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Subject[PATCH 2/2] PCI: imx6: limit DBI register length
Date
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 | 51 +++++++++++++++++++--------
1 file changed, 37 insertions(+), 14 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 4a9a673b4777..8c96af414dac 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -39,6 +39,11 @@ enum imx6_pcie_variants {
IMX7D,
};

+struct imx6_pcie_drvdata {
+ enum imx6_pcie_variants variant;
+ int dbi_length;
+};
+
struct imx6_pcie {
struct dw_pcie *pci;
int reset_gpio;
@@ -50,7 +55,6 @@ struct imx6_pcie {
struct regmap *iomuxc_gpr;
struct reset_control *pciephy_reset;
struct reset_control *apps_reset;
- enum imx6_pcie_variants variant;
u32 tx_deemph_gen1;
u32 tx_deemph_gen2_3p5db;
u32 tx_deemph_gen2_6db;
@@ -58,6 +62,7 @@ struct imx6_pcie {
u32 tx_swing_low;
int link_gen;
struct regulator *vpcie;
+ const struct imx6_pcie_drvdata *drvdata;
};

/* Parameters for the waiting for PCIe PHY PLL to lock on i.MX7 */
@@ -285,7 +290,7 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
{
struct device *dev = imx6_pcie->pci->dev;

- switch (imx6_pcie->variant) {
+ switch (imx6_pcie->drvdata->variant) {
case IMX7D:
reset_control_assert(imx6_pcie->pciephy_reset);
reset_control_assert(imx6_pcie->apps_reset);
@@ -327,7 +332,7 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
struct device *dev = pci->dev;
int ret = 0;

- switch (imx6_pcie->variant) {
+ switch (imx6_pcie->drvdata->variant) {
case IMX6SX:
ret = clk_prepare_enable(imx6_pcie->pcie_inbound_axi);
if (ret) {
@@ -430,7 +435,7 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
!imx6_pcie->gpio_active_high);
}

- switch (imx6_pcie->variant) {
+ switch (imx6_pcie->drvdata->variant) {
case IMX7D:
reset_control_deassert(imx6_pcie->pciephy_reset);
imx7d_pcie_wait_for_phy_pll_lock(imx6_pcie);
@@ -468,7 +473,7 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)

static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
{
- switch (imx6_pcie->variant) {
+ switch (imx6_pcie->drvdata->variant) {
case IMX7D:
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
IMX7D_GPR12_PCIE_PHY_REFCLK_SEL, 0);
@@ -560,7 +565,7 @@ static int imx6_pcie_establish_link(struct imx6_pcie *imx6_pcie)
dw_pcie_writel_dbi(pci, PCIE_RC_LCR, tmp);

/* Start LTSSM. */
- if (imx6_pcie->variant == IMX7D)
+ if (imx6_pcie->drvdata->variant == IMX7D)
reset_control_deassert(imx6_pcie->apps_reset);
else
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
@@ -585,7 +590,7 @@ static int imx6_pcie_establish_link(struct imx6_pcie *imx6_pcie)
tmp |= PORT_LOGIC_SPEED_CHANGE;
dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, tmp);

- if (imx6_pcie->variant != IMX7D) {
+ if (imx6_pcie->drvdata->variant != IMX7D) {
/*
* On i.MX7, DIRECT_SPEED_CHANGE behaves differently
* from i.MX6 family when no link speed transition
@@ -703,8 +708,7 @@ static int imx6_pcie_probe(struct platform_device *pdev)
pci->ops = &dw_pcie_ops;

imx6_pcie->pci = pci;
- imx6_pcie->variant =
- (enum imx6_pcie_variants)of_device_get_match_data(dev);
+ imx6_pcie->drvdata = of_device_get_match_data(dev);

dbi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
pci->dbi_base = devm_ioremap_resource(dev, dbi_base);
@@ -748,7 +752,7 @@ static int imx6_pcie_probe(struct platform_device *pdev)
return PTR_ERR(imx6_pcie->pcie);
}

- switch (imx6_pcie->variant) {
+ switch (imx6_pcie->drvdata->variant) {
case IMX6SX:
imx6_pcie->pcie_inbound_axi = devm_clk_get(dev,
"pcie_inbound_axi");
@@ -776,6 +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");
@@ -835,11 +841,28 @@ static void imx6_pcie_shutdown(struct platform_device *pdev)
imx6_pcie_assert_core_reset(imx6_pcie);
}

+static const struct imx6_pcie_drvdata imx6q_pcie_drvdata = {
+ .variant = IMX6Q,
+ .dbi_length = 0x15c,
+};
+
+static const struct imx6_pcie_drvdata imx6sx_pcie_drvdata = {
+ .variant = IMX6SX,
+};
+
+static const struct imx6_pcie_drvdata imx6qp_pcie_drvdata = {
+ .variant = IMX6QP,
+};
+
+static const struct imx6_pcie_drvdata imx7d_pcie_drvdata = {
+ .variant = IMX7D,
+};
+
static const struct of_device_id imx6_pcie_of_match[] = {
- { .compatible = "fsl,imx6q-pcie", .data = (void *)IMX6Q, },
- { .compatible = "fsl,imx6sx-pcie", .data = (void *)IMX6SX, },
- { .compatible = "fsl,imx6qp-pcie", .data = (void *)IMX6QP, },
- { .compatible = "fsl,imx7d-pcie", .data = (void *)IMX7D, },
+ { .compatible = "fsl,imx6q-pcie", .data = &imx6q_pcie_drvdata, },
+ { .compatible = "fsl,imx6sx-pcie", .data = &imx6sx_pcie_drvdata, },
+ { .compatible = "fsl,imx6qp-pcie", .data = &imx6qp_pcie_drvdata, },
+ { .compatible = "fsl,imx7d-pcie", .data = &imx7d_pcie_drvdata, },
{},
};

--
2.19.1
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