Re: [PATCH v7 10/14] usb: otg: add hcd companion support

[Peter Chen <hzpeterchen-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On Mon, May 02, 2016 at 03:18:53PM +0300, Roger Quadros wrote:
> From: Yoshihiro Shimoda <yoshihiro.shimoda.uh-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org>
> 
> 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-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org>
> Signed-off-by: Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org>

Acked-by: Peter Chen <peter.chen-3arQi8VN3Tc@public.gmane.org>

> ---
>  Documentation/devicetree/bindings/usb/generic.txt |  3 +++
>  drivers/usb/common/usb-otg.c                      | 32 ++++++++++++++++-------
>  include/linux/usb/otg.h                           |  7 ++++-
>  3 files changed, 32 insertions(+), 10 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 702bca8..77048aa 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>
> @@ -582,6 +583,10 @@ struct usb_otg *usb_otg_register(struct device *dev,
>  	else
>  		INIT_WORK(&otg->work, usb_drd_work);
>  
> +	if (of_find_property(dev->of_node, "hcd-needs-companion", NULL) ||
> +	    config->hcd_needs_companion)	/* needs companion ? */
> +		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",
> @@ -805,15 +810,18 @@ 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");
> +				dev_err(otg_dev,
> +					"otg: shared/companion host already registered\n");
>  				goto err;
>  			}
>  
> @@ -821,10 +829,12 @@ int usb_otg_register_hcd(struct usb_hcd *hcd, unsigned int irqnum,
>  			otg->shared_hcd.irqnum = irqnum;
>  			otg->shared_hcd.irqflags = irqflags;
>  			otg->shared_hcd.ops = ops;
> -			dev_info(otg_dev, "otg: shared host %s registered\n",
> +			dev_info(otg_dev,
> +				 "otg: shared/companion host %s registered\n",
>  				 dev_name(hcd->self.controller));
>  		} else {
> -			dev_err(otg_dev, "otg: invalid shared host %s\n",
> +			dev_err(otg_dev,
> +				"otg: invalid shared/companion host %s\n",
>  				dev_name(hcd->self.controller));
>  			goto err;
>  		}
> @@ -847,14 +857,17 @@ 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 */
>  
>  		/* start FSM */
>  		usb_otg_start_fsm(otg);
>  	} else {
> -		dev_dbg(otg_dev, "otg: can't start till shared host registers\n");
> +		dev_dbg(otg_dev,
> +			"otg: can't start till shared/companion host registers\n");
>  	}
>  
>  	mutex_unlock(&otg->fsm.lock);
> @@ -905,7 +918,8 @@ int usb_otg_unregister_hcd(struct usb_hcd *hcd)
>  			 dev_name(hcd_dev));
>  	} else if (hcd == otg->shared_hcd.hcd) {
>  		otg->shared_hcd.hcd = NULL;
> -		dev_info(otg_dev, "otg: shared host %s unregistered\n",
> +		dev_info(otg_dev,
> +			 "otg: shared/companion host %s unregistered\n",
>  			 dev_name(hcd_dev));
>  	} else {
>  		dev_err(otg_dev, "otg: host %s wasn't registered with otg\n",
> 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);
> -- 
> 2.7.4
> 
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-- 

Best Regards,
Peter Chen
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