PCI: imx6: fix PCIe EP device self-initialisation

This fixes PCIe EP device self-initialisation in case only a regular
reset EP GPIO is used as PERST# which is e.g. the case on our Ixora
carrier board by always waiting 20 milliseconds after releasing PERST#.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Acked-by: Max Krummenacher <max.krummenacher@toradex.com>

1 files changed, 16 insertions, 18 deletions

diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
index 53234701c2e4..fb01d6110d31 100644
--- a/drivers/pci/host/pci-imx6.c
+++ b/drivers/pci/host/pci-imx6.c
@@ -363,30 +363,28 @@ static int imx6_pcie_deassert_core_reset(struct pcie_port *pp)
 		msleep(1);
 		if (gpio_is_valid(imx6_pcie->reset_ep_gpio))
 			gpio_set_value_cansleep(imx6_pcie->reset_ep_gpio, 0);
-		/*
-		 * See 'PCI EXPRESS BASE SPECIFICATION, REV 3.0, SECTION 6.6.1'
-		 * for detailed understanding of the PCIe CR reset logic.
-		 *
-		 * The PCIe #PERST reset line _MUST_ be connected, otherwise
-		 * your design does not conform to the specification. You must
-		 * wait at least 20 mS after de-asserting the #PERST so the
-		 * EP device can do self-initialisation.
-		 *
-		 * In case your #PERST pin is connected to a plain GPIO pin of
-		 * the CPU, you can define CONFIG_PCIE_IMX_PERST_GPIO in your
-		 * board's configuration file and the condition below will
-		 * handle the rest of the reset toggling.
-		 */
-		mdelay(20);
 	} else if (gpio_is_valid(imx6_pcie->reset_ep_gpio)) {
 		gpio_set_value_cansleep(imx6_pcie->reset_ep_gpio, 1);
 		msleep(100);
 		gpio_set_value_cansleep(imx6_pcie->reset_ep_gpio, 0);
-	} else {
-		/* allow the clocks to stabilize */
-		udelay(200);
 	}
 
+	/*
+	 * See 'PCI EXPRESS BASE SPECIFICATION, REV 3.0, SECTION 6.6.1'
+	 * for detailed understanding of the PCIe CR reset logic.
+	 *
+	 * The PCIe #PERST reset line _MUST_ be connected, otherwise
+	 * your design does not conform to the specification. You must
+	 * wait at least 20 mS after de-asserting the #PERST so the
+	 * EP device can do self-initialisation.
+	 *
+	 * In case your #PERST pin is connected to a plain GPIO pin of
+	 * the CPU, you can define CONFIG_PCIE_IMX_PERST_GPIO in your
+	 * board's configuration file and the condition below will
+	 * handle the rest of the reset toggling.
+	 */
+	msleep(20);
+
 	if (imx6_pcie->force_detect_state) {
 		u32 val;