[PATCH v2 03/18] usb: xhci-mtk: get the microframe boundary for ESIT

[Chunfeng Yun]

Tune the boundary for FS/LS ESIT due to CS:
For ISOC out-ep, the controller starts transfer data after
the first SS; for others, the data is already transferred
before the last CS.

Signed-off-by: Chunfeng Yun <chunfeng....@mediatek.com>
---
v2: fix typo and use ++/-- suggested by Sergei
---
 drivers/usb/host/xhci-mtk-sch.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
index 8950d1f10a7f..450fa22b7dc7 100644
--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -513,22 +513,35 @@ static void update_sch_tt(struct usb_device *udev,
                list_del(&sch_ep->tt_endpoint);
 }
 
+static u32 get_esit_boundary(struct mu3h_sch_ep_info *sch_ep)
+{
+       u32 boundary = sch_ep->esit;
+
+       if (sch_ep->sch_tt) { /* LS/FS with TT */
+               /* tune for CS */
+               if (sch_ep->ep_type != ISOC_OUT_EP)
+                       boundary++;
+               else if (boundary > 1) /* normally esit >= 8 for FS/LS */
+                       boundary--;
+       }
+
+       return boundary;
+}
+
 static int check_sch_bw(struct usb_device *udev,
        struct mu3h_sch_bw_info *sch_bw, struct mu3h_sch_ep_info *sch_ep)
 {
        u32 offset;
-       u32 esit;
        u32 min_bw;
        u32 min_index;
        u32 worst_bw;
        u32 bw_boundary;
+       u32 esit_boundary;
        u32 min_num_budget;
        u32 min_cs_count;
        bool tt_offset_ok = false;
        int ret;
 
-       esit = sch_ep->esit;
-
        /*
         * Search through all possible schedule microframes.
         * and find a microframe where its worst bandwidth is minimum.
@@ -537,7 +550,8 @@ static int check_sch_bw(struct usb_device *udev,
        min_index = 0;
        min_cs_count = sch_ep->cs_count;
        min_num_budget = sch_ep->num_budget_microframes;
-       for (offset = 0; offset < esit; offset++) {
+       esit_boundary = get_esit_boundary(sch_ep);
+       for (offset = 0; offset < sch_ep->esit; offset++) {
                if (is_fs_or_ls(udev->speed)) {
                        ret = check_sch_tt(udev, sch_ep, offset);
                        if (ret)
@@ -546,7 +560,7 @@ static int check_sch_bw(struct usb_device *udev,
                                tt_offset_ok = true;
                }
 
-               if ((offset + sch_ep->num_budget_microframes) > sch_ep->esit)
+               if ((offset + sch_ep->num_budget_microframes) > esit_boundary)
                        break;
 
                worst_bw = get_max_bw(sch_bw, sch_ep, offset);
-- 
2.18.0