[PATCH v3 8/8] staging: fsl-mc: Management Complex restool driver

[Lijun Pan]

The kernel support for the restool (a user space resource management
tool) is a driver for the /dev/dprc.N device file.
Its purpose is to provide an ioctl interface,
which the restool uses to interact with the MC bus driver
and with the MC firmware.
We allocate a dpmcp at driver initialization,
and keep that dpmcp until driver exit.
We use that dpmcp by default.
If that dpmcp is in use, we create another portal at run time
and destroy the newly created portal after use.
The ioctl RESTOOL_SEND_MC_COMMAND sends user space command to fsl-mc
bus and utilizes the fsl-mc bus to communicate with MC firmware.
The ioctl RESTOOL_DPRC_SYNC request the mc-bus launch
objects scan under root dprc.
In order to support multiple root dprc, we utilize the bus notify
mechanism to scan fsl_mc_bus_type for the newly added root dprc.
After discovering the root dprc, it creates a miscdevice
/dev/dprc.N to associate with this root dprc.

Signed-off-by: Lijun Pan <Lijun.Pan@xxxxxxxxxxxxx>
---
v3: rebased on top of greg's staging-testing
v2:
    remove verbose printk
    improve error handling
    synchronize misc_list access
    reserve ioctl range in Documentation/ioctl/ioctl-number.txt
    remove ioctl sync command
    flip if(!...) to make them fit in 80 columns
    change if(x==NULL) to if(!x)
    change ("int error = 0;" initialization) to (int error;)

 Documentation/ioctl/ioctl-number.txt    |    1 +
 drivers/staging/fsl-mc/bus/Kconfig      |    7 +-
 drivers/staging/fsl-mc/bus/Makefile     |    3 +
 drivers/staging/fsl-mc/bus/mc-ioctl.h   |   22 ++
 drivers/staging/fsl-mc/bus/mc-restool.c |  392 +++++++++++++++++++++++++++++++
 5 files changed, 424 insertions(+), 1 deletion(-)
 create mode 100644 drivers/staging/fsl-mc/bus/mc-ioctl.h
 create mode 100644 drivers/staging/fsl-mc/bus/mc-restool.c

diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index 91261a3..64cc31d 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -170,6 +170,7 @@ Code  Seq#(hex)	Include File		Comments
 'R'	00-1F	linux/random.h		conflict!
 'R'	01	linux/rfkill.h		conflict!
 'R'	C0-DF	net/bluetooth/rfcomm.h
+'R'	E0-EF	drivers/staging/fsl-mc/bus/mc-ioctl.h
 'S'	all	linux/cdrom.h		conflict!
 'S'	80-81	scsi/scsi_ioctl.h	conflict!
 'S'	82-FF	scsi/scsi.h		conflict!
diff --git a/drivers/staging/fsl-mc/bus/Kconfig b/drivers/staging/fsl-mc/bus/Kconfig
index c498ac6..92aff45 100644
--- a/drivers/staging/fsl-mc/bus/Kconfig
+++ b/drivers/staging/fsl-mc/bus/Kconfig
@@ -22,4 +22,9 @@ config FSL_MC_BUS
 	  Only enable this option when building the kernel for
 	  Freescale QorQIQ LS2xxxx SoCs.
 
-
+config FSL_MC_RESTOOL
+        tristate "Freescale Management Complex (MC) restool driver"
+        depends on FSL_MC_BUS
+        help
+          Driver that provides kernel support for the Freescale Management
+	  Complex resource manager user-space tool.
diff --git a/drivers/staging/fsl-mc/bus/Makefile b/drivers/staging/fsl-mc/bus/Makefile
index e731517..30a63a3 100644
--- a/drivers/staging/fsl-mc/bus/Makefile
+++ b/drivers/staging/fsl-mc/bus/Makefile
@@ -17,3 +17,6 @@ mc-bus-driver-objs := mc-bus.o \
 		      irq-gic-v3-its-fsl-mc-msi.o \
 		      dpmcp.o \
 		      dpbp.o
+
+# MC restool kernel support
+obj-$(CONFIG_FSL_MC_RESTOOL) += mc-restool.o
diff --git a/drivers/staging/fsl-mc/bus/mc-ioctl.h b/drivers/staging/fsl-mc/bus/mc-ioctl.h
new file mode 100644
index 0000000..8ac502a
--- /dev/null
+++ b/drivers/staging/fsl-mc/bus/mc-ioctl.h
@@ -0,0 +1,22 @@
+/*
+ * Freescale Management Complex (MC) ioclt interface
+ *
+ * Copyright (C) 2014 Freescale Semiconductor, Inc.
+ * Author: Lijun Pan <Lijun.Pan@xxxxxxxxxxxxx>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+#ifndef _FSL_MC_IOCTL_H_
+#define _FSL_MC_IOCTL_H_
+
+#include <linux/ioctl.h>
+#include "../include/mc-sys.h"
+
+#define RESTOOL_IOCTL_TYPE   'R'
+
+#define RESTOOL_SEND_MC_COMMAND \
+	_IOWR(RESTOOL_IOCTL_TYPE, 0xE0, struct mc_command)
+
+#endif /* _FSL_MC_IOCTL_H_ */
diff --git a/drivers/staging/fsl-mc/bus/mc-restool.c b/drivers/staging/fsl-mc/bus/mc-restool.c
new file mode 100644
index 0000000..57f059a
--- /dev/null
+++ b/drivers/staging/fsl-mc/bus/mc-restool.c
@@ -0,0 +1,392 @@
+/*
+ * Freescale Management Complex (MC) restool driver
+ *
+ * Copyright (C) 2014 Freescale Semiconductor, Inc.
+ * Author: Lijun Pan <Lijun.Pan@xxxxxxxxxxxxx>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include "../include/mc-private.h"
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include "mc-ioctl.h"
+#include "../include/mc-sys.h"
+#include "../include/mc-cmd.h"
+#include "../include/dpmng.h"
+
+/**
+ * Maximum number of DPRCs that can be opened at the same time
+ */
+#define MAX_DPRC_HANDLES	    64
+
+/**
+ * restool_misc - information associated with the newly added miscdevice
+ * @misc: newly created miscdevice associated with root dprc
+ * @miscdevt: device id of this miscdevice
+ * @list: a linked list node representing this miscdevcie
+ * @static_mc_io: pointer to the static MC I/O object used by the restool
+ * @dynamic_instance_count: number of dynamically created instances
+ * @static_instance_in_use: static instance is in use or not
+ * @mutex: mutex lock to serialze the open/release operations
+ * @dev: root dprc associated with this miscdevice
+ */
+struct restool_misc {
+	struct miscdevice misc;
+	dev_t miscdevt;
+	struct list_head list;
+	struct fsl_mc_io *static_mc_io;
+	u32 dynamic_instance_count;
+	bool static_instance_in_use;
+	struct mutex mutex; /* serialze the open/release operations */
+	struct device *dev;
+};
+
+/*
+ * initialize a global list to link all
+ * the miscdevice nodes (struct restool_misc)
+ */
+static LIST_HEAD(misc_list);
+static DEFINE_MUTEX(misc_list_mutex);
+
+static int fsl_mc_restool_dev_open(struct inode *inode, struct file *filep)
+{
+	struct fsl_mc_device *root_mc_dev;
+	int error;
+	struct fsl_mc_io *dynamic_mc_io = NULL;
+	struct restool_misc *restool_misc = NULL;
+	struct restool_misc *restool_misc_cursor;
+
+	mutex_lock(&misc_list_mutex);
+
+	list_for_each_entry(restool_misc_cursor, &misc_list, list) {
+		if (restool_misc_cursor->miscdevt == inode->i_rdev) {
+			restool_misc = restool_misc_cursor;
+			break;
+		}
+	}
+
+	mutex_unlock(&misc_list_mutex);
+
+	if (!restool_misc)
+		return -EINVAL;
+
+	if (WARN_ON(!restool_misc->dev))
+		return -EINVAL;
+
+	mutex_lock(&restool_misc->mutex);
+
+	if (!restool_misc->static_instance_in_use) {
+		restool_misc->static_instance_in_use = true;
+		filep->private_data = restool_misc->static_mc_io;
+	} else {
+		dynamic_mc_io = kzalloc(sizeof(*dynamic_mc_io), GFP_KERNEL);
+		if (!dynamic_mc_io) {
+			error = -ENOMEM;
+			goto err_unlock;
+		}
+
+		root_mc_dev = to_fsl_mc_device(restool_misc->dev);
+		error = fsl_mc_portal_allocate(root_mc_dev, 0, &dynamic_mc_io);
+		if (error < 0) {
+			pr_err("Not able to allocate MC portal\n");
+			goto free_dynamic_mc_io;
+		}
+		++restool_misc->dynamic_instance_count;
+		filep->private_data = dynamic_mc_io;
+	}
+
+	mutex_unlock(&restool_misc->mutex);
+
+	return 0;
+
+free_dynamic_mc_io:
+	kfree(dynamic_mc_io);
+err_unlock:
+	mutex_unlock(&restool_misc->mutex);
+
+	return error;
+}
+
+static int fsl_mc_restool_dev_release(struct inode *inode, struct file *filep)
+{
+	struct fsl_mc_io *local_mc_io = filep->private_data;
+	struct restool_misc *restool_misc = NULL;
+	struct restool_misc *restool_misc_cursor;
+
+	if (WARN_ON(!filep->private_data))
+		return -EINVAL;
+
+	mutex_lock(&misc_list_mutex);
+
+	list_for_each_entry(restool_misc_cursor, &misc_list, list) {
+		if (restool_misc_cursor->miscdevt == inode->i_rdev) {
+			restool_misc = restool_misc_cursor;
+			break;
+		}
+	}
+
+	mutex_unlock(&misc_list_mutex);
+
+	if (!restool_misc)
+		return -EINVAL;
+
+	mutex_lock(&restool_misc->mutex);
+
+	if (WARN_ON(restool_misc->dynamic_instance_count == 0 &&
+		    !restool_misc->static_instance_in_use)) {
+		mutex_unlock(&restool_misc->mutex);
+		return -EINVAL;
+	}
+
+	/* Globally clean up opened/untracked handles */
+	fsl_mc_portal_reset(local_mc_io);
+
+	/*
+	 * must check
+	 * whether local_mc_io is dynamic or static instance
+	 * Otherwise it will free up the reserved portal by accident
+	 * or even not free up the dynamic allocated portal
+	 * if 2 or more instances running concurrently
+	 */
+	if (local_mc_io == restool_misc->static_mc_io) {
+		restool_misc->static_instance_in_use = false;
+	} else {
+		fsl_mc_portal_free(local_mc_io);
+		kfree(filep->private_data);
+		--restool_misc->dynamic_instance_count;
+	}
+
+	filep->private_data = NULL;
+	mutex_unlock(&restool_misc->mutex);
+
+	return 0;
+}
+
+static int restool_send_mc_command(unsigned long arg,
+				   struct fsl_mc_io *local_mc_io)
+{
+	int error;
+	struct mc_command mc_cmd;
+
+	if (copy_from_user(&mc_cmd, (void __user *)arg, sizeof(mc_cmd)))
+		return -EFAULT;
+
+	/*
+	 * Send MC command to the MC:
+	 */
+	error = mc_send_command(local_mc_io, &mc_cmd);
+	if (error < 0)
+		return error;
+
+	if (copy_to_user((void __user *)arg, &mc_cmd, sizeof(mc_cmd)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long
+fsl_mc_restool_dev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	int error;
+
+	switch (cmd) {
+	case RESTOOL_SEND_MC_COMMAND:
+		error = restool_send_mc_command(arg, file->private_data);
+		break;
+	default:
+		pr_err("%s: unexpected ioctl call number\n", __func__);
+		error = -EINVAL;
+	}
+
+	return error;
+}
+
+static const struct file_operations fsl_mc_restool_dev_fops = {
+	.owner = THIS_MODULE,
+	.open = fsl_mc_restool_dev_open,
+	.release = fsl_mc_restool_dev_release,
+	.unlocked_ioctl = fsl_mc_restool_dev_ioctl,
+};
+
+static int restool_add_device_file(struct device *dev)
+{
+	u32 name1 = 0;
+	char name2[20] = {0};
+	int error;
+	struct fsl_mc_device *root_mc_dev;
+	struct restool_misc *restool_misc;
+
+	if (dev->bus == &platform_bus_type && dev->driver_data) {
+		if (sscanf(dev_name(dev), "%x.%s", &name1, name2) != 2)
+			return -EINVAL;
+
+		if (strcmp(name2, "fsl-mc") == 0)
+			pr_debug("platform's root dprc name is: %s\n",
+				 dev_name(&(((struct fsl_mc *)
+				 (dev->driver_data))->root_mc_bus_dev->dev)));
+	}
+
+	if (!is_root_dprc(dev))
+		return 0;
+
+	restool_misc = kzalloc(sizeof(*restool_misc), GFP_KERNEL);
+	if (!restool_misc)
+		return -ENOMEM;
+
+	restool_misc->dev = dev;
+	root_mc_dev = to_fsl_mc_device(dev);
+	error = fsl_mc_portal_allocate(root_mc_dev, 0,
+				       &restool_misc->static_mc_io);
+	if (error < 0) {
+		pr_err("Not able to allocate MC portal\n");
+		goto free_restool_misc;
+	}
+
+	restool_misc->misc.minor = MISC_DYNAMIC_MINOR;
+	restool_misc->misc.name = dev_name(dev);
+	restool_misc->misc.fops = &fsl_mc_restool_dev_fops;
+
+	error = misc_register(&restool_misc->misc);
+	if (error < 0) {
+		pr_err("misc_register() failed: %d\n", error);
+		goto free_portal;
+	}
+
+	restool_misc->miscdevt = restool_misc->misc.this_device->devt;
+	mutex_init(&restool_misc->mutex);
+	mutex_lock(&misc_list_mutex);
+	list_add(&restool_misc->list, &misc_list);
+	mutex_unlock(&misc_list_mutex);
+
+	pr_info("/dev/%s driver registered\n", dev_name(dev));
+
+	return 0;
+
+free_portal:
+	fsl_mc_portal_free(restool_misc->static_mc_io);
+free_restool_misc:
+	kfree(restool_misc);
+
+	return error;
+}
+
+static int restool_bus_notifier(struct notifier_block *nb,
+				unsigned long action, void *data)
+{
+	int error;
+	struct device *dev = data;
+
+	switch (action) {
+	case BUS_NOTIFY_ADD_DEVICE:
+		error = restool_add_device_file(dev);
+		if (error)
+			return error;
+		break;
+	case BUS_NOTIFY_DEL_DEVICE:
+	case BUS_NOTIFY_REMOVED_DEVICE:
+	case BUS_NOTIFY_BIND_DRIVER:
+	case BUS_NOTIFY_BOUND_DRIVER:
+	case BUS_NOTIFY_UNBIND_DRIVER:
+	case BUS_NOTIFY_UNBOUND_DRIVER:
+		break;
+	default:
+		pr_err("%s: unrecognized device action from %s\n", __func__,
+		       dev_name(dev));
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int add_to_restool(struct device *dev, void *data)
+{
+	return restool_add_device_file(dev);
+}
+
+static int __init fsl_mc_restool_driver_init(void)
+{
+	int error;
+	struct notifier_block *nb;
+
+	nb = kzalloc(sizeof(*nb), GFP_KERNEL);
+	if (!nb)
+		return -ENOMEM;
+
+	nb->notifier_call = restool_bus_notifier;
+	error = bus_register_notifier(&fsl_mc_bus_type, nb);
+	if (error)
+		goto free_nb;
+
+	/*
+	 * This driver runs after fsl-mc bus driver runs.
+	 * Hence, many of the root dprcs are already attached to fsl-mc bus
+	 * In order to make sure we find all the root dprcs,
+	 * we need to scan the fsl_mc_bus_type.
+	 */
+	error  = bus_for_each_dev(&fsl_mc_bus_type, NULL, NULL, add_to_restool);
+	if (error) {
+		bus_unregister_notifier(&fsl_mc_bus_type, nb);
+		kfree(nb);
+		pr_err("restool driver registration failure\n");
+		return error;
+	}
+
+	return 0;
+
+free_nb:
+	kfree(nb);
+	return error;
+}
+
+module_init(fsl_mc_restool_driver_init);
+
+static void __exit fsl_mc_restool_driver_exit(void)
+{
+	struct restool_misc *restool_misc;
+	struct restool_misc *restool_misc_tmp;
+	char name1[20] = {0};
+	u32 name2 = 0;
+
+	list_for_each_entry_safe(restool_misc, restool_misc_tmp,
+				 &misc_list, list) {
+		if (sscanf(restool_misc->misc.name, "%4s.%u", name1, &name2)
+		    != 2)
+			continue;
+
+		pr_debug("name1=%s,name2=%u\n", name1, name2);
+		pr_debug("misc-device: %s\n", restool_misc->misc.name);
+		if (strcmp(name1, "dprc") != 0)
+			continue;
+
+		if (WARN_ON(!restool_misc->static_mc_io))
+			return;
+
+		if (WARN_ON(restool_misc->dynamic_instance_count != 0))
+			return;
+
+		if (WARN_ON(restool_misc->static_instance_in_use))
+			return;
+
+		misc_deregister(&restool_misc->misc);
+		pr_info("/dev/%s driver unregistered\n",
+			restool_misc->misc.name);
+		fsl_mc_portal_free(restool_misc->static_mc_io);
+		list_del(&restool_misc->list);
+		kfree(restool_misc);
+	}
+}
+
+module_exit(fsl_mc_restool_driver_exit);
+
+MODULE_AUTHOR("Freescale Semiconductor Inc.");
+MODULE_DESCRIPTION("Freescale's MC restool driver");
+MODULE_LICENSE("GPL");
-- 
1.7.9.5