diff options
Diffstat (limited to 'drivers/usb/host/xhci-dbgtty.c')
| -rw-r--r-- | drivers/usb/host/xhci-dbgtty.c | 554 |
1 files changed, 554 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci-dbgtty.c b/drivers/usb/host/xhci-dbgtty.c new file mode 100644 index 000000000..2a53b2831 --- /dev/null +++ b/drivers/usb/host/xhci-dbgtty.c @@ -0,0 +1,554 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * xhci-dbgtty.c - tty glue for xHCI debug capability + * + * Copyright (C) 2017 Intel Corporation + * + * Author: Lu Baolu <baolu.lu@linux.intel.com> + */ + +#include <linux/slab.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> + +#include "xhci.h" +#include "xhci-dbgcap.h" + +static int dbc_tty_init(void); +static void dbc_tty_exit(void); + +static struct tty_driver *dbc_tty_driver; + +static inline struct dbc_port *dbc_to_port(struct xhci_dbc *dbc) +{ + return dbc->priv; +} + +static unsigned int +dbc_send_packet(struct dbc_port *port, char *packet, unsigned int size) +{ + unsigned int len; + + len = kfifo_len(&port->write_fifo); + if (len < size) + size = len; + if (size != 0) + size = kfifo_out(&port->write_fifo, packet, size); + return size; +} + +static int dbc_start_tx(struct dbc_port *port) + __releases(&port->port_lock) + __acquires(&port->port_lock) +{ + int len; + struct dbc_request *req; + int status = 0; + bool do_tty_wake = false; + struct list_head *pool = &port->write_pool; + + while (!list_empty(pool)) { + req = list_entry(pool->next, struct dbc_request, list_pool); + len = dbc_send_packet(port, req->buf, DBC_MAX_PACKET); + if (len == 0) + break; + do_tty_wake = true; + + req->length = len; + list_del(&req->list_pool); + + spin_unlock(&port->port_lock); + status = dbc_ep_queue(req); + spin_lock(&port->port_lock); + + if (status) { + list_add(&req->list_pool, pool); + break; + } + } + + if (do_tty_wake && port->port.tty) + tty_wakeup(port->port.tty); + + return status; +} + +static void dbc_start_rx(struct dbc_port *port) + __releases(&port->port_lock) + __acquires(&port->port_lock) +{ + struct dbc_request *req; + int status; + struct list_head *pool = &port->read_pool; + + while (!list_empty(pool)) { + if (!port->port.tty) + break; + + req = list_entry(pool->next, struct dbc_request, list_pool); + list_del(&req->list_pool); + req->length = DBC_MAX_PACKET; + + spin_unlock(&port->port_lock); + status = dbc_ep_queue(req); + spin_lock(&port->port_lock); + + if (status) { + list_add(&req->list_pool, pool); + break; + } + } +} + +static void +dbc_read_complete(struct xhci_dbc *dbc, struct dbc_request *req) +{ + unsigned long flags; + struct dbc_port *port = dbc_to_port(dbc); + + spin_lock_irqsave(&port->port_lock, flags); + list_add_tail(&req->list_pool, &port->read_queue); + tasklet_schedule(&port->push); + spin_unlock_irqrestore(&port->port_lock, flags); +} + +static void dbc_write_complete(struct xhci_dbc *dbc, struct dbc_request *req) +{ + unsigned long flags; + struct dbc_port *port = dbc_to_port(dbc); + + spin_lock_irqsave(&port->port_lock, flags); + list_add(&req->list_pool, &port->write_pool); + switch (req->status) { + case 0: + dbc_start_tx(port); + break; + case -ESHUTDOWN: + break; + default: + dev_warn(dbc->dev, "unexpected write complete status %d\n", + req->status); + break; + } + spin_unlock_irqrestore(&port->port_lock, flags); +} + +static void xhci_dbc_free_req(struct dbc_request *req) +{ + kfree(req->buf); + dbc_free_request(req); +} + +static int +xhci_dbc_alloc_requests(struct xhci_dbc *dbc, unsigned int direction, + struct list_head *head, + void (*fn)(struct xhci_dbc *, struct dbc_request *)) +{ + int i; + struct dbc_request *req; + + for (i = 0; i < DBC_QUEUE_SIZE; i++) { + req = dbc_alloc_request(dbc, direction, GFP_KERNEL); + if (!req) + break; + + req->length = DBC_MAX_PACKET; + req->buf = kmalloc(req->length, GFP_KERNEL); + if (!req->buf) { + dbc_free_request(req); + break; + } + + req->complete = fn; + list_add_tail(&req->list_pool, head); + } + + return list_empty(head) ? -ENOMEM : 0; +} + +static void +xhci_dbc_free_requests(struct list_head *head) +{ + struct dbc_request *req; + + while (!list_empty(head)) { + req = list_entry(head->next, struct dbc_request, list_pool); + list_del(&req->list_pool); + xhci_dbc_free_req(req); + } +} + +static int dbc_tty_install(struct tty_driver *driver, struct tty_struct *tty) +{ + struct dbc_port *port = driver->driver_state; + + tty->driver_data = port; + + return tty_port_install(&port->port, driver, tty); +} + +static int dbc_tty_open(struct tty_struct *tty, struct file *file) +{ + struct dbc_port *port = tty->driver_data; + + return tty_port_open(&port->port, tty, file); +} + +static void dbc_tty_close(struct tty_struct *tty, struct file *file) +{ + struct dbc_port *port = tty->driver_data; + + tty_port_close(&port->port, tty, file); +} + +static int dbc_tty_write(struct tty_struct *tty, + const unsigned char *buf, + int count) +{ + struct dbc_port *port = tty->driver_data; + unsigned long flags; + + spin_lock_irqsave(&port->port_lock, flags); + if (count) + count = kfifo_in(&port->write_fifo, buf, count); + dbc_start_tx(port); + spin_unlock_irqrestore(&port->port_lock, flags); + + return count; +} + +static int dbc_tty_put_char(struct tty_struct *tty, unsigned char ch) +{ + struct dbc_port *port = tty->driver_data; + unsigned long flags; + int status; + + spin_lock_irqsave(&port->port_lock, flags); + status = kfifo_put(&port->write_fifo, ch); + spin_unlock_irqrestore(&port->port_lock, flags); + + return status; +} + +static void dbc_tty_flush_chars(struct tty_struct *tty) +{ + struct dbc_port *port = tty->driver_data; + unsigned long flags; + + spin_lock_irqsave(&port->port_lock, flags); + dbc_start_tx(port); + spin_unlock_irqrestore(&port->port_lock, flags); +} + +static int dbc_tty_write_room(struct tty_struct *tty) +{ + struct dbc_port *port = tty->driver_data; + unsigned long flags; + int room = 0; + + spin_lock_irqsave(&port->port_lock, flags); + room = kfifo_avail(&port->write_fifo); + spin_unlock_irqrestore(&port->port_lock, flags); + + return room; +} + +static int dbc_tty_chars_in_buffer(struct tty_struct *tty) +{ + struct dbc_port *port = tty->driver_data; + unsigned long flags; + int chars = 0; + + spin_lock_irqsave(&port->port_lock, flags); + chars = kfifo_len(&port->write_fifo); + spin_unlock_irqrestore(&port->port_lock, flags); + + return chars; +} + +static void dbc_tty_unthrottle(struct tty_struct *tty) +{ + struct dbc_port *port = tty->driver_data; + unsigned long flags; + + spin_lock_irqsave(&port->port_lock, flags); + tasklet_schedule(&port->push); + spin_unlock_irqrestore(&port->port_lock, flags); +} + +static const struct tty_operations dbc_tty_ops = { + .install = dbc_tty_install, + .open = dbc_tty_open, + .close = dbc_tty_close, + .write = dbc_tty_write, + .put_char = dbc_tty_put_char, + .flush_chars = dbc_tty_flush_chars, + .write_room = dbc_tty_write_room, + .chars_in_buffer = dbc_tty_chars_in_buffer, + .unthrottle = dbc_tty_unthrottle, +}; + +static void dbc_rx_push(struct tasklet_struct *t) +{ + struct dbc_request *req; + struct tty_struct *tty; + unsigned long flags; + bool do_push = false; + bool disconnect = false; + struct dbc_port *port = from_tasklet(port, t, push); + struct list_head *queue = &port->read_queue; + + spin_lock_irqsave(&port->port_lock, flags); + tty = port->port.tty; + while (!list_empty(queue)) { + req = list_first_entry(queue, struct dbc_request, list_pool); + + if (tty && tty_throttled(tty)) + break; + + switch (req->status) { + case 0: + break; + case -ESHUTDOWN: + disconnect = true; + break; + default: + pr_warn("ttyDBC0: unexpected RX status %d\n", + req->status); + break; + } + + if (req->actual) { + char *packet = req->buf; + unsigned int n, size = req->actual; + int count; + + n = port->n_read; + if (n) { + packet += n; + size -= n; + } + + count = tty_insert_flip_string(&port->port, packet, + size); + if (count) + do_push = true; + if (count != size) { + port->n_read += count; + break; + } + port->n_read = 0; + } + + list_move(&req->list_pool, &port->read_pool); + } + + if (do_push) + tty_flip_buffer_push(&port->port); + + if (!list_empty(queue) && tty) { + if (!tty_throttled(tty)) { + if (do_push) + tasklet_schedule(&port->push); + else + pr_warn("ttyDBC0: RX not scheduled?\n"); + } + } + + if (!disconnect) + dbc_start_rx(port); + + spin_unlock_irqrestore(&port->port_lock, flags); +} + +static int dbc_port_activate(struct tty_port *_port, struct tty_struct *tty) +{ + unsigned long flags; + struct dbc_port *port = container_of(_port, struct dbc_port, port); + + spin_lock_irqsave(&port->port_lock, flags); + dbc_start_rx(port); + spin_unlock_irqrestore(&port->port_lock, flags); + + return 0; +} + +static const struct tty_port_operations dbc_port_ops = { + .activate = dbc_port_activate, +}; + +static void +xhci_dbc_tty_init_port(struct xhci_dbc *dbc, struct dbc_port *port) +{ + tty_port_init(&port->port); + spin_lock_init(&port->port_lock); + tasklet_setup(&port->push, dbc_rx_push); + INIT_LIST_HEAD(&port->read_pool); + INIT_LIST_HEAD(&port->read_queue); + INIT_LIST_HEAD(&port->write_pool); + + port->port.ops = &dbc_port_ops; + port->n_read = 0; +} + +static void +xhci_dbc_tty_exit_port(struct dbc_port *port) +{ + tasklet_kill(&port->push); + tty_port_destroy(&port->port); +} + +static int xhci_dbc_tty_register_device(struct xhci_dbc *dbc) +{ + int ret; + struct device *tty_dev; + struct dbc_port *port = dbc_to_port(dbc); + + if (port->registered) + return -EBUSY; + + xhci_dbc_tty_init_port(dbc, port); + + ret = kfifo_alloc(&port->write_fifo, DBC_WRITE_BUF_SIZE, GFP_KERNEL); + if (ret) + goto err_exit_port; + + ret = xhci_dbc_alloc_requests(dbc, BULK_IN, &port->read_pool, + dbc_read_complete); + if (ret) + goto err_free_fifo; + + ret = xhci_dbc_alloc_requests(dbc, BULK_OUT, &port->write_pool, + dbc_write_complete); + if (ret) + goto err_free_requests; + + tty_dev = tty_port_register_device(&port->port, + dbc_tty_driver, 0, NULL); + if (IS_ERR(tty_dev)) { + ret = PTR_ERR(tty_dev); + goto err_free_requests; + } + + port->registered = true; + + return 0; + +err_free_requests: + xhci_dbc_free_requests(&port->read_pool); + xhci_dbc_free_requests(&port->write_pool); +err_free_fifo: + kfifo_free(&port->write_fifo); +err_exit_port: + xhci_dbc_tty_exit_port(port); + + dev_err(dbc->dev, "can't register tty port, err %d\n", ret); + + return ret; +} + +static void xhci_dbc_tty_unregister_device(struct xhci_dbc *dbc) +{ + struct dbc_port *port = dbc_to_port(dbc); + + if (!port->registered) + return; + tty_unregister_device(dbc_tty_driver, 0); + xhci_dbc_tty_exit_port(port); + port->registered = false; + + kfifo_free(&port->write_fifo); + xhci_dbc_free_requests(&port->read_pool); + xhci_dbc_free_requests(&port->read_queue); + xhci_dbc_free_requests(&port->write_pool); +} + +static const struct dbc_driver dbc_driver = { + .configure = xhci_dbc_tty_register_device, + .disconnect = xhci_dbc_tty_unregister_device, +}; + +int xhci_dbc_tty_probe(struct xhci_hcd *xhci) +{ + struct xhci_dbc *dbc = xhci->dbc; + struct dbc_port *port; + int status; + + /* dbc_tty_init will be called by module init() in the future */ + status = dbc_tty_init(); + if (status) + return status; + + port = kzalloc(sizeof(*port), GFP_KERNEL); + if (!port) { + status = -ENOMEM; + goto out; + } + + dbc->driver = &dbc_driver; + dbc->priv = port; + + + dbc_tty_driver->driver_state = port; + + return 0; +out: + /* dbc_tty_exit will be called by module_exit() in the future */ + dbc_tty_exit(); + return status; +} + +/* + * undo what probe did, assume dbc is stopped already. + * we also assume tty_unregister_device() is called before this + */ +void xhci_dbc_tty_remove(struct xhci_dbc *dbc) +{ + struct dbc_port *port = dbc_to_port(dbc); + + dbc->driver = NULL; + dbc->priv = NULL; + kfree(port); + + /* dbc_tty_exit will be called by module_exit() in the future */ + dbc_tty_exit(); +} + +static int dbc_tty_init(void) +{ + int ret; + + dbc_tty_driver = tty_alloc_driver(1, TTY_DRIVER_REAL_RAW | + TTY_DRIVER_DYNAMIC_DEV); + if (IS_ERR(dbc_tty_driver)) + return PTR_ERR(dbc_tty_driver); + + dbc_tty_driver->driver_name = "dbc_serial"; + dbc_tty_driver->name = "ttyDBC"; + + dbc_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; + dbc_tty_driver->subtype = SERIAL_TYPE_NORMAL; + dbc_tty_driver->init_termios = tty_std_termios; + dbc_tty_driver->init_termios.c_cflag = + B9600 | CS8 | CREAD | HUPCL | CLOCAL; + dbc_tty_driver->init_termios.c_ispeed = 9600; + dbc_tty_driver->init_termios.c_ospeed = 9600; + + tty_set_operations(dbc_tty_driver, &dbc_tty_ops); + + ret = tty_register_driver(dbc_tty_driver); + if (ret) { + pr_err("Can't register dbc tty driver\n"); + put_tty_driver(dbc_tty_driver); + } + return ret; +} + +static void dbc_tty_exit(void) +{ + if (dbc_tty_driver) { + tty_unregister_driver(dbc_tty_driver); + put_tty_driver(dbc_tty_driver); + dbc_tty_driver = NULL; + } +} |