xhci-mtk needs XHCI_MTK_HOST quirk functions in add_endpoint() and
drop_endpoint() to handle its own sw bandwidth management.

It stores bandwidth data into an internal table every time
add_endpoint() is called, and drops those in drop_endpoint().
But when bandwidth allocation fails at one endpoint, all earlier
allocation from the same interface could still remain at the table.

This patch moves bandwidth management codes to check_bandwidth() and
reset_bandwidth() path. To do so, this patch also adds those functions
to xhci_driver_overrides and lets mtk-xhci to release all failed
endpoints in reset_bandwidth() path.

Fixes: 08e469de87a2 ("usb: xhci-mtk: supports bandwidth scheduling with multi-TT")
Signed-off-by: Ikjoon Jang <redacted>

---

Changes in v6:
- use xhci overrides instead of quirk functions for
  {check|reset}_bandwidth().

Changes in v5:
- Fix a wrong commit id in Fixes tag

Changes in v4:
- bugfix in v3, check_bandwidth() return uninitialized value
  when no new endpoints were added.
- change Fixes tag to keep dependency

Changes in v3:
- drop unrelated code cleanups
- change Fixes tag to keep dependency

Changes in v2:
- fix a 0-day warning from unused variable
- split one big patch into three patches
- fix wrong offset in mediatek hw flags

 drivers/usb/host/xhci-mtk-sch.c | 123 ++++++++++++++++++++++----------
 drivers/usb/host/xhci-mtk.c     |   2 +
 drivers/usb/host/xhci-mtk.h     |  13 ++++
 drivers/usb/host/xhci.c         |   8 ++-
 drivers/usb/host/xhci.h         |   4 ++
 5 files changed, 111 insertions(+), 39 deletions(-)

diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
index 45c54d56ecbd..a313e75ff1c6 100644
--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c

@@ -200,6 +200,7 @@ static struct mu3h_sch_ep_info *create_sch_ep(struct usb_device *udev,
 [...]
+
+int xhci_mtk_check_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
+{
+	struct xhci_hcd_mtk *mtk = hcd_to_mtk(hcd);
+	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+	struct xhci_virt_device *virt_dev = xhci->devs[udev->slot_id];
+	struct mu3h_sch_bw_info *sch_bw;
+	struct mu3h_sch_ep_info *sch_ep, *tmp;
+	int bw_index, ret;
+
+	dev_dbg(&udev->dev, "%s\n", __func__);
+
+	list_for_each_entry(sch_ep, &mtk->bw_ep_list_new, endpoint) {
+		bw_index = get_bw_index(xhci, udev, sch_ep->ep);
+		sch_bw = &mtk->sch_array[bw_index];
+
+		ret = check_sch_bw(udev, sch_bw, sch_ep);
+		if (ret) {
+			xhci_err(xhci, "Not enough bandwidth!\n");
+			return -ENOSPC;
+		}
+	}
+
+	list_for_each_entry_safe(sch_ep, tmp, &mtk->bw_ep_list_new, endpoint) {
+		struct xhci_ep_ctx *ep_ctx;
+		struct usb_host_endpoint *ep = sch_ep->ep;
+		unsigned int ep_index = xhci_get_endpoint_index(&ep->desc);
+
+		bw_index = get_bw_index(xhci, udev, ep);
+		sch_bw = &mtk->sch_array[bw_index];
+
+		list_move_tail(&sch_ep->endpoint, &sch_bw->bw_ep_list);
+
+		ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, ep_index);
+		ep_ctx->reserved[0] |= cpu_to_le32(EP_BPKTS(sch_ep->pkts)
+			| EP_BCSCOUNT(sch_ep->cs_count)
+			| EP_BBM(sch_ep->burst_mode));
+		ep_ctx->reserved[1] |= cpu_to_le32(EP_BOFFSET(sch_ep->offset)
+			| EP_BREPEAT(sch_ep->repeat));
+
+		xhci_dbg(xhci, " PKTS:%x, CSCOUNT:%x, BM:%x, OFFSET:%x, REPEAT:%x\n",
+			sch_ep->pkts, sch_ep->cs_count, sch_ep->burst_mode,
+			sch_ep->offset, sch_ep->repeat);
+	}
+
+	return xhci_check_bandwidth(hcd, udev);
+}
+EXPORT_SYMBOL_GPL(xhci_mtk_check_bandwidth);
+
+void xhci_mtk_reset_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
+{
+	struct xhci_hcd_mtk *mtk = hcd_to_mtk(hcd);
+	struct mu3h_sch_ep_info *sch_ep, *tmp;
+
+	dev_dbg(&udev->dev, "%s\n", __func__);
+
+	list_for_each_entry_safe(sch_ep, tmp, &mtk->bw_ep_list_new, endpoint) {
+		xhci_mtk_drop_ep(mtk, udev, sch_ep);