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From: "Marek Behún" <marek.behun@nic.cz>
To: linux-pci@vger.kernel.org
Cc: "Jason Cooper" <jason@lakedaemon.net>,
	"Andrew Lunn" <andrew@lunn.ch>,
	"Gregory Clement" <gregory.clement@bootlin.com>,
	"Sebastian Hesselbarth" <sebastian.hesselbarth@gmail.com>,
	"Thomas Petazzoni" <thomas.petazzoni@bootlin.com>,
	"Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>,
	"Andrew Murray" <amurray@thegoodpenguin.co.uk>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Remi Pommarel" <repk@triplefau.lt>,
	"Tomasz Maciej Nowak" <tmn505@gmail.com>,
	Xogium <contact@xogium.me>, "Pali Rohár" <pali@kernel.org>,
	"Marek Behún" <marek.behun@nic.cz>,
	"Rob Herring" <robh+dt@kernel.org>,
	devicetree@vger.kernel.org
Subject: [PATCH v2 8/9] arm64: dts: marvell: armada-37xx: set pcie_reset_pin to gpio function
Date: Tue, 21 Apr 2020 13:17:00 +0200	[thread overview]
Message-ID: <20200421111701.17088-9-marek.behun@nic.cz> (raw)
In-Reply-To: <20200421111701.17088-1-marek.behun@nic.cz>

We found out that we are unable to control the PERST# signal via the
default pin dedicated to be PERST# pin (GPIO2[3] pin) on A3700 SOC when
this pin is in EP_PCIE1_Resetn mode. There is a register in the PCIe
register space called PERSTN_GPIO_EN (D0088004[3]), but changing the
value of this register does not change the pin output when measuring
with voltmeter.

We do not know if this is a bug in the SOC, or if it works only when
PCIe controller is in a certain state.

Commit f4c7d053d7f7 ("PCI: aardvark: Wait for endpoint to be ready
before training link") says that when this pin changes pinctrl mode
from EP_PCIE1_Resetn to GPIO, the PERST# signal is asserted for a brief
moment.

So currently the situation is that on A3700 boards the PERST# signal is
asserted in U-Boot (because the code in U-Boot issues reset via this pin
via GPIO mode), and then in Linux by the obscure and undocumented
mechanism described by the above mentioned commit.

We want to issue PERST# signal in a known way, therefore this patch
changes the pcie_reset_pin function from "pcie" to "gpio" and adds the
reset-gpios property to the PCIe node in device tree files of
EspressoBin and Armada 3720 Dev Board (Turris Mox device tree already
has this property and uDPU does not have a PCIe port).

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Cc: Remi Pommarel <repk@triplefau.lt>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
---
 arch/arm64/boot/dts/marvell/armada-3720-db.dts           | 3 +++
 arch/arm64/boot/dts/marvell/armada-3720-espressobin.dtsi | 1 +
 arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts   | 4 ----
 arch/arm64/boot/dts/marvell/armada-37xx.dtsi             | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/boot/dts/marvell/armada-3720-db.dts b/arch/arm64/boot/dts/marvell/armada-3720-db.dts
index f2cc00594d64..3e5789f37206 100644
--- a/arch/arm64/boot/dts/marvell/armada-3720-db.dts
+++ b/arch/arm64/boot/dts/marvell/armada-3720-db.dts
@@ -128,6 +128,9 @@ phy1: ethernet-phy@1 {
 
 /* CON15(V2.0)/CON17(V1.4) : PCIe / CON15(V2.0)/CON12(V1.4) :mini-PCIe */
 &pcie0 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pcie_reset_pins &pcie_clkreq_pins>;
+	reset-gpios = <&gpiosb 3 GPIO_ACTIVE_LOW>;
 	status = "okay";
 };
 
diff --git a/arch/arm64/boot/dts/marvell/armada-3720-espressobin.dtsi b/arch/arm64/boot/dts/marvell/armada-3720-espressobin.dtsi
index 42e992f9c8a5..c92ad664cb0e 100644
--- a/arch/arm64/boot/dts/marvell/armada-3720-espressobin.dtsi
+++ b/arch/arm64/boot/dts/marvell/armada-3720-espressobin.dtsi
@@ -47,6 +47,7 @@ &pcie0 {
 	phys = <&comphy1 0>;
 	pinctrl-names = "default";
 	pinctrl-0 = <&pcie_reset_pins &pcie_clkreq_pins>;
+	reset-gpios = <&gpiosb 3 GPIO_ACTIVE_LOW>;
 };
 
 /* J6 */
diff --git a/arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts b/arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts
index bb42d1e6a4e9..e496bd9d4737 100644
--- a/arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts
+++ b/arch/arm64/boot/dts/marvell/armada-3720-turris-mox.dts
@@ -128,10 +128,6 @@ rtc@6f {
 	};
 };
 
-&pcie_reset_pins {
-	function = "gpio";
-};
-
 &pcie0 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&pcie_reset_pins &pcie_clkreq_pins>;
diff --git a/arch/arm64/boot/dts/marvell/armada-37xx.dtsi b/arch/arm64/boot/dts/marvell/armada-37xx.dtsi
index 000c135e39b7..7909c146eabf 100644
--- a/arch/arm64/boot/dts/marvell/armada-37xx.dtsi
+++ b/arch/arm64/boot/dts/marvell/armada-37xx.dtsi
@@ -317,7 +317,7 @@ sdio_pins: sdio-pins {
 
 				pcie_reset_pins: pcie-reset-pins {
 					groups = "pcie1";
-					function = "pcie";
+					function = "gpio";
 				};
 
 				pcie_clkreq_pins: pcie-clkreq-pins {
-- 
2.24.1


  parent reply	other threads:[~2020-04-21 11:17 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-21 11:16 [PATCH v2 0/9] PCI: aardvark: Fix support for Turris MOX and Compex wifi cards Marek Behún
2020-04-21 11:16 ` [PATCH v2 1/9] PCI: aardvark: train link immediately after enabling training Marek Behún
2020-04-21 11:16 ` [PATCH v2 2/9] PCI: aardvark: don't write to read-only register Marek Behún
2020-04-23 17:27   ` Bjorn Helgaas
2020-04-23 17:51     ` Pali Rohár
2020-04-21 11:16 ` [PATCH v2 3/9] PCI: aardvark: improve link training Marek Behún
2020-04-23 18:39   ` Bjorn Helgaas
2020-04-23 18:56     ` Pali Rohár
2020-04-24 12:49       ` Pali Rohár
2020-04-21 11:16 ` [PATCH v2 4/9] PCI: aardvark: issue PERST via GPIO Marek Behún
2020-04-23 18:41   ` Bjorn Helgaas
2020-04-23 19:02     ` Pali Rohár
2020-04-23 22:17       ` Bjorn Helgaas
2020-04-23 22:23         ` Pali Rohár
2020-04-23 22:40           ` Bjorn Helgaas
2020-04-24  8:13             ` Pali Rohár
2020-04-24  9:25   ` Pali Rohár
2020-04-21 11:16 ` [PATCH v2 5/9] PCI: aardvark: add FIXME comment for PCIE_CORE_CMD_STATUS_REG access Marek Behún
2020-04-23 18:44   ` Bjorn Helgaas
2020-04-23 19:06     ` Pali Rohár
2020-04-21 11:16 ` [PATCH v2 6/9] PCI: aardvark: add PHY support Marek Behún
2020-04-21 11:16 ` [PATCH v2 7/9] dt-bindings: PCI: aardvark: describe new properties Marek Behún
2020-05-11 18:24   ` Rob Herring
2020-04-21 11:17 ` Marek Behún [this message]
2020-04-21 11:17 ` [PATCH v2 9/9] arm64: dts: marvell: armada-37xx: move PCIe comphy handle property Marek Behún
2020-04-21 11:42 ` [PATCH v2 0/9] PCI: aardvark: Fix support for Turris MOX and Compex wifi cards Pali Rohár

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