[PATCH v4] usb: gadget: f_uac1: add different speed transfers support

From: 3090101217
Date: Thu Feb 17 2022 - 00:20:47 EST


From: Jing Leng <jleng@xxxxxxxxxxxxx>

On page 61 of the UAC1 specification (
https://www.usb.org/sites/default/files/audio10.pdf),
bInterval is interval for polling endpoint for data transfers
expressed in milliseconds, must be set to 1.

On page 47 of the USB2.0 specification (
https://www.usb.org/sites/default/files/usb_20_20211008.zip),
An isochronous endpoint must specify its required bus access period.
Full-/high-speed endpoints must specify a desired period as
(2^(bInterval-1)) x F, where bInterval is in the range one to
(and including) 16 and F is 125 μs for high-speed and 1ms for full-speed.

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'.

Currently uac1 driver doesn't set bInterval to 1 in full speed transfer
and doesn't have a 'SuperSpeed Endpoint Companion Descriptor' behind
'Standard Endpoint Descriptor'.

So we should set bInterval to 1 in full speed transfer and set it to 4
in other speed transfers, and we should add 'SuperSpeed Endpoint Companion
Descriptor' behind 'Standard Endpoint Descriptor' for superspeed transfer.

Signed-off-by: Jing Leng <jleng@xxxxxxxxxxxxx>
---
ChangeLog v3->v4:
- Remove static variables which are explicitly initialized to 0
ChangeLog v2->v3:
- Add 'static' before 'struct usb_ss_ep_comp_descriptor ac_int_ep_desc_comp'.
ChangeLog v1->v2:
- Modify the title of the PATCH
- Update more detailed description of the PATCH
---
drivers/usb/gadget/function/f_uac1.c | 269 ++++++++++++++++++++++-----
1 file changed, 219 insertions(+), 50 deletions(-)

diff --git a/drivers/usb/gadget/function/f_uac1.c b/drivers/usb/gadget/function/f_uac1.c
index 03f50643fbba..d03d4ce048b6 100644
--- a/drivers/usb/gadget/function/f_uac1.c
+++ b/drivers/usb/gadget/function/f_uac1.c
@@ -123,6 +123,15 @@ static struct uac_feature_unit_descriptor *in_feature_unit_desc;
static struct uac_feature_unit_descriptor *out_feature_unit_desc;

/* AC IN Interrupt Endpoint */
+static struct usb_endpoint_descriptor fs_int_ep_desc = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+ .bEndpointAddress = USB_DIR_IN,
+ .bmAttributes = USB_ENDPOINT_XFER_INT,
+ .wMaxPacketSize = cpu_to_le16(2),
+ .bInterval = 1,
+};
+
static struct usb_endpoint_descriptor ac_int_ep_desc = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
@@ -132,6 +141,12 @@ static struct usb_endpoint_descriptor ac_int_ep_desc = {
.bInterval = 4,
};

+static struct usb_ss_ep_comp_descriptor ac_int_ep_desc_comp = {
+ .bLength = sizeof(ac_int_ep_desc_comp),
+ .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
+ .wBytesPerInterval = cpu_to_le16(2),
+};
+
/* B.4.1 Standard AS Interface Descriptor */
static struct usb_interface_descriptor as_out_interface_alt_0_desc = {
.bLength = USB_DT_INTERFACE_SIZE,
@@ -201,6 +216,16 @@ static struct uac_format_type_i_discrete_descriptor_1 as_out_type_i_desc = {
};

/* Standard ISO OUT Endpoint Descriptor */
+static struct usb_endpoint_descriptor fs_out_ep_desc = {
+ .bLength = USB_DT_ENDPOINT_AUDIO_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+ .bEndpointAddress = USB_DIR_OUT,
+ .bmAttributes = USB_ENDPOINT_SYNC_ADAPTIVE
+ | USB_ENDPOINT_XFER_ISOC,
+ .wMaxPacketSize = cpu_to_le16(UAC1_OUT_EP_MAX_PACKET_SIZE),
+ .bInterval = 1,
+};
+
static struct usb_endpoint_descriptor as_out_ep_desc = {
.bLength = USB_DT_ENDPOINT_AUDIO_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
@@ -211,6 +236,12 @@ static struct usb_endpoint_descriptor as_out_ep_desc = {
.bInterval = 4,
};

+static struct usb_ss_ep_comp_descriptor as_out_ep_desc_comp = {
+ .bLength = sizeof(as_out_ep_desc_comp),
+ .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
+ .wBytesPerInterval = cpu_to_le16(UAC1_OUT_EP_MAX_PACKET_SIZE),
+};
+
/* Class-specific AS ISO OUT Endpoint Descriptor */
static struct uac_iso_endpoint_descriptor as_iso_out_desc = {
.bLength = UAC_ISO_ENDPOINT_DESC_SIZE,
@@ -231,7 +262,17 @@ static struct uac_format_type_i_discrete_descriptor_1 as_in_type_i_desc = {
.bSamFreqType = 1,
};

-/* Standard ISO OUT Endpoint Descriptor */
+/* Standard ISO IN Endpoint Descriptor */
+static struct usb_endpoint_descriptor fs_in_ep_desc = {
+ .bLength = USB_DT_ENDPOINT_AUDIO_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+ .bEndpointAddress = USB_DIR_IN,
+ .bmAttributes = USB_ENDPOINT_SYNC_ASYNC
+ | USB_ENDPOINT_XFER_ISOC,
+ .wMaxPacketSize = cpu_to_le16(UAC1_OUT_EP_MAX_PACKET_SIZE),
+ .bInterval = 1,
+};
+
static struct usb_endpoint_descriptor as_in_ep_desc = {
.bLength = USB_DT_ENDPOINT_AUDIO_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
@@ -242,6 +283,12 @@ static struct usb_endpoint_descriptor as_in_ep_desc = {
.bInterval = 4,
};

+static struct usb_ss_ep_comp_descriptor as_in_ep_desc_comp = {
+ .bLength = sizeof(as_in_ep_desc_comp),
+ .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
+ .wBytesPerInterval = cpu_to_le16(UAC1_OUT_EP_MAX_PACKET_SIZE),
+};
+
/* Class-specific AS ISO OUT Endpoint Descriptor */
static struct uac_iso_endpoint_descriptor as_iso_in_desc = {
.bLength = UAC_ISO_ENDPOINT_DESC_SIZE,
@@ -252,7 +299,75 @@ static struct uac_iso_endpoint_descriptor as_iso_in_desc = {
.wLockDelay = 0,
};

-static struct usb_descriptor_header *f_audio_desc[] = {
+static struct usb_descriptor_header *fs_audio_desc[] = {
+ (struct usb_descriptor_header *)&ac_interface_desc,
+ (struct usb_descriptor_header *)&ac_header_desc,
+
+ (struct usb_descriptor_header *)&usb_out_it_desc,
+ (struct usb_descriptor_header *)&io_out_ot_desc,
+ (struct usb_descriptor_header *)&out_feature_unit_desc,
+
+ (struct usb_descriptor_header *)&io_in_it_desc,
+ (struct usb_descriptor_header *)&usb_in_ot_desc,
+ (struct usb_descriptor_header *)&in_feature_unit_desc,
+
+ (struct usb_descriptor_header *)&fs_int_ep_desc,
+
+ (struct usb_descriptor_header *)&as_out_interface_alt_0_desc,
+ (struct usb_descriptor_header *)&as_out_interface_alt_1_desc,
+ (struct usb_descriptor_header *)&as_out_header_desc,
+
+ (struct usb_descriptor_header *)&as_out_type_i_desc,
+
+ (struct usb_descriptor_header *)&fs_out_ep_desc,
+ (struct usb_descriptor_header *)&as_iso_out_desc,
+
+ (struct usb_descriptor_header *)&as_in_interface_alt_0_desc,
+ (struct usb_descriptor_header *)&as_in_interface_alt_1_desc,
+ (struct usb_descriptor_header *)&as_in_header_desc,
+
+ (struct usb_descriptor_header *)&as_in_type_i_desc,
+
+ (struct usb_descriptor_header *)&fs_in_ep_desc,
+ (struct usb_descriptor_header *)&as_iso_in_desc,
+ NULL,
+};
+
+static struct usb_descriptor_header *hs_audio_desc[] = {
+ (struct usb_descriptor_header *)&ac_interface_desc,
+ (struct usb_descriptor_header *)&ac_header_desc,
+
+ (struct usb_descriptor_header *)&usb_out_it_desc,
+ (struct usb_descriptor_header *)&io_out_ot_desc,
+ (struct usb_descriptor_header *)&out_feature_unit_desc,
+
+ (struct usb_descriptor_header *)&io_in_it_desc,
+ (struct usb_descriptor_header *)&usb_in_ot_desc,
+ (struct usb_descriptor_header *)&in_feature_unit_desc,
+
+ (struct usb_descriptor_header *)&ac_int_ep_desc,
+
+ (struct usb_descriptor_header *)&as_out_interface_alt_0_desc,
+ (struct usb_descriptor_header *)&as_out_interface_alt_1_desc,
+ (struct usb_descriptor_header *)&as_out_header_desc,
+
+ (struct usb_descriptor_header *)&as_out_type_i_desc,
+
+ (struct usb_descriptor_header *)&as_out_ep_desc,
+ (struct usb_descriptor_header *)&as_iso_out_desc,
+
+ (struct usb_descriptor_header *)&as_in_interface_alt_0_desc,
+ (struct usb_descriptor_header *)&as_in_interface_alt_1_desc,
+ (struct usb_descriptor_header *)&as_in_header_desc,
+
+ (struct usb_descriptor_header *)&as_in_type_i_desc,
+
+ (struct usb_descriptor_header *)&as_in_ep_desc,
+ (struct usb_descriptor_header *)&as_iso_in_desc,
+ NULL,
+};
+
+static struct usb_descriptor_header *ss_audio_desc[] = {
(struct usb_descriptor_header *)&ac_interface_desc,
(struct usb_descriptor_header *)&ac_header_desc,

@@ -265,6 +380,7 @@ static struct usb_descriptor_header *f_audio_desc[] = {
(struct usb_descriptor_header *)&in_feature_unit_desc,

(struct usb_descriptor_header *)&ac_int_ep_desc,
+ (struct usb_descriptor_header *)&ac_int_ep_desc_comp,

(struct usb_descriptor_header *)&as_out_interface_alt_0_desc,
(struct usb_descriptor_header *)&as_out_interface_alt_1_desc,
@@ -273,6 +389,7 @@ static struct usb_descriptor_header *f_audio_desc[] = {
(struct usb_descriptor_header *)&as_out_type_i_desc,

(struct usb_descriptor_header *)&as_out_ep_desc,
+ (struct usb_descriptor_header *)&as_out_ep_desc_comp,
(struct usb_descriptor_header *)&as_iso_out_desc,

(struct usb_descriptor_header *)&as_in_interface_alt_0_desc,
@@ -282,6 +399,7 @@ static struct usb_descriptor_header *f_audio_desc[] = {
(struct usb_descriptor_header *)&as_in_type_i_desc,

(struct usb_descriptor_header *)&as_in_ep_desc,
+ (struct usb_descriptor_header *)&as_in_ep_desc_comp,
(struct usb_descriptor_header *)&as_iso_in_desc,
NULL,
};
@@ -329,6 +447,89 @@ static struct usb_gadget_strings *uac1_strings[] = {
NULL,
};

+/* Use macro to overcome line length limitation */
+#define USBDHDR(p) ((struct usb_descriptor_header *)(p))
+
+static void setup_headers(struct f_uac1_opts *opts,
+ struct usb_descriptor_header **headers,
+ enum usb_device_speed speed)
+{
+ 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 *ep_int_desc_comp = NULL;
+ struct usb_endpoint_descriptor *epout_desc;
+ struct usb_endpoint_descriptor *epin_desc;
+ struct usb_endpoint_descriptor *ep_int_desc;
+ int i;
+
+ switch (speed) {
+ case USB_SPEED_FULL:
+ epout_desc = &fs_out_ep_desc;
+ epin_desc = &fs_in_ep_desc;
+ ep_int_desc = &fs_int_ep_desc;
+ break;
+ case USB_SPEED_HIGH:
+ epout_desc = &as_out_ep_desc;
+ epin_desc = &as_in_ep_desc;
+ ep_int_desc = &ac_int_ep_desc;
+ break;
+ default:
+ epout_desc = &as_out_ep_desc;
+ epout_desc_comp = &as_out_ep_desc_comp;
+ epin_desc = &as_in_ep_desc;
+ epin_desc_comp = &as_in_ep_desc_comp;
+ ep_int_desc = &ac_int_ep_desc;
+ ep_int_desc_comp = &ac_int_ep_desc_comp;
+ break;
+ }
+
+ i = 0;
+ headers[i++] = USBDHDR(&ac_interface_desc);
+ headers[i++] = USBDHDR(ac_header_desc);
+
+ if (EPOUT_EN(opts)) {
+ headers[i++] = USBDHDR(&usb_out_it_desc);
+ headers[i++] = USBDHDR(&io_out_ot_desc);
+ if (FUOUT_EN(opts))
+ headers[i++] = USBDHDR(out_feature_unit_desc);
+ }
+
+ if (EPIN_EN(opts)) {
+ headers[i++] = USBDHDR(&io_in_it_desc);
+ headers[i++] = USBDHDR(&usb_in_ot_desc);
+ if (FUIN_EN(opts))
+ headers[i++] = USBDHDR(in_feature_unit_desc);
+ }
+
+ 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(&as_out_interface_alt_0_desc);
+ headers[i++] = USBDHDR(&as_out_interface_alt_1_desc);
+ headers[i++] = USBDHDR(&as_out_header_desc);
+ headers[i++] = USBDHDR(&as_out_type_i_desc);
+ headers[i++] = USBDHDR(epout_desc);
+ if (epout_desc_comp)
+ headers[i++] = USBDHDR(epout_desc_comp);
+ headers[i++] = USBDHDR(&as_iso_out_desc);
+ }
+ if (EPIN_EN(opts)) {
+ headers[i++] = USBDHDR(&as_in_interface_alt_0_desc);
+ headers[i++] = USBDHDR(&as_in_interface_alt_1_desc);
+ headers[i++] = USBDHDR(&as_in_header_desc);
+ headers[i++] = USBDHDR(&as_in_type_i_desc);
+ headers[i++] = USBDHDR(epin_desc);
+ if (epin_desc_comp)
+ headers[i++] = USBDHDR(epin_desc_comp);
+ headers[i++] = USBDHDR(&as_iso_in_desc);
+ }
+ headers[i] = NULL;
+}
+
/*
* This function is an ALSA sound card following USB Audio Class Spec 1.0.
*/
@@ -957,9 +1158,6 @@ uac1_ac_header_descriptor *build_ac_header_desc(struct f_uac1_opts *opts)
return ac_desc;
}

-/* Use macro to overcome line length limitation */
-#define USBDHDR(p) (struct usb_descriptor_header *)(p)
-
static void setup_descriptor(struct f_uac1_opts *opts)
{
/* patch descriptors */
@@ -1015,44 +1213,9 @@ static void setup_descriptor(struct f_uac1_opts *opts)
ac_header_desc->wTotalLength = cpu_to_le16(len);
}

- i = 0;
- f_audio_desc[i++] = USBDHDR(&ac_interface_desc);
- f_audio_desc[i++] = USBDHDR(ac_header_desc);
-
- if (EPOUT_EN(opts)) {
- f_audio_desc[i++] = USBDHDR(&usb_out_it_desc);
- f_audio_desc[i++] = USBDHDR(&io_out_ot_desc);
- if (FUOUT_EN(opts))
- f_audio_desc[i++] = USBDHDR(out_feature_unit_desc);
- }
-
- if (EPIN_EN(opts)) {
- f_audio_desc[i++] = USBDHDR(&io_in_it_desc);
- f_audio_desc[i++] = USBDHDR(&usb_in_ot_desc);
- if (FUIN_EN(opts))
- f_audio_desc[i++] = USBDHDR(in_feature_unit_desc);
- }
-
- if (FUOUT_EN(opts) || FUIN_EN(opts))
- f_audio_desc[i++] = USBDHDR(&ac_int_ep_desc);
-
- if (EPOUT_EN(opts)) {
- f_audio_desc[i++] = USBDHDR(&as_out_interface_alt_0_desc);
- f_audio_desc[i++] = USBDHDR(&as_out_interface_alt_1_desc);
- f_audio_desc[i++] = USBDHDR(&as_out_header_desc);
- f_audio_desc[i++] = USBDHDR(&as_out_type_i_desc);
- f_audio_desc[i++] = USBDHDR(&as_out_ep_desc);
- f_audio_desc[i++] = USBDHDR(&as_iso_out_desc);
- }
- if (EPIN_EN(opts)) {
- f_audio_desc[i++] = USBDHDR(&as_in_interface_alt_0_desc);
- f_audio_desc[i++] = USBDHDR(&as_in_interface_alt_1_desc);
- f_audio_desc[i++] = USBDHDR(&as_in_header_desc);
- f_audio_desc[i++] = USBDHDR(&as_in_type_i_desc);
- f_audio_desc[i++] = USBDHDR(&as_in_ep_desc);
- f_audio_desc[i++] = USBDHDR(&as_iso_in_desc);
- }
- f_audio_desc[i] = NULL;
+ setup_headers(opts, fs_audio_desc, USB_SPEED_FULL);
+ setup_headers(opts, hs_audio_desc, USB_SPEED_HIGH);
+ setup_headers(opts, ss_audio_desc, USB_SPEED_SUPER);
}

static int f_audio_validate_opts(struct g_audio *audio, struct device *dev)
@@ -1264,7 +1427,6 @@ static int f_audio_bind(struct usb_configuration *c, struct usb_function *f)
if (!ep)
goto err_free_fu;
uac1->int_ep = ep;
- uac1->int_ep->desc = &ac_int_ep_desc;

ac_interface_desc.bNumEndpoints = 1;
}
@@ -1275,7 +1437,6 @@ static int f_audio_bind(struct usb_configuration *c, struct usb_function *f)
if (!ep)
goto err_free_fu;
audio->out_ep = ep;
- audio->out_ep->desc = &as_out_ep_desc;
}

if (EPIN_EN(audio_opts)) {
@@ -1283,19 +1444,27 @@ static int f_audio_bind(struct usb_configuration *c, struct usb_function *f)
if (!ep)
goto err_free_fu;
audio->in_ep = ep;
- audio->in_ep->desc = &as_in_ep_desc;
}

+ /* FS endpoint addresses are copied from autoconfigured HS descriptors */
+ fs_int_ep_desc.bEndpointAddress = ac_int_ep_desc.bEndpointAddress;
+ fs_out_ep_desc.bEndpointAddress = as_out_ep_desc.bEndpointAddress;
+ fs_in_ep_desc.bEndpointAddress = as_in_ep_desc.bEndpointAddress;
+
setup_descriptor(audio_opts);

/* copy descriptors, and track endpoint copies */
- status = usb_assign_descriptors(f, f_audio_desc, f_audio_desc, NULL,
- NULL);
+ status = usb_assign_descriptors(f, fs_audio_desc, hs_audio_desc,
+ ss_audio_desc, ss_audio_desc);
if (status)
goto err_free_fu;

- audio->out_ep_maxpsize = le16_to_cpu(as_out_ep_desc.wMaxPacketSize);
- audio->in_ep_maxpsize = le16_to_cpu(as_in_ep_desc.wMaxPacketSize);
+ audio->out_ep_maxpsize = max_t(u16,
+ le16_to_cpu(fs_out_ep_desc.wMaxPacketSize),
+ le16_to_cpu(as_out_ep_desc.wMaxPacketSize));
+ audio->in_ep_maxpsize = max_t(u16,
+ le16_to_cpu(fs_in_ep_desc.wMaxPacketSize),
+ le16_to_cpu(as_in_ep_desc.wMaxPacketSize));
audio->params.c_chmask = audio_opts->c_chmask;
audio->params.c_srate = audio_opts->c_srate;
audio->params.c_ssize = audio_opts->c_ssize;
--
2.17.1