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BACKPORT: usb: gadget: f_uac1: finalize wMaxPacketSize according to bandwidth

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According to USB Audio Device 1.0 Spec, Ch4.6.1.1:
The wMaxPacketSize of endpoint is defined as follows:
Maximum packet size of endpoint is capable of sending
or receiving when this configuration is selected. This
is determined by the audio bandwidth constraints of
the endpoint.

In current code, the wMaxPacketSize is limited to 200,
and the bInterval is set to 4 (1ms). That is, the maximum
bandwidth over USB bus is 200 * 1000 = 200000 bytes.

We find an issue about bandwidth limitation when we try to
support UAC1 with 8ch * 16bit * 16KHz on RK3308 platform,
which needs more bandwidth than it can support.

This patch sets the wMaxPacketSize dynamically according
to the parameters of UAC1. It is similar to the same thing
done earlier for f_uac2.

Signed-off-by: William Wu <william.wu@rock-chips.com>

(backported from develop-4.19 commit 573d2e1e2e)
Change-Id: I3304f9eb4d1eee18f4beb44af46a246940c2dfe3
Signed-off-by: Frank Wang <frank.wang@rock-chips.com>
This commit is contained in:
William Wu
2021-05-13 11:59:21 +08:00
committed by Tao Huang
parent 931b12539b
commit 02c6e7f24b
1 changed files with 95 additions and 4 deletions
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99
drivers/usb/gadget/function/f_uac1.c
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@@ -238,7 +238,7 @@ static struct usb_endpoint_descriptor fs_out_ep_desc = {
.bEndpointAddress = USB_DIR_OUT,
.bmAttributes = USB_ENDPOINT_SYNC_ADAPTIVE
| USB_ENDPOINT_XFER_ISOC,
.wMaxPacketSize = cpu_to_le16(UAC1_OUT_EP_MAX_PACKET_SIZE),
/* .wMaxPacketSize = DYNAMIC */
.bInterval = 1,
};
@@ -248,7 +248,7 @@ static struct usb_endpoint_descriptor as_out_ep_desc = {
.bEndpointAddress = USB_DIR_OUT,
.bmAttributes = USB_ENDPOINT_SYNC_ADAPTIVE
| USB_ENDPOINT_XFER_ISOC,
.wMaxPacketSize = cpu_to_le16(UAC1_OUT_EP_MAX_PACKET_SIZE),
/* .wMaxPacketSize = DYNAMIC */
.bInterval = 4,
};
@@ -285,7 +285,7 @@ static struct usb_endpoint_descriptor fs_in_ep_desc = {
.bEndpointAddress = USB_DIR_IN,
.bmAttributes = USB_ENDPOINT_SYNC_ASYNC
| USB_ENDPOINT_XFER_ISOC,
.wMaxPacketSize = cpu_to_le16(UAC1_OUT_EP_MAX_PACKET_SIZE),
/* .wMaxPacketSize = DYNAMIC */
.bInterval = 1,
};
@@ -295,7 +295,7 @@ static struct usb_endpoint_descriptor as_in_ep_desc = {
.bEndpointAddress = USB_DIR_IN,
.bmAttributes = USB_ENDPOINT_SYNC_ASYNC
| USB_ENDPOINT_XFER_ISOC,
.wMaxPacketSize = cpu_to_le16(UAC1_OUT_EP_MAX_PACKET_SIZE),
/* .wMaxPacketSize = DYNAMIC */
.bInterval = 4,
};
@@ -1381,6 +1381,60 @@ static int f_audio_validate_opts(struct g_audio *audio, struct device *dev)
return 0;
}
static int set_ep_max_packet_size(const struct f_uac1_opts *opts,
struct usb_endpoint_descriptor *ep_desc,
enum usb_device_speed speed, bool is_playback)
{
int chmask, srate = 0, ssize;
u16 max_size_bw, max_size_ep;
unsigned int factor;
int i;
switch (speed) {
case USB_SPEED_FULL:
max_size_ep = 1023;
factor = 1000;
break;
case USB_SPEED_HIGH:
fallthrough;
case USB_SPEED_SUPER:
max_size_ep = 1024;
factor = 8000;
break;
default:
return -EINVAL;
}
if (is_playback) {
chmask = opts->p_chmask;
for (i = 0; i < UAC_MAX_RATES; i++) {
if (opts->p_srates[i] == 0)
break;
if (opts->p_srates[i] > srate)
srate = opts->p_srates[i];
}
ssize = opts->p_ssize;
} else {
chmask = opts->c_chmask;
for (i = 0; i < UAC_MAX_RATES; i++) {
if (opts->c_srates[i] == 0)
break;
if (opts->c_srates[i] > srate)
srate = opts->c_srates[i];
}
ssize = opts->c_ssize;
}
max_size_bw = num_channels(chmask) * ssize *
((srate / (factor / (1 << (ep_desc->bInterval - 1)))) + 1);
ep_desc->wMaxPacketSize = cpu_to_le16(min_t(u16, max_size_bw,
max_size_ep));
return 0;
}
/* audio function driver setup/binding */
static int f_audio_bind(struct usb_configuration *c, struct usb_function *f)
{
@@ -1495,6 +1549,43 @@ static int f_audio_bind(struct usb_configuration *c, struct usb_function *f)
memcpy(as_out_type_i_desc.tSamFreq[idx++],
&audio_opts->c_srates[i], 3);
}
/*
* Calculate wMaxPacketSize according to audio bandwidth.
* Set the max packet with USB_SPEED_HIGH by default to
* be compatible with larger bandwidth requirements for
* high speed mode.
*/
status = set_ep_max_packet_size(audio_opts, &fs_out_ep_desc,
USB_SPEED_FULL, false);
if (status < 0) {
dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
goto fail;
}
status = set_ep_max_packet_size(audio_opts, &fs_in_ep_desc,
USB_SPEED_FULL, true);
if (status < 0) {
dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
goto fail;
}
status = set_ep_max_packet_size(audio_opts, &as_out_ep_desc,
USB_SPEED_HIGH, false);
if (status < 0) {
dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
goto fail;
}
status = set_ep_max_packet_size(audio_opts, &as_in_ep_desc,
USB_SPEED_HIGH, true);
if (status < 0) {
dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
goto fail;
}
as_out_ep_desc_comp.wBytesPerInterval = as_out_ep_desc.wMaxPacketSize;
as_in_ep_desc_comp.wBytesPerInterval = as_in_ep_desc.wMaxPacketSize;
as_out_type_i_desc.bLength = UAC_FORMAT_TYPE_I_DISCRETE_DESC_SIZE(idx);
as_out_type_i_desc.bSamFreqType = idx;