Hello USB devs,
The patch 7d50195f6c50: "usb: host: Faraday fotg210-hcd driver" from
Jul 29, 2013, leads to the following static checker warning:
drivers/usb/host/fotg210-hcd.c:3945 iso_stream_init()
warn: mask and shift to zero
drivers/usb/host/fotg210-hcd.c
3922 static void iso_stream_init(struct fotg210_hcd *fotg210,
3923 struct fotg210_iso_stream *stream, struct usb_device *dev,
3924 int pipe, unsigned interval)
3925 {
3926 u32 buf1;
3927 unsigned epnum, maxp;
3928 int is_input;
3929 long bandwidth;
3930 unsigned multi;
3931
3932 /*
3933 * this might be a "high bandwidth" highspeed endpoint,
3934 * as encoded in the ep descriptor's wMaxPacket field
3935 */
3936 epnum = usb_pipeendpoint(pipe);
3937 is_input = usb_pipein(pipe) ? USB_DIR_IN : 0;
3938 maxp = usb_maxpacket(dev, pipe, !is_input);
3939 if (is_input)
3940 buf1 = (1 << 11);
3941 else
3942 buf1 = 0;
3943
3944 maxp = max_packet(maxp);
3945 multi = hb_mult(maxp);
3946 buf1 |= maxp;
3947 maxp *= multi;
3948
3949 stream->buf0 = cpu_to_hc32(fotg210, (epnum << 8) | dev->devnum);
3950 stream->buf1 = cpu_to_hc32(fotg210, buf1);
3951 stream->buf2 = cpu_to_hc32(fotg210, multi);
The problem is these two defines:
#define max_packet(wMaxPacketSize) ((wMaxPacketSize) & 0x07ff)
#define hb_mult(wMaxPacketSize) (1 + (((wMaxPacketSize) >> 11) & 0x03))
0x07ff >> 11 is always zero so multi is always 1.
Should we pass the original value that usb_maxpacket() returned instead
of the masked value?
regards,
dan carpenter
