diff options
| -rw-r--r-- | Documentation/userspace-api/ioctl/ioctl-number.rst | 2 | ||||
| -rw-r--r-- | drivers/platform/surface/surface_aggregator_cdev.c | 460 | ||||
| -rw-r--r-- | include/uapi/linux/surface_aggregator/cdev.h | 41 |
3 files changed, 477 insertions, 26 deletions
diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst index 9bfc2b510c64..1409e40e6345 100644 --- a/Documentation/userspace-api/ioctl/ioctl-number.rst +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst @@ -325,7 +325,7 @@ Code Seq# Include File Comments 0xA3 90-9F linux/dtlk.h 0xA4 00-1F uapi/linux/tee.h Generic TEE subsystem 0xA4 00-1F uapi/asm/sgx.h <mailto:linux-sgx@vger.kernel.org> -0xA5 01 linux/surface_aggregator/cdev.h Microsoft Surface Platform System Aggregator +0xA5 01-05 linux/surface_aggregator/cdev.h Microsoft Surface Platform System Aggregator <mailto:luzmaximilian@gmail.com> 0xA5 20-2F linux/surface_aggregator/dtx.h Microsoft Surface DTX driver <mailto:luzmaximilian@gmail.com> diff --git a/drivers/platform/surface/surface_aggregator_cdev.c b/drivers/platform/surface/surface_aggregator_cdev.c index 79e28fab7e40..dcda377896b7 100644 --- a/drivers/platform/surface/surface_aggregator_cdev.c +++ b/drivers/platform/surface/surface_aggregator_cdev.c @@ -3,29 +3,69 @@ * Provides user-space access to the SSAM EC via the /dev/surface/aggregator * misc device. Intended for debugging and development. * - * Copyright (C) 2020 Maximilian Luz <luzmaximilian@gmail.com> + * Copyright (C) 2020-2021 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) @@ -47,24 +87,169 @@ static void ssam_cdev_put(struct ssam_cdev *cdev) kref_put(&cdev->kref, __ssam_cdev_release); } -static int ssam_cdev_device_open(struct inode *inode, struct file *filp) + +/* -- Notifier handling. ---------------------------------------------------- */ + +static u32 ssam_cdev_notifier(struct ssam_event_notifier *nf, const struct ssam_event *in) { - struct miscdevice *mdev = filp->private_data; - struct ssam_cdev *cdev = container_of(mdev, struct ssam_cdev, mdev); + 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; + } - filp->private_data = ssam_cdev_get(cdev); - return stream_open(inode, filp); + /* 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_device_release(struct inode *inode, struct file *filp) +static int ssam_cdev_notifier_register(struct ssam_cdev_client *client, u8 tc, int priority) { - ssam_cdev_put(filp->private_data); - return 0; + const u16 rqid = ssh_tc_to_rqid(tc); + const u16 event = ssh_rqid_to_event(rqid); + struct ssam_cdev_notifier *nf; + int status; + + /* 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 long ssam_cdev_request(struct ssam_cdev *cdev, unsigned long arg) +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; + + /* 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 __user *r; struct ssam_cdev_request rqst; struct ssam_request spec = {}; struct ssam_response rsp = {}; @@ -72,7 +257,6 @@ static long ssam_cdev_request(struct ssam_cdev *cdev, unsigned long arg) void __user *rspdata; int status = 0, ret = 0, tmp; - r = (struct ssam_cdev_request __user *)arg; ret = copy_struct_from_user(&rqst, sizeof(rqst), r, sizeof(*r)); if (ret) goto out; @@ -152,7 +336,7 @@ static long ssam_cdev_request(struct ssam_cdev *cdev, unsigned long arg) } /* Perform request. */ - status = ssam_request_sync(cdev->ctrl, &spec, &rsp); + status = ssam_request_sync(client->cdev->ctrl, &spec, &rsp); if (status) goto out; @@ -177,48 +361,247 @@ out: return ret; } -static long __ssam_cdev_device_ioctl(struct ssam_cdev *cdev, unsigned int cmd, +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; + + 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; + + ret = copy_struct_from_user(&desc, sizeof(desc), d, sizeof(*d)); + if (ret) + return ret; + + return ssam_cdev_notifier_unregister(client, desc.target_category); +} + + +/* -- 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) { switch (cmd) { case SSAM_CDEV_REQUEST: - return ssam_cdev_request(cdev, arg); + 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); default: return -ENOTTY; } } -static long ssam_cdev_device_ioctl(struct file *file, unsigned int cmd, - unsigned long arg) +static long ssam_cdev_device_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { - struct ssam_cdev *cdev = file->private_data; + 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; - if (!cdev->ctrl) { + /* Make sure we're not shut down. */ + if (test_bit(SSAM_CDEV_DEVICE_SHUTDOWN_BIT, &cdev->flags)) { up_read(&cdev->lock); return -ENODEV; } - status = __ssam_cdev_device_ioctl(cdev, cmd, arg); + 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 status; + 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 = noop_llseek, + .llseek = no_llseek, }; + +/* -- Device and driver setup ----------------------------------------------- */ + static int ssam_dbg_device_probe(struct platform_device *pdev) { struct ssam_controller *ctrl; @@ -236,6 +619,7 @@ static int ssam_dbg_device_probe(struct platform_device *pdev) 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; @@ -243,6 +627,9 @@ static int ssam_dbg_device_probe(struct platform_device *pdev) 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); @@ -256,8 +643,32 @@ static int ssam_dbg_device_probe(struct platform_device *pdev) static int ssam_dbg_device_remove(struct platform_device *pdev) { struct ssam_cdev *cdev = platform_get_drvdata(pdev); + struct ssam_cdev_client *client; - misc_deregister(&cdev->mdev); + /* + * 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 @@ -266,8 +677,11 @@ static int ssam_dbg_device_remove(struct platform_device *pdev) */ down_write(&cdev->lock); cdev->ctrl = NULL; + cdev->dev = NULL; up_write(&cdev->lock); + misc_deregister(&cdev->mdev); + ssam_cdev_put(cdev); return 0; } diff --git a/include/uapi/linux/surface_aggregator/cdev.h b/include/uapi/linux/surface_aggregator/cdev.h index fbcce04abfe9..4f393fafc235 100644 --- a/include/uapi/linux/surface_aggregator/cdev.h +++ b/include/uapi/linux/surface_aggregator/cdev.h @@ -6,7 +6,7 @@ * device. This device provides direct user-space access to the SSAM EC. * Intended for debugging and development. * - * Copyright (C) 2020 Maximilian Luz <luzmaximilian@gmail.com> + * Copyright (C) 2020-2021 Maximilian Luz <luzmaximilian@gmail.com> */ #ifndef _UAPI_LINUX_SURFACE_AGGREGATOR_CDEV_H @@ -73,6 +73,43 @@ struct ssam_cdev_request { } response; } __attribute__((__packed__)); -#define SSAM_CDEV_REQUEST _IOWR(0xA5, 1, struct ssam_cdev_request) +/** + * struct ssam_cdev_notifier_desc - Notifier descriptor. + * @priority: Priority value determining the order in which notifier + * callbacks will be called. A higher value means higher + * priority, i.e. the associated callback will be executed + * earlier than other (lower priority) callbacks. + * @target_category: The event target category for which this notifier should + * receive events. + * + * Specifies the notifier that should be registered or unregistered, + * specifically with which priority and for which target category of events. + */ +struct ssam_cdev_notifier_desc { + __s32 priority; + __u8 target_category; +} __attribute__((__packed__)); + +/** + * struct ssam_cdev_event - SSAM event sent by the EC. + * @target_category: Target category of the event source. See &enum ssam_ssh_tc. + * @target_id: Target ID of the event source. + * @command_id: Command ID of the event. + * @instance_id: Instance ID of the event source. + * @length: Length of the event payload in bytes. + * @data: Event payload data. + */ +struct ssam_cdev_event { + __u8 target_category; + __u8 target_id; + __u8 command_id; + __u8 instance_id; + __u16 length; + __u8 data[]; +} __attribute__((__packed__)); + +#define SSAM_CDEV_REQUEST _IOWR(0xA5, 1, struct ssam_cdev_request) +#define SSAM_CDEV_NOTIF_REGISTER _IOW(0xA5, 2, struct ssam_cdev_notifier_desc) +#define SSAM_CDEV_NOTIF_UNREGISTER _IOW(0xA5, 3, struct ssam_cdev_notifier_desc) #endif /* _UAPI_LINUX_SURFACE_AGGREGATOR_CDEV_H */ |