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