From: Ben Peled <[email protected]> Added pcie reset via gpio support as described in the designware-pcie.txt DT binding document. In cases link down cause still exist in device. The device need to be reset to reestablish the link. If reset-gpio pin provided in the device tree, then the linkdown handle resets the device before reestablishing link.
Signed-off-by: Ben Peled <[email protected]> --- drivers/pci/controller/dwc/pcie-armada8k.c | 24 ++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) diff --git a/drivers/pci/controller/dwc/pcie-armada8k.c b/drivers/pci/controller/dwc/pcie-armada8k.c index 34b253c..04bba97 100644 --- a/drivers/pci/controller/dwc/pcie-armada8k.c +++ b/drivers/pci/controller/dwc/pcie-armada8k.c @@ -24,6 +24,7 @@ #include <linux/of_irq.h> #include <linux/mfd/syscon.h> #include <linux/regmap.h> +#include <linux/of_gpio.h> #include "pcie-designware.h" @@ -38,6 +39,8 @@ struct armada8k_pcie { struct regmap *sysctrl_base; u32 mac_rest_bitmask; struct work_struct recover_link_work; + enum of_gpio_flags flags; + struct gpio_desc *reset_gpio; }; #define PCIE_VENDOR_REGS_OFFSET 0x8000 @@ -247,9 +250,18 @@ static void armada8k_pcie_recover_link(struct work_struct *ws) } pci_lock_rescan_remove(); pci_stop_and_remove_bus_device(root_port); + /* Reset device if reset gpio is set */ + if (pcie->reset_gpio) { + /* assert and then deassert the reset signal */ + gpiod_set_value_cansleep(pcie->reset_gpio, 0); + msleep(100); + gpiod_set_value_cansleep(pcie->reset_gpio, + (pcie->flags & OF_GPIO_ACTIVE_LOW) ? 0 : 1); + } /* - * Sleep needed to make sure all pcie transactions and access - * are flushed before resetting the mac + * Sleep used for two reasons. + * First make sure all pcie transactions and access are flushed before resetting the mac + * and second to make sure pci device is ready in case we reset the device */ msleep(100); @@ -369,6 +381,7 @@ static int armada8k_pcie_probe(struct platform_device *pdev) struct armada8k_pcie *pcie; struct device *dev = &pdev->dev; struct resource *base; + int reset_gpio; int ret; pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL); @@ -413,6 +426,13 @@ static int armada8k_pcie_probe(struct platform_device *pdev) goto fail_clkreg; } + /* Config reset gpio for pcie if the reset connected to gpio */ + reset_gpio = of_get_named_gpio_flags(pdev->dev.of_node, + "reset-gpios", 0, + &pcie->flags); + if (gpio_is_valid(reset_gpio)) + pcie->reset_gpio = gpio_to_desc(reset_gpio); + pcie->sysctrl_base = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "marvell,system-controller"); if (IS_ERR(pcie->sysctrl_base)) { -- 2.7.4
