[U-Boot] [PATCH] usb: ehci: Fix test mode for connected ports

[Marek Vasut <marex@denx.de>]

Dear Julius Werner,

> The EHCI controller has some very specific requirements for the USB 2.0
> port test modes, which were not closely followed in the initial test
> mode commit. It demands that the host controller is completely shut down
> (all ports suspended, Run/Stop bit unset) when activating test mode, and
> will not work on an already enumerated port.
> 
> This patch fixes that by introducing a new ehci_shutdown() function that
> closely follows the procedure listed in EHCI 4.14. Also, when we have
> such a function anyway, we might as well also use it in
> usb_lowlevel_stop() to make the normal host controller shutdown cleaner.
> 
> Signed-off-by: Julius Werner <jwerner@chromium.org>
> ---
>  drivers/usb/host/ehci-hcd.c | 31 +++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)
> 
> diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
> index fdad739..3143021 100644
> --- a/drivers/usb/host/ehci-hcd.c
> +++ b/drivers/usb/host/ehci-hcd.c
> @@ -190,6 +190,35 @@ out:
>  	return ret;
>  }
> 
> +static int ehci_shutdown(struct ehci_ctrl *ctrl)
> +{
> +	int i, ret = 0;
> +	uint32_t cmd, reg;
> +
> +	cmd = ehci_readl(&ctrl->hcor->or_usbcmd);
> +	cmd &= ~(CMD_PSE | CMD_ASE);
> +	ehci_writel(&ctrl->hcor->or_usbcmd, cmd);
> +	ret = handshake(&ctrl->hcor->or_usbsts, STS_ASS | STS_PSS, 0, 8 * 1000);

Why 8 * 1000? It's not clear.

> +
> +	if (!ret) {
> +		for (i = 0; i < CONFIG_SYS_USB_EHCI_MAX_ROOT_PORTS; i++) {
> +			reg = ehci_readl(&ctrl->hcor->or_portsc[i]);
> +			reg |= EHCI_PS_SUSP;
> +			ehci_writel(&ctrl->hcor->or_portsc[i], reg);
> +		}
> +
> +		cmd &= ~CMD_RUN;
> +		ehci_writel(&ctrl->hcor->or_usbcmd, cmd);
> +		ret = handshake(&ctrl->hcor->or_usbsts, STS_HALT, STS_HALT,
> +			8 * 1000);

DTTO

> +	}
> +
> +	if (ret)
> +		printf("EHCI failed to shut down host controller.\n");

puts()

> +
> +	return ret;
> +}
> +
>  static int ehci_td_buffer(struct qTD *td, void *buf, size_t sz)
>  {
>  	uint32_t delta, next;
> @@ -808,6 +837,7 @@ ehci_submit_root(struct usb_device *dev, unsigned long
> pipe, void *buffer, }
>  			break;
>  		case USB_PORT_FEAT_TEST:
> +			ehci_shutdown(ctrl);
>  			reg &= ~(0xf << 16);
>  			reg |= ((le16_to_cpu(req->index) >> 8) & 0xf) << 16;
>  			ehci_writel(status_reg, reg);
> @@ -878,6 +908,7 @@ unknown:
> 
>  int usb_lowlevel_stop(int index)
>  {
> +	ehci_shutdown(&ehcic[index]);
>  	return ehci_hcd_stop(index);
>  }

Best regards,
Marek Vasut