/* Copyright (c) 2018-2020, The Linux Foundation. All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 and * only version 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DEVICE_NAME "mhi" #define MHI_UCI_DRIVER_NAME "mhi_uci" struct uci_chan { wait_queue_head_t wq; spinlock_t lock; struct list_head pending; /* user space waiting to read */ struct uci_buf *cur_buf; /* current buffer user space reading */ size_t rx_size; }; struct uci_buf { void *data; size_t len; struct list_head node; }; struct uci_dev { struct list_head node; dev_t devt; struct device *dev; struct mhi_device *mhi_dev; const char *chan; struct mutex mutex; /* sync open and close */ struct uci_chan ul_chan; struct uci_chan dl_chan; size_t mtu; size_t actual_mtu; /* maximum size of incoming buffer */ int ref_count; bool enabled; u32 tiocm; void *ipc_log; enum MHI_DEBUG_LEVEL *ipc_log_lvl; }; struct mhi_uci_drv { struct list_head head; struct mutex lock; struct class *class; int major; dev_t dev_t; }; enum MHI_DEBUG_LEVEL msg_lvl = MHI_MSG_LVL_ERROR; #ifdef CONFIG_MHI_DEBUG #define MHI_UCI_IPC_LOG_PAGES (25) #define MSG_VERB(fmt, ...) do { \ if (msg_lvl <= MHI_MSG_LVL_VERBOSE) \ pr_err("[D][%s] " fmt, __func__, ##__VA_ARGS__); \ if (uci_dev->ipc_log && uci_dev->ipc_log_lvl && \ (*uci_dev->ipc_log_lvl <= MHI_MSG_LVL_VERBOSE)) \ ipc_log_string(uci_dev->ipc_log, \ "[D][%s] " fmt, __func__, ##__VA_ARGS__); \ } while (0) #else #define MHI_UCI_IPC_LOG_PAGES (1) #define MSG_VERB(fmt, ...) do { \ if (uci_dev->ipc_log && uci_dev->ipc_log_lvl && \ (*uci_dev->ipc_log_lvl <= MHI_MSG_LVL_VERBOSE)) \ ipc_log_string(uci_dev->ipc_log, \ "[D][%s] " fmt, __func__, ##__VA_ARGS__); \ } while (0) #endif #define MSG_LOG(fmt, ...) do { \ if (msg_lvl <= MHI_MSG_LVL_INFO) \ pr_err("[I][%s] " fmt, __func__, ##__VA_ARGS__); \ if (uci_dev->ipc_log && uci_dev->ipc_log_lvl && \ (*uci_dev->ipc_log_lvl <= MHI_MSG_LVL_INFO)) \ ipc_log_string(uci_dev->ipc_log, "[I][%s] " fmt, \ __func__, ##__VA_ARGS__); \ } while (0) #define MSG_ERR(fmt, ...) do { \ if (msg_lvl <= MHI_MSG_LVL_ERROR) \ pr_err("[E][%s] " fmt, __func__, ##__VA_ARGS__); \ if (uci_dev->ipc_log && uci_dev->ipc_log_lvl && \ (*uci_dev->ipc_log_lvl <= MHI_MSG_LVL_ERROR)) \ ipc_log_string(uci_dev->ipc_log, "[E][%s] " fmt, \ __func__, ##__VA_ARGS__); \ } while (0) #define MAX_UCI_DEVICES (64) static DECLARE_BITMAP(uci_minors, MAX_UCI_DEVICES); static struct mhi_uci_drv mhi_uci_drv; static int mhi_queue_inbound(struct uci_dev *uci_dev) { struct mhi_device *mhi_dev = uci_dev->mhi_dev; int nr_trbs = mhi_get_no_free_descriptors(mhi_dev, DMA_FROM_DEVICE); size_t mtu = uci_dev->mtu; size_t actual_mtu = uci_dev->actual_mtu; void *buf; struct uci_buf *uci_buf; int ret = -EIO, i; for (i = 0; i < nr_trbs; i++) { buf = kmalloc(mtu, GFP_KERNEL); if (!buf) return -ENOMEM; uci_buf = buf + actual_mtu; uci_buf->data = buf; MSG_VERB("Allocated buf %d of %d size %ld\n", i, nr_trbs, actual_mtu); ret = mhi_queue_transfer(mhi_dev, DMA_FROM_DEVICE, buf, actual_mtu, MHI_EOT); if (ret) { kfree(buf); MSG_ERR("Failed to queue buffer %d\n", i); return ret; } } return ret; } static long mhi_uci_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct uci_dev *uci_dev = file->private_data; struct mhi_device *mhi_dev = uci_dev->mhi_dev; struct uci_chan *uci_chan = &uci_dev->dl_chan; long ret = -ERESTARTSYS; mutex_lock(&uci_dev->mutex); if (cmd == TIOCMGET) { spin_lock_bh(&uci_chan->lock); ret = uci_dev->tiocm; spin_unlock_bh(&uci_chan->lock); } else if (uci_dev->enabled) { ret = mhi_ioctl(mhi_dev, cmd, arg); if (!ret) { spin_lock_bh(&uci_chan->lock); uci_dev->tiocm = mhi_dev->tiocm; spin_unlock_bh(&uci_chan->lock); } } mutex_unlock(&uci_dev->mutex); return ret; } static int mhi_uci_release(struct inode *inode, struct file *file) { struct uci_dev *uci_dev = file->private_data; mutex_lock(&uci_dev->mutex); uci_dev->ref_count--; if (!uci_dev->ref_count) { struct uci_buf *itr, *tmp; struct uci_chan *uci_chan; MSG_LOG("Last client left, closing node\n"); if (uci_dev->enabled) mhi_unprepare_from_transfer(uci_dev->mhi_dev); /* clean inbound channel */ uci_chan = &uci_dev->dl_chan; list_for_each_entry_safe(itr, tmp, &uci_chan->pending, node) { list_del(&itr->node); kfree(itr->data); } if (uci_chan->cur_buf) kfree(uci_chan->cur_buf->data); uci_chan->cur_buf = NULL; if (!uci_dev->enabled) { MSG_LOG("Node is deleted, freeing dev node\n"); mutex_unlock(&uci_dev->mutex); mutex_destroy(&uci_dev->mutex); clear_bit(MINOR(uci_dev->devt), uci_minors); kfree(uci_dev); return 0; } } MSG_LOG("exit: ref_count:%d\n", uci_dev->ref_count); mutex_unlock(&uci_dev->mutex); return 0; } static unsigned int mhi_uci_poll(struct file *file, poll_table *wait) { struct uci_dev *uci_dev = file->private_data; struct mhi_device *mhi_dev = uci_dev->mhi_dev; struct uci_chan *uci_chan; unsigned int mask = 0; poll_wait(file, &uci_dev->dl_chan.wq, wait); poll_wait(file, &uci_dev->ul_chan.wq, wait); uci_chan = &uci_dev->dl_chan; spin_lock_bh(&uci_chan->lock); if (!uci_dev->enabled) { mask = POLLERR; } else { if (!list_empty(&uci_chan->pending) || uci_chan->cur_buf) { MSG_VERB("Client can read from node\n"); mask |= POLLIN | POLLRDNORM; } if (uci_dev->tiocm) { MSG_VERB("Line status changed\n"); mask |= POLLPRI; } } spin_unlock_bh(&uci_chan->lock); uci_chan = &uci_dev->ul_chan; spin_lock_bh(&uci_chan->lock); if (!uci_dev->enabled) { mask |= POLLERR; } else if (mhi_get_no_free_descriptors(mhi_dev, DMA_TO_DEVICE) > 0) { MSG_VERB("Client can write to node\n"); mask |= POLLOUT | POLLWRNORM; } spin_unlock_bh(&uci_chan->lock); MSG_LOG("Client attempted to poll, returning mask 0x%x\n", mask); return mask; } static ssize_t mhi_uci_write(struct file *file, const char __user *buf, size_t count, loff_t *offp) { struct uci_dev *uci_dev = file->private_data; struct mhi_device *mhi_dev = uci_dev->mhi_dev; struct uci_chan *uci_chan = &uci_dev->ul_chan; size_t bytes_xfered = 0; int ret, nr_avail; if (!buf || !count) return -EINVAL; /* confirm channel is active */ spin_lock_bh(&uci_chan->lock); if (!uci_dev->enabled) { spin_unlock_bh(&uci_chan->lock); return -ERESTARTSYS; } MSG_VERB("Enter: to xfer:%lu bytes\n", count); while (count) { size_t xfer_size; void *kbuf; enum MHI_FLAGS flags; spin_unlock_bh(&uci_chan->lock); /* wait for free descriptors */ ret = wait_event_interruptible(uci_chan->wq, (!uci_dev->enabled) || (nr_avail = mhi_get_no_free_descriptors(mhi_dev, DMA_TO_DEVICE)) > 0); if (ret == -ERESTARTSYS || !uci_dev->enabled) { MSG_LOG("Exit signal caught for node or not enabled\n"); return -ERESTARTSYS; } xfer_size = min_t(size_t, count, uci_dev->mtu); kbuf = kmalloc(xfer_size, GFP_KERNEL); if (!kbuf) { MSG_ERR("Failed to allocate memory %lu\n", xfer_size); return -ENOMEM; } ret = copy_from_user(kbuf, buf, xfer_size); if (unlikely(ret)) { kfree(kbuf); return ret; } spin_lock_bh(&uci_chan->lock); /* if ring is full after this force EOT */ if (nr_avail > 1 && (count - xfer_size)) flags = MHI_CHAIN; else flags = MHI_EOT; if (uci_dev->enabled) ret = mhi_queue_transfer(mhi_dev, DMA_TO_DEVICE, kbuf, xfer_size, flags); else ret = -ERESTARTSYS; if (ret) { kfree(kbuf); goto sys_interrupt; } bytes_xfered += xfer_size; count -= xfer_size; buf += xfer_size; } spin_unlock_bh(&uci_chan->lock); MSG_VERB("Exit: Number of bytes xferred:%lu\n", bytes_xfered); return bytes_xfered; sys_interrupt: spin_unlock_bh(&uci_chan->lock); return ret; } static ssize_t mhi_uci_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct uci_dev *uci_dev = file->private_data; struct mhi_device *mhi_dev = uci_dev->mhi_dev; struct uci_chan *uci_chan = &uci_dev->dl_chan; struct uci_buf *uci_buf; char *ptr; size_t to_copy; int ret = 0; if (!buf) return -EINVAL; MSG_VERB("Client provided buf len:%lu\n", count); /* confirm channel is active */ spin_lock_bh(&uci_chan->lock); if (!uci_dev->enabled) { spin_unlock_bh(&uci_chan->lock); return -ERESTARTSYS; } /* No data available to read, wait */ if (!uci_chan->cur_buf && list_empty(&uci_chan->pending)) { MSG_VERB("No data available to read waiting\n"); spin_unlock_bh(&uci_chan->lock); ret = wait_event_interruptible(uci_chan->wq, (!uci_dev->enabled || !list_empty(&uci_chan->pending))); if (ret == -ERESTARTSYS) { MSG_LOG("Exit signal caught for node\n"); return -ERESTARTSYS; } spin_lock_bh(&uci_chan->lock); if (!uci_dev->enabled) { MSG_LOG("node is disabled\n"); ret = -ERESTARTSYS; goto read_error; } } /* new read, get the next descriptor from the list */ if (!uci_chan->cur_buf) { uci_buf = list_first_entry_or_null(&uci_chan->pending, struct uci_buf, node); if (unlikely(!uci_buf)) { ret = -EIO; goto read_error; } list_del(&uci_buf->node); uci_chan->cur_buf = uci_buf; uci_chan->rx_size = uci_buf->len; MSG_VERB("Got pkt of size:%zu\n", uci_chan->rx_size); } uci_buf = uci_chan->cur_buf; spin_unlock_bh(&uci_chan->lock); /* Copy the buffer to user space */ to_copy = min_t(size_t, count, uci_chan->rx_size); ptr = uci_buf->data + (uci_buf->len - uci_chan->rx_size); ret = copy_to_user(buf, ptr, to_copy); if (ret) return ret; MSG_VERB("Copied %lu of %lu bytes\n", to_copy, uci_chan->rx_size); uci_chan->rx_size -= to_copy; /* we finished with this buffer, queue it back to hardware */ if (!uci_chan->rx_size) { spin_lock_bh(&uci_chan->lock); uci_chan->cur_buf = NULL; if (uci_dev->enabled) ret = mhi_queue_transfer(mhi_dev, DMA_FROM_DEVICE, uci_buf->data, uci_dev->actual_mtu, MHI_EOT); else ret = -ERESTARTSYS; if (ret) { MSG_ERR("Failed to recycle element\n"); kfree(uci_buf->data); goto read_error; } spin_unlock_bh(&uci_chan->lock); } MSG_VERB("Returning %lu bytes\n", to_copy); return to_copy; read_error: spin_unlock_bh(&uci_chan->lock); return ret; } static int mhi_uci_open(struct inode *inode, struct file *filp) { struct uci_dev *uci_dev = NULL, *tmp_dev; int ret = -EIO; struct uci_buf *buf_itr, *tmp; struct uci_chan *dl_chan; mutex_lock(&mhi_uci_drv.lock); list_for_each_entry(tmp_dev, &mhi_uci_drv.head, node) { if (tmp_dev->devt == inode->i_rdev) { uci_dev = tmp_dev; break; } } /* could not find a minor node */ if (!uci_dev) goto error_exit; mutex_lock(&uci_dev->mutex); if (!uci_dev->enabled) { MSG_ERR("Node exist, but not in active state!\n"); goto error_open_chan; } uci_dev->ref_count++; MSG_LOG("Node open, ref counts %u\n", uci_dev->ref_count); if (uci_dev->ref_count == 1) { MSG_LOG("Starting channel\n"); ret = mhi_prepare_for_transfer(uci_dev->mhi_dev); if (ret) { MSG_ERR("Error starting transfer channels\n"); uci_dev->ref_count--; goto error_open_chan; } ret = mhi_queue_inbound(uci_dev); if (ret) goto error_rx_queue; } filp->private_data = uci_dev; mutex_unlock(&uci_dev->mutex); mutex_unlock(&mhi_uci_drv.lock); return 0; error_rx_queue: dl_chan = &uci_dev->dl_chan; mhi_unprepare_from_transfer(uci_dev->mhi_dev); list_for_each_entry_safe(buf_itr, tmp, &dl_chan->pending, node) { list_del(&buf_itr->node); kfree(buf_itr->data); } error_open_chan: mutex_unlock(&uci_dev->mutex); error_exit: mutex_unlock(&mhi_uci_drv.lock); return ret; } static const struct file_operations mhidev_fops = { .open = mhi_uci_open, .release = mhi_uci_release, .read = mhi_uci_read, .write = mhi_uci_write, .poll = mhi_uci_poll, .unlocked_ioctl = mhi_uci_ioctl, }; static void mhi_uci_remove(struct mhi_device *mhi_dev) { struct uci_dev *uci_dev = mhi_device_get_devdata(mhi_dev); MSG_LOG("Enter\n"); mutex_lock(&mhi_uci_drv.lock); mutex_lock(&uci_dev->mutex); /* disable the node */ spin_lock_irq(&uci_dev->dl_chan.lock); spin_lock_irq(&uci_dev->ul_chan.lock); uci_dev->enabled = false; spin_unlock_irq(&uci_dev->ul_chan.lock); spin_unlock_irq(&uci_dev->dl_chan.lock); wake_up(&uci_dev->dl_chan.wq); wake_up(&uci_dev->ul_chan.wq); /* delete the node to prevent new opens */ device_destroy(mhi_uci_drv.class, uci_dev->devt); uci_dev->dev = NULL; list_del(&uci_dev->node); /* safe to free memory only if all file nodes are closed */ if (!uci_dev->ref_count) { mutex_unlock(&uci_dev->mutex); mutex_destroy(&uci_dev->mutex); clear_bit(MINOR(uci_dev->devt), uci_minors); kfree(uci_dev); mutex_unlock(&mhi_uci_drv.lock); return; } MSG_LOG("Exit\n"); mutex_unlock(&uci_dev->mutex); mutex_unlock(&mhi_uci_drv.lock); } static int mhi_uci_probe(struct mhi_device *mhi_dev, const struct mhi_device_id *id) { struct uci_dev *uci_dev; struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl; int minor; char node_name[32]; int dir; uci_dev = kzalloc(sizeof(*uci_dev), GFP_KERNEL); if (!uci_dev) return -ENOMEM; mutex_init(&uci_dev->mutex); uci_dev->mhi_dev = mhi_dev; minor = find_first_zero_bit(uci_minors, MAX_UCI_DEVICES); if (minor >= MAX_UCI_DEVICES) { kfree(uci_dev); return -ENOSPC; } mutex_lock(&uci_dev->mutex); mutex_lock(&mhi_uci_drv.lock); uci_dev->devt = MKDEV(mhi_uci_drv.major, minor); uci_dev->dev = device_create(mhi_uci_drv.class, &mhi_dev->dev, uci_dev->devt, uci_dev, DEVICE_NAME "_%04x_%02u.%02u.%02u%s%d", mhi_dev->dev_id, mhi_dev->domain, mhi_dev->bus, mhi_dev->slot, "_pipe_", mhi_dev->ul_chan_id); set_bit(minor, uci_minors); /* create debugging buffer */ snprintf(node_name, sizeof(node_name), "mhi_uci_%04x_%02u.%02u.%02u_%d", mhi_dev->dev_id, mhi_dev->domain, mhi_dev->bus, mhi_dev->slot, mhi_dev->ul_chan_id); uci_dev->ipc_log = ipc_log_context_create(MHI_UCI_IPC_LOG_PAGES, node_name, 0); uci_dev->ipc_log_lvl = &mhi_cntrl->log_lvl; for (dir = 0; dir < 2; dir++) { struct uci_chan *uci_chan = (dir) ? &uci_dev->ul_chan : &uci_dev->dl_chan; spin_lock_init(&uci_chan->lock); init_waitqueue_head(&uci_chan->wq); INIT_LIST_HEAD(&uci_chan->pending); }; uci_dev->mtu = min_t(size_t, id->driver_data, mhi_dev->mtu); uci_dev->actual_mtu = uci_dev->mtu - sizeof(struct uci_buf); mhi_device_set_devdata(mhi_dev, uci_dev); uci_dev->enabled = true; list_add(&uci_dev->node, &mhi_uci_drv.head); mutex_unlock(&mhi_uci_drv.lock); mutex_unlock(&uci_dev->mutex); MSG_LOG("channel:%s successfully probed\n", mhi_dev->chan_name); return 0; }; static void mhi_ul_xfer_cb(struct mhi_device *mhi_dev, struct mhi_result *mhi_result) { struct uci_dev *uci_dev = mhi_device_get_devdata(mhi_dev); struct uci_chan *uci_chan = &uci_dev->ul_chan; MSG_VERB("status:%d xfer_len:%zu\n", mhi_result->transaction_status, mhi_result->bytes_xferd); kfree(mhi_result->buf_addr); if (!mhi_result->transaction_status) wake_up(&uci_chan->wq); } static void mhi_dl_xfer_cb(struct mhi_device *mhi_dev, struct mhi_result *mhi_result) { struct uci_dev *uci_dev = mhi_device_get_devdata(mhi_dev); struct uci_chan *uci_chan = &uci_dev->dl_chan; unsigned long flags; struct uci_buf *buf; MSG_VERB("status:%d receive_len:%zu\n", mhi_result->transaction_status, mhi_result->bytes_xferd); if (mhi_result->transaction_status == -ENOTCONN) { kfree(mhi_result->buf_addr); return; } spin_lock_irqsave(&uci_chan->lock, flags); buf = mhi_result->buf_addr + uci_dev->actual_mtu; buf->data = mhi_result->buf_addr; buf->len = mhi_result->bytes_xferd; list_add_tail(&buf->node, &uci_chan->pending); spin_unlock_irqrestore(&uci_chan->lock, flags); if (mhi_dev->dev.power.wakeup) __pm_wakeup_event(mhi_dev->dev.power.wakeup, 0); wake_up(&uci_chan->wq); } static void mhi_status_cb(struct mhi_device *mhi_dev, enum MHI_CB reason) { struct uci_dev *uci_dev = mhi_device_get_devdata(mhi_dev); struct uci_chan *uci_chan = &uci_dev->dl_chan; unsigned long flags; if (reason == MHI_CB_DTR_SIGNAL) { spin_lock_irqsave(&uci_chan->lock, flags); uci_dev->tiocm = mhi_dev->tiocm; spin_unlock_irqrestore(&uci_chan->lock, flags); wake_up(&uci_chan->wq); } } /* .driver_data stores max mtu */ static const struct mhi_device_id mhi_uci_match_table[] = { { .chan = "LOOPBACK", .driver_data = 0x1000 }, { .chan = "SAHARA", .driver_data = 0x8000 }, { .chan = "EFS", .driver_data = 0x1000 }, { .chan = "QMI0", .driver_data = 0x1000 }, { .chan = "QMI1", .driver_data = 0x1000 }, { .chan = "TF", .driver_data = 0x1000 }, { .chan = "DUN", .driver_data = 0x1000 }, {}, }; static struct mhi_driver mhi_uci_driver = { .id_table = mhi_uci_match_table, .remove = mhi_uci_remove, .probe = mhi_uci_probe, .ul_xfer_cb = mhi_ul_xfer_cb, .dl_xfer_cb = mhi_dl_xfer_cb, .status_cb = mhi_status_cb, .driver = { .name = MHI_UCI_DRIVER_NAME, .owner = THIS_MODULE, }, }; static int mhi_uci_init(void) { int ret; ret = register_chrdev(0, MHI_UCI_DRIVER_NAME, &mhidev_fops); if (ret < 0) return ret; mhi_uci_drv.major = ret; mhi_uci_drv.class = class_create(THIS_MODULE, MHI_UCI_DRIVER_NAME); if (IS_ERR(mhi_uci_drv.class)) return -ENODEV; mutex_init(&mhi_uci_drv.lock); INIT_LIST_HEAD(&mhi_uci_drv.head); ret = mhi_driver_register(&mhi_uci_driver); if (ret) class_destroy(mhi_uci_drv.class); return ret; } module_init(mhi_uci_init); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("MHI_UCI"); MODULE_DESCRIPTION("MHI UCI Driver");