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* [PATCH v2 0/4] usb: gadget: serial: add supend resume support
@ 2020-04-23 11:55 Fabrice Gasnier
  2020-04-23 11:55 ` [PATCH v2 1/4] usb: dwc2: gadget: move gadget resume after the core is in L0 state Fabrice Gasnier
                   ` (3 more replies)
  0 siblings, 4 replies; 6+ messages in thread
From: Fabrice Gasnier @ 2020-04-23 11:55 UTC (permalink / raw)
  To: hminas, gregkh, balbi
  Cc: linux-usb, linux-kernel, linux-stm32, amelie.delaunay, fabrice.gasnier

This series handles an issue seen when doing basic testing using ACM or SERIAL
gadget functions like in [1], and using the DWC2 gadget driver. It occurs when
the HOST has suspended the bus before testing, in this order:
- On the device:
  cat /dev/ttyGS<Y>
  Dmesg error log is seen on device side:
  configfs-gadget gadget: acm ttyGS0 can't notify serial state, -11
- On the host:
  echo test > /dev/ttyACM<X>
  The bus resumes, but the serial link isn't functional.

So, implement suspend/resume callbacks in gadget serial drivers to handle this.
There is a precursor patch in DWC2 to enable submitting usb requests from the
gadget resume routine, once in L0 state.

[1] https://www.kernel.org/doc/html/latest/usb/gadget-testing.html#testing-the-acm-function

Changes in v2:
- update dwc2 with Minas suggestions

Fabrice Gasnier (4):
  usb: dwc2: gadget: move gadget resume after the core is in L0 state
  usb: gadget: u_serial: add suspend resume callbacks
  usb: gadget: f_serial: add suspend resume callbacks
  usb: gadget: f_acm: add suspend resume callbacks

 drivers/usb/dwc2/core_intr.c           |  7 +++--
 drivers/usb/gadget/function/f_acm.c    | 16 ++++++++++
 drivers/usb/gadget/function/f_serial.c | 16 ++++++++++
 drivers/usb/gadget/function/u_serial.c | 57 +++++++++++++++++++++++++++++-----
 drivers/usb/gadget/function/u_serial.h |  2 ++
 5 files changed, 88 insertions(+), 10 deletions(-)

-- 
2.7.4


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH v2 1/4] usb: dwc2: gadget: move gadget resume after the core is in L0 state
  2020-04-23 11:55 [PATCH v2 0/4] usb: gadget: serial: add supend resume support Fabrice Gasnier
@ 2020-04-23 11:55 ` Fabrice Gasnier
  2020-04-23 13:06   ` Minas Harutyunyan
  2020-04-23 11:55 ` [PATCH v2 2/4] usb: gadget: u_serial: add suspend resume callbacks Fabrice Gasnier
                   ` (2 subsequent siblings)
  3 siblings, 1 reply; 6+ messages in thread
From: Fabrice Gasnier @ 2020-04-23 11:55 UTC (permalink / raw)
  To: hminas, gregkh, balbi
  Cc: linux-usb, linux-kernel, linux-stm32, amelie.delaunay, fabrice.gasnier

When the remote wakeup interrupt is triggered, lx_state is resumed from L2
to L0 state. But when the gadget resume is called, lx_state is still L2.
This prevents the resume callback to queue any request. Any attempt
to queue a request from resume callback will result in:
- "submit request only in active state" debug message to be issued
- dwc2_hsotg_ep_queue() returns -EAGAIN

Call the gadget resume routine after the core is in L0 state.

Fixes: f81f46e1f530 ("usb: dwc2: implement hibernation during bus suspend/resume")

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
Changes in v2:
- Minor update to follow Minas suggestions
---
 drivers/usb/dwc2/core_intr.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c
index 876ff31..55f1d14 100644
--- a/drivers/usb/dwc2/core_intr.c
+++ b/drivers/usb/dwc2/core_intr.c
@@ -416,10 +416,13 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
 			if (ret && (ret != -ENOTSUPP))
 				dev_err(hsotg->dev, "exit power_down failed\n");
 
+			/* Change to L0 state */
+			hsotg->lx_state = DWC2_L0;
 			call_gadget(hsotg, resume);
+		} else {
+			/* Change to L0 state */
+			hsotg->lx_state = DWC2_L0;
 		}
-		/* Change to L0 state */
-		hsotg->lx_state = DWC2_L0;
 	} else {
 		if (hsotg->params.power_down)
 			return;
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH v2 2/4] usb: gadget: u_serial: add suspend resume callbacks
  2020-04-23 11:55 [PATCH v2 0/4] usb: gadget: serial: add supend resume support Fabrice Gasnier
  2020-04-23 11:55 ` [PATCH v2 1/4] usb: dwc2: gadget: move gadget resume after the core is in L0 state Fabrice Gasnier
@ 2020-04-23 11:55 ` Fabrice Gasnier
  2020-04-23 11:55 ` [PATCH v2 3/4] usb: gadget: f_serial: " Fabrice Gasnier
  2020-04-23 11:55 ` [PATCH v2 4/4] usb: gadget: f_acm: " Fabrice Gasnier
  3 siblings, 0 replies; 6+ messages in thread
From: Fabrice Gasnier @ 2020-04-23 11:55 UTC (permalink / raw)
  To: hminas, gregkh, balbi
  Cc: linux-usb, linux-kernel, linux-stm32, amelie.delaunay, fabrice.gasnier

Add suspend resume callbacks to handle the case seen when the bus is
suspended by the HOST, and the device opens the port (cat /dev/ttyGS0).

Gadget controller (like DWC2) doesn't accept usb requests to be queued in
this case (when in L2 state), from the gs_open() call. Error log is printed
- configfs-gadget gadget: acm ttyGS0 can't notify serial state, -11
If the HOST resumes (opens) the bus, the port still isn't functional.

Use suspend/resume callbacks to monitor the gadget suspended state by using
'suspended' flag. In case the port gets opened (cat /dev/ttyGS0), the I/O
stream will be delayed until the bus gets resumed by the HOST.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
 drivers/usb/gadget/function/u_serial.c | 57 +++++++++++++++++++++++++++++-----
 drivers/usb/gadget/function/u_serial.h |  2 ++
 2 files changed, 51 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c
index 8167d37..3cfc6e2 100644
--- a/drivers/usb/gadget/function/u_serial.c
+++ b/drivers/usb/gadget/function/u_serial.c
@@ -120,6 +120,8 @@ struct gs_port {
 	wait_queue_head_t	drain_wait;	/* wait while writes drain */
 	bool                    write_busy;
 	wait_queue_head_t	close_wait;
+	bool			suspended;	/* port suspended */
+	bool			start_delayed;	/* delay start when suspended */
 
 	/* REVISIT this state ... */
 	struct usb_cdc_line_coding port_line_coding;	/* 8-N-1 etc */
@@ -630,13 +632,19 @@ static int gs_open(struct tty_struct *tty, struct file *file)
 
 	/* if connected, start the I/O stream */
 	if (port->port_usb) {
-		struct gserial	*gser = port->port_usb;
-
-		pr_debug("gs_open: start ttyGS%d\n", port->port_num);
-		gs_start_io(port);
-
-		if (gser->connect)
-			gser->connect(gser);
+		/* if port is suspended, wait resume to start I/0 stream */
+		if (!port->suspended) {
+			struct gserial	*gser = port->port_usb;
+
+			pr_debug("gs_open: start ttyGS%d\n", port->port_num);
+			gs_start_io(port);
+
+			if (gser->connect)
+				gser->connect(gser);
+		} else {
+			pr_debug("delay start of ttyGS%d\n", port->port_num);
+			port->start_delayed = true;
+		}
 	}
 
 	pr_debug("gs_open: ttyGS%d (%p,%p)\n", port->port_num, tty, file);
@@ -680,7 +688,7 @@ static void gs_close(struct tty_struct *tty, struct file *file)
 	pr_debug("gs_close: ttyGS%d (%p,%p) ...\n", port->port_num, tty, file);
 
 	gser = port->port_usb;
-	if (gser && gser->disconnect)
+	if (gser && !port->suspended && gser->disconnect)
 		gser->disconnect(gser);
 
 	/* wait for circular write buffer to drain, disconnect, or at
@@ -708,6 +716,7 @@ static void gs_close(struct tty_struct *tty, struct file *file)
 	else
 		kfifo_reset(&port->port_write_buf);
 
+	port->start_delayed = false;
 	port->port.count = 0;
 	port->port.tty = NULL;
 
@@ -1403,6 +1412,38 @@ void gserial_disconnect(struct gserial *gser)
 }
 EXPORT_SYMBOL_GPL(gserial_disconnect);
 
+void gserial_suspend(struct gserial *gser)
+{
+	struct gs_port	*port = gser->ioport;
+	unsigned long	flags;
+
+	spin_lock_irqsave(&port->port_lock, flags);
+	port->suspended = true;
+	spin_unlock_irqrestore(&port->port_lock, flags);
+}
+EXPORT_SYMBOL_GPL(gserial_suspend);
+
+void gserial_resume(struct gserial *gser)
+{
+	struct gs_port *port = gser->ioport;
+	unsigned long	flags;
+
+	spin_lock_irqsave(&port->port_lock, flags);
+	port->suspended = false;
+	if (!port->start_delayed) {
+		spin_unlock_irqrestore(&port->port_lock, flags);
+		return;
+	}
+
+	pr_debug("delayed start ttyGS%d\n", port->port_num);
+	gs_start_io(port);
+	if (gser->connect)
+		gser->connect(gser);
+	port->start_delayed = false;
+	spin_unlock_irqrestore(&port->port_lock, flags);
+}
+EXPORT_SYMBOL_GPL(gserial_resume);
+
 static int userial_init(void)
 {
 	unsigned			i;
diff --git a/drivers/usb/gadget/function/u_serial.h b/drivers/usb/gadget/function/u_serial.h
index e5b08ab..009a959 100644
--- a/drivers/usb/gadget/function/u_serial.h
+++ b/drivers/usb/gadget/function/u_serial.h
@@ -68,6 +68,8 @@ ssize_t gserial_get_console(unsigned char port_num, char *page);
 /* connect/disconnect is handled by individual functions */
 int gserial_connect(struct gserial *, u8 port_num);
 void gserial_disconnect(struct gserial *);
+void gserial_suspend(struct gserial *p);
+void gserial_resume(struct gserial *p);
 
 /* functions are bound to configurations by a config or gadget driver */
 int gser_bind_config(struct usb_configuration *c, u8 port_num);
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH v2 3/4] usb: gadget: f_serial: add suspend resume callbacks
  2020-04-23 11:55 [PATCH v2 0/4] usb: gadget: serial: add supend resume support Fabrice Gasnier
  2020-04-23 11:55 ` [PATCH v2 1/4] usb: dwc2: gadget: move gadget resume after the core is in L0 state Fabrice Gasnier
  2020-04-23 11:55 ` [PATCH v2 2/4] usb: gadget: u_serial: add suspend resume callbacks Fabrice Gasnier
@ 2020-04-23 11:55 ` Fabrice Gasnier
  2020-04-23 11:55 ` [PATCH v2 4/4] usb: gadget: f_acm: " Fabrice Gasnier
  3 siblings, 0 replies; 6+ messages in thread
From: Fabrice Gasnier @ 2020-04-23 11:55 UTC (permalink / raw)
  To: hminas, gregkh, balbi
  Cc: linux-usb, linux-kernel, linux-stm32, amelie.delaunay, fabrice.gasnier

Add suspend resume callbacks to notify u_serial of the bus suspend/resume
state.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
 drivers/usb/gadget/function/f_serial.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/usb/gadget/function/f_serial.c b/drivers/usb/gadget/function/f_serial.c
index 1406255..e627138 100644
--- a/drivers/usb/gadget/function/f_serial.c
+++ b/drivers/usb/gadget/function/f_serial.c
@@ -348,6 +348,20 @@ static void gser_unbind(struct usb_configuration *c, struct usb_function *f)
 	usb_free_all_descriptors(f);
 }
 
+static void gser_resume(struct usb_function *f)
+{
+	struct f_gser *gser = func_to_gser(f);
+
+	gserial_resume(&gser->port);
+}
+
+static void gser_suspend(struct usb_function *f)
+{
+	struct f_gser *gser = func_to_gser(f);
+
+	gserial_suspend(&gser->port);
+}
+
 static struct usb_function *gser_alloc(struct usb_function_instance *fi)
 {
 	struct f_gser	*gser;
@@ -369,6 +383,8 @@ static struct usb_function *gser_alloc(struct usb_function_instance *fi)
 	gser->port.func.set_alt = gser_set_alt;
 	gser->port.func.disable = gser_disable;
 	gser->port.func.free_func = gser_free;
+	gser->port.func.resume = gser_resume;
+	gser->port.func.suspend = gser_suspend;
 
 	return &gser->port.func;
 }
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH v2 4/4] usb: gadget: f_acm: add suspend resume callbacks
  2020-04-23 11:55 [PATCH v2 0/4] usb: gadget: serial: add supend resume support Fabrice Gasnier
                   ` (2 preceding siblings ...)
  2020-04-23 11:55 ` [PATCH v2 3/4] usb: gadget: f_serial: " Fabrice Gasnier
@ 2020-04-23 11:55 ` Fabrice Gasnier
  3 siblings, 0 replies; 6+ messages in thread
From: Fabrice Gasnier @ 2020-04-23 11:55 UTC (permalink / raw)
  To: hminas, gregkh, balbi
  Cc: linux-usb, linux-kernel, linux-stm32, amelie.delaunay, fabrice.gasnier

Add suspend resume callbacks to notify u_serial of the bus suspend/resume
state.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
---
 drivers/usb/gadget/function/f_acm.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/usb/gadget/function/f_acm.c b/drivers/usb/gadget/function/f_acm.c
index 7c152c2..200596e 100644
--- a/drivers/usb/gadget/function/f_acm.c
+++ b/drivers/usb/gadget/function/f_acm.c
@@ -723,6 +723,20 @@ static void acm_free_func(struct usb_function *f)
 	kfree(acm);
 }
 
+static void acm_resume(struct usb_function *f)
+{
+	struct f_acm *acm = func_to_acm(f);
+
+	gserial_resume(&acm->port);
+}
+
+static void acm_suspend(struct usb_function *f)
+{
+	struct f_acm *acm = func_to_acm(f);
+
+	gserial_suspend(&acm->port);
+}
+
 static struct usb_function *acm_alloc_func(struct usb_function_instance *fi)
 {
 	struct f_serial_opts *opts;
@@ -750,6 +764,8 @@ static struct usb_function *acm_alloc_func(struct usb_function_instance *fi)
 	acm->port_num = opts->port_num;
 	acm->port.func.unbind = acm_unbind;
 	acm->port.func.free_func = acm_free_func;
+	acm->port.func.resume = acm_resume;
+	acm->port.func.suspend = acm_suspend;
 
 	return &acm->port.func;
 }
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH v2 1/4] usb: dwc2: gadget: move gadget resume after the core is in L0 state
  2020-04-23 11:55 ` [PATCH v2 1/4] usb: dwc2: gadget: move gadget resume after the core is in L0 state Fabrice Gasnier
@ 2020-04-23 13:06   ` Minas Harutyunyan
  0 siblings, 0 replies; 6+ messages in thread
From: Minas Harutyunyan @ 2020-04-23 13:06 UTC (permalink / raw)
  To: Fabrice Gasnier, gregkh, balbi
  Cc: linux-usb, linux-kernel, linux-stm32, amelie.delaunay



On 4/23/2020 3:55 PM, Fabrice Gasnier wrote:
> When the remote wakeup interrupt is triggered, lx_state is resumed from L2
> to L0 state. But when the gadget resume is called, lx_state is still L2.
> This prevents the resume callback to queue any request. Any attempt
> to queue a request from resume callback will result in:
> - "submit request only in active state" debug message to be issued
> - dwc2_hsotg_ep_queue() returns -EAGAIN
> 
> Call the gadget resume routine after the core is in L0 state.
> 
> Fixes: f81f46e1f530 ("usb: dwc2: implement hibernation during bus suspend/resume")
> 
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Minas Harutyunyan <hminas@synopsys.com>

> ---
> Changes in v2:
> - Minor update to follow Minas suggestions
> ---
>   drivers/usb/dwc2/core_intr.c | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c
> index 876ff31..55f1d14 100644
> --- a/drivers/usb/dwc2/core_intr.c
> +++ b/drivers/usb/dwc2/core_intr.c
> @@ -416,10 +416,13 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
>   			if (ret && (ret != -ENOTSUPP))
>   				dev_err(hsotg->dev, "exit power_down failed\n");
>   
> +			/* Change to L0 state */
> +			hsotg->lx_state = DWC2_L0;
>   			call_gadget(hsotg, resume);
> +		} else {
> +			/* Change to L0 state */
> +			hsotg->lx_state = DWC2_L0;
>   		}
> -		/* Change to L0 state */
> -		hsotg->lx_state = DWC2_L0;
>   	} else {
>   		if (hsotg->params.power_down)
>   			return;
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2020-04-23 13:06 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-04-23 11:55 [PATCH v2 0/4] usb: gadget: serial: add supend resume support Fabrice Gasnier
2020-04-23 11:55 ` [PATCH v2 1/4] usb: dwc2: gadget: move gadget resume after the core is in L0 state Fabrice Gasnier
2020-04-23 13:06   ` Minas Harutyunyan
2020-04-23 11:55 ` [PATCH v2 2/4] usb: gadget: u_serial: add suspend resume callbacks Fabrice Gasnier
2020-04-23 11:55 ` [PATCH v2 3/4] usb: gadget: f_serial: " Fabrice Gasnier
2020-04-23 11:55 ` [PATCH v2 4/4] usb: gadget: f_acm: " Fabrice Gasnier

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