usb: xhci: fix loss of data on Cadence xHC

Streams should flush their TRB cache, re-read TRBs, and start executing
TRBs from the beginning of the new dequeue pointer after a 'Set TR Dequeue
Pointer' command.

Cadence controllers may fail to start from the beginning of the dequeue
TRB as it doesn't clear the Opaque 'RsvdO' field of the stream context
during 'Set TR Dequeue' command. This stream context area is where xHC
stores information about the last partially executed TD when a stream
is stopped. xHC uses this information to resume the transfer where it left
mid TD, when the stream is restarted.

Patch fixes this by clearing out all RsvdO fields before initializing new
Stream transfer using a 'Set TR Dequeue Pointer' command.

Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
cc: stable@vger.kernel.org
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Reviewed-by: Peter Chen <peter.chen@kernel.org>
Link: https://lore.kernel.org/r/PH7PR07MB95386A40146E3EC64086F409DD9D2@PH7PR07MB9538.namprd07.prod.outlook.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/cdns3/host.c b/drivers/usb/cdns3/host.c
index ceca4d839dfd42b87167f4de3019ab63776fa6c2..7ba760ee62e3310e9c678d269d7675c9cb952ec6 100644 (file)
--- a/drivers/usb/cdns3/host.c
+++ b/drivers/usb/cdns3/host.c
@@ -62,7 +62,9 @@ static const struct xhci_plat_priv xhci_plat_cdns3_xhci = {
        .resume_quirk = xhci_cdns3_resume_quirk,
 };
 
-static const struct xhci_plat_priv xhci_plat_cdnsp_xhci;
+static const struct xhci_plat_priv xhci_plat_cdnsp_xhci = {
+       .quirks = XHCI_CDNS_SCTX_QUIRK,
+};
 
 static int __cdns_host_init(struct cdns *cdns)
 {

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 8a5df569221a19df631a7ea8652a177faaa2d6f4..91dccd25a55142661f58e8f26feb79b8cda3ce74 100644 (file)
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -81,6 +81,9 @@
 #define PCI_DEVICE_ID_ASMEDIA_2142_XHCI                        0x2142
 #define PCI_DEVICE_ID_ASMEDIA_3242_XHCI                        0x3242
 
+#define PCI_DEVICE_ID_CADENCE                          0x17CD
+#define PCI_DEVICE_ID_CADENCE_SSP                      0x0200
+
 static const char hcd_name[] = "xhci_hcd";
 
 static struct hc_driver __read_mostly xhci_pci_hc_driver;
@@ -474,6 +477,10 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
                        xhci->quirks |= XHCI_ZHAOXIN_TRB_FETCH;
        }
 
+       if (pdev->vendor == PCI_DEVICE_ID_CADENCE &&
+           pdev->device == PCI_DEVICE_ID_CADENCE_SSP)
+               xhci->quirks |= XHCI_CDNS_SCTX_QUIRK;
+
        /* xHC spec requires PCI devices to support D3hot and D3cold */
        if (xhci->hci_version >= 0x120)
                xhci->quirks |= XHCI_DEFAULT_PM_RUNTIME_ALLOW;

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index a4383735b16cf459e959693c7716733fd5284c54..4d664ba53fe9a45a7ed5bb36624a905497267f89 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1399,6 +1399,20 @@ static void xhci_handle_cmd_set_deq(struct xhci_hcd *xhci, int slot_id,
                        struct xhci_stream_ctx *ctx =
                                &ep->stream_info->stream_ctx_array[stream_id];
                        deq = le64_to_cpu(ctx->stream_ring) & SCTX_DEQ_MASK;
+
+                       /*
+                        * Cadence xHCI controllers store some endpoint state
+                        * information within Rsvd0 fields of Stream Endpoint
+                        * context. This field is not cleared during Set TR
+                        * Dequeue Pointer command which causes XDMA to skip
+                        * over transfer ring and leads to data loss on stream
+                        * pipe.
+                        * To fix this issue driver must clear Rsvd0 field.
+                        */
+                       if (xhci->quirks & XHCI_CDNS_SCTX_QUIRK) {
+                               ctx->reserved[0] = 0;
+                               ctx->reserved[1] = 0;
+                       }
                } else {
                        deq = le64_to_cpu(ep_ctx->deq) & ~EP_CTX_CYCLE_MASK;
                }

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 1e50ebbe9514efb2cfddbcc838e586ae16fbaa4b..620502de971a435b76e37d53ef1c0e6ff7c2e771 100644 (file)
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1623,6 +1623,7 @@ struct xhci_hcd {
 #define XHCI_ZHAOXIN_TRB_FETCH BIT_ULL(45)
 #define XHCI_ZHAOXIN_HOST      BIT_ULL(46)
 #define XHCI_WRITE_64_HI_LO    BIT_ULL(47)
+#define XHCI_CDNS_SCTX_QUIRK   BIT_ULL(48)
 
        unsigned int            num_active_eps;
        unsigned int            limit_active_eps;