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From:   3090101217@zju.edu.cn
To:     balbi@kernel.org, gregkh@linuxfoundation.org,
        ruslan.bilovol@gmail.com, pavel.hofman@ivitera.com,
        jbrunet@baylibre.com, jackp@codeaurora.org, colin.king@intel.com,
        pawell@cadence.com
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jing Leng <jleng@ambarella.com>
Subject: [PATCH v2] usb: gadget: f_uac2: fix superspeed transfer
Date:   Mon, 14 Feb 2022 22:32:23 +0800
Message-Id: <20220214143223.5658-1-3090101217@zju.edu.cn>
In-Reply-To: <20220214032606.17227-1-3090101217@zju.edu.cn>
References: <20220214032606.17227-1-3090101217@zju.edu.cn>
Precedence: bulk

From: Jing Leng <jleng@ambarella.com>

On page 362 of the USB3.2 specification (
https://usb.org/sites/default/files/usb_32_20210125.zip),
The 'SuperSpeed Endpoint Companion Descriptor' shall only be returned
by Enhanced SuperSpeed devices that are operating at Gen X speed.
Each endpoint described in an interface is followed by a 'SuperSpeed
Endpoint Companion Descriptor'.

If we use SuperSpeed UDC, host can't recognize the device if endpoint
doesn't have 'SuperSpeed Endpoint Companion Descriptor' followed.

Currently in the uac2 driver code:
1. ss_epout_desc_comp follows ss_epout_desc;
2. ss_epin_fback_desc_comp follows ss_epin_fback_desc;
3. ss_epin_desc_comp follows ss_epin_desc;
4. Only ss_ep_int_desc endpoint doesn't have 'SuperSpeed Endpoint
Companion Descriptor' followed, so we should add it.

Signed-off-by: Jing Leng <jleng@ambarella.com>
---
 drivers/usb/gadget/function/f_uac2.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c
index 097a709549d6..a6fc492f9148 100644
--- a/drivers/usb/gadget/function/f_uac2.c
+++ b/drivers/usb/gadget/function/f_uac2.c
@@ -282,6 +282,14 @@ static struct usb_endpoint_descriptor ss_ep_int_desc = {
 	.bInterval = 4,
 };
 
+static struct usb_ss_ep_comp_descriptor ss_ep_int_desc_comp = {
+	.bLength = sizeof(ss_ep_int_desc_comp),
+	.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
+	.bMaxBurst = 0,
+	.bmAttributes = 0,
+	.wBytesPerInterval = cpu_to_le16(6),
+};
+
 /* Audio Streaming OUT Interface - Alt0 */
 static struct usb_interface_descriptor std_as_out_if0_desc = {
 	.bLength = sizeof std_as_out_if0_desc,
@@ -595,7 +603,8 @@ static struct usb_descriptor_header *ss_audio_desc[] = {
 	(struct usb_descriptor_header *)&in_feature_unit_desc,
 	(struct usb_descriptor_header *)&io_out_ot_desc,
 
-  (struct usb_descriptor_header *)&ss_ep_int_desc,
+	(struct usb_descriptor_header *)&ss_ep_int_desc,
+	(struct usb_descriptor_header *)&ss_ep_int_desc_comp,
 
 	(struct usb_descriptor_header *)&std_as_out_if0_desc,
 	(struct usb_descriptor_header *)&std_as_out_if1_desc,
@@ -657,6 +666,7 @@ static int set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
 
 	case USB_SPEED_HIGH:
 	case USB_SPEED_SUPER:
+	case USB_SPEED_SUPER_PLUS:
 		max_size_ep = 1024;
 		factor = 8000;
 		break;
@@ -723,6 +733,7 @@ static void setup_headers(struct f_uac2_opts *opts,
 	struct usb_ss_ep_comp_descriptor *epout_desc_comp = NULL;
 	struct usb_ss_ep_comp_descriptor *epin_desc_comp = NULL;
 	struct usb_ss_ep_comp_descriptor *epin_fback_desc_comp = NULL;
+	struct usb_ss_ep_comp_descriptor *ep_int_desc_comp = NULL;
 	struct usb_endpoint_descriptor *epout_desc;
 	struct usb_endpoint_descriptor *epin_desc;
 	struct usb_endpoint_descriptor *epin_fback_desc;
@@ -750,6 +761,7 @@ static void setup_headers(struct f_uac2_opts *opts,
 		epin_fback_desc = &ss_epin_fback_desc;
 		epin_fback_desc_comp = &ss_epin_fback_desc_comp;
 		ep_int_desc = &ss_ep_int_desc;
+		ep_int_desc_comp = &ss_ep_int_desc_comp;
 	}
 
 	i = 0;
@@ -778,8 +790,11 @@ static void setup_headers(struct f_uac2_opts *opts,
 	if (EPOUT_EN(opts))
 		headers[i++] = USBDHDR(&io_out_ot_desc);
 
-	if (FUOUT_EN(opts) || FUIN_EN(opts))
+	if (FUOUT_EN(opts) || FUIN_EN(opts)) {
 		headers[i++] = USBDHDR(ep_int_desc);
+		if (ep_int_desc_comp)
+			headers[i++] = USBDHDR(ep_int_desc_comp);
+	}
 
 	if (EPOUT_EN(opts)) {
 		headers[i++] = USBDHDR(&std_as_out_if0_desc);
-- 
2.17.1