linux-kernel - [PATCH v4 7/7] PCI: dwc: Add validation that PCIe core is set to correct mode

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Message-ID: <20190821154745.31834-3-jonnyc@amazon.com>
Date:   Wed, 21 Aug 2019 18:47:45 +0300
From:   Jonathan Chocron <jonnyc@...zon.com>
To:     <lorenzo.pieralisi@....com>, <bhelgaas@...gle.com>,
        <jingoohan1@...il.com>, <gustavo.pimentel@...opsys.com>,
        <robh+dt@...nel.org>, <mark.rutland@....com>
CC:     <andrew.murray@....com>, <dwmw@...zon.co.uk>,
        <benh@...nel.crashing.org>, <alisaidi@...zon.com>,
        <ronenk@...zon.com>, <barakw@...zon.com>, <talel@...zon.com>,
        <hanochu@...zon.com>, <hhhawa@...zon.com>,
        <linux-pci@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <jonnyc@...zon.com>
Subject: [PATCH v4 7/7] PCI: dwc: Add validation that PCIe core is set to correct mode

Some PCIe controllers can be set to either Host or EP according to some
early boot FW. To make sure there is no discrepancy (e.g. FW configured
the port to EP mode while the DT specifies it as a host bridge or vice
versa), a check has been added for each mode.

Signed-off-by: Jonathan Chocron <jonnyc@...zon.com>
Acked-by: Gustavo Pimentel <gustavo.pimentel@...opsys.com>
---
 drivers/pci/controller/dwc/pcie-designware-ep.c   | 8 ++++++++
 drivers/pci/controller/dwc/pcie-designware-host.c | 8 ++++++++
 2 files changed, 16 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 2bf5a35c0570..00e59a134b93 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -531,6 +531,7 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 	int ret;
 	u32 reg;
 	void *addr;
+	u8 hdr_type;
 	unsigned int nbars;
 	unsigned int offset;
 	struct pci_epc *epc;
@@ -543,6 +544,13 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 		return -EINVAL;
 	}
 
+	hdr_type = dw_pcie_readb_dbi(pci, PCI_HEADER_TYPE);
+	if (hdr_type != PCI_HEADER_TYPE_NORMAL) {
+		dev_err(pci->dev, "PCIe controller is not set to EP mode (hdr_type:0x%x)!\n",
+			hdr_type);
+		return -EIO;
+	}
+
 	ret = of_property_read_u32(np, "num-ib-windows", &ep->num_ib_windows);
 	if (ret < 0) {
 		dev_err(dev, "Unable to read *num-ib-windows* property\n");
diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index f93252d0da5b..d2ca748e4c85 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -323,6 +323,7 @@ int dw_pcie_host_init(struct pcie_port *pp)
 	struct pci_bus *child;
 	struct pci_host_bridge *bridge;
 	struct resource *cfg_res;
+	u8 hdr_type;
 	int ret;
 
 	raw_spin_lock_init(&pci->pp.lock);
@@ -396,6 +397,13 @@ int dw_pcie_host_init(struct pcie_port *pp)
 		}
 	}
 
+	hdr_type = dw_pcie_readb_dbi(pci, PCI_HEADER_TYPE);
+	if (hdr_type != PCI_HEADER_TYPE_BRIDGE) {
+		dev_err(pci->dev, "PCIe controller is not set to bridge type (hdr_type: 0x%x)!\n",
+			hdr_type);
+		return -EIO;
+	}
+
 	pp->mem_base = pp->mem->start;
 
 	if (!pp->va_cfg0_base) {
-- 
2.17.1