Commit 9c03e30e authored by Richard Zhu's avatar Richard Zhu Committed by Manivannan Sadhasivam
Browse files

PCI: imx6: Skip link up workaround for newer platforms 



The current link setup procedure has one workaround to detect the devices
behind PCIe switches on some i.MX6 platforms. But this workaround is not
needed on recent i.MX7 platforms. So skip the workaround for platforms that
do not set the flag and start LTSSM directly.

Also, change the flag name from IMX_PCIE_FLAG_IMX_SPEED_CHANGE to
IMX_PCIE_FLAG_SPEED_CHANGE_WORKAROUND to match the usecase.

Signed-off-by: default avatarRichard Zhu <hongxing.zhu@nxp.com>
[mani: subject and description rewording]
Signed-off-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: default avatarFrank Li <Frank.Li@nxp.com>
Reviewed-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://patch.msgid.link/20250416081314.3929794-2-hongxing.zhu@nxp.com
parent 0af2f6be

drivers/pci/controller/dwc/pci-imx6.c

+14 −20
Original line number Diff line number Diff line
@@ -91,7 +91,7 @@ enum imx_pcie_variants { 
};



#define IMX_PCIE_FLAG_IMX_PHY			BIT(0)

#define IMX_PCIE_FLAG_IMX_SPEED_CHANGE		BIT(1)

#define IMX_PCIE_FLAG_SPEED_CHANGE_WORKAROUND	BIT(1)

#define IMX_PCIE_FLAG_SUPPORTS_SUSPEND		BIT(2)

#define IMX_PCIE_FLAG_HAS_PHYDRV		BIT(3)

#define IMX_PCIE_FLAG_HAS_APP_RESET		BIT(4)
@@ -860,6 +860,12 @@ static int imx_pcie_start_link(struct dw_pcie *pci) 
	u32 tmp;

	int ret;



	if (!(imx_pcie->drvdata->flags &

	    IMX_PCIE_FLAG_SPEED_CHANGE_WORKAROUND)) {

		imx_pcie_ltssm_enable(dev);

		return 0;

	}



	/*

	 * Force Gen1 operation when starting the link.  In case the link is

	 * started in Gen2 mode, there is a possibility the devices on the
@@ -896,23 +902,11 @@ static int imx_pcie_start_link(struct dw_pcie *pci) 
		dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, tmp);

		dw_pcie_dbi_ro_wr_dis(pci);



		if (imx_pcie->drvdata->flags &

		    IMX_PCIE_FLAG_IMX_SPEED_CHANGE) {



			/*

			 * On i.MX7, DIRECT_SPEED_CHANGE behaves differently

			 * from i.MX6 family when no link speed transition

			 * occurs and we go Gen1 -> yep, Gen1. The difference

			 * is that, in such case, it will not be cleared by HW

			 * which will cause the following code to report false

			 * failure.

			 */

		ret = imx_pcie_wait_for_speed_change(imx_pcie);

		if (ret) {

			dev_err(dev, "Failed to bring link up!\n");

			goto err_reset_phy;

		}

		}



		/* Make sure link training is finished as well! */

		ret = dw_pcie_wait_for_link(pci);
@@ -1649,7 +1643,7 @@ static const struct imx_pcie_drvdata drvdata[] = { 
	[IMX6Q] = {

		.variant = IMX6Q,

		.flags = IMX_PCIE_FLAG_IMX_PHY |

			 IMX_PCIE_FLAG_IMX_SPEED_CHANGE |

			 IMX_PCIE_FLAG_SPEED_CHANGE_WORKAROUND |

			 IMX_PCIE_FLAG_BROKEN_SUSPEND |

			 IMX_PCIE_FLAG_SUPPORTS_SUSPEND,

		.dbi_length = 0x200,
@@ -1665,7 +1659,7 @@ static const struct imx_pcie_drvdata drvdata[] = { 
	[IMX6SX] = {

		.variant = IMX6SX,

		.flags = IMX_PCIE_FLAG_IMX_PHY |

			 IMX_PCIE_FLAG_IMX_SPEED_CHANGE |

			 IMX_PCIE_FLAG_SPEED_CHANGE_WORKAROUND |

			 IMX_PCIE_FLAG_SUPPORTS_SUSPEND,

		.gpr = "fsl,imx6q-iomuxc-gpr",

		.ltssm_off = IOMUXC_GPR12,
@@ -1680,7 +1674,7 @@ static const struct imx_pcie_drvdata drvdata[] = { 
	[IMX6QP] = {

		.variant = IMX6QP,

		.flags = IMX_PCIE_FLAG_IMX_PHY |

			 IMX_PCIE_FLAG_IMX_SPEED_CHANGE |

			 IMX_PCIE_FLAG_SPEED_CHANGE_WORKAROUND |

			 IMX_PCIE_FLAG_SUPPORTS_SUSPEND,

		.dbi_length = 0x200,

		.gpr = "fsl,imx6q-iomuxc-gpr",