[PATCH 1/2] USB: musb: add two states to handle vbus error

[PATCH 1/2] USB: musb: add two states to handle vbus error

[Wang Hui]

When the MUSB is configured as host mode or OTG mode, the xceiv->state
will be set to OTG_STATE_A_IDLE or OTG_STATE_B_IDLE unconditionally
during init process. These init states can change to other
states When the MUSB module detects id pin change, devices connect or
disconnect.
But on some platforms(omap2, omap3), the id pin change
can't raise IRQ request to the MUSB module, so on these platforms,
the init xceiv->state will be A_IDLE or B_IDLE. Under this condition,
when we want the MUSB to act as a host and hotplug a usb device in
mini-B side of the cable, the MUSB will have a possibility to suffer
power underrun under A_IDLE or B_IDLE state, So here adding these
two states under which we can handle VBUSERROR IRQ.

Signed-off-by: Wang Hui <Hui.Wang@windriver.com>
---
 drivers/usb/musb/musb_core.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index b4bbf8f..655413c 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -516,6 +516,8 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
 			 * another reset is due (at least for high speed,
 			 * to redo the chirp etc), it might work OK...
 			 */
+		case OTG_STATE_A_IDLE:
+		case OTG_STATE_B_IDLE:
 		case OTG_STATE_A_WAIT_BCON:
 		case OTG_STATE_A_WAIT_VRISE:
 			if (musb->vbuserr_retry) {
-- 
1.5.6.5

[PATCH 2/2] USB: musb: omap2430: add mode change from A to B

[Wang Hui]

On omap2/3 series platforms, the musb can't raise id pin change
detection interrupt, so we must change otg mode through sysfs
interface manually. Currently when the musb is in B mode, if we
want musb to be changed to A mode, we should plug a mini-A cable
and then execute echo host > /sys/devices/platform/musb_hdrc/mode.
But if the musb is in A mode, we can't change it to B mode through
this method.
To solve this problem, add a process for sending end session request.
This process works like this, if the musb is in A mode, it will send
an end session request first, then it will follow original routine:
start a new session, during this session, it will identify whether
A or B is plugging in the socket,  then it will init controller to A
or B mode according to its identification.

Usage: change cable as you desired,
       change musb mode by #>echo host[peripheral] > /sys/devices/\
       platform/musb_hdrc/mode,
       then you will get required musb mode.

Signed-off-by: Wang Hui <Hui.Wang-CWA4WttNNZF54TAoqtyWWQ@public.gmane.org>
---
 drivers/usb/musb/omap2430.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/musb/omap2430.c b/drivers/usb/musb/omap2430.c
index 3fe1686..b02897e 100644
--- a/drivers/usb/musb/omap2430.c
+++ b/drivers/usb/musb/omap2430.c
@@ -194,6 +194,11 @@ int musb_platform_set_mode(struct musb *musb, u8 musb_mode)
 {
 	u8	devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
 
+	if ((devctl & MUSB_DEVCTL_BDEVICE) == 0x0) {
+		devctl &= ~MUSB_DEVCTL_SESSION;
+		musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);
+	}
+
 	devctl |= MUSB_DEVCTL_SESSION;
 	musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);
 
-- 
1.5.6.5

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Re: [PATCH 2/2] USB: musb: omap2430: add mode change from A to B

[Sergei Shtylyov]

Hello.

Wang Hui wrote:

> On omap2/3 series platforms, the musb can't raise id pin change
> detection interrupt, so we must change otg mode through sysfs
> interface manually. Currently when the musb is in B mode, if we
> want musb to be changed to A mode, we should plug a mini-A cable
> and then execute echo host > /sys/devices/platform/musb_hdrc/mode.
> But if the musb is in A mode, we can't change it to B mode through
> this method.
> To solve this problem, add a process for sending end session request.
> This process works like this, if the musb is in A mode, it will send
> an end session request first, then it will follow original routine:
> start a new session, during this session, it will identify whether
> A or B is plugging in the socket,  then it will init controller to A
> or B mode according to its identification.
>
> Usage: change cable as you desired,
>        change musb mode by #>echo host[peripheral] > /sys/devices/\
>        platform/musb_hdrc/mode,
>        then you will get required musb mode.
>
> Signed-off-by: Wang Hui <Hui.Wang-CWA4WttNNZF54TAoqtyWWQ@public.gmane.org>
> ---
>  drivers/usb/musb/omap2430.c |    5 +++++
>  1 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/usb/musb/omap2430.c b/drivers/usb/musb/omap2430.c
> index 3fe1686..b02897e 100644
> --- a/drivers/usb/musb/omap2430.c
> +++ b/drivers/usb/musb/omap2430.c
> @@ -194,6 +194,11 @@ int musb_platform_set_mode(struct musb *musb, u8 musb_mode)
>  {
>  	u8	devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
>  
> +	if ((devctl & MUSB_DEVCTL_BDEVICE) == 0x0) {
> +		devctl &= ~MUSB_DEVCTL_SESSION;
> +		musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);
> +	}
> +
>  	devctl |= MUSB_DEVCTL_SESSION;
>  	musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);
>   

   The whole musb_platform_set_mode() seems to be implemented 
incorrectly on OMAPs -- it shouldn't touch the DevCtl.Session bit. This 
function should control the ID pin override instead -- if the controller 
supports it. SRP must be initiated thru other means, i.e. 'srp' file in 
sysfs.

WBR, Sergei

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Re: [PATCH 2/2] USB: musb: omap2430: add mode change from A to B

[Felipe Balbi]

On Mon, Mar 15, 2010 at 02:22:38PM +0300, Sergei Shtylyov wrote:
>    The whole musb_platform_set_mode() seems to be implemented 
> incorrectly on OMAPs -- it shouldn't touch the DevCtl.Session bit. This 

correct. It should be changing the id pin rules just like in tusb6010.c

> function should control the ID pin override instead -- if the controller 
> supports it. SRP must be initiated thru other means, i.e. 'srp' file in 
> sysfs.

via musb_gadget_wakeup()

-- 
balbi

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Re: [PATCH 2/2] USB: musb: omap2430: add mode change from A to B

[wanghui]

Felipe Balbi wrote:
> On Mon, Mar 15, 2010 at 02:22:38PM +0300, Sergei Shtylyov wrote:
>   
>>    The whole musb_platform_set_mode() seems to be implemented 
>> incorrectly on OMAPs -- it shouldn't touch the DevCtl.Session bit. This 
>>     
>
> correct. It should be changing the id pin rules just like in tusb6010.c
>
>   
>> function should control the ID pin override instead -- if the controller 
>> supports it. SRP must be initiated thru other means, i.e. 'srp' file in 
>> sysfs.
>>     
>
> via musb_gadget_wakeup()
>
>   
Thank you for your comments.
It is right that in this function, we should only change id pin rules 
according to user's choice, and
leave mode transition to the ISR.
But things are different on omap platforms, because the id pin change 
can't trigger ISR.
For example, when we configure the kernel, we choose musb working as OTG 
mode. Then we plug a mini-A or a mini-B cable in the socket, after
that we execute insmod g_ether.ko, at this time, the musb will 
initialize to A or B working mode. how to change
its working mode from A to B or B to A at this time? I think if the 
platform can support id detection ISR, your method
is workable. But on omap platforms, we must change cable(id pin state) 
manually first, then let the controller to re-initiate a session forcibly.
This action (clear/set session bit) don't 100% equal to send a SRP, and 
i don't really want to send a SRP too.

If without this function for omap platforms, we can change musb working 
mode only through rebooting kernel or rmmod/insmod gadget driver module.

Re: [PATCH 2/2] USB: musb: omap2430: add mode change from A to B

[Felipe Balbi]

Hi,

On Tue, Mar 16, 2010 at 06:13:50PM +0800, wanghui wrote:
> Thank you for your comments.
> It is right that in this function, we should only change id pin rules 
> according to user's choice, and
> leave mode transition to the ISR.
> But things are different on omap platforms, because the id pin change 
> can't trigger ISR.
> For example, when we configure the kernel, we choose musb working as OTG 
> mode. Then we plug a mini-A or a mini-B cable in the socket, after
> that we execute insmod g_ether.ko, at this time, the musb will 
> initialize to A or B working mode. how to change
> its working mode from A to B or B to A at this time? I think if the 
> platform can support id detection ISR, your method
> is workable. But on omap platforms, we must change cable(id pin state) 
> manually first, then let the controller to re-initiate a session forcibly.
> This action (clear/set session bit) don't 100% equal to send a SRP, and 
> i don't really want to send a SRP too.
> 
> If without this function for omap platforms, we can change musb working 
> mode only through rebooting kernel or rmmod/insmod gadget driver module.

it should be doable with the transceiver ISR. When you get id pin irq,
you should put the transceiver into A_IDLE state and power up vbus. MUSB
changes to host mode automatically.

-- 
balbi
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Re: [PATCH 2/2] USB: musb: omap2430: add mode change from A to B

[Kan-Ru Chen]

--text follows this line--
Hi,

On Mon, 15 Mar 2010 18:23:42 +0800, Wang Hui <Hui.Wang@windriver.com> wrote:
> On omap2/3 series platforms, the musb can't raise id pin change
> detection interrupt, so we must change otg mode through sysfs
> interface manually. Currently when the musb is in B mode, if we
> want musb to be changed to A mode, we should plug a mini-A cable
> and then execute echo host > /sys/devices/platform/musb_hdrc/mode.
> But if the musb is in A mode, we can't change it to B mode through
> this method.
> To solve this problem, add a process for sending end session request.
> This process works like this, if the musb is in A mode, it will send
> an end session request first, then it will follow original routine:
> start a new session, during this session, it will identify whether
> A or B is plugging in the socket,  then it will init controller to A
> or B mode according to its identification.

Just curious about how to do this in a more automatic way.

I think setup a daemon to monitor the musb_hdrc mode and try to alter
it's state via sysfs interface will work, but it may be error prone and
not always desirable solution.

Can we query the id pin state periodically in the kernel and change to
corresponding role?

Regards,
Kanru 
> 
> Usage: change cable as you desired,
>        change musb mode by #>echo host[peripheral] > /sys/devices/\
>        platform/musb_hdrc/mode,
>        then you will get required musb mode.
> 
> Signed-off-by: Wang Hui <Hui.Wang@windriver.com>
> ---
>  drivers/usb/musb/omap2430.c |    5 +++++
>  1 files changed, 5 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/usb/musb/omap2430.c b/drivers/usb/musb/omap2430.c
> index 3fe1686..b02897e 100644
> --- a/drivers/usb/musb/omap2430.c
> +++ b/drivers/usb/musb/omap2430.c
> @@ -194,6 +194,11 @@ int musb_platform_set_mode(struct musb *musb, u8 musb_mode)
>  {
>  	u8	devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
>  
> +	if ((devctl & MUSB_DEVCTL_BDEVICE) == 0x0) {
> +		devctl &= ~MUSB_DEVCTL_SESSION;
> +		musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);
> +	}
> +
>  	devctl |= MUSB_DEVCTL_SESSION;
>  	musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);
>  
> -- 
> 1.5.6.5
> 
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Re: [PATCH 2/2] USB: musb: omap2430: add mode change from A to B

[Felipe Balbi]

On 07/22/2010 06:16 PM, Kan-Ru Chen wrote:
> Just curious about how to do this in a more automatic way.
> 
> I think setup a daemon to monitor the musb_hdrc mode and try to alter
> it's state via sysfs interface will work, but it may be error prone and
> not always desirable solution.
> 
> Can we query the id pin state periodically in the kernel and change to
> corresponding role?

the transceiver has an interrupt for id pin changes. You can use that
instead of polling.

-- 
balbi
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Re: [PATCH 2/2] USB: musb: omap2430: add mode change from A to B

[Kan-Ru Chen]

On Thu, 22 Jul 2010 19:40:44 +0300, Felipe Balbi <me@felipebalbi.com> wrote:
> On 07/22/2010 06:16 PM, Kan-Ru Chen wrote:
> > Just curious about how to do this in a more automatic way.
> > 
> > I think setup a daemon to monitor the musb_hdrc mode and try to alter
> > it's state via sysfs interface will work, but it may be error prone and
> > not always desirable solution.
> > 
> > Can we query the id pin state periodically in the kernel and change to
> > corresponding role?
> 
> the transceiver has an interrupt for id pin changes. You can use that
> instead of polling.

Thanks, I see.

The twl4030_usb transceiver did get the id pin chanegs

    <7>twl4030_usb twl4030_usb: HW_CONDITIONS 0x50/80; link 1
    <7>twl4030_usb twl4030_usb: HW_CONDITIONS 0x54/84; link 3

So the problem is when OTG enter a_host mode then disconnected, it
becomes idle. Plug the peripheral device back would not trigger new
session unless I do "echo otg > /sys/devices/platform/musb_hdrc/mode"

Re: [PATCH 1/2] USB: musb: add two states to handle vbus error

[wanghui]

On omap platforms, when configuring the kernel, if we choose the musb 
work as host or OTG mode and we plug
a mini-A cable into the socket, after the kernel boot up in host mode or 
insmod gadget driver in OTG mode,
the state of musb's xceiv is A_IDLE or B_IDLE correspondingly because id 
change can't trigger ISR. Under this
condition, if we hotplug a usb device(without self-powered) at the other 
side of the cable, the musb will suffer a vbus error,
This patch can handle this vbus error.

Wang Hui wrote:
> When the MUSB is configured as host mode or OTG mode, the xceiv->state
> will be set to OTG_STATE_A_IDLE or OTG_STATE_B_IDLE unconditionally
> during init process. These init states can change to other
> states When the MUSB module detects id pin change, devices connect or
> disconnect.
> But on some platforms(omap2, omap3), the id pin change
> can't raise IRQ request to the MUSB module, so on these platforms,
> the init xceiv->state will be A_IDLE or B_IDLE. Under this condition,
> when we want the MUSB to act as a host and hotplug a usb device in
> mini-B side of the cable, the MUSB will have a possibility to suffer
> power underrun under A_IDLE or B_IDLE state, So here adding these
> two states under which we can handle VBUSERROR IRQ.
>
> Signed-off-by: Wang Hui <Hui.Wang@windriver.com>
> ---
>  drivers/usb/musb/musb_core.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
> index b4bbf8f..655413c 100644
> --- a/drivers/usb/musb/musb_core.c
> +++ b/drivers/usb/musb/musb_core.c
> @@ -516,6 +516,8 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
>  			 * another reset is due (at least for high speed,
>  			 * to redo the chirp etc), it might work OK...
>  			 */
> +		case OTG_STATE_A_IDLE:
> +		case OTG_STATE_B_IDLE:
>  		case OTG_STATE_A_WAIT_BCON:
>  		case OTG_STATE_A_WAIT_VRISE:
>  			if (musb->vbuserr_retry) {
>