On Fri, Jan 8, 2021 at 10:44 PM Mathias Nyman
[off-list ref] wrote:

On 8.1.2021 8.11, Chunfeng Yun wrote:

quoted

On Thu, 2021-01-07 at 13:09 +0200, Mathias Nyman wrote:

quoted

On 29.12.2020 8.24, Ikjoon Jang wrote:

quoted

xhci-mtk has hooks on add_endpoint() and drop_endpoint() from xhci
to handle its own sw bandwidth managements and stores bandwidth data
into internal table every time add_endpoint() is called,
so when bandwidth allocation fails at one endpoint, all earlier
allocation from the same interface could still remain at the table.

This patch adds two more hooks from check_bandwidth() and
reset_bandwidth(), and make mtk-xhci to releases all failed endpoints
from reset_bandwidth().

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

...

quoted

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index d4a8d0efbbc4..e1fcd3cf723f 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c

@@ -2882,6 +2882,12 @@ static int xhci_check_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
    xhci_dbg(xhci, "%s called for udev %p\n", __func__, udev);
    virt_dev = xhci->devs[udev->slot_id];

+   if (xhci->quirks & XHCI_MTK_HOST) {
+           ret = xhci_mtk_check_bandwidth(hcd, udev);
+           if (ret < 0)
+                   return ret;
+   }
+

Just noticed that XHCI_MTK_HOST quirk is only set in xhci-mtk.c.
xhci-mtk.c calls xhci_init_driver(..., xhci_mtk_overrides) with a .reset override function.

why not add override functions for .check_bandwidth and .reset_bandwidth to xhci_mtk_overrides instead?

Another patch to add similar overrides for .add_endpoint and .drop_endpoint should probably be
done so that we can get rid of the xhci_mtk_add/drop_ep_quirk() calls in xhci.c as well

You mean, we can export xhci_add/drop_endpoint()?

I think so, unless you have a better idea.
I prefer exporting the generic add/drop_endpoint functions rather than the vendor specific quirk functions.

When moving out all MTK_HOST quirks and unlink xhci-mtk-sch from xhci,
xhci-mtk-sch still needs to touch the xhci internals, at least struct
xhci_ep_ctx.

My naive idea is just let xhci export one more function to expose xhci_ep_ctx.
But I'm not sure whether this is acceptable:

+struct xhci_ep_ctx* xhci_get_ep_contex(struct xhci_hcd *xhci, struct
usb_host_endpoint *ep)
+{ ... }
+EXPORT_SYMBOL(xhci_get_ep_context);

But for v6, I'm going to submit a patch with {check|reset}_bandwidth()
quirk function
 switched into xhci_driver_overrides first. (and preserve existing
MTK_HOST quirk functions).

Thanks!

-Mathias

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