+++ /dev/null
-From 5169a9851daaa2782a7bd2bb83d5b1bd224b2879 Mon Sep 17 00:00:00 2001
-From: =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali@kernel.org>
-Date: Thu, 30 Apr 2020 10:06:18 +0200
-Subject: [PATCH] PCI: aardvark: Issue PERST via GPIO
-MIME-Version: 1.0
-Content-Type: text/plain; charset=UTF-8
-Content-Transfer-Encoding: 8bit
-
-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.
-
-If bootloader already enabled link training then issuing PERST has no
-effect for some buggy cards (e.g. Compex WLE900VX) and these cards are
-not detected. We therefore clear the LINK_TRAINING_EN register before.
-
-It was observed that Compex WLE900VX card needs to be in PERST reset
-for at least 10ms if bootloader enabled link training.
-
-Tested on Turris MOX.
-
-Link: https://lore.kernel.org/r/20200430080625.26070-6-pali@kernel.org
-Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
-Signed-off-by: Pali Rohár <pali@kernel.org>
-Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
-Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
----
- drivers/pci/controller/pci-aardvark.c | 43 ++++++++++++++++++++++++++-
- 1 file changed, 42 insertions(+), 1 deletion(-)
-
---- 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>
-@@ -17,6 +18,7 @@
- #include <linux/init.h>
- #include <linux/platform_device.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 ad
-
- /*
- * 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.
- */
-@@ -1093,6 +1118,22 @@ static int advk_pcie_probe(struct platfo
- return ret;
- }
-
-+ 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;
projects / openwrt / openwrt.git / blobdiff