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path: root/drivers/pci/host/pci-imx6.c
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Diffstat (limited to 'drivers/pci/host/pci-imx6.c')
-rw-r--r--drivers/pci/host/pci-imx6.c38
1 files changed, 38 insertions, 0 deletions
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
index a568efaa331c..35fc73a8d0b3 100644
--- a/drivers/pci/host/pci-imx6.c
+++ b/drivers/pci/host/pci-imx6.c
@@ -49,6 +49,9 @@ struct imx6_pcie {
/* PCIe Port Logic registers (memory-mapped) */
#define PL_OFFSET 0x700
+#define PCIE_PL_PFLR (PL_OFFSET + 0x08)
+#define PCIE_PL_PFLR_LINK_STATE_MASK (0x3f << 16)
+#define PCIE_PL_PFLR_FORCE_LINK (1 << 15)
#define PCIE_PHY_DEBUG_R0 (PL_OFFSET + 0x28)
#define PCIE_PHY_DEBUG_R1 (PL_OFFSET + 0x2c)
#define PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING (1 << 29)
@@ -214,6 +217,32 @@ static int imx6q_pcie_abort_handler(unsigned long addr,
static int imx6_pcie_assert_core_reset(struct pcie_port *pp)
{
struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
+ u32 val, gpr1, gpr12;
+
+ /*
+ * If the bootloader already enabled the link we need some special
+ * handling to get the core back into a state where it is safe to
+ * touch it for configuration. As there is no dedicated reset signal
+ * wired up for MX6QDL, we need to manually force LTSSM into "detect"
+ * state before completely disabling LTSSM, which is a prerequisite
+ * for core configuration.
+ *
+ * If both LTSSM_ENABLE and REF_SSP_ENABLE are active we have a strong
+ * indication that the bootloader activated the link.
+ */
+ regmap_read(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1, &gpr1);
+ regmap_read(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, &gpr12);
+
+ if ((gpr1 & IMX6Q_GPR1_PCIE_REF_CLK_EN) &&
+ (gpr12 & IMX6Q_GPR12_PCIE_CTL_2)) {
+ val = readl(pp->dbi_base + PCIE_PL_PFLR);
+ val &= ~PCIE_PL_PFLR_LINK_STATE_MASK;
+ val |= PCIE_PL_PFLR_FORCE_LINK;
+ writel(val, pp->dbi_base + PCIE_PL_PFLR);
+
+ regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
+ IMX6Q_GPR12_PCIE_CTL_2, 0 << 10);
+ }
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
IMX6Q_GPR1_PCIE_TEST_PD, 1 << 18);
@@ -589,6 +618,14 @@ static int __init imx6_pcie_probe(struct platform_device *pdev)
return 0;
}
+static void imx6_pcie_shutdown(struct platform_device *pdev)
+{
+ struct imx6_pcie *imx6_pcie = platform_get_drvdata(pdev);
+
+ /* bring down link, so bootloader gets clean state in case of reboot */
+ imx6_pcie_assert_core_reset(&imx6_pcie->pp);
+}
+
static const struct of_device_id imx6_pcie_of_match[] = {
{ .compatible = "fsl,imx6q-pcie", },
{},
@@ -601,6 +638,7 @@ static struct platform_driver imx6_pcie_driver = {
.owner = THIS_MODULE,
.of_match_table = imx6_pcie_of_match,
},
+ .shutdown = imx6_pcie_shutdown,
};
/* Freescale PCIe driver does not allow module unload */