Re: [PATCH v6 07/12] usb: otg: add OTG/dual-role core

[Peter Chen <hzpeterchen@gmail.com>]

On Fri, Apr 15, 2016 at 10:03:16AM +0000, Yoshihiro Shimoda wrote:
> Hi,
> 
> > From: Yoshihiro Shimoda
> > Sent: Friday, April 15, 2016 6:59 PM
> > 
> > Hi,
> > 
> > > From: Roger Quadros
> > > Sent: Thursday, April 14, 2016 8:32 PM
> > >
> > > On 14/04/16 14:15, Yoshihiro Shimoda wrote:
> > > > Hi,
> > > >
> > < snip >
> > > >>> @@ -865,7 +867,8 @@ int usb_otg_register_hcd(struct usb_hcd *hcd, unsigned int irqnum,
> > > >>>  	 * we're ready only if we have shared HCD
> > > >>>  	 * or we don't need shared HCD.
> > > >>>  	 */
> > > >>> -	if (otg->shared_hcd.hcd || !otg->primary_hcd.hcd->shared_hcd) {
> > > >>> +	if (otg->shared_hcd.hcd || (!otg->caps->needs_companion &&
> > > >>> +				    !otg->primary_hcd.hcd->shared_hcd)) {
> > > >>>  		otg->host = hcd_to_bus(hcd);
> > > >>>  		/* FIXME: set bus->otg_port if this is true OTG port with HNP */
> > > >>>
> > > >>
> > > >> These changes look good to me. Thanks.
> > > >
> > > > Thank you for the comment.
> > > > If we change the "needs_companion" place to the otg_config,
> > > > do we need to add a flag into the otg, instead of otg->caps?
> > >
> > > Yes we can add a flag in struct usb_otg.
> > 
> > Thank you for the comment.
> > 
> > I made a fixed patch.
> > So, should I send this patch to ML after you sent v7 patches?
> > Or, would you apply this patch before you send v7 patches?
> 
> Oops, I sent this email without my patch...
> 
> ---
> Subject: [PATCH] usb: otg: add hcd companion support
> 
> Since some host controller (e.g. EHCI) needs a companion host controller
> (e.g. OHCI), this patch adds such a configuration to use it in the OTG
> core.
> 
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> ---
>  Documentation/devicetree/bindings/usb/generic.txt |  3 +++
>  drivers/usb/common/usb-otg.c                      | 17 +++++++++++++----
>  include/linux/usb/otg.h                           |  7 ++++++-
>  3 files changed, 22 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/usb/generic.txt b/Documentation/devicetree/bindings/usb/generic.txt
> index f6866c1..1db1c33 100644
> --- a/Documentation/devicetree/bindings/usb/generic.txt
> +++ b/Documentation/devicetree/bindings/usb/generic.txt
> @@ -27,6 +27,9 @@ Optional properties:
>   - otg-controller: phandle to otg controller. Host or gadget controllers can
>  			contain this property to link it to a particular OTG
>  			controller.
> + - hcd-needs-companion: must be present if otg controller is dealing with
> +			EHCI host controller that needs a companion OHCI host
> +			controller.
>  
>  This is an attribute to a USB controller such as:
>  
> diff --git a/drivers/usb/common/usb-otg.c b/drivers/usb/common/usb-otg.c
> index 41e762a..83c8c96 100644
> --- a/drivers/usb/common/usb-otg.c
> +++ b/drivers/usb/common/usb-otg.c
> @@ -20,6 +20,7 @@
>  #include <linux/list.h>
>  #include <linux/of.h>
>  #include <linux/of_platform.h>
> +#include <linux/usb/of.h>
>  #include <linux/usb/otg.h>
>  #include <linux/usb/gadget.h>
>  #include <linux/workqueue.h>
> @@ -600,6 +601,10 @@ struct usb_otg *usb_otg_register(struct device *dev,
>  	else
>  		INIT_WORK(&otg->work, usb_otg_work);
>  
> +	if (of_find_property(dev->of_node, "hcd-needs-companion", NULL) ||
> +	    config->hcd_needs_companion)	/* needs comanion ? */
> +		otg->flags |= OTG_FLAG_HCD_NEEDS_COMPANION;
> +
>  	otg->wq = create_singlethread_workqueue("usb_otg");
>  	if (!otg->wq) {
>  		dev_err(dev, "otg: %s: can't create workqueue\n",
> @@ -823,13 +828,15 @@ int usb_otg_register_hcd(struct usb_hcd *hcd, unsigned int irqnum,
>  	/* HCD will be started by OTG fsm when needed */
>  	mutex_lock(&otg->fsm.lock);
>  	if (otg->primary_hcd.hcd) {
> -		/* probably a shared HCD ? */
> -		if (usb_otg_hcd_is_primary_hcd(hcd)) {
> +		/* probably a shared HCD or a companion OHCI HCD ? */
> +		if (!(otg->flags & OTG_FLAG_HCD_NEEDS_COMPANION) &&
> +		    usb_otg_hcd_is_primary_hcd(hcd)) {
>  			dev_err(otg_dev, "otg: primary host already registered\n");
>  			goto err;
>  		}
>  
> -		if (hcd->shared_hcd == otg->primary_hcd.hcd) {
> +		if (otg->flags & OTG_FLAG_HCD_NEEDS_COMPANION ||
> +		    (hcd->shared_hcd == otg->primary_hcd.hcd)) {
>  			if (otg->shared_hcd.hcd) {
>  				dev_err(otg_dev, "otg: shared host already registered\n");
>  				goto err;
> @@ -865,7 +872,9 @@ int usb_otg_register_hcd(struct usb_hcd *hcd, unsigned int irqnum,
>  	 * we're ready only if we have shared HCD
>  	 * or we don't need shared HCD.
>  	 */
> -	if (otg->shared_hcd.hcd || !otg->primary_hcd.hcd->shared_hcd) {
> +	if (otg->shared_hcd.hcd ||
> +	    (!(otg->flags & OTG_FLAG_HCD_NEEDS_COMPANION) &&
> +	     !otg->primary_hcd.hcd->shared_hcd)) {
>  		otg->host = hcd_to_bus(hcd);
>  		/* FIXME: set bus->otg_port if this is true OTG port with HNP */
>  
> diff --git a/include/linux/usb/otg.h b/include/linux/usb/otg.h
> index b094352..6f4ca77 100644
> --- a/include/linux/usb/otg.h
> +++ b/include/linux/usb/otg.h
> @@ -57,7 +57,8 @@ struct otg_hcd {
>   * @list: list of otg controllers
>   * @work: otg state machine work
>   * @wq: otg state machine work queue
> - * @flags: to track if host/gadget is running
> + * @flags: to track if host/gadget is running, or to indicate if hcd needs
> + *	   companion
>   */
>  struct usb_otg {
>  	u8			default_a;
> @@ -84,6 +85,7 @@ struct usb_otg {
>  	u32 flags;
>  #define OTG_FLAG_GADGET_RUNNING (1 << 0)
>  #define OTG_FLAG_HOST_RUNNING (1 << 1)
> +#define OTG_FLAG_HCD_NEEDS_COMPANION (1 << 2)
>  	/* use otg->fsm.lock for serializing access */
>  
>  /*------------- deprecated interface -----------------------------*/
> @@ -125,11 +127,14 @@ struct usb_otg_caps {
>   * @caps: otg capabilities of the controller
>   * @ops: otg fsm operations
>   * @otg_work: optional custom otg state machine work function
> + * @hcd_needs_companion: Indicates if host controller needs a companion
> + *			 controller
>   */
>  struct usb_otg_config {
>  	struct usb_otg_caps *otg_caps;
>  	struct otg_fsm_ops *fsm_ops;
>  	void (*otg_work)(struct work_struct *work);
> +	bool hcd_needs_companion;
>  };
>  
>  extern const char *usb_otg_state_string(enum usb_otg_state state);
> -- 

Hi Yoshihiro, the shared_hcd is used for USB3 only [1], this patch may
not be suitable for supporting companion controller at OTG framework.
For companion or other USB2 controllers, both primary hcd and shard hcd
are NULL for HCD core.

[1] http://www.spinics.net/lists/linux-usb/msg139630.html
-- 

Best Regards,
Peter Chen