Re: [RFC/PATCH 2/2] usb:gadget: Add SuperSpeed support to the Gadget Framework
From: Maulik Mankad
Date: Mon Oct 04 2010 - 10:21:53 EST
Hi,
On Sun, Oct 3, 2010 at 1:32 PM, tlinder <tlinder@xxxxxxxxxxxxxx> wrote:
>
> From: Tatyana Linder <tlinder@xxxxxxxxxxxxxx>
>
> This patch adds the SuperSpeed functionality to the gadget framework.
> In order not to force all the FDs to supply SuperSpeed descriptors when
> operating in SuperSpeed mode the following approach was taken:
> If we're operating in SuperSpeed mode and the FD didn't supply SuperSpeed
> descriptors, the composite layer will automatically create SuperSpeed
> descriptors with default values.
> Support for new SuperSpeed BOS descriptor was added.
> Support for SET_FEATURE and GET_STATUS requests in SuperSpeed mode was
> added.
>
> Signed-off-by: Tatyana Linder <tlinder@xxxxxxxxxxxxxx>
Some comments on coding guidelines below.
> ---
> This patch was verified by USBCV 3.0 and 2.0.
>
> drivers/usb/gadget/Kconfig | 20 ++-
> drivers/usb/gadget/composite.c | 319 +++++++++++++++++++++++++++++++++++++---
> include/linux/usb/ch9.h | 54 +++++++-
> include/linux/usb/composite.h | 24 +++
> include/linux/usb/gadget.h | 19 +++
> 5 files changed, 407 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
> index cd27f9b..9afdd08 100644
> --- a/drivers/usb/gadget/Kconfig
> +++ b/drivers/usb/gadget/Kconfig
> @@ -520,11 +520,11 @@ config USB_GADGET_DUMMY_HCD
> side is the master; the gadget side is the slave. Gadget drivers
> can be high, full, or low speed; and they have access to endpoints
> like those from NET2280, PXA2xx, or SA1100 hardware.
> -
> +
> This may help in some stages of creating a driver to embed in a
> Linux device, since it lets you debug several parts of the gadget
> driver without its hardware or drivers being involved.
> -
> +
> Since such a gadget side driver needs to interoperate with a host
> side Linux-USB device driver, this may help to debug both sides
> of a USB protocol stack.
> @@ -552,6 +552,18 @@ config USB_GADGET_DUALSPEED
> Means that gadget drivers should include extra descriptors
> and code to handle dual-speed controllers.
>
> +config USB_GADGET_SUPERSPEED
> + boolean "Gadget opperating in Super Speed"
spelling "operating"
> + depends on USB_GADGET
> + depends on USB_GADGET_DUALSPEED
> + default n
> + help
> + Enabling this feature enables Super Speed support in the Gadget
> + driver. It means that gadget drivers should include extra (SuperSpeed)
> + descriptors.
> + For composite devices: if SupeSpeed descriptors weren't supplied by
spelling "Superspeed"
> + the FD, they will be automatically generated with default values.
> +
> #
> # USB Gadget Drivers
> #
> @@ -633,7 +645,7 @@ config USB_ETH
> help
> This driver implements Ethernet style communication, in one of
> several ways:
> -
> +
> - The "Communication Device Class" (CDC) Ethernet Control Model.
> That protocol is often avoided with pure Ethernet adapters, in
> favor of simpler vendor-specific hardware, but is widely
> @@ -673,7 +685,7 @@ config USB_ETH_RNDIS
> If you say "y" here, the Ethernet gadget driver will try to provide
> a second device configuration, supporting RNDIS to talk to such
> Microsoft USB hosts.
> -
> +
> To make MS-Windows work with this, use Documentation/usb/linux.inf
> as the "driver info file". For versions of MS-Windows older than
> XP, you'll need to download drivers from Microsoft's website; a URL
> diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
> index c619c80..a5dcfe1 100644
> --- a/drivers/usb/gadget/composite.c
> +++ b/drivers/usb/gadget/composite.c
> @@ -70,6 +70,102 @@ static char *iSerialNumber;
> module_param(iSerialNumber, charp, 0);
> MODULE_PARM_DESC(iSerialNumber, "SerialNumber string");
>
> +/** Default endpoint companion descriptor */
> +static struct usb_ss_ep_comp_descriptor ep_comp_desc = {
> + .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
> + .bLength = 0x06,
> + .bMaxBurst = 0, /*the default is we don't support bursting*/
Commenting style not proper. It should be like "/* Leave a space as shown */"
> + .bmAttributes = 0, /*2^0 streams supported*/
> + .wBytesPerInterval = 0,
> +};
> +
> +/**This function receives a pointer to usb_function and adds
> + * missing super speed descriptors in the ss_descriptor field
> + * according to its hs_descriptors field.
> + *
> + * In more details: this function copies f->hs_descriptors while
> + * updating the endpoint descriptor and adding endpoint
> + * companion descriptor
> + */
> +static void create_ss_descriptors(struct usb_function *f)
> +{
> + unsigned bytes; /*number of bytes to allocate*/
> + unsigned n_desc; /* number of descriptors*/
> + void *mem; /*allocated memory to copy to*/
> + struct usb_descriptor_header **tmp;
> + struct usb_endpoint_descriptor *ep_desc ;
> + struct usb_descriptor_header **src = f->hs_descriptors;
> +
> + if (!f->hs_descriptors)
> + return;
> +
> + /* Count number of EPs (in order to know how many SS_EP_COMPANION
> + descriptors to add), the total number of descriptors and the sum of
> + each descriptor bLength field in order to know how much memory to
> + allocate*/
Multi line comment style as per coding guidelines is as below.
/*
* First line
* Second line
* Third line
*/
> + for (bytes = 0, n_desc = 0, tmp = src; *tmp; tmp++, n_desc++) {
> + if ((*tmp)->bDescriptorType == USB_DT_ENDPOINT) {
> + bytes += ep_comp_desc.bLength;
> + n_desc++;
> + }
> + bytes += (*tmp)->bLength;
> + }
> +
> + bytes += (n_desc + 1) * sizeof(*tmp);
> + mem = kmalloc(bytes, GFP_KERNEL);
> + if (!mem)
> + return;
> +
> + /* fill in pointers starting at "tmp",
> + * to descriptors copied starting at "mem";
> + * and return "ret"
> + */
Same here.
> + tmp = mem;
> + f->ss_descriptors = mem;
> + mem += (n_desc + 1) * sizeof(*tmp);
> + while (*src) {
> + /*Copy the original descriptor*/
> + memcpy(mem, *src, (*src)->bLength);
> + switch ((*src)->bDescriptorType) {
> + case USB_DT_ENDPOINT:
> + /*update ep descriptor*/
> + ep_desc = (struct usb_endpoint_descriptor *)mem;
> + switch (ep_desc->bmAttributes &
> + USB_ENDPOINT_XFERTYPE_MASK) {
> + case USB_ENDPOINT_XFER_CONTROL:
> + ep_desc->wMaxPacketSize = 512;
> + ep_desc->bInterval = 0;
> + break;
> + case USB_ENDPOINT_XFER_BULK:
> + ep_desc->wMaxPacketSize = 1024;
> + ep_desc->bInterval = 0;
> + break;
> + case USB_ENDPOINT_XFER_INT:
> + case USB_ENDPOINT_XFER_ISOC:
> + break;
> + }
> + *tmp = mem;
> + tmp++;
> + mem += (*src)->bLength;
> + /*add ep companion descriptor*/
> + memcpy(mem, &ep_comp_desc, ep_comp_desc.bLength);
> + *tmp = mem;
> + tmp++;
> + mem += ep_comp_desc.bLength;
> + break;
> + default:
> + *tmp = mem;
> + tmp++;
> + mem += (*src)->bLength;
> + break;
> + }
> + src++;
> + }
> + *tmp = NULL; /*The last (struct usb_descriptor_header *) in the
> + descriptors vector is NULL*/
Fix commenting style.
> + f->ss_desc_allocated = true;
> +}
> +
> /*-------------------------------------------------------------------------*/
> /**
> * next_ep_desc - advance to the next EP descriptor
> @@ -110,6 +206,9 @@ int ep_choose(struct usb_gadget *g, struct usb_function *f, struct usb_ep *_ep)
> struct usb_endpoint_descriptor *chosen_desc = NULL;
> struct usb_descriptor_header **speed_desc = NULL;
>
> + struct usb_ss_ep_comp_descriptor *comp_desc = NULL;
> + int want_comp_desc = 0;
> +
> struct usb_descriptor_header **d_spd; /* cursor for speed desc */
>
> if (!g || !f || !_ep)
> @@ -117,6 +216,13 @@ int ep_choose(struct usb_gadget *g, struct usb_function *f, struct usb_ep *_ep)
>
> /* select desired speed */
> switch (g->speed) {
> + case USB_SPEED_SUPER:
> + if (gadget_is_superspeed(g)) {
> + speed_desc = f->ss_descriptors;
> + want_comp_desc = 1;
> + break;
> + }
> + /*else: Fall trough*/
> case USB_SPEED_HIGH:
> if (gadget_is_dualspeed(g)) {
> speed_desc = f->hs_descriptors;
> @@ -143,7 +249,18 @@ ep_found:
> /* commit results */
> _ep->maxpacket = chosen_desc->wMaxPacketSize;
> _ep->desc = chosen_desc;
> -
> + _ep->comp_desc = NULL;
> + if (want_comp_desc) {
> + /**
> + * Companion descriptor should follow EP descriptor
> + * USB 3.0 spec, #9.6.7
> + */
Same here. No two **.
> + comp_desc = (struct usb_ss_ep_comp_descriptor *)*(++d_spd);
> + if (!comp_desc ||
> + (comp_desc->bDescriptorType != USB_DT_SS_ENDPOINT_COMP))
> + return -EIO;
> + _ep->comp_desc = comp_desc;
> + }
> return 0;
> }
>
> @@ -185,6 +302,12 @@ int usb_add_function(struct usb_configuration *config,
> list_del(&function->list);
> function->config = NULL;
> }
> + /*Add SS descriptors if there are any. This has to be done
> + after the bind since we need the hs_descriptors to be set in
> + usb_function and some of the FDs does it in the bind. */
And here.
Please run scripts/checkpatch.pl to fix up the coding style issues at
several places in this patch.
Regards,
Maulik
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