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@xxxxxxxxxx>
---
drivers/usb/gadget/Kconfig | 6 +
drivers/usb/gadget/function/u_serial.c | 258 ++++++++++++++++++++++++++++++++
2 files changed, 264 insertions(+)
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 33834aa..be5aab9 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -127,6 +127,12 @@ config USB_GADGET_STORAGE_NUM_BUFFERS
a module parameter as well.
If unsure, say 2.
+config U_SERIAL_CONSOLE
+ bool "Serial gadget console support"
+ depends on USB_G_SERIAL
+ help
+ It supports the serial gadget can be used as a console.
+
source "drivers/usb/gadget/udc/Kconfig"
#
diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c
index f7771d8..6af145f 100644
--- a/drivers/usb/gadget/function/u_serial.c
+++ b/drivers/usb/gadget/function/u_serial.c
@@ -27,6 +27,8 @@
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/module.h>
+#include <linux/console.h>
+#include <linux/kthread.h>
#include "u_serial.h"
@@ -79,6 +81,7 @@
*/
#define QUEUE_SIZE 16
#define WRITE_BUF_SIZE 8192 /* TX only */
+#define GS_CONSOLE_BUF_SIZE 8192
/* circular buffer */
struct gs_buf {
@@ -88,6 +91,17 @@ struct gs_buf {
char *buf_put;
};
+/* console info */
+struct gscons_info {
+ struct gs_port *port;
+ struct task_struct *console_thread;
+ struct gs_buf con_buf;
+ /* protect the buf and busy flag */
+ spinlock_t con_lock;
+ int req_busy;
+ struct usb_request *console_req;
+};
+
/*
* The port structure holds info for each port, one for each minor number
* (and thus for each /dev/ node).
@@ -1023,6 +1037,246 @@ static const struct tty_operations gs_tty_ops = {
static struct tty_driver *gs_tty_driver;
+#ifdef CONFIG_U_SERIAL_CONSOLE
+
+static struct gscons_info gscons_info;
+static struct console gserial_cons;
+
+static struct usb_request *gs_request_new(struct usb_ep *ep)
+{
+ struct usb_request *req = usb_ep_alloc_request(ep, GFP_ATOMIC);
+ if (!req)
+ return NULL;
+
+ req->buf = kmalloc(ep->maxpacket, GFP_ATOMIC);
+ if (!req->buf) {
+ usb_ep_free_request(ep, req);
+ return NULL;
+ }
+
+ return req;
+}
+
+static void gs_request_free(struct usb_request *req, struct usb_ep *ep)
+{
+ if (!req)
+ return;
+
+ kfree(req->buf);
+ usb_ep_free_request(ep, req);
+}
+
+static void gs_complete_out(struct usb_ep *ep, struct usb_request *req)
+{
+ struct gscons_info *info = &gscons_info;
+
+ switch (req->status) {
+ default:
+ pr_warn("%s: unexpected %s status %d\n",
+ __func__, ep->name, req->status);
+ case 0:
+ /* normal completion */
+ spin_lock(&info->con_lock);
+ info->req_busy = 0;
+ spin_unlock(&info->con_lock);
+
+ wake_up_process(info->console_thread);
+ break;
+ case -ESHUTDOWN:
+ /* disconnect */
+ pr_vdebug("%s: %s shutdown\n", __func__, ep->name);
+ break;
+ }
+}
+
+static int gs_console_connect(int port_num)
+{
+ struct gscons_info *info = &gscons_info;
+ struct gs_port *port;
+ struct usb_ep *ep;
+
+ if (port_num != gserial_cons.index) {
+ pr_err("%s: port num [%d] is not support console\n",
+ __func__, port_num);
+ return -ENXIO;
+ }
+
+ port = ports[port_num].port;
+ ep = port->port_usb->in;
+ if (!info->console_req) {
+ info->console_req = gs_request_new(ep);
+ if (!info->console_req)
+ return -ENOMEM;
+ info->console_req->complete = gs_complete_out;
+ }
+
+ info->port = port;
+ spin_lock(&info->con_lock);
+ info->req_busy = 0;
+ spin_unlock(&info->con_lock);
+ pr_vdebug("port[%d] console connect!\n", port_num);
+ return 0;
+}
+
+static void gs_console_disconnect(struct usb_ep *ep)
+{
+ struct gscons_info *info = &gscons_info;
+ struct usb_request *req = info->console_req;
+
+ gs_request_free(req, ep);
+ info->console_req = NULL;
+}
+
+static int gs_console_thread(void *data)
+{
+ struct gscons_info *info = &gscons_info;
+ struct gs_port *port;
+ struct usb_request *req;
+ struct usb_ep *ep;
+ int xfer, ret, count, size;
+
+ do {
+ port = info->port;
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (!port || !port->port_usb
+ || !port->port_usb->in || !info->console_req)
+ goto sched;
+
+ req = info->console_req;
+ ep = port->port_usb->in;
+
+ spin_lock_irq(&info->con_lock);
+ count = gs_buf_data_avail(&info->con_buf);
+ size = ep->maxpacket;
+
+ if (count > 0 && !info->req_busy) {
+ set_current_state(TASK_RUNNING);
+ if (count < size)
+ size = count;
+
+ xfer = gs_buf_get(&info->con_buf, req->buf, size);
+ req->length = xfer;
+
+ spin_unlock(&info->con_lock);
+ ret = usb_ep_queue(ep, req, GFP_ATOMIC);
+ spin_lock(&info->con_lock);
+ if (ret < 0)
+ info->req_busy = 0;
+ else
+ info->req_busy = 1;
+
+ spin_unlock_irq(&info->con_lock);
+ } else {
+ spin_unlock_irq(&info->con_lock);
+sched:
+ if (kthread_should_stop()) {
+ set_current_state(TASK_RUNNING);
+ break;
+ }
+ schedule();
+ }
+ } while (1);
+
+ return 0;
+}
+
+static int gs_console_setup(struct console *co, char *options)
+{
+ struct gscons_info *info = &gscons_info;
+ int status;
+
+ info->port = NULL;
+ info->console_req = NULL;
+ info->req_busy = 0;
+ spin_lock_init(&info->con_lock);
+
+ status = gs_buf_alloc(&info->con_buf, GS_CONSOLE_BUF_SIZE);
+ if (status) {
+ pr_err("%s: allocate console buffer failed\n", __func__);
+ return status;
+ }
+
+ info->console_thread = kthread_create(gs_console_thread,
+ co, "gs_console");
+ if (IS_ERR(info->console_thread)) {
+ pr_err("%s: cannot create console thread\n", __func__);
+ gs_buf_free(&info->con_buf);
+ return PTR_ERR(info->console_thread);
+ }
+ wake_up_process(info->console_thread);
+
+ return 0;
+}
+
+static void gs_console_write(struct console *co,
+ const char *buf, unsigned count)
+{
+ struct gscons_info *info = &gscons_info;
+ unsigned long flags;
+
+ spin_lock_irqsave(&info->con_lock, flags);
+ gs_buf_put(&info->con_buf, buf, count);
+ spin_unlock_irqrestore(&info->con_lock, flags);
+
+ wake_up_process(info->console_thread);
+}
+
+static struct tty_driver *gs_console_device(struct console *co, int *index)
+{
+ struct tty_driver **p = (struct tty_driver **)co->data;
+
+ if (!*p)
+ return NULL;
+
+ *index = co->index;
+ return *p;
+}
+
+static struct console gserial_cons = {
+ .name = "ttyGS",
+ .write = gs_console_write,
+ .device = gs_console_device,
+ .setup = gs_console_setup,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+ .data = &gs_tty_driver,
+};
+
+static void gserial_console_init(void)
+{
+ register_console(&gserial_cons);
+}
+
+static void gserial_console_exit(void)
+{
+ struct gscons_info *info = &gscons_info;
+
+ unregister_console(&gserial_cons);
+ kthread_stop(info->console_thread);
+ gs_buf_free(&info->con_buf);
+}
+
+#else
+
+static int gs_console_connect(int port_num)
+{
+ return 0;
+}
+
+static void gs_console_disconnect(struct usb_ep *ep)
+{
+}
+
+static void gserial_console_init(void)
+{
+}
+
+static void gserial_console_exit(void)
+{
+}
+
+#endif
+
static int
gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding)
{
@@ -1096,6 +1350,7 @@ void gserial_free_line(unsigned char port_num)
gserial_free_port(port);
tty_unregister_device(gs_tty_driver, port_num);
+ gserial_console_exit();
}
EXPORT_SYMBOL_GPL(gserial_free_line);
@@ -1138,6 +1393,7 @@ int gserial_alloc_line(unsigned char *line_num)
goto err;
}
*line_num = port_num;
+ gserial_console_init();
err:
return ret;
}
@@ -1219,6 +1475,7 @@ int gserial_connect(struct gserial *gser, u8 port_num)
gser->disconnect(gser);
}
+ status = gs_console_connect(port_num);
spin_unlock_irqrestore(&port->port_lock, flags);
return status;
@@ -1277,6 +1534,7 @@ void gserial_disconnect(struct gserial *gser)
port->read_allocated = port->read_started =
port->write_allocated = port->write_started = 0;
+ gs_console_disconnect(gser->in);
spin_unlock_irqrestore(&port->port_lock, flags);
}
EXPORT_SYMBOL_GPL(gserial_disconnect);
--
1.7.9.5
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