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From:   Alexandru Gagniuc <mr.nuke.me@gmail.com>
To:     bhelgaas@google.com
Cc:     austin_bolen@dell.com, alex_gagniuc@dellteam.com,
        keith.busch@intel.com, Shyam_Iyer@Dell.com, lukas@wunner.de,
        okaya@kernel.org, linux-pci@vger.kernel.org,
        Alexandru Gagniuc <mr.nuke.me@gmail.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Sinan Kaya <okaya@codeaurora.org>,
        Oza Pawandeep <poza@codeaurora.org>,
        linux-kernel@vger.kernel.org
Subject: [PATCH RFC v2 4/4] PCI: hotplug: Add quirk For Dell nvme pcie switches
Date:   Tue, 19 Feb 2019 19:20:30 -0600
Message-Id: <20190220012031.10741-5-mr.nuke.me@gmail.com>
In-Reply-To: <20190220012031.10741-1-mr.nuke.me@gmail.com>
References: <20190220012031.10741-1-mr.nuke.me@gmail.com>
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These switches are used to fornicate the motherboard's x16 PCIe ports
into four x4 ports for NVMe drives. In conjunction with the storage
backplane, the PDS bit reports only the out-of-band presence. The fact
that inband presence is disabled is not reported in the slot
capabilities 2 (SLTCAP2) register.
Because this does not conform to the PCIe spec, add a quirk to let
hotplug code know to expect and handle this.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
---
 drivers/pci/hotplug/pciehp_hpc.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 9bcadb5d3561..853fb4ab53de 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -952,3 +952,23 @@ DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_QCOM, 0x0400,
 			      PCI_CLASS_BRIDGE_PCI, 8, quirk_cmd_compl);
 DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_QCOM, 0x0401,
 			      PCI_CLASS_BRIDGE_PCI, 8, quirk_cmd_compl);
+
+
+static void fixup_dell_nvme_backplane_switches(struct pci_dev *pdev)
+{
+	if (!pci_is_pcie(pdev))
+		return;
+
+	if (pci_pcie_type(pdev) != PCI_EXP_TYPE_DOWNSTREAM)
+		return;
+
+	if (pdev->subsystem_vendor != PCI_VENDOR_ID_DELL
+		|| pdev->subsystem_device != 0x1fc7)
+		return;
+
+	pdev->no_in_band_presence = 1;
+}
+
+DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_PLX, 0x9733,
+			      PCI_CLASS_BRIDGE_PCI, 8,
+			      fixup_dell_nvme_backplane_switches);
-- 
2.19.2