Commit f99298bf authored by Andiry Xu's avatar Andiry Xu Committed by Sarah Sharp
Browse files

xHCI: BESL calculation based on USB2.0 LPM errata 



The latest released errata for USB2.0 ECN LPM adds new fields to USB2.0
extension descriptor, defines two BESL values for device: baseline BESL
and deep BESL. Baseline BESL value communicates a nominal power savings
design point and the deep BESL value communicates a significant power
savings design point.

If device indicates BESL value, driver will use a value count in both
host BESL and device BESL. Use baseline BESL value as default.

Signed-off-by: default avatarAndiry Xu <andiry.xu@amd.com>
Tested-by: default avatarJason Fan <jcfan@qca.qualcomm.com>
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
parent f7a0d426

drivers/usb/host/xhci.c

+27 −24
Original line number Diff line number Diff line
@@ -3614,26 +3614,38 @@ static int xhci_besl_encoding[16] = {125, 150, 200, 300, 400, 500, 1000, 2000, 
	3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000};



/* Calculate HIRD/BESL for USB2 PORTPMSC*/

static int xhci_calculate_hird_besl(int u2del, bool use_besl)

static int xhci_calculate_hird_besl(struct xhci_hcd *xhci,

					struct usb_device *udev)

{

	int hird;

	int u2del, besl, besl_host;

	int besl_device = 0;

	u32 field;



	u2del = HCS_U2_LATENCY(xhci->hcs_params3);

	field = le32_to_cpu(udev->bos->ext_cap->bmAttributes);



	if (use_besl) {

		for (hird = 0; hird < 16; hird++) {

			if (xhci_besl_encoding[hird] >= u2del)

	if (field & USB_BESL_SUPPORT) {

		for (besl_host = 0; besl_host < 16; besl_host++) {

			if (xhci_besl_encoding[besl_host] >= u2del)

				break;

		}

		/* Use baseline BESL value as default */

		if (field & USB_BESL_BASELINE_VALID)

			besl_device = USB_GET_BESL_BASELINE(field);

		else if (field & USB_BESL_DEEP_VALID)

			besl_device = USB_GET_BESL_DEEP(field);

	} else {

		if (u2del <= 50)

			hird = 0;

			besl_host = 0;

		else

			hird = (u2del - 51) / 75 + 1;



		if (hird > 15)

			hird = 15;

			besl_host = (u2del - 51) / 75 + 1;

	}



	return hird;

	besl = besl_host + besl_device;

	if (besl > 15)

		besl = 15;



	return besl;

}



static int xhci_usb2_software_lpm_test(struct usb_hcd *hcd,
@@ -3646,7 +3658,7 @@ static int xhci_usb2_software_lpm_test(struct usb_hcd *hcd, 
	u32		temp, dev_id;

	unsigned int	port_num;

	unsigned long	flags;

	int		u2del, hird;

	int		hird;

	int		ret;



	if (hcd->speed == HCD_USB3 || !xhci->sw_lpm_support ||
@@ -3692,12 +3704,7 @@ static int xhci_usb2_software_lpm_test(struct usb_hcd *hcd, 
	 * HIRD or BESL shoule be used. See USB2.0 LPM errata.

	 */

	pm_addr = port_array[port_num] + 1;

	u2del = HCS_U2_LATENCY(xhci->hcs_params3);

	if (le32_to_cpu(udev->bos->ext_cap->bmAttributes) & (1 << 2))

		hird = xhci_calculate_hird_besl(u2del, 1);

	else

		hird = xhci_calculate_hird_besl(u2del, 0);



	hird = xhci_calculate_hird_besl(xhci, udev);

	temp = PORT_L1DS(udev->slot_id) | PORT_HIRD(hird);

	xhci_writel(xhci, temp, pm_addr);
@@ -3776,7 +3783,7 @@ int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd, 
	u32		temp;

	unsigned int	port_num;

	unsigned long	flags;

	int		u2del, hird;

	int		hird;



	if (hcd->speed == HCD_USB3 || !xhci->hw_lpm_support ||

			!udev->lpm_capable)
@@ -3799,11 +3806,7 @@ int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd, 
	xhci_dbg(xhci, "%s port %d USB2 hardware LPM\n",

			enable ? "enable" : "disable", port_num);



	u2del = HCS_U2_LATENCY(xhci->hcs_params3);

	if (le32_to_cpu(udev->bos->ext_cap->bmAttributes) & (1 << 2))

		hird = xhci_calculate_hird_besl(u2del, 1);

	else

		hird = xhci_calculate_hird_besl(u2del, 0);

	hird = xhci_calculate_hird_besl(xhci, udev);



	if (enable) {

		temp &= ~PORT_HIRD_MASK;

include/linux/usb/ch9.h

+5 −0
Original line number Diff line number Diff line
@@ -789,6 +789,11 @@ struct usb_ext_cap_descriptor { /* Link Power Management */ 
	__u8  bDevCapabilityType;

	__le32 bmAttributes;

#define USB_LPM_SUPPORT			(1 << 1)	/* supports LPM */

#define USB_BESL_SUPPORT		(1 << 2)	/* supports BESL */

#define USB_BESL_BASELINE_VALID		(1 << 3)	/* Baseline BESL valid*/

#define USB_BESL_DEEP_VALID		(1 << 4)	/* Deep BESL valid */

#define USB_GET_BESL_BASELINE(p)	(((p) & (0xf << 8)) >> 8)

#define USB_GET_BESL_DEEP(p)		(((p) & (0xf << 12)) >> 12)

} __attribute__((packed));



#define USB_DT_USB_EXT_CAP_SIZE	7

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