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PCI: imx6: Implement reset sequence for i.MX6+ 

I.MX6+ has a dedicated bit for resetting PCIe core, which should be used
instead of a regular reset sequence since using the latter will hang the
SoC.

This commit is based on c34068d48273e24d392d9a49a38be807954420ed from
http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git

Tested-by: Gary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
This commit is contained in:
Andrey Smirnov 2016-05-02 14:09:10 -05:00 committed by Bjorn Helgaas
parent e6f1fef04c
commit 4d31c6109a
3 changed files with 23 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
View File

@ -4,7 +4,7 @@ This PCIe host controller is based on the Synopsis Designware PCIe IP
and thus inherits all the common properties defined in designware-pcie.txt.
Required properties:
- compatible: "fsl,imx6q-pcie", "fsl,imx6sx-pcie"
- compatible: "fsl,imx6q-pcie", "fsl,imx6sx-pcie", "fsl,imx6qp-pcie"
- reg: base address and length of the PCIe controller
- interrupts: A list of interrupt outputs of the controller. Must contain an
entry for each entry in the interrupt-names property.

23
drivers/pci/host/pci-imx6.c
View File

@ -34,7 +34,8 @@
enum imx6_pcie_variants {
IMX6Q,
IMX6SX
IMX6SX,
IMX6QP,
};
struct imx6_pcie {
@ -256,6 +257,11 @@ static int imx6_pcie_assert_core_reset(struct pcie_port *pp)
IMX6SX_GPR5_PCIE_BTNRST_RESET,
IMX6SX_GPR5_PCIE_BTNRST_RESET);
break;
case IMX6QP:
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
IMX6Q_GPR1_PCIE_SW_RST,
IMX6Q_GPR1_PCIE_SW_RST);
break;
case IMX6Q:
/*
* If the bootloader already enabled the link we need some
@ -310,6 +316,7 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
IMX6SX_GPR12_PCIE_TEST_POWERDOWN, 0);
break;
case IMX6QP: /* FALLTHROUGH */
case IMX6Q:
/* power up core phy and enable ref clock */
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
@ -370,9 +377,20 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp)
!imx6_pcie->gpio_active_high);
}
if (imx6_pcie->variant == IMX6SX)
switch (imx6_pcie->variant) {
case IMX6SX:
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR5,
IMX6SX_GPR5_PCIE_BTNRST_RESET, 0);
break;
case IMX6QP:
regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
IMX6Q_GPR1_PCIE_SW_RST, 0);
usleep_range(200, 500);
break;
case IMX6Q: /* Nothing to do */
break;
}
return 0;
@ -718,6 +736,7 @@ static void imx6_pcie_shutdown(struct platform_device *pdev)
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, },
{},
};
MODULE_DEVICE_TABLE(of, imx6_pcie_of_match);

1
include/linux/mfd/syscon/imx6q-iomuxc-gpr.h
View File

@ -95,6 +95,7 @@
#define IMX6Q_GPR0_DMAREQ_MUX_SEL0_IOMUX BIT(0)
#define IMX6Q_GPR1_PCIE_REQ_MASK (0x3 << 30)
#define IMX6Q_GPR1_PCIE_SW_RST BIT(29)
#define IMX6Q_GPR1_PCIE_EXIT_L1 BIT(28)
#define IMX6Q_GPR1_PCIE_RDY_L23 BIT(27)
#define IMX6Q_GPR1_PCIE_ENTER_L1 BIT(26)