This is a note to let you know that I've just added the patch titled
PCI: aardvark: Issue PERST via GPIO
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pci-aardvark-issue-perst-via-gpio.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Mon Nov 29 01:32:04 PM CET 2021
From: "Marek Behún" <kabel@xxxxxxxxxx>
Date: Wed, 24 Nov 2021 23:49:15 +0100
Subject: PCI: aardvark: Issue PERST via GPIO
To: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>, Sasha Levin <sashal@xxxxxxxxxx>
Cc: pali@xxxxxxxxxx, stable@xxxxxxxxxxxxxxx, "Tomasz Maciej Nowak" <tmn505@xxxxxxxxx>, "Lorenzo Pieralisi" <lorenzo.pieralisi@xxxxxxx>, "Thomas Petazzoni" <thomas.petazzoni@xxxxxxxxxxx>, "Marek Behún" <kabel@xxxxxxxxxx>
Message-ID: <20211124224933.24275-7-kabel@xxxxxxxxxx>
From: Pali Rohár <pali@xxxxxxxxxx>
commit 5169a9851daaa2782a7bd2bb83d5b1bd224b2879 upstream.
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@xxxxxxxxxx
Tested-by: Tomasz Maciej Nowak <tmn505@xxxxxxxxx>
Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Acked-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxx>
Signed-off-by: Marek Behún <kabel@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/pci/host/pci-aardvark.c | 44 +++++++++++++++++++++++++++++++++++++++-
1 file changed, 43 insertions(+), 1 deletion(-)
--- a/drivers/pci/host/pci-aardvark.c
+++ b/drivers/pci/host/pci-aardvark.c
@@ -12,6 +12,7 @@
*/
#include <linux/delay.h>
+#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
@@ -20,6 +21,7 @@
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/of_address.h>
+#include <linux/of_gpio.h>
#include <linux/of_pci.h>
/* PCIe core registers */
@@ -214,6 +216,7 @@ struct advk_pcie {
u16 msi_msg;
int root_bus_nr;
int link_gen;
+ struct gpio_desc *reset_gpio;
};
static inline void advk_writel(struct advk_pcie *pcie, u32 val, u64 reg)
@@ -349,6 +352,25 @@ 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;
@@ -358,6 +380,8 @@ static void advk_pcie_setup_hw(struct ad
for (i = 0; i < 8; i++)
advk_pcie_set_ob_win(pcie, i, 0, 0, 0, 0, 0, 0, 0);
+ advk_pcie_issue_perst(pcie);
+
/* Set to Direct mode */
reg = advk_readl(pcie, CTRL_CONFIG_REG);
reg &= ~(CTRL_MODE_MASK << CTRL_MODE_SHIFT);
@@ -430,7 +454,8 @@ 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.
*/
@@ -1075,6 +1100,23 @@ static int advk_pcie_probe(struct platfo
return ret;
}
+ pcie->reset_gpio = devm_fwnode_get_index_gpiod_from_child(dev, "reset",
+ 0,
+ dev_fwnode(dev),
+ 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;
Patches currently in stable-queue which might be from kabel@xxxxxxxxxx are
queue-4.14/pci-aardvark-move-pcie-reset-card-code-to-advk_pcie_train_link.patch
queue-4.14/pci-aardvark-introduce-an-advk_pcie_valid_device-helper.patch
queue-4.14/pci-aardvark-update-comment-about-disabling-link-training.patch
queue-4.14/pci-aardvark-train-link-immediately-after-enabling-training.patch
queue-4.14/arm64-dts-marvell-armada-37xx-declare-pcie-reset-pin.patch
queue-4.14/pci-aardvark-replace-custom-macros-by-standard-linux-pci_regs.h-macros.patch
queue-4.14/pci-aardvark-fix-a-leaked-reference-by-adding-missing-of_node_put.patch
queue-4.14/pci-aardvark-fix-pcie-max-payload-size-setting.patch
queue-4.14/pinctrl-armada-37xx-correct-pwm-pins-definitions.patch
queue-4.14/arm64-dts-marvell-armada-37xx-set-pcie_reset_pin-to-gpio-function.patch
queue-4.14/pci-aardvark-configure-pcie-resources-from-ranges-dt-property.patch
queue-4.14/pci-aardvark-improve-link-training.patch
queue-4.14/pci-aardvark-fix-link-training.patch
queue-4.14/pci-aardvark-fix-checking-for-link-up-via-ltssm-state.patch
queue-4.14/pci-aardvark-issue-perst-via-gpio.patch
queue-4.14/pinctrl-armada-37xx-correct-mpp-definitions.patch
queue-4.14/pci-add-pci_exp_lnkctl2_tls-macros.patch
queue-4.14/pci-aardvark-wait-for-endpoint-to-be-ready-before-training-link.patch
queue-4.14/pinctrl-armada-37xx-add-missing-pin-pcie1-wakeup.patch
queue-4.14/pci-aardvark-fix-compilation-on-s390.patch
queue-4.14/pci-aardvark-fix-i-o-space-page-leak.patch
queue-4.14/pci-aardvark-don-t-touch-pcie-registers-if-no-card-connected.patch
queue-4.14/pci-aardvark-remove-pcie-outbound-window-configuration.patch
queue-4.14/pci-aardvark-indicate-error-in-val-when-config-read-fails.patch
