[+cc Rob]
On Tue, Apr 21, 2020 at 01:16:56PM +0200, Marek Behún wrote:
> From: Pali Rohár <pali@xxxxxxxxxx>
>
> Add support for issuing PERST via GPIO specified in 'reset-gpios'
> property (as described in PCI device tree bindings).
>
> Some buggy cards (e.g. Compex WLE900VX or WLE1216) are not detected
> after reboot when PERST is not issued during driver initialization.
Does this slot support hotplug? If so, I don't think this fix will
help the hot-add case, will it?
> Tested on Turris MOX.
>
> Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
> ---
> drivers/pci/controller/pci-aardvark.c | 32 +++++++++++++++++++++++++++
> 1 file changed, 32 insertions(+)
>
> diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
> index 606bae1e7a88..e2d18094d8ca 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)
> @@ -329,10 +332,23 @@ static void advk_pcie_train_link(struct advk_pcie *pcie)
> dev_err(dev, "link never came up\n");
> }
>
> +static void advk_pcie_issue_perst(struct advk_pcie *pcie)
> +{
> + if (!pcie->reset_gpio)
> + return;
> +
> + dev_info(&pcie->pdev->dev, "issuing PERST via reset GPIO for 1ms\n");
> + gpiod_set_value_cansleep(pcie->reset_gpio, 1);
> + usleep_range(1000, 2000);
> + 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);
> @@ -1045,6 +1061,22 @@ 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;
> + }
> + }
> +
> pcie->link_gen = of_pci_get_max_link_speed(dev->of_node);
> if (pcie->link_gen < 1 || pcie->link_gen > 2)
> pcie->link_gen = 2;
> --
> 2.24.1
>
