+{
+	struct device *parent;
+	struct intel_th_device *thdev;
+
+	if (type == INTEL_TH_SWITCH)
+		parent = th->dev;
+	else
+		parent = &th->hub->dev;
+
+	thdev = kzalloc(sizeof(*thdev) + strlen(name) + 1, GFP_KERNEL);
+	if (!thdev)
+		return NULL;
+
+	thdev->id = id;
+	thdev->type = type;
+
+	strcpy(thdev->name, name);
+	device_initialize(&thdev->dev);
+	thdev->dev.bus = &intel_th_bus;
+	thdev->dev.type = intel_th_device_type[type];
+	thdev->dev.parent = parent;
+	thdev->dev.dma_mask = parent->dma_mask;
+	thdev->dev.dma_parms = parent->dma_parms;
+	dma_set_coherent_mask(&thdev->dev, parent->coherent_dma_mask);
+	if (id >= 0)
+		dev_set_name(&thdev->dev, "%d-%s%d", th->id, name, id);
+	else
+		dev_set_name(&thdev->dev, "%d-%s", th->id, name);
+
+	return thdev;
+}
+
+static int intel_th_device_add_resources(struct intel_th_device *thdev,
+					 struct resource *res, int nres)
+{
+	struct resource *r;
+
+	r = kmemdup(res, sizeof(*res) * nres, GFP_KERNEL);
+	if (!r)
+		return -ENOMEM;
+
+	thdev->resource = r;
+	thdev->num_resources = nres;
+
+	return 0;
+}
+
+static void intel_th_device_remove(struct intel_th_device *thdev)
+{
+	device_del(&thdev->dev);
+	put_device(&thdev->dev);
+}
+
+static void intel_th_device_free(struct intel_th_device *thdev)
+{
+	kfree(thdev->resource);
+	kfree(thdev);
+}
+
+/*
+ * Intel(R) Trace Hub subdevices
+ */
+static struct intel_th_subdevice {
+	const char		*name;
+	struct resource		res[3];
+	unsigned		nres;
+	unsigned		type;
+	unsigned		otype;
+	int			id;
+} intel_th_subdevices[TH_SUBDEVICE_MAX] = {
+	{
+		.nres	= 1,
+		.res	= {
+			{
+				.start	= REG_GTH_OFFSET,
+				.end	= REG_GTH_OFFSET + REG_GTH_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+		},
+		.name	= "gth",
+		.type	= INTEL_TH_SWITCH,
+		.id	= -1,
+	},
+	{
+		.nres	= 2,
+		.res	= {
+			{
+				.start	= REG_MSU_OFFSET,
+				.end	= REG_MSU_OFFSET + REG_MSU_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+			{
+				.start	= BUF_MSU_OFFSET,
+				.end	= BUF_MSU_OFFSET + BUF_MSU_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+		},
+		.name	= "msc",
+		.id	= 0,
+		.type	= INTEL_TH_OUTPUT,
+		.otype	= GTH_MSU,
+	},
+	{
+		.nres	= 2,
+		.res	= {
+			{
+				.start	= REG_MSU_OFFSET,
+				.end	= REG_MSU_OFFSET + REG_MSU_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+			{
+				.start	= BUF_MSU_OFFSET,
+				.end	= BUF_MSU_OFFSET + BUF_MSU_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+		},
+		.name	= "msc",
+		.id	= 1,
+		.type	= INTEL_TH_OUTPUT,
+		.otype	= GTH_MSU,
+	},
+	{
+		.nres	= 2,
+		.res	= {
+			{
+				.start	= REG_STH_OFFSET,
+				.end	= REG_STH_OFFSET + REG_STH_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+			{
+				.start	= TH_MMIO_SW,
+				.end	= 0,
+				.flags	= IORESOURCE_MEM,
+			},
+		},
+		.id	= -1,
+		.name	= "sth",
+		.type	= INTEL_TH_SOURCE,
+	},
+	{
+		.nres	= 1,
+		.res	= {
+			{
+				.start	= REG_PTI_OFFSET,
+				.end	= REG_PTI_OFFSET + REG_PTI_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+		},
+		.id	= -1,
+		.name	= "pti",
+		.type	= INTEL_TH_OUTPUT,
+		.otype	= GTH_PTI,
+	},
+	{
+		.nres	= 1,
+		.res	= {
+			{
+				.start	= REG_DCIH_OFFSET,
+				.end	= REG_DCIH_OFFSET + REG_DCIH_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+		},
+		.id	= -1,
+		.name	= "dcih",
+		.type	= INTEL_TH_OUTPUT,
+	},
+};
+
+static int intel_th_populate(struct intel_th *th, struct resource *devres,
+			     unsigned int ndevres, int irq)
+{
+	struct resource res[3];
+	unsigned int req = 0;
+	int i, err;
+
+	/* create devices for each intel_th_subdevice */
+	for (i = 0; i < ARRAY_SIZE(intel_th_subdevices); i++) {
+		struct intel_th_subdevice *subdev = &intel_th_subdevices[i];
+		struct intel_th_device *thdev;
+		int r;
+
+		thdev = intel_th_device_alloc(th, subdev->type, subdev->name,
+					      subdev->id);
+		if (!thdev) {
+			err = -ENOMEM;
+			goto kill_subdevs;
+		}
+
+		memcpy(res, subdev->res,
+		       sizeof(struct resource) * subdev->nres);
+
+		for (r = 0; r < subdev->nres; r++) {
+			int bar = TH_MMIO_CONFIG;
+
+			/*
+			 * Take .end == 0 to mean 'take the whole bar',
+			 * .start then tells us which bar it is. Default to
+			 * TH_MMIO_CONFIG.
+			 */
+			if (!res[r].end && res[r].flags == IORESOURCE_MEM) {
+				bar = res[r].start;
+				res[r].start = 0;
+				res[r].end = resource_size(&devres[bar]) - 1;
+			}
+
+			if (res[r].flags & IORESOURCE_MEM) {
+				res[r].start	+= devres[bar].start;
+				res[r].end	+= devres[bar].start;
+
+				dev_dbg(th->dev, "%s:%d @ %pR\n",
+					subdev->name, r, &res[r]);
+			} else if (res[r].flags & IORESOURCE_IRQ) {
+				res[r].start	= irq;
+			}
+		}
+
+		err = intel_th_device_add_resources(thdev, res, subdev->nres);
+		if (err) {
+			put_device(&thdev->dev);
+			goto kill_subdevs;
+		}
+
+		if (subdev->type == INTEL_TH_OUTPUT) {
+			thdev->dev.devt = MKDEV(th->major, i);
+			thdev->output.type = subdev->otype;
+			thdev->output.port = -1;
+		}
+
+		err = device_add(&thdev->dev);
+		if (err) {
+			put_device(&thdev->dev);
+			goto kill_subdevs;
+		}
+
+		/* need switch driver to be loaded to enumerate the rest */
+		if (subdev->type == INTEL_TH_SWITCH && !req) {
+			th->hub = thdev;
+			err = request_module("intel_th_%s", subdev->name);
+			if (!err)
+				req++;
+		}
+
+		th->thdev[i] = thdev;
+	}
+
+	return 0;
+
+kill_subdevs:
+	for (i-- ; i >= 0; i--)
+		intel_th_device_remove(th->thdev[i]);
+
+	return err;
+}
+
+static int match_devt(struct device *dev, void *data)
+{
+	dev_t devt = (dev_t)(unsigned long)data;
+
+	return dev->devt == devt;
+}
+
+static int intel_th_output_open(struct inode *inode, struct file *file)
+{
+	const struct file_operations *fops;
+	struct intel_th_driver *thdrv;
+	struct device *dev;
+	int err;
+
+	dev = bus_find_device(&intel_th_bus, NULL,
+			      (void *)(unsigned long)inode->i_rdev,
+			      match_devt);
+	if (!dev || !dev->driver)
+		return -ENODEV;
+
+	thdrv = to_intel_th_driver(dev->driver);
+	fops = fops_get(thdrv->fops);
+	if (!fops)
+		return -ENODEV;
+
+	replace_fops(file, fops);
+
+	file->private_data = to_intel_th_device(dev);
+
+	if (file->f_op->open) {
+		err = file->f_op->open(inode, file);
+		return err;
+	}
+
+	return 0;
+}
+
+static const struct file_operations intel_th_output_fops = {
+	.open	= intel_th_output_open,
+	.llseek	= noop_llseek,
+};
+
+/**
+ * intel_th_alloc() - allocate a new Intel TH device and its subdevices
+ * @dev:	parent device
+ * @devres:	parent's resources
+ * @ndevres:	number of resources
+ * @irq:	irq number
+ */
+struct intel_th *
+intel_th_alloc(struct device *dev, struct resource *devres,
+	       unsigned int ndevres, int irq)
+{
+	struct intel_th *th;
+	int err;
+
+	th = kzalloc(sizeof(*th), GFP_KERNEL);
+	if (!th)
+		return ERR_PTR(-ENOMEM);
+
+	th->id = ida_simple_get(&intel_th_ida, 0, 0, GFP_KERNEL);
+	if (th->id < 0) {
+		err = th->id;
+		goto err_alloc;
+	}
+
+	th->major = __register_chrdev(0, 0, TH_POSSIBLE_OUTPUTS,
+				      "intel_th/output", &intel_th_output_fops);
+	if (th->major < 0) {
+		err = th->major;
+		goto err_ida;
+	}
+	th->dev = dev;
+
+	err = intel_th_populate(th, devres, ndevres, irq);
+	if (err)
+		goto err_chrdev;
+
+	return th;
+
+err_chrdev:
+	__unregister_chrdev(th->major, 0, TH_POSSIBLE_OUTPUTS,
+			    "intel_th/output");
+
+err_ida:
+	ida_simple_remove(&intel_th_ida, th->id);
+
+err_alloc:
+	kfree(th);
+
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(intel_th_alloc);
+
+void intel_th_free(struct intel_th *th)
+{
+	int i;
+
+	for (i = 0; i < TH_SUBDEVICE_MAX; i++)
+		if (th->thdev[i] != th->hub)
+			intel_th_device_remove(th->thdev[i]);
+
+	intel_th_device_remove(th->hub);
+
+	__unregister_chrdev(th->major, 0, TH_POSSIBLE_OUTPUTS,
+			    "intel_th/output");
+
+	ida_simple_remove(&intel_th_ida, th->id);
+
+	kfree(th);
+}
+EXPORT_SYMBOL_GPL(intel_th_free);
+
+/**
+ * intel_th_trace_enable() - enable tracing for an output device
+ * @thdev:	output device that requests tracing be enabled
+ */
+int intel_th_trace_enable(struct intel_th_device *thdev)
+{
+	struct intel_th_device *hub = to_intel_th_device(thdev->dev.parent);
+	struct intel_th_driver *hubdrv = to_intel_th_driver(hub->dev.driver);
+
+	if (WARN_ON_ONCE(hub->type != INTEL_TH_SWITCH))
+		return -EINVAL;
+
+	if (WARN_ON_ONCE(thdev->type != INTEL_TH_OUTPUT))
+		return -EINVAL;
+
+	hubdrv->enable(hub, &thdev->output);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(intel_th_trace_enable);
+
+/**
+ * intel_th_trace_disable() - disable tracing for an output device
+ * @thdev:	output device that requests tracing be disabled
+ */
+int intel_th_trace_disable(struct intel_th_device *thdev)
+{
+	struct intel_th_device *hub = to_intel_th_device(thdev->dev.parent);
+	struct intel_th_driver *hubdrv = to_intel_th_driver(hub->dev.driver);
+
+	WARN_ON_ONCE(hub->type != INTEL_TH_SWITCH);
+	if (WARN_ON_ONCE(thdev->type != INTEL_TH_OUTPUT))
+		return -EINVAL;
+
+	hubdrv->disable(hub, &thdev->output);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(intel_th_trace_disable);
+
+int intel_th_set_output(struct intel_th_device *thdev,
+			unsigned int master)
+{
+	struct intel_th_device *hub = to_intel_th_device(thdev->dev.parent);
+	struct intel_th_driver *hubdrv = to_intel_th_driver(hub->dev.driver);
+
+	if (!hubdrv->set_output)
+		return -ENOTSUPP;
+
+	return hubdrv->set_output(hub, master);
+}
+EXPORT_SYMBOL_GPL(intel_th_set_output);
+
+static int __init intel_th_init(void)
+{
+	intel_th_debug_init();
+
+	return bus_register(&intel_th_bus);
+}
+subsys_initcall(intel_th_init);
+
+static void __exit intel_th_exit(void)
+{
+	intel_th_debug_done();
+
+	bus_unregister(&intel_th_bus);
+}
+module_exit(intel_th_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Intel(R) Trace Hub controller driver");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");