On 07/28/2015 03:38 AM, Peter Chen wrote:
> +static void set_ep_max_packet_size (struct f_uac2_opts *uac2_opts,
> + struct usb_endpoint_descriptor *ep_desc, unsigned int factor)
> +{
> + int chmask;
> + int srate;
> + int ssize;
> + u16 max_packet_size;
> +
> + if (ep_desc == &fs_epin_desc || ep_desc == &hs_epin_desc) {
> + chmask = uac2_opts->p_chmask;
> + srate = uac2_opts->p_srate;
> + ssize = uac2_opts->p_ssize;
> + } else {
> + WARN_ON (ep_desc != &fs_epout_desc && ep_desc != &hs_epout_desc);
> + chmask = uac2_opts->c_chmask;
> + srate = uac2_opts->c_srate;
> + ssize = uac2_opts->c_ssize;
> + }
> +
> + max_packet_size = num_channels(chmask) * ssize *
> + DIV_ROUND_UP(srate, factor / (1 << (ep_desc->bInterval - 1)));
> + ep_desc->wMaxPacketSize = min(cpu_to_le16(max_packet_size),
> + ep_desc->wMaxPacketSize);
> +}
Thinking about it again, it would probably be nicer to make this
function return wMaxPacketSize directly:
fs_epin_desc.wMaxPacketSize =
calc_ep_max_packet_size(uac2_opts->p_chmask,
uac2_opts->p_srate,
uac2_opts->p_ssize,
1000);
hs_epin_desc.wMaxPacketSize =
calc_ep_max_packet_size(uac2_opts->p_chmask,
uac2_opts->p_srate,
uac2_opts->p_ssize,
8000);
...
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