[PATCH] usb: ehci: pass full speed devices to companion controller

[Sascha Hauer]

On Thu, Jan 26, 2017 at 04:03:03PM +0300, Peter Mamonov wrote:
> According to the "Enhanced Host Controller Interface Specification for
> Universal Serial Bus" after a USB port reset the EHCI Driver checks the
> PortEnable bit in the PORTSC register. If set to a one, the connected device is
> a high-speed device [...]. At the time the EHCI Driver receives the port reset
> and enable request the LineStatus bits might indicate a low-speed device.
> Additionally, when the port reset process is complete, the PortEnable field may
> indicate that a full-speed device is attached. In either case the EHCI driver
> sets the PortOwner bit in the PORTSC register to a one to release port
> ownership to a companion host controller.
> 
> Signed-off-by: Peter Mamonov <pmamonov at gmail.com>
> ---
>  drivers/usb/host/ehci-hcd.c | 27 +++++++++++++++++++++------
>  1 file changed, 21 insertions(+), 6 deletions(-)

Applied, thanks

Sascha

> 
> diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
> index 79bf4fb9d..d0be2104d 100644
> --- a/drivers/usb/host/ehci-hcd.c
> +++ b/drivers/usb/host/ehci-hcd.c
> @@ -477,6 +477,18 @@ static inline void ehci_powerup_fixup(struct ehci_priv *ehci)
>  }
>  #endif
>  
> +static void pass_to_companion(struct ehci_priv *ehci, int port)
> +{
> +	uint32_t *status_reg = (uint32_t *)&ehci->hcor->or_portsc[port - 1];
> +	uint32_t reg = ehci_readl(status_reg);
> +
> +	reg &= ~EHCI_PS_CLEAR;
> +	dev_dbg(ehci->dev, "port %d --> companion\n",
> +	      port - 1);
> +	reg |= EHCI_PS_PO;
> +	ehci_writel(status_reg, reg);
> +}
> +
>  static int
>  ehci_submit_root(struct usb_device *dev, unsigned long pipe, void *buffer,
>  		 int length, struct devrequest *req)
> @@ -509,6 +521,10 @@ ehci_submit_root(struct usb_device *dev, unsigned long pipe, void *buffer,
>  			return -1;
>  		}
>  		status_reg = (uint32_t *)&ehci->hcor->or_portsc[port - 1];
> +		if (ehci_readl(status_reg) & EHCI_PS_PO) {
> +			dev_dbg(ehci->dev, "Port %d is owned by companion controller\n", port);
> +			return -1;
> +		}
>  		break;
>  	default:
>  		status_reg = NULL;
> @@ -655,11 +671,7 @@ ehci_submit_root(struct usb_device *dev, unsigned long pipe, void *buffer,
>  			if ((reg & (EHCI_PS_PE | EHCI_PS_CS)) == EHCI_PS_CS &&
>  			    !ehci_is_TDI() &&
>  			    EHCI_PS_IS_LOWSPEED(reg)) {
> -				/* Low speed device, give up ownership. */
> -				dev_dbg(ehci->dev, "port %d low speed --> companion\n",
> -				      port - 1);
> -				reg |= EHCI_PS_PO;
> -				ehci_writel(status_reg, reg);
> +				pass_to_companion(ehci, port);
>  				break;
>  			} else {
>  				int ret;
> @@ -690,7 +702,10 @@ ehci_submit_root(struct usb_device *dev, unsigned long pipe, void *buffer,
>  				else
>  					dev_err(ehci->dev, "port(%d) reset error\n",
>  						port - 1);
> -
> +				mdelay(200);
> +				reg = ehci_readl(status_reg);
> +				if (!(reg & EHCI_PS_PE))
> +					pass_to_companion(ehci, port);
>  			}
>  			break;
>  		default:
> -- 
> 2.11.0
> 
> 
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> 

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