usb: gadget: Add the console support for usb-to-serial port
It dose not work when we want to use the usb-to-serial port based on one usb gadget as a console. Thus this patch adds the console initialization to support this request. To avoid the re-entrance when transferring data with usb endpoint, it introduces a kthread to do the IO transmission. Signed-off-by: Baolin Wang <baolin.wang@linaro.org> Signed-off-by: Felipe Balbi <balbi@ti.com>hifive-unleashed-5.1
Baolin Wang
Felipe Balbi
parent
be99c84300
commit
a5beaaf394
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@ -127,6 +127,12 @@ config USB_GADGET_STORAGE_NUM_BUFFERS
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a module parameter as well.
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If unsure, say 2.
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config U_SERIAL_CONSOLE
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bool "Serial gadget console support"
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depends on USB_G_SERIAL
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help
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It supports the serial gadget can be used as a console.
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source "drivers/usb/gadget/udc/Kconfig"
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#
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@ -27,6 +27,8 @@
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#include <linux/slab.h>
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#include <linux/export.h>
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#include <linux/module.h>
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#include <linux/console.h>
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#include <linux/kthread.h>
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#include "u_serial.h"
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@ -79,6 +81,7 @@
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*/
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#define QUEUE_SIZE 16
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#define WRITE_BUF_SIZE 8192 /* TX only */
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#define GS_CONSOLE_BUF_SIZE 8192
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/* circular buffer */
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struct gs_buf {
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@ -88,6 +91,17 @@ struct gs_buf {
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char *buf_put;
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};
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/* console info */
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struct gscons_info {
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struct gs_port *port;
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struct task_struct *console_thread;
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struct gs_buf con_buf;
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/* protect the buf and busy flag */
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spinlock_t con_lock;
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int req_busy;
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struct usb_request *console_req;
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};
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/*
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* The port structure holds info for each port, one for each minor number
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* (and thus for each /dev/ node).
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@ -1023,6 +1037,246 @@ static const struct tty_operations gs_tty_ops = {
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static struct tty_driver *gs_tty_driver;
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#ifdef CONFIG_U_SERIAL_CONSOLE
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static struct gscons_info gscons_info;
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static struct console gserial_cons;
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static struct usb_request *gs_request_new(struct usb_ep *ep)
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{
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struct usb_request *req = usb_ep_alloc_request(ep, GFP_ATOMIC);
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if (!req)
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return NULL;
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req->buf = kmalloc(ep->maxpacket, GFP_ATOMIC);
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if (!req->buf) {
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usb_ep_free_request(ep, req);
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return NULL;
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}
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return req;
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}
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static void gs_request_free(struct usb_request *req, struct usb_ep *ep)
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{
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if (!req)
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return;
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kfree(req->buf);
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usb_ep_free_request(ep, req);
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}
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static void gs_complete_out(struct usb_ep *ep, struct usb_request *req)
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{
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struct gscons_info *info = &gscons_info;
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switch (req->status) {
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default:
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pr_warn("%s: unexpected %s status %d\n",
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__func__, ep->name, req->status);
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case 0:
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/* normal completion */
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spin_lock(&info->con_lock);
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info->req_busy = 0;
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spin_unlock(&info->con_lock);
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wake_up_process(info->console_thread);
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break;
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case -ESHUTDOWN:
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/* disconnect */
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pr_vdebug("%s: %s shutdown\n", __func__, ep->name);
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break;
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}
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}
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static int gs_console_connect(int port_num)
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{
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struct gscons_info *info = &gscons_info;
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struct gs_port *port;
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struct usb_ep *ep;
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if (port_num != gserial_cons.index) {
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pr_err("%s: port num [%d] is not support console\n",
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__func__, port_num);
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return -ENXIO;
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}
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port = ports[port_num].port;
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ep = port->port_usb->in;
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if (!info->console_req) {
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info->console_req = gs_request_new(ep);
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if (!info->console_req)
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return -ENOMEM;
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info->console_req->complete = gs_complete_out;
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}
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info->port = port;
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spin_lock(&info->con_lock);
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info->req_busy = 0;
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spin_unlock(&info->con_lock);
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pr_vdebug("port[%d] console connect!\n", port_num);
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return 0;
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}
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static void gs_console_disconnect(struct usb_ep *ep)
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{
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struct gscons_info *info = &gscons_info;
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struct usb_request *req = info->console_req;
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gs_request_free(req, ep);
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info->console_req = NULL;
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}
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static int gs_console_thread(void *data)
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{
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struct gscons_info *info = &gscons_info;
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struct gs_port *port;
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struct usb_request *req;
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struct usb_ep *ep;
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int xfer, ret, count, size;
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do {
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port = info->port;
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set_current_state(TASK_INTERRUPTIBLE);
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if (!port || !port->port_usb
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|| !port->port_usb->in || !info->console_req)
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goto sched;
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req = info->console_req;
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ep = port->port_usb->in;
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spin_lock_irq(&info->con_lock);
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count = gs_buf_data_avail(&info->con_buf);
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size = ep->maxpacket;
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if (count > 0 && !info->req_busy) {
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set_current_state(TASK_RUNNING);
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if (count < size)
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size = count;
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xfer = gs_buf_get(&info->con_buf, req->buf, size);
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req->length = xfer;
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spin_unlock(&info->con_lock);
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ret = usb_ep_queue(ep, req, GFP_ATOMIC);
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spin_lock(&info->con_lock);
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if (ret < 0)
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info->req_busy = 0;
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else
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info->req_busy = 1;
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spin_unlock_irq(&info->con_lock);
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} else {
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spin_unlock_irq(&info->con_lock);
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sched:
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if (kthread_should_stop()) {
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set_current_state(TASK_RUNNING);
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break;
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}
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schedule();
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}
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} while (1);
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return 0;
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}
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static int gs_console_setup(struct console *co, char *options)
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{
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struct gscons_info *info = &gscons_info;
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int status;
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info->port = NULL;
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info->console_req = NULL;
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info->req_busy = 0;
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spin_lock_init(&info->con_lock);
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status = gs_buf_alloc(&info->con_buf, GS_CONSOLE_BUF_SIZE);
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if (status) {
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pr_err("%s: allocate console buffer failed\n", __func__);
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return status;
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}
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info->console_thread = kthread_create(gs_console_thread,
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co, "gs_console");
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if (IS_ERR(info->console_thread)) {
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pr_err("%s: cannot create console thread\n", __func__);
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gs_buf_free(&info->con_buf);
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return PTR_ERR(info->console_thread);
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}
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wake_up_process(info->console_thread);
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return 0;
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}
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static void gs_console_write(struct console *co,
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const char *buf, unsigned count)
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{
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struct gscons_info *info = &gscons_info;
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unsigned long flags;
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spin_lock_irqsave(&info->con_lock, flags);
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gs_buf_put(&info->con_buf, buf, count);
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spin_unlock_irqrestore(&info->con_lock, flags);
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wake_up_process(info->console_thread);
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}
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static struct tty_driver *gs_console_device(struct console *co, int *index)
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{
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struct tty_driver **p = (struct tty_driver **)co->data;
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if (!*p)
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return NULL;
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*index = co->index;
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return *p;
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}
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static struct console gserial_cons = {
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.name = "ttyGS",
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.write = gs_console_write,
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.device = gs_console_device,
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.setup = gs_console_setup,
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.flags = CON_PRINTBUFFER,
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.index = -1,
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.data = &gs_tty_driver,
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};
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static void gserial_console_init(void)
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{
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register_console(&gserial_cons);
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}
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static void gserial_console_exit(void)
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{
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struct gscons_info *info = &gscons_info;
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unregister_console(&gserial_cons);
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kthread_stop(info->console_thread);
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gs_buf_free(&info->con_buf);
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}
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#else
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static int gs_console_connect(int port_num)
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{
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return 0;
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}
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static void gs_console_disconnect(struct usb_ep *ep)
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{
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}
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static void gserial_console_init(void)
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{
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}
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static void gserial_console_exit(void)
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{
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}
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#endif
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static int
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gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding)
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{
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@ -1096,6 +1350,7 @@ void gserial_free_line(unsigned char port_num)
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gserial_free_port(port);
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tty_unregister_device(gs_tty_driver, port_num);
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gserial_console_exit();
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}
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EXPORT_SYMBOL_GPL(gserial_free_line);
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@ -1138,6 +1393,7 @@ int gserial_alloc_line(unsigned char *line_num)
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goto err;
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}
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*line_num = port_num;
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gserial_console_init();
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err:
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return ret;
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}
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@ -1219,6 +1475,7 @@ int gserial_connect(struct gserial *gser, u8 port_num)
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gser->disconnect(gser);
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}
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status = gs_console_connect(port_num);
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spin_unlock_irqrestore(&port->port_lock, flags);
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return status;
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@ -1277,6 +1534,7 @@ void gserial_disconnect(struct gserial *gser)
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port->read_allocated = port->read_started =
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port->write_allocated = port->write_started = 0;
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gs_console_disconnect(gser->in);
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spin_unlock_irqrestore(&port->port_lock, flags);
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}
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EXPORT_SYMBOL_GPL(gserial_disconnect);
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