RE: [PATCH] usb: xhci: fix loss of data on Cadence xHC

[Pawel Laszczak]

Hi,

Please ignore this patch. I send it again with correct version in subject.

Thanks,
Pawel,

>Subject: FW: [PATCH] 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@xxxxxxxxxxxxxxx>
>Signed-off-by: Pawel Laszczak <pawell@xxxxxxxxxxx>
>
>---
>Changelog:
>v3:
>- changed patch to patch Cadence specific
>
>v2:
>- removed restoring of EDTLA field
>
> drivers/usb/cdns3/host.c     |  4 +++-
> drivers/usb/host/xhci-pci.c  |  7 +++++++  drivers/usb/host/xhci-ring.c | 14
>++++++++++++++
> drivers/usb/host/xhci.h      |  1 +
> 4 files changed, 25 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/usb/cdns3/host.c b/drivers/usb/cdns3/host.c index
>ceca4d839dfd..7ba760ee62e3 100644
>--- 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
>b9ae5c2a2527..9199dbfcea07 100644
>--- a/drivers/usb/host/xhci-pci.c
>+++ b/drivers/usb/host/xhci-pci.c
>@@ -74,6 +74,9 @@
> #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; @@ -532,6 +535,10
>@@ 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
>1dde53f6eb31..a1ad2658c0c7 100644
>--- a/drivers/usb/host/xhci-ring.c
>+++ b/drivers/usb/host/xhci-ring.c
>@@ -1386,6 +1386,20 @@ 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
>101e74c9060f..4cbd58eed214 100644
>--- a/drivers/usb/host/xhci.h
>+++ b/drivers/usb/host/xhci.h
>@@ -1907,6 +1907,7 @@ 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;
>--
>2.43.0