diff options
| -rw-r--r-- | drivers/pci/host/pci-mvebu.c | 56 |
1 files changed, 43 insertions, 13 deletions
diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c index ab619ee0ef49..97208233d901 100644 --- a/drivers/pci/host/pci-mvebu.c +++ b/drivers/pci/host/pci-mvebu.c @@ -1042,6 +1042,46 @@ err: return ret; } +/* + * Power up a PCIe port. PCIe requires the refclk to be stable for 100µs + * prior to releasing PERST. See table 2-4 in section 2.6.2 AC Specifications + * of the PCI Express Card Electromechanical Specification, 1.1. + */ +static int mvebu_pcie_powerup(struct mvebu_pcie_port *port) +{ + int ret; + + ret = clk_prepare_enable(port->clk); + if (ret < 0) + return ret; + + if (port->reset_gpio) { + u32 reset_udelay = 20000; + + of_property_read_u32(port->dn, "reset-delay-us", + &reset_udelay); + + udelay(100); + + gpiod_set_value_cansleep(port->reset_gpio, 0); + msleep(reset_udelay / 1000); + } + + return 0; +} + +/* + * Power down a PCIe port. Strictly, PCIe requires us to place the card + * in D3hot state before asserting PERST#. + */ +static void mvebu_pcie_powerdown(struct mvebu_pcie_port *port) +{ + if (port->reset_gpio) + gpiod_set_value_cansleep(port->reset_gpio, 1); + + clk_disable_unprepare(port->clk); +} + static int mvebu_pcie_probe(struct platform_device *pdev) { struct mvebu_pcie *pcie; @@ -1114,18 +1154,8 @@ static int mvebu_pcie_probe(struct platform_device *pdev) if (!child) continue; - if (port->reset_gpio) { - u32 reset_udelay = 20000; - - of_property_read_u32(child, "reset-delay-us", - &reset_udelay); - - gpiod_set_value_cansleep(port->reset_gpio, 0); - msleep(reset_udelay / 1000); - } - - ret = clk_prepare_enable(port->clk); - if (ret) + ret = mvebu_pcie_powerup(port); + if (ret < 0) continue; port->base = mvebu_pcie_map_registers(pdev, child, port); @@ -1133,7 +1163,7 @@ static int mvebu_pcie_probe(struct platform_device *pdev) dev_err(&pdev->dev, "%s: cannot map registers\n", port->name); port->base = NULL; - clk_disable_unprepare(port->clk); + mvebu_pcie_powerdown(port); continue; } |