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From:   =?UTF-8?q?Antti=20J=C3=A4rvinen?= <antti.jarvinen@gmail.com>
To:     helgaas@kernel.org
Cc:     alex.williamson@redhat.com, antti.jarvinen@gmail.com,
        bhelgaas@google.com, kishon@ti.com, linux-kernel@vger.kernel.org,
        linux-pci@vger.kernel.org, m-karicheri2@ti.com
Subject: [PATCH v2] PCI: quirk for preventing bus reset on TI C667X
Date:   Sun, 28 Feb 2021 13:53:11 +0000
Message-Id: <20210228135311.668-1-antti.jarvinen@gmail.com>
In-Reply-To: <20210217211817.GA914074@bjorn-Precision-5520>
References: <20210217211817.GA914074@bjorn-Precision-5520>
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Some TI keystone C667X devices do no support bus/hot reset. Its PCIESS
automatically disables LTSSM when secondary bus reset is received and
device stops working. Prevent bus reset by adding quirk_no_bus_reset to
the device. With this change device can be assigned to VMs with VFIO,
but it will leak state between VMs.

Reference https://e2e.ti.com/support/processors/f/791/t/954382

Signed-off-by: Antti Järvinen <antti.jarvinen@gmail.com>
---
 drivers/pci/quirks.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 653660e3ba9e..d9201ad1ca39 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3578,6 +3578,16 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATHEROS, 0x0034, quirk_no_bus_reset);
  */
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_CAVIUM, 0xa100, quirk_no_bus_reset);
 
+/*
+ * Some TI keystone C667X devices do no support bus/hot reset.
+ * Its PCIESS automatically disables LTSSM when secondary bus reset is
+ * received and device stops working. Prevent bus reset by adding
+ * quirk_no_bus_reset to the device. With this change device can be
+ * assigned to VMs with VFIO, but it will leak state between VMs.
+ * Reference https://e2e.ti.com/support/processors/f/791/t/954382
+ */
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_TI, 0xb005, quirk_no_bus_reset);
+
 static void quirk_no_pm_reset(struct pci_dev *dev)
 {
 	/*
-- 
2.17.1