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From:   Stefan Agner <stefan@agner.ch>
To:     jingoohan1@gmail.com, gustavo.pimentel@synopsys.com,
        l.stach@pengutronix.de, tpiepho@impinj.com
Cc:     bhelgaas@google.com, linux-pci@vger.kernel.org,
        linux-kernel@vger.kernel.org, Stefan Agner <stefan@agner.ch>
Subject: [PATCH v2 3/3] PCI: imx6: limit DBI register length
Date:   Tue, 20 Nov 2018 14:27:05 +0100
Message-Id: <20181120132705.6917-3-stefan@agner.ch>
In-Reply-To: <20181120132705.6917-1-stefan@agner.ch>
References: <20181120132705.6917-1-stefan@agner.ch>
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Define the length of the DBI registers. This makes sure that
the kernel does not access registers beyond that point, avoiding
the following abort on a i.MX 6Quad:
  # cat /sys/devices/soc0/soc/1ffc000.pcie/pci0000\:00/0000\:00\:00.0/config
  [  100.021433] Unhandled fault: imprecise external abort (0x1406) at 0xb6ea7000
  ...
  [  100.056423] PC is at dw_pcie_read+0x50/0x84
  [  100.060790] LR is at dw_pcie_rd_own_conf+0x44/0x48
  ...

Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 drivers/pci/controller/dwc/pci-imx6.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 7ac1a639fe91..41d6127b40ad 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -41,6 +41,7 @@ enum imx6_pcie_variants {
 
 struct imx6_pcie_drvdata {
 	enum imx6_pcie_variants variant;
+	int			dbi_length;
 };
 
 struct imx6_pcie {
@@ -779,6 +780,8 @@ static int imx6_pcie_probe(struct platform_device *pdev)
 		break;
 	}
 
+	pci->dbi_length = imx6_pcie->drvdata->dbi_length;
+
 	/* Grab GPR config register range */
 	imx6_pcie->iomuxc_gpr =
 		 syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
@@ -839,7 +842,7 @@ static void imx6_pcie_shutdown(struct platform_device *pdev)
 }
 
 static const struct imx6_pcie_drvdata drvdata[] = {
-	[IMX6Q] = { .variant = IMX6Q },
+	[IMX6Q] = { .variant = IMX6Q, .dbi_length = 0x15c },
 	[IMX6SX] = { .variant = IMX6SX },
 	[IMX6QP] = { .variant = IMX6QP },
 	[IMX7D] = { .variant = IMX7D },
-- 
2.19.1