usb: xhci-mtk: fix fs isoc's transfer error

commit c237566b78ad8c72bc0431c5d6171db8d12e6f94 upstream.

Due to the scheduler allocates the optimal bandwidth for FS ISOC endpoints,
this may be not enough actually and causes data transfer error, so come up
with an estimate that is no less than the worst case bandwidth used for
any one mframe, but may be an over-estimate.

Fixes: 451d3912586a ("usb: xhci-mtk: update fs bus bandwidth by bw_budget_table")
Cc: stable@vger.kernel.org
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20220512064931.31670-1-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
index b4c84b3635074babe8a1de677db8b66de5a0798a..f91a30432056376922ff479a659ec1a80805f1e1 100644 (file)
--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -465,7 +465,7 @@ static int check_fs_bus_bw(struct mu3h_sch_ep_info *sch_ep, int offset)
                 */
                for (j = 0; j < sch_ep->num_budget_microframes; j++) {
                        k = XHCI_MTK_BW_INDEX(base + j);
-                       tmp = tt->fs_bus_bw[k] + sch_ep->bw_budget_table[j];
+                       tmp = tt->fs_bus_bw[k] + sch_ep->bw_cost_per_microframe;
                        if (tmp > FS_PAYLOAD_MAX)
                                return -ESCH_BW_OVERFLOW;
                }
@@ -539,19 +539,17 @@ static int check_sch_tt(struct mu3h_sch_ep_info *sch_ep, u32 offset)
 static void update_sch_tt(struct mu3h_sch_ep_info *sch_ep, bool used)
 {
        struct mu3h_sch_tt *tt = sch_ep->sch_tt;
+       int bw_updated;
        u32 base;
-       int i, j, k;
+       int i, j;
+
+       bw_updated = sch_ep->bw_cost_per_microframe * (used ? 1 : -1);
 
        for (i = 0; i < sch_ep->num_esit; i++) {
                base = sch_ep->offset + i * sch_ep->esit;
 
-               for (j = 0; j < sch_ep->num_budget_microframes; j++) {
-                       k = XHCI_MTK_BW_INDEX(base + j);
-                       if (used)
-                               tt->fs_bus_bw[k] += sch_ep->bw_budget_table[j];
-                       else
-                               tt->fs_bus_bw[k] -= sch_ep->bw_budget_table[j];
-               }
+               for (j = 0; j < sch_ep->num_budget_microframes; j++)
+                       tt->fs_bus_bw[XHCI_MTK_BW_INDEX(base + j)] += bw_updated;
        }
 
        if (used)