On 7/1/2021 10:00 PM, Greg KH wrote:

On Wed, Jun 30, 2021 at 02:00:38AM -0700, Wesley Cheng wrote:

quoted

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 <redacted>
---
 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

Hi Greg,

Thanks for the feedback.

"eps"?  What is that?

Fixed to "endpoints"

quoted

+ * @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?

Removed the ep_map comment, as we've removed it from the arguments.

quoted

+ *
+ * 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;
}

thanks for this suggestion.

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

How is this working?

The USB gadget will have ep_list, do we'll be looping through the
endpoints that have been claimed to get the number of IN eps being used
by a particular configuration.

Thanks
Wesley Cheng

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