diff options
Diffstat (limited to 'drivers/pci/controller/pci-aardvark.c')
| -rw-r--r-- | drivers/pci/controller/pci-aardvark.c | 43 |
1 files changed, 42 insertions, 1 deletions
diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c index e202f954eb84..2ecc79c03ade 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -9,6 +9,7 @@ */ #include <linux/delay.h> +#include <linux/gpio.h> #include <linux/interrupt.h> #include <linux/irq.h> #include <linux/irqdomain.h> @@ -18,6 +19,7 @@ #include <linux/platform_device.h> #include <linux/msi.h> #include <linux/of_address.h> +#include <linux/of_gpio.h> #include <linux/of_pci.h> #include "../pci.h" @@ -204,6 +206,7 @@ struct advk_pcie { int root_bus_nr; int link_gen; struct pci_bridge_emul bridge; + struct gpio_desc *reset_gpio; }; static inline void advk_writel(struct advk_pcie *pcie, u32 val, u64 reg) @@ -330,10 +333,31 @@ err: dev_err(dev, "link never came up\n"); } +static void advk_pcie_issue_perst(struct advk_pcie *pcie) +{ + u32 reg; + + if (!pcie->reset_gpio) + return; + + /* PERST does not work for some cards when link training is enabled */ + reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG); + reg &= ~LINK_TRAINING_EN; + advk_writel(pcie, reg, PCIE_CORE_CTRL0_REG); + + /* 10ms delay is needed for some cards */ + dev_info(&pcie->pdev->dev, "issuing PERST via reset GPIO for 10ms\n"); + gpiod_set_value_cansleep(pcie->reset_gpio, 1); + usleep_range(10000, 11000); + gpiod_set_value_cansleep(pcie->reset_gpio, 0); +} + static void advk_pcie_setup_hw(struct advk_pcie *pcie) { u32 reg; + advk_pcie_issue_perst(pcie); + /* Set to Direct mode */ reg = advk_readl(pcie, CTRL_CONFIG_REG); reg &= ~(CTRL_MODE_MASK << CTRL_MODE_SHIFT); @@ -406,7 +430,8 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie) /* * PERST# signal could have been asserted by pinctrl subsystem before - * probe() callback has been called, making the endpoint going into + * probe() callback has been called or issued explicitly by reset gpio + * function advk_pcie_issue_perst(), making the endpoint going into * fundamental reset. As required by PCI Express spec a delay for at * least 100ms after such a reset before link training is needed. */ @@ -1046,6 +1071,22 @@ static int advk_pcie_probe(struct platform_device *pdev) } pcie->root_bus_nr = bus->start; + pcie->reset_gpio = devm_gpiod_get_from_of_node(dev, dev->of_node, + "reset-gpios", 0, + GPIOD_OUT_LOW, + "pcie1-reset"); + ret = PTR_ERR_OR_ZERO(pcie->reset_gpio); + if (ret) { + if (ret == -ENOENT) { + pcie->reset_gpio = NULL; + } else { + if (ret != -EPROBE_DEFER) + dev_err(dev, "Failed to get reset-gpio: %i\n", + ret); + return ret; + } + } + ret = of_pci_get_max_link_speed(dev->of_node); if (ret <= 0 || ret > 3) pcie->link_gen = 3; |