UPSTREAML: usb: gadget: f_uac2: reset wMaxPacketSize

With commit 913e4a9 ("usb: gadget: f_uac2: finalize wMaxPacketSize according to bandwidth")
wMaxPacketSize is computed dynamically but the value is never reset.

Because of this, the actual maximum packet size can only decrease each time
the audio gadget is instantiated.

Reset the endpoint maximum packet size and mark wMaxPacketSize as dynamic
to solve the problem.

Change-Id: Idccb5e19358f1cab9d08325f39969cf216a98b8e
Fixes: 913e4a9 ("usb: gadget: f_uac2: finalize wMaxPacketSize according to bandwidth")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20201221173531.215169-2-jbrunet@baylibre.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: William Wu <william.wu@rock-chips.com>
(cherry picked from commit 9389044f27081d6ec77730c36d5bf9a1288bcda2)

Author: jbrun3t

drivers/usb/gadget/function/f_uac2.c

@@ -336,7 +336,7 @@ static struct usb_endpoint_descriptor fs_epout_desc = {
 
 	.bEndpointAddress = USB_DIR_OUT,
 	.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ADAPTIVE,
-	.wMaxPacketSize = cpu_to_le16(1023),
+	/* .wMaxPacketSize = DYNAMIC */
 	.bInterval = 1,
 };
 
@@ -345,7 +345,7 @@ static struct usb_endpoint_descriptor hs_epout_desc = {
 	.bDescriptorType = USB_DT_ENDPOINT,
 
 	.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_ADAPTIVE,
-	.wMaxPacketSize = cpu_to_le16(1024),
+	/* .wMaxPacketSize = DYNAMIC */
 	.bInterval = 4,
 };
 
@@ -413,7 +413,7 @@ static struct usb_endpoint_descriptor fs_epin_desc = {
 
 	.bEndpointAddress = USB_DIR_IN,
 	.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_SYNC,
-	.wMaxPacketSize = cpu_to_le16(1023),
+	/* .wMaxPacketSize = DYNAMIC */
 	.bInterval = 1,
 };
 
@@ -422,7 +422,7 @@ static struct usb_endpoint_descriptor hs_epin_desc = {
 	.bDescriptorType = USB_DT_ENDPOINT,
 
 	.bmAttributes = USB_ENDPOINT_XFER_ISOC | USB_ENDPOINT_SYNC_SYNC,
-	.wMaxPacketSize = cpu_to_le16(1024),
+	/* .wMaxPacketSize = DYNAMIC */
 	.bInterval = 4,
 };
 
@@ -530,14 +530,30 @@ struct cntrl_ranges_lay3 {
 	struct cntrl_range_lay3 r[UAC_MAX_RATES];
 } __packed;
 
-static void set_ep_max_packet_size(const struct f_uac_opts *uac2_opts,
+static int set_ep_max_packet_size(const struct f_uac_opts *uac2_opts,
 	struct usb_endpoint_descriptor *ep_desc,
-	unsigned int factor, bool is_playback)
+	enum usb_device_speed speed, bool is_playback)
 {
 	int chmask, srate = 0, ssize;
-	u16 max_packet_size;
+	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:
+		max_size_ep = 1024;
+		factor = 8000;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
 	if (is_playback) {
 		chmask = uac2_opts->p_chmask;
 		for (i = 0; i < UAC_MAX_RATES; i++) {
@@ -558,10 +574,12 @@ static void set_ep_max_packet_size(const struct f_uac_opts *uac2_opts,
 		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 = cpu_to_le16(min_t(u16, max_packet_size,
-				le16_to_cpu(ep_desc->wMaxPacketSize)));
+	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;
 }
 
 /* Use macro to overcome line length limitation */
@@ -794,10 +812,33 @@ afunc_bind(struct usb_configuration *cfg, struct usb_function *fn)
 	}
 
 	/* Calculate wMaxPacketSize according to audio bandwidth */
-	set_ep_max_packet_size(uac2_opts, &fs_epin_desc, 1000, true);
-	set_ep_max_packet_size(uac2_opts, &fs_epout_desc, 1000, false);
-	set_ep_max_packet_size(uac2_opts, &hs_epin_desc, 8000, true);
-	set_ep_max_packet_size(uac2_opts, &hs_epout_desc, 8000, false);
+	ret = set_ep_max_packet_size(uac2_opts, &fs_epin_desc, USB_SPEED_FULL,
+				     true);
+	if (ret < 0) {
+		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+		return ret;
+	}
+
+	ret = set_ep_max_packet_size(uac2_opts, &fs_epout_desc, USB_SPEED_FULL,
+				     false);
+	if (ret < 0) {
+		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+		return ret;
+	}
+
+	ret = set_ep_max_packet_size(uac2_opts, &hs_epin_desc, USB_SPEED_HIGH,
+				     true);
+	if (ret < 0) {
+		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+		return ret;
+	}
+
+	ret = set_ep_max_packet_size(uac2_opts, &hs_epout_desc, USB_SPEED_HIGH,
+				     false);
+	if (ret < 0) {
+		dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
+		return ret;
+	}
 
 	if (EPOUT_EN(uac2_opts)) {
 		agdev->out_ep = usb_ep_autoconfig(gadget, &fs_epout_desc);