diff mbox series

[v3,1/6] PCI: imx6: Start link directly when workaround is not required

Message ID 20250328030213.1650990-2-hongxing.zhu@nxp.com (mailing list archive)
State New
Headers show
Series Add some enhancements for i.MX95 PCIe | expand

Commit Message

Richard Zhu March 28, 2025, 3:02 a.m. UTC 
The current link setup procedure is one workaround to detect the device
behind PCIe switches on some i.MX6 platforms.

To describe more accurately, change the flag name from
IMX_PCIE_FLAG_IMX_SPEED_CHANGE to IMX_PCIE_FLAG_SPEED_CHANGE_WORKAROUND.

Start PCIe link directly when this flag is not set on i.MX7 or later
platforms to simple and speed up link training.

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 34 +++++++++++----------------
 1 file changed, 14 insertions(+), 20 deletions(-)

Comments

Frank Li March 28, 2025, 2:47 p.m. UTC | #1 
On Fri, Mar 28, 2025 at 11:02:08AM +0800, Richard Zhu wrote:
> The current link setup procedure is one workaround to detect the device
> behind PCIe switches on some i.MX6 platforms.
>
> To describe more accurately, change the flag name from
> IMX_PCIE_FLAG_IMX_SPEED_CHANGE to IMX_PCIE_FLAG_SPEED_CHANGE_WORKAROUND.
>
> Start PCIe link directly when this flag is not set on i.MX7 or later
> platforms to simple and speed up link training.
>
> Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>

>  drivers/pci/controller/dwc/pci-imx6.c | 34 +++++++++++----------------
>  1 file changed, 14 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index c1f7904e3600..57aa777231ae 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -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
> @@ -896,22 +902,10 @@ 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;
> -			}
> +		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! */
> @@ -1665,7 +1659,7 @@ 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,
> @@ -1681,7 +1675,7 @@ 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,
> @@ -1696,7 +1690,7 @@ 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",
> --
> 2.37.1
>
diff mbox series

Patch

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index c1f7904e3600..57aa777231ae 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -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
@@ -896,22 +902,10 @@  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;
-			}
+		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! */
@@ -1665,7 +1659,7 @@  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,
@@ -1681,7 +1675,7 @@  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,
@@ -1696,7 +1690,7 @@  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",