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-rw-r--r--drivers/pci/host/pci-mvebu.c56
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;
}