diff options
| -rw-r--r-- | Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt | 4 | ||||
| -rw-r--r-- | drivers/pci/host/pci-imx6.c | 24 |
2 files changed, 21 insertions, 7 deletions
diff --git a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt index 636707df0952..d742f917505a 100644 --- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt +++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt @@ -19,6 +19,10 @@ Optional properties: - fsl,tx-deemph-gen2-6db: Gen2 (6db) De-emphasis value. Default: 20 - fsl,tx-swing-full: Gen2 TX SWING FULL value. Default: 127 - fsl,tx-swing-low: TX launch amplitude swing_low value. Default: 127 +- fsl,max-link-speed: Specify PCI gen for link capability. Must be '2' for + gen2, otherwise will default to gen1. Note that the IMX6 LVDS clock outputs + do not meet gen2 jitter requirements and thus for gen2 capability a gen2 + compliant clock generator should be used and configured. - reset-gpio: Should specify the GPIO for controlling the PCI bus device reset signal. It's not polarity aware and defaults to active-low reset sequence (L=reset state, H=operation state). diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c index 0b8793d908de..837d5e0447ac 100644 --- a/drivers/pci/host/pci-imx6.c +++ b/drivers/pci/host/pci-imx6.c @@ -47,6 +47,7 @@ struct imx6_pcie { u32 tx_deemph_gen2_6db; u32 tx_swing_full; u32 tx_swing_low; + int link_gen; }; /* PCIe Root Complex registers (memory-mapped) */ @@ -471,11 +472,15 @@ static int imx6_pcie_establish_link(struct pcie_port *pp) goto err_reset_phy; } - /* Allow Gen2 mode after the link is up. */ - tmp = readl(pp->dbi_base + PCIE_RC_LCR); - tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK; - tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2; - writel(tmp, pp->dbi_base + PCIE_RC_LCR); + if (imx6_pcie->link_gen == 2) { + /* Allow Gen2 mode after the link is up. */ + tmp = readl(pp->dbi_base + PCIE_RC_LCR); + tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK; + tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2; + writel(tmp, pp->dbi_base + PCIE_RC_LCR); + } else { + dev_info(pp->dev, "Link: Gen2 disabled\n"); + } /* * Start Directed Speed Change so the best possible speed both link @@ -499,8 +504,7 @@ static int imx6_pcie_establish_link(struct pcie_port *pp) } tmp = readl(pp->dbi_base + PCIE_RC_LCSR); - dev_dbg(pp->dev, "Link up, Gen=%i\n", (tmp >> 16) & 0xf); - + dev_info(pp->dev, "Link up, Gen%i\n", (tmp >> 16) & 0xf); return 0; err_reset_phy: @@ -678,6 +682,12 @@ static int __init imx6_pcie_probe(struct platform_device *pdev) &imx6_pcie->tx_swing_low)) imx6_pcie->tx_swing_low = 127; + /* Limit link speed */ + ret = of_property_read_u32(pp->dev->of_node, "fsl,max-link-speed", + &imx6_pcie->link_gen); + if (ret) + imx6_pcie->link_gen = 1; + ret = imx6_add_pcie_port(pp, pdev); if (ret < 0) return ret; |