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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 2/3] xhci: Add zhaoxin xHCI U1/U2 feature support
Date:   Fri, 21 Apr 2023 01:21:29 +0800
Message-ID: <20230420172130.375819-3-WeitaoWang-oc@zhaoxin.com>
In-Reply-To: <20230420172130.375819-1-WeitaoWang-oc@zhaoxin.com>
References: <20230420172130.375819-1-WeitaoWang-oc@zhaoxin.com>
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Add U1/U2 feature support of xHCI for zhaoxin.

Signed-off-by: Weitao Wang <WeitaoWang-oc@zhaoxin.com>
---
 drivers/usb/host/xhci-pci.c |  5 +++++
 drivers/usb/host/xhci.c     | 27 +++++++++++++++++++++++++--
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 6db07ca419c3..a235effe8e5c 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) {
+		xhci->quirks |= XHCI_LPM_SUPPORT;
+		xhci->quirks |= XHCI_ZHAOXIN_HOST;
+	}
+
 	/* 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.c b/drivers/usb/host/xhci.c
index 6307bae9cddf..730c0f68518d 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4802,7 +4802,7 @@ static u16 xhci_calculate_u1_timeout(struct xhci_hcd *xhci,
 		}
 	}
 
-	if (xhci->quirks & XHCI_INTEL_HOST)
+	if (xhci->quirks & (XHCI_INTEL_HOST | XHCI_ZHAOXIN_HOST))
 		timeout_ns = xhci_calculate_intel_u1_timeout(udev, desc);
 	else
 		timeout_ns = udev->u1_params.sel;
@@ -4866,7 +4866,7 @@ static u16 xhci_calculate_u2_timeout(struct xhci_hcd *xhci,
 		}
 	}
 
-	if (xhci->quirks & XHCI_INTEL_HOST)
+	if (xhci->quirks & (XHCI_INTEL_HOST | XHCI_ZHAOXIN_HOST))
 		timeout_ns = xhci_calculate_intel_u2_timeout(udev, desc);
 	else
 		timeout_ns = udev->u2_params.sel;
@@ -4938,6 +4938,27 @@ static int xhci_update_timeout_for_interface(struct xhci_hcd *xhci,
 	return 0;
 }
 
+static int xhci_check_zhaoxin_tier_policy(struct usb_device *udev,
+		enum usb3_link_state state)
+{
+	struct usb_device *parent;
+	unsigned int num_hubs;
+
+	/* Don't enable U1/U2 if the device is on an external hub. */
+	for (parent = udev->parent, num_hubs = 0; parent->parent;
+			parent = parent->parent)
+		num_hubs++;
+
+	if (num_hubs < 1)
+		return 0;
+
+	dev_dbg(&udev->dev, "Disabling U1/U2 link state for device"
+			" below external hub.\n");
+	dev_dbg(&udev->dev, "Plug device into root hub "
+			"to decrease power consumption.\n");
+	return -E2BIG;
+}
+
 static int xhci_check_intel_tier_policy(struct usb_device *udev,
 		enum usb3_link_state state)
 {
@@ -4965,6 +4986,8 @@ static int xhci_check_tier_policy(struct xhci_hcd *xhci,
 {
 	if (xhci->quirks & XHCI_INTEL_HOST)
 		return xhci_check_intel_tier_policy(udev, state);
+	else if (xhci->quirks & XHCI_ZHAOXIN_HOST)
+		return xhci_check_zhaoxin_tier_policy(udev, state);
 	else
 		return 0;
 }
-- 
2.32.0