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: Andiry Xu <andiry.xu@amd.com>
Tested-by: Jason Fan <jcfan@qca.qualcomm.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>

1 files changed, 27 insertions, 24 deletions

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index a629ad860329..262400c10075 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -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;