From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- drivers/platform/surface/surface_aggregator_cdev.c | 810 +++++++++++++++++++++ 1 file changed, 810 insertions(+) create mode 100644 drivers/platform/surface/surface_aggregator_cdev.c (limited to 'drivers/platform/surface/surface_aggregator_cdev.c') 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 + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include + +#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 "); +MODULE_DESCRIPTION("User-space interface for Surface System Aggregator Module"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3