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From:   Weitao Wang <WeitaoWang-oc@zhaoxin.com>
To:     <gregkh@linuxfoundation.org>, <mathias.nyman@intel.com>,
        <linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>
CC:     <tonywwang@zhaoxin.com>, <weitaowang@zhaoxin.com>
Subject: [PATCH] xhci: fix issue of cross page boundary in TRB prefetch
Date:   Thu, 20 Apr 2023 18:48:26 +0800
Message-ID: <20230420104826.4727-1-WeitaoWang-oc@zhaoxin.com>
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On some Zhaoxin platforms, xHCI will prefetch TRB for performance
improvement. However this TRB prefetch mechanism may cross page boundary,
which may access memory not allocated by xHCI driver. In order to fix
this issue, two pages was allocated for TRB and only the first
page will be used.

Signed-off-by: Weitao Wang <WeitaoWang-oc@zhaoxin.com>
---
 drivers/usb/host/xhci-mem.c | 6 +++++-
 drivers/usb/host/xhci-pci.c | 5 +++++
 drivers/usb/host/xhci.h     | 1 +
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index d0a9467aa5fc..69f8d44d2c9f 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -2369,7 +2369,11 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 	 * and our use of dma addresses in the trb_address_map radix tree needs
 	 * TRB_SEGMENT_SIZE alignment, so we pick the greater alignment need.
 	 */
-	xhci->segment_pool = dma_pool_create("xHCI ring segments", dev,
+	if (xhci->quirks & XHCI_ZHAOXIN_TRB_FETCH) {
+		xhci->segment_pool = dma_pool_create("xHCI ring segments", dev,
+			TRB_SEGMENT_SIZE * 2, TRB_SEGMENT_SIZE * 2, xhci->page_size * 2);
+	} else
+		xhci->segment_pool = dma_pool_create("xHCI ring segments", dev,
 			TRB_SEGMENT_SIZE, TRB_SEGMENT_SIZE, xhci->page_size);
 
 	/* See Table 46 and Note on Figure 55 */
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 6db07ca419c3..3b3bff36def3 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -334,6 +334,11 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 	     pdev->device == PCI_DEVICE_ID_AMD_PROMONTORYA_4))
 		xhci->quirks |= XHCI_NO_SOFT_RETRY;
 
+	if (pdev->vendor == PCI_VENDOR_ID_ZHAOXIN &&
+			(pdev->device == 0x9202 ||
+			pdev->device == 0x9203))
+		xhci->quirks |= XHCI_ZHAOXIN_TRB_FETCH;
+
 	/* 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.h b/drivers/usb/host/xhci.h
index 786002bb35db..ed1f2f894af6 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1905,6 +1905,7 @@ struct xhci_hcd {
 #define XHCI_EP_CTX_BROKEN_DCS	BIT_ULL(42)
 #define XHCI_SUSPEND_RESUME_CLKS	BIT_ULL(43)
 #define XHCI_RESET_TO_DEFAULT	BIT_ULL(44)
+#define XHCI_ZHAOXIN_TRB_FETCH	BIT_ULL(45)
 
 	unsigned int		num_active_eps;
 	unsigned int		limit_active_eps;
-- 
2.32.0