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810 lines
20 KiB
810 lines
20 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* Provides user-space access to the SSAM EC via the /dev/surface/aggregator |
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* misc device. Intended for debugging and development. |
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* |
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* Copyright (C) 2020-2021 Maximilian Luz <[email protected]> |
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*/ |
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|
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#include <linux/fs.h> |
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#include <linux/ioctl.h> |
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#include <linux/kernel.h> |
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#include <linux/kfifo.h> |
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#include <linux/kref.h> |
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#include <linux/miscdevice.h> |
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#include <linux/module.h> |
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#include <linux/platform_device.h> |
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#include <linux/poll.h> |
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#include <linux/rwsem.h> |
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#include <linux/slab.h> |
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#include <linux/uaccess.h> |
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#include <linux/vmalloc.h> |
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#include <linux/surface_aggregator/cdev.h> |
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#include <linux/surface_aggregator/controller.h> |
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#include <linux/surface_aggregator/serial_hub.h> |
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#define SSAM_CDEV_DEVICE_NAME "surface_aggregator_cdev" |
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/* -- Main structures. ------------------------------------------------------ */ |
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|
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enum ssam_cdev_device_state { |
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SSAM_CDEV_DEVICE_SHUTDOWN_BIT = BIT(0), |
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}; |
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struct ssam_cdev { |
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struct kref kref; |
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struct rw_semaphore lock; |
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struct device *dev; |
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struct ssam_controller *ctrl; |
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struct miscdevice mdev; |
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unsigned long flags; |
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struct rw_semaphore client_lock; /* Guards client list. */ |
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struct list_head client_list; |
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}; |
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struct ssam_cdev_client; |
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struct ssam_cdev_notifier { |
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struct ssam_cdev_client *client; |
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struct ssam_event_notifier nf; |
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}; |
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struct ssam_cdev_client { |
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struct ssam_cdev *cdev; |
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struct list_head node; |
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struct mutex notifier_lock; /* Guards notifier access for registration */ |
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struct ssam_cdev_notifier *notifier[SSH_NUM_EVENTS]; |
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struct mutex read_lock; /* Guards FIFO buffer read access */ |
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struct mutex write_lock; /* Guards FIFO buffer write access */ |
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DECLARE_KFIFO(buffer, u8, 4096); |
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wait_queue_head_t waitq; |
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struct fasync_struct *fasync; |
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}; |
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static void __ssam_cdev_release(struct kref *kref) |
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{ |
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kfree(container_of(kref, struct ssam_cdev, kref)); |
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} |
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static struct ssam_cdev *ssam_cdev_get(struct ssam_cdev *cdev) |
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{ |
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if (cdev) |
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kref_get(&cdev->kref); |
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return cdev; |
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} |
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static void ssam_cdev_put(struct ssam_cdev *cdev) |
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{ |
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if (cdev) |
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kref_put(&cdev->kref, __ssam_cdev_release); |
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} |
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/* -- Notifier handling. ---------------------------------------------------- */ |
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static u32 ssam_cdev_notifier(struct ssam_event_notifier *nf, const struct ssam_event *in) |
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{ |
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struct ssam_cdev_notifier *cdev_nf = container_of(nf, struct ssam_cdev_notifier, nf); |
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struct ssam_cdev_client *client = cdev_nf->client; |
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struct ssam_cdev_event event; |
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size_t n = struct_size(&event, data, in->length); |
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|
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/* Translate event. */ |
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event.target_category = in->target_category; |
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event.target_id = in->target_id; |
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event.command_id = in->command_id; |
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event.instance_id = in->instance_id; |
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event.length = in->length; |
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mutex_lock(&client->write_lock); |
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/* Make sure we have enough space. */ |
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if (kfifo_avail(&client->buffer) < n) { |
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dev_warn(client->cdev->dev, |
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"buffer full, dropping event (tc: %#04x, tid: %#04x, cid: %#04x, iid: %#04x)\n", |
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in->target_category, in->target_id, in->command_id, in->instance_id); |
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mutex_unlock(&client->write_lock); |
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return 0; |
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} |
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/* Copy event header and payload. */ |
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kfifo_in(&client->buffer, (const u8 *)&event, struct_size(&event, data, 0)); |
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kfifo_in(&client->buffer, &in->data[0], in->length); |
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mutex_unlock(&client->write_lock); |
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/* Notify waiting readers. */ |
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kill_fasync(&client->fasync, SIGIO, POLL_IN); |
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wake_up_interruptible(&client->waitq); |
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/* |
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* Don't mark events as handled, this is the job of a proper driver and |
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* not the debugging interface. |
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*/ |
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return 0; |
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} |
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static int ssam_cdev_notifier_register(struct ssam_cdev_client *client, u8 tc, int priority) |
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{ |
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const u16 rqid = ssh_tc_to_rqid(tc); |
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const u16 event = ssh_rqid_to_event(rqid); |
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struct ssam_cdev_notifier *nf; |
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int status; |
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lockdep_assert_held_read(&client->cdev->lock); |
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/* Validate notifier target category. */ |
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if (!ssh_rqid_is_event(rqid)) |
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return -EINVAL; |
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mutex_lock(&client->notifier_lock); |
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/* Check if the notifier has already been registered. */ |
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if (client->notifier[event]) { |
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mutex_unlock(&client->notifier_lock); |
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return -EEXIST; |
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} |
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/* Allocate new notifier. */ |
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nf = kzalloc(sizeof(*nf), GFP_KERNEL); |
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if (!nf) { |
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mutex_unlock(&client->notifier_lock); |
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return -ENOMEM; |
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} |
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/* |
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* Create a dummy notifier with the minimal required fields for |
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* observer registration. Note that we can skip fully specifying event |
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* and registry here as we do not need any matching and use silent |
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* registration, which does not enable the corresponding event. |
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*/ |
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nf->client = client; |
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nf->nf.base.fn = ssam_cdev_notifier; |
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nf->nf.base.priority = priority; |
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nf->nf.event.id.target_category = tc; |
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nf->nf.event.mask = 0; /* Do not do any matching. */ |
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nf->nf.flags = SSAM_EVENT_NOTIFIER_OBSERVER; |
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/* Register notifier. */ |
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status = ssam_notifier_register(client->cdev->ctrl, &nf->nf); |
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if (status) |
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kfree(nf); |
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else |
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client->notifier[event] = nf; |
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mutex_unlock(&client->notifier_lock); |
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return status; |
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} |
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static int ssam_cdev_notifier_unregister(struct ssam_cdev_client *client, u8 tc) |
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{ |
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const u16 rqid = ssh_tc_to_rqid(tc); |
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const u16 event = ssh_rqid_to_event(rqid); |
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int status; |
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lockdep_assert_held_read(&client->cdev->lock); |
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/* Validate notifier target category. */ |
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if (!ssh_rqid_is_event(rqid)) |
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return -EINVAL; |
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mutex_lock(&client->notifier_lock); |
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/* Check if the notifier is currently registered. */ |
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if (!client->notifier[event]) { |
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mutex_unlock(&client->notifier_lock); |
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return -ENOENT; |
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} |
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/* Unregister and free notifier. */ |
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status = ssam_notifier_unregister(client->cdev->ctrl, &client->notifier[event]->nf); |
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kfree(client->notifier[event]); |
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client->notifier[event] = NULL; |
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mutex_unlock(&client->notifier_lock); |
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return status; |
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} |
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static void ssam_cdev_notifier_unregister_all(struct ssam_cdev_client *client) |
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{ |
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int i; |
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down_read(&client->cdev->lock); |
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/* |
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* This function may be used during shutdown, thus we need to test for |
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* cdev->ctrl instead of the SSAM_CDEV_DEVICE_SHUTDOWN_BIT bit. |
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*/ |
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if (client->cdev->ctrl) { |
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for (i = 0; i < SSH_NUM_EVENTS; i++) |
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ssam_cdev_notifier_unregister(client, i + 1); |
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} else { |
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int count = 0; |
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/* |
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* Device has been shut down. Any notifier remaining is a bug, |
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* so warn about that as this would otherwise hardly be |
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* noticeable. Nevertheless, free them as well. |
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*/ |
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mutex_lock(&client->notifier_lock); |
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for (i = 0; i < SSH_NUM_EVENTS; i++) { |
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count += !!(client->notifier[i]); |
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kfree(client->notifier[i]); |
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client->notifier[i] = NULL; |
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} |
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mutex_unlock(&client->notifier_lock); |
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WARN_ON(count > 0); |
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} |
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up_read(&client->cdev->lock); |
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} |
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/* -- IOCTL functions. ------------------------------------------------------ */ |
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static long ssam_cdev_request(struct ssam_cdev_client *client, struct ssam_cdev_request __user *r) |
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{ |
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struct ssam_cdev_request rqst; |
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struct ssam_request spec = {}; |
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struct ssam_response rsp = {}; |
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const void __user *plddata; |
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void __user *rspdata; |
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int status = 0, ret = 0, tmp; |
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lockdep_assert_held_read(&client->cdev->lock); |
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ret = copy_struct_from_user(&rqst, sizeof(rqst), r, sizeof(*r)); |
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if (ret) |
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goto out; |
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plddata = u64_to_user_ptr(rqst.payload.data); |
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rspdata = u64_to_user_ptr(rqst.response.data); |
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/* Setup basic request fields. */ |
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spec.target_category = rqst.target_category; |
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spec.target_id = rqst.target_id; |
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spec.command_id = rqst.command_id; |
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spec.instance_id = rqst.instance_id; |
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spec.flags = 0; |
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spec.length = rqst.payload.length; |
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spec.payload = NULL; |
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if (rqst.flags & SSAM_CDEV_REQUEST_HAS_RESPONSE) |
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spec.flags |= SSAM_REQUEST_HAS_RESPONSE; |
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if (rqst.flags & SSAM_CDEV_REQUEST_UNSEQUENCED) |
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spec.flags |= SSAM_REQUEST_UNSEQUENCED; |
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rsp.capacity = rqst.response.length; |
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rsp.length = 0; |
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rsp.pointer = NULL; |
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/* Get request payload from user-space. */ |
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if (spec.length) { |
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if (!plddata) { |
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ret = -EINVAL; |
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goto out; |
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} |
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/* |
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* Note: spec.length is limited to U16_MAX bytes via struct |
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* ssam_cdev_request. This is slightly larger than the |
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* theoretical maximum (SSH_COMMAND_MAX_PAYLOAD_SIZE) of the |
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* underlying protocol (note that nothing remotely this size |
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* should ever be allocated in any normal case). This size is |
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* validated later in ssam_request_sync(), for allocation the |
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* bound imposed by u16 should be enough. |
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*/ |
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spec.payload = kzalloc(spec.length, GFP_KERNEL); |
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if (!spec.payload) { |
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ret = -ENOMEM; |
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goto out; |
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} |
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if (copy_from_user((void *)spec.payload, plddata, spec.length)) { |
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ret = -EFAULT; |
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goto out; |
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} |
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} |
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/* Allocate response buffer. */ |
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if (rsp.capacity) { |
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if (!rspdata) { |
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ret = -EINVAL; |
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goto out; |
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} |
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/* |
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* Note: rsp.capacity is limited to U16_MAX bytes via struct |
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* ssam_cdev_request. This is slightly larger than the |
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* theoretical maximum (SSH_COMMAND_MAX_PAYLOAD_SIZE) of the |
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* underlying protocol (note that nothing remotely this size |
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* should ever be allocated in any normal case). In later use, |
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* this capacity does not have to be strictly bounded, as it |
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* is only used as an output buffer to be written to. For |
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* allocation the bound imposed by u16 should be enough. |
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*/ |
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rsp.pointer = kzalloc(rsp.capacity, GFP_KERNEL); |
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if (!rsp.pointer) { |
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ret = -ENOMEM; |
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goto out; |
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} |
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} |
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/* Perform request. */ |
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status = ssam_request_sync(client->cdev->ctrl, &spec, &rsp); |
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if (status) |
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goto out; |
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/* Copy response to user-space. */ |
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if (rsp.length && copy_to_user(rspdata, rsp.pointer, rsp.length)) |
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ret = -EFAULT; |
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out: |
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/* Always try to set response-length and status. */ |
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tmp = put_user(rsp.length, &r->response.length); |
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if (tmp) |
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ret = tmp; |
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tmp = put_user(status, &r->status); |
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if (tmp) |
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ret = tmp; |
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/* Cleanup. */ |
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kfree(spec.payload); |
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kfree(rsp.pointer); |
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return ret; |
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} |
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static long ssam_cdev_notif_register(struct ssam_cdev_client *client, |
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const struct ssam_cdev_notifier_desc __user *d) |
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{ |
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struct ssam_cdev_notifier_desc desc; |
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long ret; |
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lockdep_assert_held_read(&client->cdev->lock); |
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ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d)); |
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if (ret) |
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return ret; |
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return ssam_cdev_notifier_register(client, desc.target_category, desc.priority); |
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} |
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static long ssam_cdev_notif_unregister(struct ssam_cdev_client *client, |
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const struct ssam_cdev_notifier_desc __user *d) |
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{ |
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struct ssam_cdev_notifier_desc desc; |
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long ret; |
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lockdep_assert_held_read(&client->cdev->lock); |
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ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d)); |
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if (ret) |
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return ret; |
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return ssam_cdev_notifier_unregister(client, desc.target_category); |
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} |
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static long ssam_cdev_event_enable(struct ssam_cdev_client *client, |
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const struct ssam_cdev_event_desc __user *d) |
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{ |
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struct ssam_cdev_event_desc desc; |
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struct ssam_event_registry reg; |
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struct ssam_event_id id; |
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long ret; |
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lockdep_assert_held_read(&client->cdev->lock); |
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/* Read descriptor from user-space. */ |
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ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d)); |
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if (ret) |
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return ret; |
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/* Translate descriptor. */ |
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reg.target_category = desc.reg.target_category; |
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reg.target_id = desc.reg.target_id; |
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reg.cid_enable = desc.reg.cid_enable; |
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reg.cid_disable = desc.reg.cid_disable; |
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id.target_category = desc.id.target_category; |
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id.instance = desc.id.instance; |
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/* Disable event. */ |
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return ssam_controller_event_enable(client->cdev->ctrl, reg, id, desc.flags); |
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} |
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static long ssam_cdev_event_disable(struct ssam_cdev_client *client, |
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const struct ssam_cdev_event_desc __user *d) |
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{ |
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struct ssam_cdev_event_desc desc; |
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struct ssam_event_registry reg; |
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struct ssam_event_id id; |
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long ret; |
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lockdep_assert_held_read(&client->cdev->lock); |
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/* Read descriptor from user-space. */ |
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ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d)); |
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if (ret) |
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return ret; |
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/* Translate descriptor. */ |
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reg.target_category = desc.reg.target_category; |
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reg.target_id = desc.reg.target_id; |
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reg.cid_enable = desc.reg.cid_enable; |
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reg.cid_disable = desc.reg.cid_disable; |
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id.target_category = desc.id.target_category; |
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id.instance = desc.id.instance; |
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/* Disable event. */ |
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return ssam_controller_event_disable(client->cdev->ctrl, reg, id, desc.flags); |
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} |
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/* -- File operations. ------------------------------------------------------ */ |
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static int ssam_cdev_device_open(struct inode *inode, struct file *filp) |
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{ |
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struct miscdevice *mdev = filp->private_data; |
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struct ssam_cdev_client *client; |
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struct ssam_cdev *cdev = container_of(mdev, struct ssam_cdev, mdev); |
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/* Initialize client */ |
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client = vzalloc(sizeof(*client)); |
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if (!client) |
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return -ENOMEM; |
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client->cdev = ssam_cdev_get(cdev); |
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INIT_LIST_HEAD(&client->node); |
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mutex_init(&client->notifier_lock); |
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mutex_init(&client->read_lock); |
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mutex_init(&client->write_lock); |
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INIT_KFIFO(client->buffer); |
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init_waitqueue_head(&client->waitq); |
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filp->private_data = client; |
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/* Attach client. */ |
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down_write(&cdev->client_lock); |
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if (test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &cdev->flags)) { |
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up_write(&cdev->client_lock); |
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mutex_destroy(&client->write_lock); |
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mutex_destroy(&client->read_lock); |
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mutex_destroy(&client->notifier_lock); |
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ssam_cdev_put(client->cdev); |
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vfree(client); |
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return -ENODEV; |
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} |
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list_add_tail(&client->node, &cdev->client_list); |
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up_write(&cdev->client_lock); |
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stream_open(inode, filp); |
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return 0; |
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} |
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static int ssam_cdev_device_release(struct inode *inode, struct file *filp) |
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{ |
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struct ssam_cdev_client *client = filp->private_data; |
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/* Force-unregister all remaining notifiers of this client. */ |
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ssam_cdev_notifier_unregister_all(client); |
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/* Detach client. */ |
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down_write(&client->cdev->client_lock); |
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list_del(&client->node); |
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up_write(&client->cdev->client_lock); |
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/* Free client. */ |
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mutex_destroy(&client->write_lock); |
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mutex_destroy(&client->read_lock); |
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mutex_destroy(&client->notifier_lock); |
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ssam_cdev_put(client->cdev); |
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vfree(client); |
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return 0; |
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} |
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static long __ssam_cdev_device_ioctl(struct ssam_cdev_client *client, unsigned int cmd, |
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unsigned long arg) |
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{ |
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lockdep_assert_held_read(&client->cdev->lock); |
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switch (cmd) { |
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case SSAM_CDEV_REQUEST: |
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return ssam_cdev_request(client, (struct ssam_cdev_request __user *)arg); |
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case SSAM_CDEV_NOTIF_REGISTER: |
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return ssam_cdev_notif_register(client, |
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(struct ssam_cdev_notifier_desc __user *)arg); |
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case SSAM_CDEV_NOTIF_UNREGISTER: |
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return ssam_cdev_notif_unregister(client, |
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(struct ssam_cdev_notifier_desc __user *)arg); |
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case SSAM_CDEV_EVENT_ENABLE: |
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return ssam_cdev_event_enable(client, (struct ssam_cdev_event_desc __user *)arg); |
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case SSAM_CDEV_EVENT_DISABLE: |
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return ssam_cdev_event_disable(client, (struct ssam_cdev_event_desc __user *)arg); |
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default: |
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return -ENOTTY; |
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} |
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} |
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static long ssam_cdev_device_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
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{ |
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struct ssam_cdev_client *client = file->private_data; |
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long status; |
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|
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/* Ensure that controller is valid for as long as we need it. */ |
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if (down_read_killable(&client->cdev->lock)) |
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return -ERESTARTSYS; |
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if (test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &client->cdev->flags)) { |
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up_read(&client->cdev->lock); |
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return -ENODEV; |
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} |
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status = __ssam_cdev_device_ioctl(client, cmd, arg); |
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up_read(&client->cdev->lock); |
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return status; |
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} |
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|
|
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 <[email protected]>"); |
|
MODULE_DESCRIPTION("User-space interface for Surface System Aggregator Module"); |
|
MODULE_LICENSE("GPL");
|
|
|