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staging: most: usb: fix calculation of the extra_len

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The final size of the buffer used for the streaming transfer consists of
the size for the user payload (buffer_size) and the size for the gaps
needed by the controller (extra_len).

The current implementation of the hdm_configure_channel() corrects the
buffer size down to the next appropriate for the hardware value, that is
the whole number of frames, but uses the old unaligned value to
calculate the extra_len.

Current patch fixes the described problem.

Signed-off-by: Andrey Shvetsov <andrey.shvetsov@k2l.de>
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andrey Shvetsov 2017-04-07 15:38:38 +02:00 committed by Greg Kroah-Hartman
parent 2c4aaa1fff
commit f500192890
1 changed files with 9 additions and 18 deletions
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27
drivers/staging/most/hdm-usb/hdm_usb.c
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@ -649,8 +649,6 @@ static int hdm_configure_channel(struct most_interface *iface, int channel,
{
unsigned int num_frames;
unsigned int frame_size;
unsigned int temp_size;
unsigned int tail_space;
struct most_dev *mdev = to_mdev(iface);
struct device *dev = &mdev->usb_device->dev;
@ -685,7 +683,6 @@ static int hdm_configure_channel(struct most_interface *iface, int channel,
}
mdev->padding_active[channel] = true;
temp_size = conf->buffer_size;
frame_size = get_stream_frame_size(conf);
if (frame_size == 0 || frame_size > USB_MTU) {
@ -693,25 +690,19 @@ static int hdm_configure_channel(struct most_interface *iface, int channel,
return -EINVAL;
}
if (conf->buffer_size % frame_size) {
u16 tmp_val;
num_frames = conf->buffer_size / frame_size;
tmp_val = conf->buffer_size / frame_size;
conf->buffer_size = tmp_val * frame_size;
dev_notice(dev,
"Channel %d - rounding buffer size to %d bytes, channel config says %d bytes\n",
channel,
conf->buffer_size,
temp_size);
if (conf->buffer_size % frame_size) {
u16 old_size = conf->buffer_size;
conf->buffer_size = num_frames * frame_size;
dev_warn(dev, "%s: fixed buffer size (%d -> %d)\n",
mdev->suffix[channel], old_size, conf->buffer_size);
}
num_frames = conf->buffer_size / frame_size;
tail_space = num_frames * (USB_MTU - frame_size);
temp_size += tail_space;
/* calculate extra length to comply w/ HW padding */
conf->extra_len = (DIV_ROUND_UP(temp_size, USB_MTU) * USB_MTU)
- conf->buffer_size;
conf->extra_len = num_frames * (USB_MTU - frame_size);
exit:
mdev->conf[channel] = *conf;
if (conf->data_type == MOST_CH_ASYNC) {