[PATCH 1/3] usb: early: Avoid using DbC if already enabled
From: Connor Davis <hidden>
Date: 2021-05-12 00:18:30
Also in:
lkml, xen-devel
Subsystem:
the rest, usb subsystem · Maintainers:
Linus Torvalds, Greg Kroah-Hartman
Check if the debug capability is enabled in early_xdbc_parse_parameter, and if it is, return with an error. This avoids collisions with whatever enabled the DbC prior to linux starting. Signed-off-by: Connor Davis <redacted> --- drivers/usb/early/xhci-dbc.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c
index be4ecbabdd58..ca67fddc2d36 100644
--- a/drivers/usb/early/xhci-dbc.c
+++ b/drivers/usb/early/xhci-dbc.c@@ -642,6 +642,16 @@ int __init early_xdbc_parse_parameter(char *s) } xdbc.xdbc_reg = (struct xdbc_regs __iomem *)(xdbc.xhci_base + offset); + if (readl(&xdbc.xdbc_reg->control) & CTRL_DBC_ENABLE) { + pr_notice("xhci debug capability already in use\n"); + early_iounmap(xdbc.xhci_base, xdbc.xhci_length); + xdbc.xdbc_reg = NULL; + xdbc.xhci_base = NULL; + xdbc.xhci_length = 0; + + return -ENODEV; + } + return 0; } --
2.31.1