Re: [PATCH v3 10/22] usb: gadget: configfs: init and add usb_otg_descriptor for usb configurations

[Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org>]

On Tue, 16 Jun 2015 14:52:00 +0800
Li Jun <jun.li-KZfg59tc24xl57MIdRCFDg@public.gmane.org> wrote:

> Use usb_otg_descriptor_add to allocate and initialize usb_otg_descriptor,
> add it for each usb configurations, free it while composite unbind.
> 
> Signed-off-by: Li Jun <jun.li-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
> ---
>  drivers/usb/gadget/configfs.c | 34 +++++++++++++++++++++++++---------
>  1 file changed, 25 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
> index 0495c94..773b746 100644
> --- a/drivers/usb/gadget/configfs.c
> +++ b/drivers/usb/gadget/configfs.c
> @@ -41,6 +41,8 @@ int check_user_usb_string(const char *name,
>  #define MAX_NAME_LEN	40
>  #define MAX_USB_STRING_LANGS 2
>  
> +static const struct usb_descriptor_header *otg_desc[2];
> +
>  struct gadget_info {
>  	struct config_group group;
>  	struct config_group functions_group;
> @@ -55,9 +57,6 @@ struct gadget_info {
>  	struct list_head available_func;
>  
>  	const char *udc_name;
> -#ifdef CONFIG_USB_OTG
> -	struct usb_otg_descriptor otg;
> -#endif
>  	struct usb_composite_driver composite;
>  	struct usb_composite_dev cdev;
>  	bool use_os_desc;
> @@ -1376,6 +1375,24 @@ static int configfs_composite_bind(struct usb_gadget *gadget,
>  		memcpy(cdev->qw_sign, gi->qw_sign, OS_STRING_QW_SIGN_LEN);
>  	}
>  
> +	if (gadget_is_otg(gadget) && !otg_desc[0]) {
> +		struct usb_descriptor_header *usb_desc;
> +		unsigned length;
> +
> +		if (gadget->otg_rev >= 0x0200)
> +			length = sizeof(struct usb_otg20_descriptor);
> +		else
> +			length = sizeof(struct usb_otg_descriptor);
> +		usb_desc = kzalloc(length, GFP_KERNEL);
> +		if (!usb_desc) {
> +			ret = -ENOMEM;
> +			goto err_comp_cleanup;
> +		}

This code seems to be common across all gadgets.
Can we have usb_otg_descriptor_alloc() that takes care of allocating the
right size based on descriptor version?

Then we can have
		usb_desc = usb_otg_descriptor_alloc(gadget);
		if (IS_ERR(usb_desc)) {
			ret = PTR_ERR(usb_desc);
			goto err_comp_cleanup;
		}

> +		usb_otg_descriptor_init(gadget, usb_desc);
> +		otg_desc[0] = usb_desc;
> +		otg_desc[1] = NULL;
> +	}
> +
>  	/* Go through all configs, attach all functions */
>  	list_for_each_entry(c, &gi->cdev.configs, list) {
>  		struct config_usb_cfg *cfg;
> @@ -1383,6 +1400,9 @@ static int configfs_composite_bind(struct usb_gadget *gadget,
>  		struct usb_function *tmp;
>  		struct gadget_config_name *cn;
>  
> +		if (gadget_is_otg(gadget))
> +			c->descriptors = otg_desc;
> +
>  		cfg = container_of(c, struct config_usb_cfg, c);
>  		if (!list_empty(&cfg->string_list)) {
>  			i = 0;
> @@ -1437,6 +1457,8 @@ static void configfs_composite_unbind(struct usb_gadget *gadget)
>  	cdev = get_gadget_data(gadget);
>  	gi = container_of(cdev, struct gadget_info, cdev);
>  
> +	kfree(otg_desc[0]);
> +	otg_desc[0] = NULL;
>  	purge_configs_funcs(gi);
>  	composite_dev_cleanup(cdev);
>  	usb_ep_autoconfig_reset(cdev->gadget);
> @@ -1510,12 +1532,6 @@ static struct config_group *gadgets_make(
>  	if (!gi->composite.gadget_driver.function)
>  		goto err;
>  
> -#ifdef CONFIG_USB_OTG
> -	gi->otg.bLength = sizeof(struct usb_otg_descriptor);
> -	gi->otg.bDescriptorType = USB_DT_OTG;
> -	gi->otg.bmAttributes = USB_OTG_SRP | USB_OTG_HNP;
> -#endif
> -
>  	config_group_init_type_name(&gi->group, name,
>  				&gadget_root_type);
>  	return &gi->group;

cheers,
-roger
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