[PATCH v6 4/4] usb: xhci: Add reset controller support

[Matthias Brugger]

On 29/06/2020 18:37, Nicolas Saenz Julienne wrote:
> Some atypical users of xhci might need to manually reset their xHCI
> controller before starting the HCD setup. Check if a reset controller
> device is available to the PCI bus and trigger a reset.
> 
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne at suse.de>
> 
> ---
> Changes since v5:
>   - Take !CONFIG_IS_ENABLED(DM_RESET) into account
> 
>   drivers/usb/host/xhci-mem.c |  2 ++
>   drivers/usb/host/xhci.c     | 33 +++++++++++++++++++++++++++++++++
>   include/usb/xhci.h          |  2 ++
>   3 files changed, 37 insertions(+)
> 
> diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
> index f446520528..108f4bd8cf 100644
> --- a/drivers/usb/host/xhci-mem.c
> +++ b/drivers/usb/host/xhci-mem.c
> @@ -180,6 +180,8 @@ void xhci_cleanup(struct xhci_ctrl *ctrl)
>   	xhci_free_virt_devices(ctrl);
>   	free(ctrl->erst.entries);
>   	free(ctrl->dcbaa);
> +	if (reset_valid(&ctrl->reset))
> +		reset_free(&ctrl->reset);
>   	memset(ctrl, '\0', sizeof(struct xhci_ctrl));
>   }
>   
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index ebd2954571..e252964d0d 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -190,6 +190,35 @@ static int xhci_start(struct xhci_hcor *hcor)
>   	return ret;
>   }
>   
> +/**
> + * Resets XHCI Hardware
> + *
> + * @param ctrl	pointer to host controller
> + * @return 0 if OK, or a negative error code.
> + */
> +static int xhci_reset_hw(struct xhci_ctrl *ctrl)
> +{
> +	int ret;
> +
> +	ret = reset_get_by_index(ctrl->dev, 0, &ctrl->reset);

That seems to break arm32 builds:
https://pastebin.com/eHBf7Xp0
https://gitlab.denx.de/u-boot/custodians/u-boot-raspberrypi/-/jobs/121247

Nicolas, can you have a look?

Thanks
Matthias

> +	if (ret && ret != -ENOENT && ret != -ENOTSUPP) {
> +		dev_err(ctrl->dev, "failed to get reset\n");
> +		return ret;
> +	}
> +
> +	if (reset_valid(&ctrl->reset)) {
> +		ret = reset_assert(&ctrl->reset);
> +		if (ret)
> +			return ret;
> +
> +		ret = reset_deassert(&ctrl->reset);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
>   /**
>    * Resets the XHCI Controller
>    *
> @@ -1508,6 +1537,10 @@ int xhci_register(struct udevice *dev, struct xhci_hccr *hccr,
>   
>   	ctrl->dev = dev;
>   
> +	ret = xhci_reset_hw(ctrl);
> +	if (ret)
> +		goto err;
> +
>   	/*
>   	 * XHCI needs to issue a Address device command to setup
>   	 * proper device context structures, before it can interact
> diff --git a/include/usb/xhci.h b/include/usb/xhci.h
> index 1170c0ac69..7d34103fd5 100644
> --- a/include/usb/xhci.h
> +++ b/include/usb/xhci.h
> @@ -16,6 +16,7 @@
>   #ifndef HOST_XHCI_H_
>   #define HOST_XHCI_H_
>   
> +#include <reset.h>
>   #include <asm/types.h>
>   #include <asm/cache.h>
>   #include <asm/io.h>
> @@ -1209,6 +1210,7 @@ struct xhci_ctrl {
>   #if CONFIG_IS_ENABLED(DM_USB)
>   	struct udevice *dev;
>   #endif
> +	struct reset_ctl reset;
>   	struct xhci_hccr *hccr;	/* R/O registers, not need for volatile */
>   	struct xhci_hcor *hcor;
>   	struct xhci_doorbell_array *dba;
>