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Commit 9502c46c authored by Pratyush Anand's avatar Pratyush Anand Committed by Greg Kroah-Hartman
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xhci: A default implementation for Ux timeout calculation and tier policy check 



As best case, a host controller should support U0 to U1 switching for
the devices connected below any tier of hub level supported by usb
specification. Therefore xhci_check_tier_policy should always return
success as default implementation.

A host should be able to issue LGO_Ux after the timeout calculated as
per definition of system exit latency defined in C.1.5.2. Therefore
xhci_calculate_ux_timeout returns ux_params.sel as the default
implementation.

Use default calculation in absence of any vendor specific limitations.

Signed-off-by: default avatarPratyush Anand <pratyush.anand@st.com>
Tested-by: default avatarAymen Bouattay <aymen.bouattay@st.com>
Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ec5734c4

drivers/usb/host/xhci.c

+48 −18
Original line number Diff line number Diff line
@@ -4288,8 +4288,7 @@ static u16 xhci_get_timeout_no_hub_lpm(struct usb_device *udev, 
	return USB3_LPM_DISABLED;

}



/* Returns the hub-encoded U1 timeout value.

 * The U1 timeout should be the maximum of the following values:

/* The U1 timeout should be the maximum of the following values:

 *  - For control endpoints, U1 system exit latency (SEL) * 3

 *  - For bulk endpoints, U1 SEL * 5

 *  - For interrupt endpoints:
@@ -4297,7 +4296,8 @@ static u16 xhci_get_timeout_no_hub_lpm(struct usb_device *udev, 
 *    - Periodic EPs, max(105% of bInterval, U1 SEL * 2)

 *  - For isochronous endpoints, max(105% of bInterval, U1 SEL * 2)

 */

static u16 xhci_calculate_intel_u1_timeout(struct usb_device *udev,

static unsigned long long xhci_calculate_intel_u1_timeout(

		struct usb_device *udev,

		struct usb_endpoint_descriptor *desc)

{

	unsigned long long timeout_ns;
@@ -4329,11 +4329,28 @@ static u16 xhci_calculate_intel_u1_timeout(struct usb_device *udev, 
		return 0;

	}



	/* The U1 timeout is encoded in 1us intervals. */

	timeout_ns = DIV_ROUND_UP_ULL(timeout_ns, 1000);

	/* Don't return a timeout of zero, because that's USB3_LPM_DISABLED. */

	return timeout_ns;

}



/* Returns the hub-encoded U1 timeout value. */

static u16 xhci_calculate_u1_timeout(struct xhci_hcd *xhci,

		struct usb_device *udev,

		struct usb_endpoint_descriptor *desc)

{

	unsigned long long timeout_ns;



	if (xhci->quirks & XHCI_INTEL_HOST)

		timeout_ns = xhci_calculate_intel_u1_timeout(udev, desc);

	else

		timeout_ns = udev->u1_params.sel;



	/* The U1 timeout is encoded in 1us intervals.

	 * Don't return a timeout of zero, because that's USB3_LPM_DISABLED.

	 */

	if (timeout_ns == USB3_LPM_DISABLED)

		timeout_ns++;

		timeout_ns = 1;

	else

		timeout_ns = DIV_ROUND_UP_ULL(timeout_ns, 1000);



	/* If the necessary timeout value is bigger than what we can set in the

	 * USB 3.0 hub, we have to disable hub-initiated U1.
@@ -4345,14 +4362,14 @@ static u16 xhci_calculate_intel_u1_timeout(struct usb_device *udev, 
	return xhci_get_timeout_no_hub_lpm(udev, USB3_LPM_U1);

}



/* Returns the hub-encoded U2 timeout value.

 * The U2 timeout should be the maximum of:

/* The U2 timeout should be the maximum of:

 *  - 10 ms (to avoid the bandwidth impact on the scheduler)

 *  - largest bInterval of any active periodic endpoint (to avoid going

 *    into lower power link states between intervals).

 *  - the U2 Exit Latency of the device

 */

static u16 xhci_calculate_intel_u2_timeout(struct usb_device *udev,

static unsigned long long xhci_calculate_intel_u2_timeout(

		struct usb_device *udev,

		struct usb_endpoint_descriptor *desc)

{

	unsigned long long timeout_ns;
@@ -4368,6 +4385,21 @@ static u16 xhci_calculate_intel_u2_timeout(struct usb_device *udev, 
	if (u2_del_ns > timeout_ns)

		timeout_ns = u2_del_ns;



	return timeout_ns;

}



/* Returns the hub-encoded U2 timeout value. */

static u16 xhci_calculate_u2_timeout(struct xhci_hcd *xhci,

		struct usb_device *udev,

		struct usb_endpoint_descriptor *desc)

{

	unsigned long long timeout_ns;



	if (xhci->quirks & XHCI_INTEL_HOST)

		timeout_ns = xhci_calculate_intel_u2_timeout(udev, desc);

	else

		timeout_ns = udev->u2_params.sel;



	/* The U2 timeout is encoded in 256us intervals */

	timeout_ns = DIV_ROUND_UP_ULL(timeout_ns, 256 * 1000);

	/* If the necessary timeout value is bigger than what we can set in the
@@ -4386,13 +4418,10 @@ static u16 xhci_call_host_update_timeout_for_endpoint(struct xhci_hcd *xhci, 
		enum usb3_link_state state,

		u16 *timeout)

{

	if (state == USB3_LPM_U1) {

		if (xhci->quirks & XHCI_INTEL_HOST)

			return xhci_calculate_intel_u1_timeout(udev, desc);

	} else {

		if (xhci->quirks & XHCI_INTEL_HOST)

			return xhci_calculate_intel_u2_timeout(udev, desc);

	}

	if (state == USB3_LPM_U1)

		return xhci_calculate_u1_timeout(xhci, udev, desc);

	else if (state == USB3_LPM_U2)

		return xhci_calculate_u2_timeout(xhci, udev, desc);



	return USB3_LPM_DISABLED;

}
@@ -4469,7 +4498,8 @@ static int xhci_check_tier_policy(struct xhci_hcd *xhci, 
{

	if (xhci->quirks & XHCI_INTEL_HOST)

		return xhci_check_intel_tier_policy(udev, state);

	return -EINVAL;

	else

		return 0;

}



/* Returns the U1 or U2 timeout that should be enabled.