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From: Greg KH <gregkh@linuxfoundation.org>
To: Wesley Cheng <wcheng@codeaurora.org>
Cc: robh+dt@kernel.org, agross@kernel.org,
	bjorn.andersson@linaro.org, balbi@kernel.org,
	linux-usb@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	jackp@codeaurora.org, fntoth@gmail.com
Subject: Re: [PATCH v11 1/5] usb: gadget: udc: core: Introduce check_config to verify USB configuration
Date: Fri, 2 Jul 2021 07:00:19 +0200	[thread overview]
Message-ID: <YN6dY8RBXRN4BW3n@kroah.com> (raw)
In-Reply-To: <1625043642-29822-2-git-send-email-wcheng@codeaurora.org>

On Wed, Jun 30, 2021 at 02:00:38AM -0700, Wesley Cheng wrote:
> Some UDCs may have constraints on how many high bandwidth endpoints it can
> support in a certain configuration.  This API allows for the composite
> driver to pass down the total number of endpoints to the UDC so it can verify
> it has the required resources to support the configuration.
> 
> Signed-off-by: Wesley Cheng <wcheng@codeaurora.org>
> ---
>  drivers/usb/gadget/udc/core.c | 25 +++++++++++++++++++++++++
>  include/linux/usb/gadget.h    |  4 ++++
>  2 files changed, 29 insertions(+)
> 
> diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
> index b7f0b1e..f1f44a6 100644
> --- a/drivers/usb/gadget/udc/core.c
> +++ b/drivers/usb/gadget/udc/core.c
> @@ -1003,6 +1003,31 @@ int usb_gadget_ep_match_desc(struct usb_gadget *gadget,
>  }
>  EXPORT_SYMBOL_GPL(usb_gadget_ep_match_desc);
>  
> +/**
> + * usb_gadget_check_config - checks if the UDC can support the number of eps

"eps"?  What is that?

> + * @gadget: controller to check the USB configuration
> + * @ep_map: bitmap of endpoints being requested by a USB configuration

There is no such option in this function, did you run 'make htmldocs'
and see that this adds a warning?

> + *
> + * Ensure that a UDC is able to support the number of endpoints within a USB
> + * configuration, and that there are no resource limitations to support all
> + * requested eps.
> + *
> + * Returns zero on success, else a negative errno.
> + */
> +int usb_gadget_check_config(struct usb_gadget *gadget)
> +{
> +	int ret = 0;
> +
> +	if (!gadget->ops->check_config)
> +		goto out;
> +
> +	ret = gadget->ops->check_config(gadget);
> +
> +out:
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(usb_gadget_check_config);

This can be written in the much simpler form:
{
	if (gadget->ops->check_config)
		return gadget->ops->check_config(gadget);
	return 0;
}

But where are the endpoints that need to be checked???

How is this working?

thanks,

greg k-h

  reply	other threads:[~2021-07-02  5:00 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-30  9:00 [PATCH v11 0/5] Re-introduce TX FIFO resize for larger EP bursting Wesley Cheng
2021-06-30  9:00 ` [PATCH v11 1/5] usb: gadget: udc: core: Introduce check_config to verify USB configuration Wesley Cheng
2021-07-02  5:00   ` Greg KH [this message]
2021-07-02  8:00     ` Wesley Cheng
2021-06-30  9:00 ` [PATCH v11 2/5] usb: gadget: configfs: Check USB configuration before adding Wesley Cheng
2021-06-30  9:00 ` [PATCH v11 3/5] usb: dwc3: Resize TX FIFOs to meet EP bursting requirements Wesley Cheng
2021-06-30  9:00 ` [PATCH v11 4/5] usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default Wesley Cheng
2021-07-01  1:09   ` kernel test robot
2021-07-02  5:06   ` Greg KH
2021-07-02  8:10     ` Wesley Cheng
2021-07-02  8:19       ` Greg KH
2021-06-30  9:00 ` [PATCH v11 5/5] dt-bindings: usb: dwc3: Update dwc3 TX fifo properties Wesley Cheng
2021-07-02  5:04 ` [PATCH v11 0/5] Re-introduce TX FIFO resize for larger EP bursting Greg KH

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