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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/platform/surface/surface_aggregator_cdev.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/platform/surface/surface_aggregator_cdev.c')
-rw-r--r--drivers/platform/surface/surface_aggregator_cdev.c810
1 files changed, 810 insertions, 0 deletions
diff --git a/drivers/platform/surface/surface_aggregator_cdev.c b/drivers/platform/surface/surface_aggregator_cdev.c
new file mode 100644
index 000000000..492c82e69
--- /dev/null
+++ b/drivers/platform/surface/surface_aggregator_cdev.c
@@ -0,0 +1,810 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Provides user-space access to the SSAM EC via the /dev/surface/aggregator
+ * misc device. Intended for debugging and development.
+ *
+ * Copyright (C) 2020-2022 Maximilian Luz <luzmaximilian@gmail.com>
+ */
+
+#include <linux/fs.h>
+#include <linux/ioctl.h>
+#include <linux/kernel.h>
+#include <linux/kfifo.h>
+#include <linux/kref.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/poll.h>
+#include <linux/rwsem.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+
+#include <linux/surface_aggregator/cdev.h>
+#include <linux/surface_aggregator/controller.h>
+#include <linux/surface_aggregator/serial_hub.h>
+
+#define SSAM_CDEV_DEVICE_NAME "surface_aggregator_cdev"
+
+
+/* -- Main structures. ------------------------------------------------------ */
+
+enum ssam_cdev_device_state {
+ SSAM_CDEV_DEVICE_SHUTDOWN_BIT = BIT(0),
+};
+
+struct ssam_cdev {
+ struct kref kref;
+ struct rw_semaphore lock;
+
+ struct device *dev;
+ struct ssam_controller *ctrl;
+ struct miscdevice mdev;
+ unsigned long flags;
+
+ struct rw_semaphore client_lock; /* Guards client list. */
+ struct list_head client_list;
+};
+
+struct ssam_cdev_client;
+
+struct ssam_cdev_notifier {
+ struct ssam_cdev_client *client;
+ struct ssam_event_notifier nf;
+};
+
+struct ssam_cdev_client {
+ struct ssam_cdev *cdev;
+ struct list_head node;
+
+ struct mutex notifier_lock; /* Guards notifier access for registration */
+ struct ssam_cdev_notifier *notifier[SSH_NUM_EVENTS];
+
+ struct mutex read_lock; /* Guards FIFO buffer read access */
+ struct mutex write_lock; /* Guards FIFO buffer write access */
+ DECLARE_KFIFO(buffer, u8, 4096);
+
+ wait_queue_head_t waitq;
+ struct fasync_struct *fasync;
+};
+
+static void __ssam_cdev_release(struct kref *kref)
+{
+ kfree(container_of(kref, struct ssam_cdev, kref));
+}
+
+static struct ssam_cdev *ssam_cdev_get(struct ssam_cdev *cdev)
+{
+ if (cdev)
+ kref_get(&cdev->kref);
+
+ return cdev;
+}
+
+static void ssam_cdev_put(struct ssam_cdev *cdev)
+{
+ if (cdev)
+ kref_put(&cdev->kref, __ssam_cdev_release);
+}
+
+
+/* -- Notifier handling. ---------------------------------------------------- */
+
+static u32 ssam_cdev_notifier(struct ssam_event_notifier *nf, const struct ssam_event *in)
+{
+ struct ssam_cdev_notifier *cdev_nf = container_of(nf, struct ssam_cdev_notifier, nf);
+ struct ssam_cdev_client *client = cdev_nf->client;
+ struct ssam_cdev_event event;
+ size_t n = struct_size(&event, data, in->length);
+
+ /* Translate event. */
+ event.target_category = in->target_category;
+ event.target_id = in->target_id;
+ event.command_id = in->command_id;
+ event.instance_id = in->instance_id;
+ event.length = in->length;
+
+ mutex_lock(&client->write_lock);
+
+ /* Make sure we have enough space. */
+ if (kfifo_avail(&client->buffer) < n) {
+ dev_warn(client->cdev->dev,
+ "buffer full, dropping event (tc: %#04x, tid: %#04x, cid: %#04x, iid: %#04x)\n",
+ in->target_category, in->target_id, in->command_id, in->instance_id);
+ mutex_unlock(&client->write_lock);
+ return 0;
+ }
+
+ /* Copy event header and payload. */
+ kfifo_in(&client->buffer, (const u8 *)&event, struct_size(&event, data, 0));
+ kfifo_in(&client->buffer, &in->data[0], in->length);
+
+ mutex_unlock(&client->write_lock);
+
+ /* Notify waiting readers. */
+ kill_fasync(&client->fasync, SIGIO, POLL_IN);
+ wake_up_interruptible(&client->waitq);
+
+ /*
+ * Don't mark events as handled, this is the job of a proper driver and
+ * not the debugging interface.
+ */
+ return 0;
+}
+
+static int ssam_cdev_notifier_register(struct ssam_cdev_client *client, u8 tc, int priority)
+{
+ const u16 rqid = ssh_tc_to_rqid(tc);
+ const u16 event = ssh_rqid_to_event(rqid);
+ struct ssam_cdev_notifier *nf;
+ int status;
+
+ lockdep_assert_held_read(&client->cdev->lock);
+
+ /* Validate notifier target category. */
+ if (!ssh_rqid_is_event(rqid))
+ return -EINVAL;
+
+ mutex_lock(&client->notifier_lock);
+
+ /* Check if the notifier has already been registered. */
+ if (client->notifier[event]) {
+ mutex_unlock(&client->notifier_lock);
+ return -EEXIST;
+ }
+
+ /* Allocate new notifier. */
+ nf = kzalloc(sizeof(*nf), GFP_KERNEL);
+ if (!nf) {
+ mutex_unlock(&client->notifier_lock);
+ return -ENOMEM;
+ }
+
+ /*
+ * Create a dummy notifier with the minimal required fields for
+ * observer registration. Note that we can skip fully specifying event
+ * and registry here as we do not need any matching and use silent
+ * registration, which does not enable the corresponding event.
+ */
+ nf->client = client;
+ nf->nf.base.fn = ssam_cdev_notifier;
+ nf->nf.base.priority = priority;
+ nf->nf.event.id.target_category = tc;
+ nf->nf.event.mask = 0; /* Do not do any matching. */
+ nf->nf.flags = SSAM_EVENT_NOTIFIER_OBSERVER;
+
+ /* Register notifier. */
+ status = ssam_notifier_register(client->cdev->ctrl, &nf->nf);
+ if (status)
+ kfree(nf);
+ else
+ client->notifier[event] = nf;
+
+ mutex_unlock(&client->notifier_lock);
+ return status;
+}
+
+static int ssam_cdev_notifier_unregister(struct ssam_cdev_client *client, u8 tc)
+{
+ const u16 rqid = ssh_tc_to_rqid(tc);
+ const u16 event = ssh_rqid_to_event(rqid);
+ int status;
+
+ lockdep_assert_held_read(&client->cdev->lock);
+
+ /* Validate notifier target category. */
+ if (!ssh_rqid_is_event(rqid))
+ return -EINVAL;
+
+ mutex_lock(&client->notifier_lock);
+
+ /* Check if the notifier is currently registered. */
+ if (!client->notifier[event]) {
+ mutex_unlock(&client->notifier_lock);
+ return -ENOENT;
+ }
+
+ /* Unregister and free notifier. */
+ status = ssam_notifier_unregister(client->cdev->ctrl, &client->notifier[event]->nf);
+ kfree(client->notifier[event]);
+ client->notifier[event] = NULL;
+
+ mutex_unlock(&client->notifier_lock);
+ return status;
+}
+
+static void ssam_cdev_notifier_unregister_all(struct ssam_cdev_client *client)
+{
+ int i;
+
+ down_read(&client->cdev->lock);
+
+ /*
+ * This function may be used during shutdown, thus we need to test for
+ * cdev->ctrl instead of the SSAM_CDEV_DEVICE_SHUTDOWN_BIT bit.
+ */
+ if (client->cdev->ctrl) {
+ for (i = 0; i < SSH_NUM_EVENTS; i++)
+ ssam_cdev_notifier_unregister(client, i + 1);
+
+ } else {
+ int count = 0;
+
+ /*
+ * Device has been shut down. Any notifier remaining is a bug,
+ * so warn about that as this would otherwise hardly be
+ * noticeable. Nevertheless, free them as well.
+ */
+ mutex_lock(&client->notifier_lock);
+ for (i = 0; i < SSH_NUM_EVENTS; i++) {
+ count += !!(client->notifier[i]);
+ kfree(client->notifier[i]);
+ client->notifier[i] = NULL;
+ }
+ mutex_unlock(&client->notifier_lock);
+
+ WARN_ON(count > 0);
+ }
+
+ up_read(&client->cdev->lock);
+}
+
+
+/* -- IOCTL functions. ------------------------------------------------------ */
+
+static long ssam_cdev_request(struct ssam_cdev_client *client, struct ssam_cdev_request __user *r)
+{
+ struct ssam_cdev_request rqst;
+ struct ssam_request spec = {};
+ struct ssam_response rsp = {};
+ const void __user *plddata;
+ void __user *rspdata;
+ int status = 0, ret = 0, tmp;
+
+ lockdep_assert_held_read(&client->cdev->lock);
+
+ ret = copy_struct_from_user(&rqst, sizeof(rqst), r, sizeof(*r));
+ if (ret)
+ goto out;
+
+ plddata = u64_to_user_ptr(rqst.payload.data);
+ rspdata = u64_to_user_ptr(rqst.response.data);
+
+ /* Setup basic request fields. */
+ spec.target_category = rqst.target_category;
+ spec.target_id = rqst.target_id;
+ spec.command_id = rqst.command_id;
+ spec.instance_id = rqst.instance_id;
+ spec.flags = 0;
+ spec.length = rqst.payload.length;
+ spec.payload = NULL;
+
+ if (rqst.flags & SSAM_CDEV_REQUEST_HAS_RESPONSE)
+ spec.flags |= SSAM_REQUEST_HAS_RESPONSE;
+
+ if (rqst.flags & SSAM_CDEV_REQUEST_UNSEQUENCED)
+ spec.flags |= SSAM_REQUEST_UNSEQUENCED;
+
+ rsp.capacity = rqst.response.length;
+ rsp.length = 0;
+ rsp.pointer = NULL;
+
+ /* Get request payload from user-space. */
+ if (spec.length) {
+ if (!plddata) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * Note: spec.length is limited to U16_MAX bytes via struct
+ * ssam_cdev_request. This is slightly larger than the
+ * theoretical maximum (SSH_COMMAND_MAX_PAYLOAD_SIZE) of the
+ * underlying protocol (note that nothing remotely this size
+ * should ever be allocated in any normal case). This size is
+ * validated later in ssam_request_sync(), for allocation the
+ * bound imposed by u16 should be enough.
+ */
+ spec.payload = kzalloc(spec.length, GFP_KERNEL);
+ if (!spec.payload) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ if (copy_from_user((void *)spec.payload, plddata, spec.length)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ }
+
+ /* Allocate response buffer. */
+ if (rsp.capacity) {
+ if (!rspdata) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * Note: rsp.capacity is limited to U16_MAX bytes via struct
+ * ssam_cdev_request. This is slightly larger than the
+ * theoretical maximum (SSH_COMMAND_MAX_PAYLOAD_SIZE) of the
+ * underlying protocol (note that nothing remotely this size
+ * should ever be allocated in any normal case). In later use,
+ * this capacity does not have to be strictly bounded, as it
+ * is only used as an output buffer to be written to. For
+ * allocation the bound imposed by u16 should be enough.
+ */
+ rsp.pointer = kzalloc(rsp.capacity, GFP_KERNEL);
+ if (!rsp.pointer) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ }
+
+ /* Perform request. */
+ status = ssam_request_sync(client->cdev->ctrl, &spec, &rsp);
+ if (status)
+ goto out;
+
+ /* Copy response to user-space. */
+ if (rsp.length && copy_to_user(rspdata, rsp.pointer, rsp.length))
+ ret = -EFAULT;
+
+out:
+ /* Always try to set response-length and status. */
+ tmp = put_user(rsp.length, &r->response.length);
+ if (tmp)
+ ret = tmp;
+
+ tmp = put_user(status, &r->status);
+ if (tmp)
+ ret = tmp;
+
+ /* Cleanup. */
+ kfree(spec.payload);
+ kfree(rsp.pointer);
+
+ return ret;
+}
+
+static long ssam_cdev_notif_register(struct ssam_cdev_client *client,
+ const struct ssam_cdev_notifier_desc __user *d)
+{
+ struct ssam_cdev_notifier_desc desc;
+ long ret;
+
+ lockdep_assert_held_read(&client->cdev->lock);
+
+ ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d));
+ if (ret)
+ return ret;
+
+ return ssam_cdev_notifier_register(client, desc.target_category, desc.priority);
+}
+
+static long ssam_cdev_notif_unregister(struct ssam_cdev_client *client,
+ const struct ssam_cdev_notifier_desc __user *d)
+{
+ struct ssam_cdev_notifier_desc desc;
+ long ret;
+
+ lockdep_assert_held_read(&client->cdev->lock);
+
+ ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d));
+ if (ret)
+ return ret;
+
+ return ssam_cdev_notifier_unregister(client, desc.target_category);
+}
+
+static long ssam_cdev_event_enable(struct ssam_cdev_client *client,
+ const struct ssam_cdev_event_desc __user *d)
+{
+ struct ssam_cdev_event_desc desc;
+ struct ssam_event_registry reg;
+ struct ssam_event_id id;
+ long ret;
+
+ lockdep_assert_held_read(&client->cdev->lock);
+
+ /* Read descriptor from user-space. */
+ ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d));
+ if (ret)
+ return ret;
+
+ /* Translate descriptor. */
+ reg.target_category = desc.reg.target_category;
+ reg.target_id = desc.reg.target_id;
+ reg.cid_enable = desc.reg.cid_enable;
+ reg.cid_disable = desc.reg.cid_disable;
+
+ id.target_category = desc.id.target_category;
+ id.instance = desc.id.instance;
+
+ /* Disable event. */
+ return ssam_controller_event_enable(client->cdev->ctrl, reg, id, desc.flags);
+}
+
+static long ssam_cdev_event_disable(struct ssam_cdev_client *client,
+ const struct ssam_cdev_event_desc __user *d)
+{
+ struct ssam_cdev_event_desc desc;
+ struct ssam_event_registry reg;
+ struct ssam_event_id id;
+ long ret;
+
+ lockdep_assert_held_read(&client->cdev->lock);
+
+ /* Read descriptor from user-space. */
+ ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d));
+ if (ret)
+ return ret;
+
+ /* Translate descriptor. */
+ reg.target_category = desc.reg.target_category;
+ reg.target_id = desc.reg.target_id;
+ reg.cid_enable = desc.reg.cid_enable;
+ reg.cid_disable = desc.reg.cid_disable;
+
+ id.target_category = desc.id.target_category;
+ id.instance = desc.id.instance;
+
+ /* Disable event. */
+ return ssam_controller_event_disable(client->cdev->ctrl, reg, id, desc.flags);
+}
+
+
+/* -- File operations. ------------------------------------------------------ */
+
+static int ssam_cdev_device_open(struct inode *inode, struct file *filp)
+{
+ struct miscdevice *mdev = filp->private_data;
+ struct ssam_cdev_client *client;
+ struct ssam_cdev *cdev = container_of(mdev, struct ssam_cdev, mdev);
+
+ /* Initialize client */
+ client = vzalloc(sizeof(*client));
+ if (!client)
+ return -ENOMEM;
+
+ client->cdev = ssam_cdev_get(cdev);
+
+ INIT_LIST_HEAD(&client->node);
+
+ mutex_init(&client->notifier_lock);
+
+ mutex_init(&client->read_lock);
+ mutex_init(&client->write_lock);
+ INIT_KFIFO(client->buffer);
+ init_waitqueue_head(&client->waitq);
+
+ filp->private_data = client;
+
+ /* Attach client. */
+ down_write(&cdev->client_lock);
+
+ if (test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &cdev->flags)) {
+ up_write(&cdev->client_lock);
+ mutex_destroy(&client->write_lock);
+ mutex_destroy(&client->read_lock);
+ mutex_destroy(&client->notifier_lock);
+ ssam_cdev_put(client->cdev);
+ vfree(client);
+ return -ENODEV;
+ }
+ list_add_tail(&client->node, &cdev->client_list);
+
+ up_write(&cdev->client_lock);
+
+ stream_open(inode, filp);
+ return 0;
+}
+
+static int ssam_cdev_device_release(struct inode *inode, struct file *filp)
+{
+ struct ssam_cdev_client *client = filp->private_data;
+
+ /* Force-unregister all remaining notifiers of this client. */
+ ssam_cdev_notifier_unregister_all(client);
+
+ /* Detach client. */
+ down_write(&client->cdev->client_lock);
+ list_del(&client->node);
+ up_write(&client->cdev->client_lock);
+
+ /* Free client. */
+ mutex_destroy(&client->write_lock);
+ mutex_destroy(&client->read_lock);
+
+ mutex_destroy(&client->notifier_lock);
+
+ ssam_cdev_put(client->cdev);
+ vfree(client);
+
+ return 0;
+}
+
+static long __ssam_cdev_device_ioctl(struct ssam_cdev_client *client, unsigned int cmd,
+ unsigned long arg)
+{
+ lockdep_assert_held_read(&client->cdev->lock);
+
+ switch (cmd) {
+ case SSAM_CDEV_REQUEST:
+ return ssam_cdev_request(client, (struct ssam_cdev_request __user *)arg);
+
+ case SSAM_CDEV_NOTIF_REGISTER:
+ return ssam_cdev_notif_register(client,
+ (struct ssam_cdev_notifier_desc __user *)arg);
+
+ case SSAM_CDEV_NOTIF_UNREGISTER:
+ return ssam_cdev_notif_unregister(client,
+ (struct ssam_cdev_notifier_desc __user *)arg);
+
+ case SSAM_CDEV_EVENT_ENABLE:
+ return ssam_cdev_event_enable(client, (struct ssam_cdev_event_desc __user *)arg);
+
+ case SSAM_CDEV_EVENT_DISABLE:
+ return ssam_cdev_event_disable(client, (struct ssam_cdev_event_desc __user *)arg);
+
+ default:
+ return -ENOTTY;
+ }
+}
+
+static long ssam_cdev_device_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct ssam_cdev_client *client = file->private_data;
+ long status;
+
+ /* Ensure that controller is valid for as long as we need it. */
+ if (down_read_killable(&client->cdev->lock))
+ return -ERESTARTSYS;
+
+ if (test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &client->cdev->flags)) {
+ up_read(&client->cdev->lock);
+ return -ENODEV;
+ }
+
+ status = __ssam_cdev_device_ioctl(client, cmd, arg);
+
+ up_read(&client->cdev->lock);
+ return status;
+}
+
+static ssize_t ssam_cdev_read(struct file *file, char __user *buf, size_t count, loff_t *offs)
+{
+ struct ssam_cdev_client *client = file->private_data;
+ struct ssam_cdev *cdev = client->cdev;
+ unsigned int copied;
+ int status = 0;
+
+ if (down_read_killable(&cdev->lock))
+ return -ERESTARTSYS;
+
+ /* Make sure we're not shut down. */
+ if (test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &cdev->flags)) {
+ up_read(&cdev->lock);
+ return -ENODEV;
+ }
+
+ do {
+ /* Check availability, wait if necessary. */
+ if (kfifo_is_empty(&client->buffer)) {
+ up_read(&cdev->lock);
+
+ if (file->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+
+ status = wait_event_interruptible(client->waitq,
+ !kfifo_is_empty(&client->buffer) ||
+ test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT,
+ &cdev->flags));
+ if (status < 0)
+ return status;
+
+ if (down_read_killable(&cdev->lock))
+ return -ERESTARTSYS;
+
+ /* Need to check that we're not shut down again. */
+ if (test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &cdev->flags)) {
+ up_read(&cdev->lock);
+ return -ENODEV;
+ }
+ }
+
+ /* Try to read from FIFO. */
+ if (mutex_lock_interruptible(&client->read_lock)) {
+ up_read(&cdev->lock);
+ return -ERESTARTSYS;
+ }
+
+ status = kfifo_to_user(&client->buffer, buf, count, &copied);
+ mutex_unlock(&client->read_lock);
+
+ if (status < 0) {
+ up_read(&cdev->lock);
+ return status;
+ }
+
+ /* We might not have gotten anything, check this here. */
+ if (copied == 0 && (file->f_flags & O_NONBLOCK)) {
+ up_read(&cdev->lock);
+ return -EAGAIN;
+ }
+ } while (copied == 0);
+
+ up_read(&cdev->lock);
+ return copied;
+}
+
+static __poll_t ssam_cdev_poll(struct file *file, struct poll_table_struct *pt)
+{
+ struct ssam_cdev_client *client = file->private_data;
+ __poll_t events = 0;
+
+ if (test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &client->cdev->flags))
+ return EPOLLHUP | EPOLLERR;
+
+ poll_wait(file, &client->waitq, pt);
+
+ if (!kfifo_is_empty(&client->buffer))
+ events |= EPOLLIN | EPOLLRDNORM;
+
+ return events;
+}
+
+static int ssam_cdev_fasync(int fd, struct file *file, int on)
+{
+ struct ssam_cdev_client *client = file->private_data;
+
+ return fasync_helper(fd, file, on, &client->fasync);
+}
+
+static const struct file_operations ssam_controller_fops = {
+ .owner = THIS_MODULE,
+ .open = ssam_cdev_device_open,
+ .release = ssam_cdev_device_release,
+ .read = ssam_cdev_read,
+ .poll = ssam_cdev_poll,
+ .fasync = ssam_cdev_fasync,
+ .unlocked_ioctl = ssam_cdev_device_ioctl,
+ .compat_ioctl = ssam_cdev_device_ioctl,
+ .llseek = no_llseek,
+};
+
+
+/* -- Device and driver setup ----------------------------------------------- */
+
+static int ssam_dbg_device_probe(struct platform_device *pdev)
+{
+ struct ssam_controller *ctrl;
+ struct ssam_cdev *cdev;
+ int status;
+
+ ctrl = ssam_client_bind(&pdev->dev);
+ if (IS_ERR(ctrl))
+ return PTR_ERR(ctrl) == -ENODEV ? -EPROBE_DEFER : PTR_ERR(ctrl);
+
+ cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
+ if (!cdev)
+ return -ENOMEM;
+
+ kref_init(&cdev->kref);
+ init_rwsem(&cdev->lock);
+ cdev->ctrl = ctrl;
+ cdev->dev = &pdev->dev;
+
+ cdev->mdev.parent = &pdev->dev;
+ cdev->mdev.minor = MISC_DYNAMIC_MINOR;
+ cdev->mdev.name = "surface_aggregator";
+ cdev->mdev.nodename = "surface/aggregator";
+ cdev->mdev.fops = &ssam_controller_fops;
+
+ init_rwsem(&cdev->client_lock);
+ INIT_LIST_HEAD(&cdev->client_list);
+
+ status = misc_register(&cdev->mdev);
+ if (status) {
+ kfree(cdev);
+ return status;
+ }
+
+ platform_set_drvdata(pdev, cdev);
+ return 0;
+}
+
+static int ssam_dbg_device_remove(struct platform_device *pdev)
+{
+ struct ssam_cdev *cdev = platform_get_drvdata(pdev);
+ struct ssam_cdev_client *client;
+
+ /*
+ * Mark device as shut-down. Prevent new clients from being added and
+ * new operations from being executed.
+ */
+ set_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &cdev->flags);
+
+ down_write(&cdev->client_lock);
+
+ /* Remove all notifiers registered by us. */
+ list_for_each_entry(client, &cdev->client_list, node) {
+ ssam_cdev_notifier_unregister_all(client);
+ }
+
+ /* Wake up async clients. */
+ list_for_each_entry(client, &cdev->client_list, node) {
+ kill_fasync(&client->fasync, SIGIO, POLL_HUP);
+ }
+
+ /* Wake up blocking clients. */
+ list_for_each_entry(client, &cdev->client_list, node) {
+ wake_up_interruptible(&client->waitq);
+ }
+
+ up_write(&cdev->client_lock);
+
+ /*
+ * The controller is only guaranteed to be valid for as long as the
+ * driver is bound. Remove controller so that any lingering open files
+ * cannot access it any more after we're gone.
+ */
+ down_write(&cdev->lock);
+ cdev->ctrl = NULL;
+ cdev->dev = NULL;
+ up_write(&cdev->lock);
+
+ misc_deregister(&cdev->mdev);
+
+ ssam_cdev_put(cdev);
+ return 0;
+}
+
+static struct platform_device *ssam_cdev_device;
+
+static struct platform_driver ssam_cdev_driver = {
+ .probe = ssam_dbg_device_probe,
+ .remove = ssam_dbg_device_remove,
+ .driver = {
+ .name = SSAM_CDEV_DEVICE_NAME,
+ .probe_type = PROBE_PREFER_ASYNCHRONOUS,
+ },
+};
+
+static int __init ssam_debug_init(void)
+{
+ int status;
+
+ ssam_cdev_device = platform_device_alloc(SSAM_CDEV_DEVICE_NAME,
+ PLATFORM_DEVID_NONE);
+ if (!ssam_cdev_device)
+ return -ENOMEM;
+
+ status = platform_device_add(ssam_cdev_device);
+ if (status)
+ goto err_device;
+
+ status = platform_driver_register(&ssam_cdev_driver);
+ if (status)
+ goto err_driver;
+
+ return 0;
+
+err_driver:
+ platform_device_del(ssam_cdev_device);
+err_device:
+ platform_device_put(ssam_cdev_device);
+ return status;
+}
+module_init(ssam_debug_init);
+
+static void __exit ssam_debug_exit(void)
+{
+ platform_driver_unregister(&ssam_cdev_driver);
+ platform_device_unregister(ssam_cdev_device);
+}
+module_exit(ssam_debug_exit);
+
+MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
+MODULE_DESCRIPTION("User-space interface for Surface System Aggregator Module");
+MODULE_LICENSE("GPL");