Re: [V2 PATCH 02/10] added media agnostic (MA) USB HCD roothubs

Oliver Neukum
2014-11-12T08:35:43Z

On Mon, 2014-11-10 at 18:09 -0800, Stephanie Wallick wrote:
> This is where we implement USB 2.0 and 3.0 roothubs. From the host's
> perspective, hub state is set and tracked just like any other USB roothub.
> Likewise, requests to the roothub appear to be handled like any other wired
> USB request.
>
> Signed-off-by: Sean O. Stalley <sean.stalley@intel.com>
> Signed-off-by: Stephanie Wallick <stephanie.s.wallick@intel.com>
> ---
> drivers/staging/mausb/drivers/mausb_hub.c | 849 ++++++++++++++++++++++++++++++
> drivers/staging/mausb/drivers/mausb_hub.h | 128 +++++
> 2 files changed, 977 insertions(+)
> create mode 100644 drivers/staging/mausb/drivers/mausb_hub.c
> create mode 100644 drivers/staging/mausb/drivers/mausb_hub.h
>
> diff --git a/drivers/staging/mausb/drivers/mausb_hub.c b/drivers/staging/mausb/drivers/mausb_hub.c
> new file mode 100644
> index 0000000..63c0fe4
> --- /dev/null
> +++ b/drivers/staging/mausb/drivers/mausb_hub.c

> +/**
> + * Returns true if the given is the superspeed HCD. Note: The primary HCD is
> + * High Speed and the shared HCD is SuperSpeed.
> + */

Why in that order?

> +bool mausb_is_ss_hcd(struct usb_hcd *hcd)
> +{
> + if (usb_hcd_is_primary_hcd(hcd))
> + return false;
> + else
> + return true;
> +}

> +
> +/**
> + * Called by usb core when polling for a port status change.
> + *
> + * @hcd: USB HCD being polled.
> + * @buf: Holds port status changes (if any).
> + *
> + * Returns zero if there is no status change, otherwise returns number of
> + * bytes in buf. When there is a status change on a port, the bit indexed
> + * at the port number + 1 (e.g. bit 2 for port 1) is set in the buffer.
> + */
> +int mausb_hub_status_data(struct usb_hcd *hcd, char *buf)
> +{
> + int i;
> + u16 port_change = 0;
> + u32 status = 0;
> + int ret = 1;
> + struct mausb_hcd *mhcd = usb_hcd_to_mausb_hcd(hcd);
> + struct mausb_root_hub *roothub = usb_hcd_to_roothub(hcd);
> +
> + /*
> + * Buf should never be more that 2 bytes. USB 3.0 hubs cannot have
> + * more than 15 downstream ports.
> + */
> + buf[0] = 0;
> + if (MAUSB_ROOTHUB_NUM_PORTS > 7) {
> + buf[1] = 0;
> + ret++;
> + }

Endianness bug.

> +
> + for (i = 0; i < MAUSB_ROOTHUB_NUM_PORTS; i++) {
> + port_change = roothub->port_status[i].wPortChange;
> + if (port_change)
> + status |= (1 << (i + 1));
> + }
> +
> + mausb_dbg(mhcd, "%s: hub status is 0x%x\n", __func__, status);
> +
> + /* hcd might be suspended, resume if there is a status change */
> + if (mhcd->disabled == 0) {
> + if ((hcd->state == HC_STATE_SUSPENDED) && status)
> + usb_hcd_resume_root_hub(hcd);
> + }
> +
> + memcpy(buf, (char *)&status, ret);
> +
> + return status ? ret : 0;
> +}
> +
> +/**
> + * Sets the bitfields in the hub descriptor of the 2.0 root hub. Always
> + * returns zero.
> + */
> +int mausb_set_hub_descriptor(struct usb_hub_descriptor *hub_des)
> +{
> + /* set the values to the default */
> + hub_des->bDescLength = sizeof(struct usb_hub_descriptor);
> + hub_des->bDescriptorType = USB_DT_HUB;
> + hub_des->bNbrPorts = MAUSB_ROOTHUB_NUM_PORTS;
> + hub_des->wHubCharacteristics = MAUSB_ROOTHUB_CHAR;
> + hub_des->bPwrOn2PwrGood = MAUSB_ROOTHUB_PWR_ON_2_PWR_GOOD;
> + hub_des->bHubContrCurrent = MAUSB_ROOTHUB_CONTR_CURRENT;

Is that descriptor in bus or host endianness?

> +
> + return 0;
> +}
> +
> +/**
> + * Sets the bitfields in the hub descriptor of the 3.0 root hub. Always
> + * returns zero.

Then why return anything?

> + */
> +int mausb_set_ss_hub_descriptor(struct usb_hub_descriptor *hub_des)
> +{
> + /* set the values to the default */
> + hub_des->bDescLength = sizeof(struct usb_hub_descriptor);
> + hub_des->bDescriptorType = USB_DT_SS_HUB;
> + hub_des->bNbrPorts = MAUSB_ROOTHUB_NUM_PORTS;
> + hub_des->wHubCharacteristics = MAUSB_ROOTHUB_CHAR;
> + hub_des->bPwrOn2PwrGood = MAUSB_ROOTHUB_PWR_ON_2_PWR_GOOD;
> + hub_des->bHubContrCurrent = MAUSB_ROOTHUB_CONTR_CURRENT;
> +
> + /* USB3-specific parameters */
> + hub_des->u.ss.bHubHdrDecLat = MAUSB_ROOTHUB_HDR_DEC_LAT;
> + hub_des->u.ss.wHubDelay = MAUSB_ROOTHUB_DELAY;
> + hub_des->u.ss.DeviceRemovable = MAUSB_ALL_DEV_REMOVABLE;
> +
> + return 0;
> +}

> +/**
> + * Contains all the structures required to emulate a root hub. One instance
> + * exists per root hub.
> + */
> +struct __attribute__((__packed__)) mausb_root_hub {

Why __packed__ ?
> +
> + /* hub parameters */
> + struct usb_hub_descriptor descriptor;
> + struct usb_hub_status status;
> +
> + /* port parameters*/
> + struct usb_port_status port_status[MAUSB_ROOTHUB_NUM_PORTS];
> +
> + /* root hub state */
> + enum mausb_rh_state rh_state;
> +
> +};

HTH
Oliver

--
Oliver Neukum <oneukum@suse.de>