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path: root/drivers/usb/host/xhci-dbgtty.c
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-rw-r--r--drivers/usb/host/xhci-dbgtty.c582
1 files changed, 582 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..d3acc0829
--- /dev/null
+++ b/drivers/usb/host/xhci-dbgtty.c
@@ -0,0 +1,582 @@
+// 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 <linux/idr.h>
+
+#include "xhci.h"
+#include "xhci-dbgcap.h"
+
+static struct tty_driver *dbc_tty_driver;
+static struct idr dbc_tty_minors;
+static DEFINE_MUTEX(dbc_tty_minors_lock);
+
+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;
+
+ mutex_lock(&dbc_tty_minors_lock);
+ port = idr_find(&dbc_tty_minors, tty->index);
+ mutex_unlock(&dbc_tty_minors_lock);
+
+ if (!port)
+ return -ENXIO;
+
+ 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 unsigned int dbc_tty_write_room(struct tty_struct *tty)
+{
+ struct dbc_port *port = tty->driver_data;
+ unsigned long flags;
+ unsigned int room;
+
+ spin_lock_irqsave(&port->port_lock, flags);
+ room = kfifo_avail(&port->write_fifo);
+ spin_unlock_irqrestore(&port->port_lock, flags);
+
+ return room;
+}
+
+static unsigned int dbc_tty_chars_in_buffer(struct tty_struct *tty)
+{
+ struct dbc_port *port = tty->driver_data;
+ unsigned long flags;
+ unsigned int chars;
+
+ 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);
+
+ mutex_lock(&dbc_tty_minors_lock);
+ port->minor = idr_alloc(&dbc_tty_minors, port, 0, 64, GFP_KERNEL);
+ mutex_unlock(&dbc_tty_minors_lock);
+
+ if (port->minor < 0) {
+ ret = port->minor;
+ goto err_idr;
+ }
+
+ 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, port->minor, 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:
+ idr_remove(&dbc_tty_minors, port->minor);
+err_idr:
+ 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, port->minor);
+ xhci_dbc_tty_exit_port(port);
+ port->registered = false;
+
+ mutex_lock(&dbc_tty_minors_lock);
+ idr_remove(&dbc_tty_minors, port->minor);
+ mutex_unlock(&dbc_tty_minors_lock);
+
+ 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 device *dev, void __iomem *base, struct xhci_hcd *xhci)
+{
+ struct xhci_dbc *dbc;
+ struct dbc_port *port;
+ int status;
+
+ if (!dbc_tty_driver)
+ return -ENODEV;
+
+ port = kzalloc(sizeof(*port), GFP_KERNEL);
+ if (!port)
+ return -ENOMEM;
+
+ dbc = xhci_alloc_dbc(dev, base, &dbc_driver);
+
+ if (!dbc) {
+ status = -ENOMEM;
+ goto out2;
+ }
+
+ dbc->priv = port;
+
+ /* get rid of xhci once this is a real driver binding to a device */
+ xhci->dbc = dbc;
+
+ return 0;
+out2:
+ kfree(port);
+
+ 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);
+
+ xhci_dbc_remove(dbc);
+ kfree(port);
+}
+
+int dbc_tty_init(void)
+{
+ int ret;
+
+ idr_init(&dbc_tty_minors);
+
+ dbc_tty_driver = tty_alloc_driver(64, TTY_DRIVER_REAL_RAW |
+ TTY_DRIVER_DYNAMIC_DEV);
+ if (IS_ERR(dbc_tty_driver)) {
+ idr_destroy(&dbc_tty_minors);
+ 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");
+ tty_driver_kref_put(dbc_tty_driver);
+ idr_destroy(&dbc_tty_minors);
+ }
+
+ return ret;
+}
+
+void dbc_tty_exit(void)
+{
+ if (dbc_tty_driver) {
+ tty_unregister_driver(dbc_tty_driver);
+ tty_driver_kref_put(dbc_tty_driver);
+ dbc_tty_driver = NULL;
+ }
+
+ idr_destroy(&dbc_tty_minors);
+}