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authorJann Horn <jannh@google.com>2020-04-01 09:46:19 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-04-29 16:31:26 +0200
commitd932c9f111742749a31ec1b0dc9562daabd3ab67 (patch)
tree24686430077d830e61e8d6046d1e86cc267b897c
parent188551e1e883595a32c6b11f9183d38a1e455170 (diff)
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USB: early: Handle AMD's spec-compliant identifiers, too
commit 7dbdb53d72a51cea9b921d9dbba54be00752212a upstream. This fixes a bug that causes the USB3 early console to freeze after printing a single line on AMD machines because it can't parse the Transfer TRB properly. The spec at https://www.intel.com/content/dam/www/public/us/en/documents/technical-specifications/extensible-host-controler-interface-usb-xhci.pdf says in section "4.5.1 Device Context Index" that the Context Index, also known as Endpoint ID according to section "1.6 Terms and Abbreviations", is normally computed as `DCI = (Endpoint Number * 2) + Direction`, which matches the current definitions of XDBC_EPID_OUT and XDBC_EPID_IN. However, the numbering in a Debug Capability Context data structure is supposed to be different: Section "7.6.3.2 Endpoint Contexts and Transfer Rings" explains that a Debug Capability Context data structure has the endpoints mapped to indices 0 and 1. Change XDBC_EPID_OUT/XDBC_EPID_IN to the spec-compliant values, add XDBC_EPID_OUT_INTEL/XDBC_EPID_IN_INTEL with Intel's incorrect values, and let xdbc_handle_tx_event() handle both. I have verified that with this patch applied, the USB3 early console works on both an Intel and an AMD machine. Fixes: aeb9dd1de98c ("usb/early: Add driver for xhci debug capability") Cc: stable@vger.kernel.org Signed-off-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20200401074619.8024-1-jannh@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/usb/early/xhci-dbc.c8
-rw-r--r--drivers/usb/early/xhci-dbc.h18
2 files changed, 20 insertions, 6 deletions
diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c
index e15e896f356c..97885eb57be6 100644
--- a/drivers/usb/early/xhci-dbc.c
+++ b/drivers/usb/early/xhci-dbc.c
@@ -735,19 +735,19 @@ static void xdbc_handle_tx_event(struct xdbc_trb *evt_trb)
case COMP_USB_TRANSACTION_ERROR:
case COMP_STALL_ERROR:
default:
- if (ep_id == XDBC_EPID_OUT)
+ if (ep_id == XDBC_EPID_OUT || ep_id == XDBC_EPID_OUT_INTEL)
xdbc.flags |= XDBC_FLAGS_OUT_STALL;
- if (ep_id == XDBC_EPID_IN)
+ if (ep_id == XDBC_EPID_IN || ep_id == XDBC_EPID_IN_INTEL)
xdbc.flags |= XDBC_FLAGS_IN_STALL;
xdbc_trace("endpoint %d stalled\n", ep_id);
break;
}
- if (ep_id == XDBC_EPID_IN) {
+ if (ep_id == XDBC_EPID_IN || ep_id == XDBC_EPID_IN_INTEL) {
xdbc.flags &= ~XDBC_FLAGS_IN_PROCESS;
xdbc_bulk_transfer(NULL, XDBC_MAX_PACKET, true);
- } else if (ep_id == XDBC_EPID_OUT) {
+ } else if (ep_id == XDBC_EPID_OUT || ep_id == XDBC_EPID_OUT_INTEL) {
xdbc.flags &= ~XDBC_FLAGS_OUT_PROCESS;
} else {
xdbc_trace("invalid endpoint id %d\n", ep_id);
diff --git a/drivers/usb/early/xhci-dbc.h b/drivers/usb/early/xhci-dbc.h
index 673686eeddd7..6e2b7266a695 100644
--- a/drivers/usb/early/xhci-dbc.h
+++ b/drivers/usb/early/xhci-dbc.h
@@ -120,8 +120,22 @@ struct xdbc_ring {
u32 cycle_state;
};
-#define XDBC_EPID_OUT 2
-#define XDBC_EPID_IN 3
+/*
+ * These are the "Endpoint ID" (also known as "Context Index") values for the
+ * OUT Transfer Ring and the IN Transfer Ring of a Debug Capability Context data
+ * structure.
+ * According to the "eXtensible Host Controller Interface for Universal Serial
+ * Bus (xHCI)" specification, section "7.6.3.2 Endpoint Contexts and Transfer
+ * Rings", these should be 0 and 1, and those are the values AMD machines give
+ * you; but Intel machines seem to use the formula from section "4.5.1 Device
+ * Context Index", which is supposed to be used for the Device Context only.
+ * Luckily the values from Intel don't overlap with those from AMD, so we can
+ * just test for both.
+ */
+#define XDBC_EPID_OUT 0
+#define XDBC_EPID_IN 1
+#define XDBC_EPID_OUT_INTEL 2
+#define XDBC_EPID_IN_INTEL 3
struct xdbc_state {
u16 vendor;