reset: Add Raspberry Pi 4 firmware reset controller (abffc82a) · Commits · EulixOS / Software / Kernel

drivers/reset/Kconfig

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		@@ -140,6 +140,17 @@ config RESET_QCOM_PDC
		to control reset signals provided by PDC for Modem, Compute,
		Display, GPU, Debug, AOP, Sensors, Audio, SP and APPS.

		config RESET_RASPBERRYPI
		tristate "Raspberry Pi 4 Firmware Reset Driver"
		depends on RASPBERRYPI_FIRMWARE \|\| (RASPBERRYPI_FIRMWARE=n && COMPILE_TEST)
		default USB_XHCI_PCI
		help
		Raspberry Pi 4's co-processor controls some of the board's HW
		initialization process, but it's up to Linux to trigger it when
		relevant. This driver provides a reset controller capable of
		interfacing with RPi4's co-processor and model these firmware
		initialization routines as reset lines.

		config RESET_SCMI
		tristate "Reset driver controlled via ARM SCMI interface"
		depends on ARM_SCMI_PROTOCOL \|\| COMPILE_TEST

drivers/reset/Makefile

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		@@ -21,6 +21,7 @@ obj-$(CONFIG_RESET_OXNAS) += reset-oxnas.o
		obj-$(CONFIG_RESET_PISTACHIO) += reset-pistachio.o
		obj-$(CONFIG_RESET_QCOM_AOSS) += reset-qcom-aoss.o
		obj-$(CONFIG_RESET_QCOM_PDC) += reset-qcom-pdc.o
		obj-$(CONFIG_RESET_RASPBERRYPI) += reset-raspberrypi.o
		obj-$(CONFIG_RESET_SCMI) += reset-scmi.o
		obj-$(CONFIG_RESET_SIMPLE) += reset-simple.o
		obj-$(CONFIG_RESET_STM32MP157) += reset-stm32mp1.o

drivers/reset/reset-raspberrypi.c

0 → 100644

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		// SPDX-License-Identifier: GPL-2.0
		/*
		* Raspberry Pi 4 firmware reset driver
		*
		* Copyright (C) 2020 Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
		*/
		#include <linux/delay.h>
		#include <linux/device.h>
		#include <linux/module.h>
		#include <linux/of.h>
		#include <linux/platform_device.h>
		#include <linux/reset-controller.h>
		#include <soc/bcm2835/raspberrypi-firmware.h>
		#include <dt-bindings/reset/raspberrypi,firmware-reset.h>

		struct rpi_reset {
		struct reset_controller_dev rcdev;
		struct rpi_firmware *fw;
		};

		static inline struct rpi_reset to_rpi(struct reset_controller_dev rcdev)
		{
		return container_of(rcdev, struct rpi_reset, rcdev);
		}

		static int rpi_reset_reset(struct reset_controller_dev *rcdev, unsigned long id)
		{
		struct rpi_reset *priv = to_rpi(rcdev);
		u32 dev_addr;
		int ret;

		switch (id) {
		case RASPBERRYPI_FIRMWARE_RESET_ID_USB:
		/*
		* The Raspberry Pi 4 gets its USB functionality from VL805, a
		* PCIe chip that implements xHCI. After a PCI reset, VL805's
		* firmware may either be loaded directly from an EEPROM or, if
		* not present, by the SoC's co-processor, VideoCore. rpi's
		* VideoCore OS contains both the non public firmware load
		* logic and the VL805 firmware blob. This triggers the
		* aforementioned process.
		*
		* The pci device address is expected is expected by the
		* firmware encoded like this:
		*
		* PCI_BUS << 20 \| PCI_SLOT << 15 \| PCI_FUNC << 12
		*
		* But since rpi's PCIe is hardwired, we know the address in
		* advance.
		*/
		dev_addr = 0x100000;
		ret = rpi_firmware_property(priv->fw, RPI_FIRMWARE_NOTIFY_XHCI_RESET,
		&dev_addr, sizeof(dev_addr));
		if (ret)
		return ret;

		/* Wait for vl805 to startup */
		usleep_range(200, 1000);
		break;

		default:
		return -EINVAL;
		}

		return 0;
		}

		static const struct reset_control_ops rpi_reset_ops = {
		.reset = rpi_reset_reset,
		};

		static int rpi_reset_probe(struct platform_device *pdev)
		{
		struct device *dev = &pdev->dev;
		struct rpi_firmware *fw;
		struct device_node *np;
		struct rpi_reset *priv;

		np = of_get_parent(dev->of_node);
		if (!np) {
		dev_err(dev, "Missing firmware node\n");
		return -ENOENT;
		}

		fw = rpi_firmware_get(np);
		of_node_put(np);
		if (!fw)
		return -EPROBE_DEFER;

		priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
		if (!priv)
		return -ENOMEM;

		dev_set_drvdata(dev, priv);

		priv->fw = fw;
		priv->rcdev.owner = THIS_MODULE;
		priv->rcdev.nr_resets = RASPBERRYPI_FIRMWARE_RESET_NUM_IDS;
		priv->rcdev.ops = &rpi_reset_ops;
		priv->rcdev.of_node = dev->of_node;

		return devm_reset_controller_register(dev, &priv->rcdev);
		}

		static const struct of_device_id rpi_reset_of_match[] = {
		{ .compatible = "raspberrypi,firmware-reset" },
		{ /* sentinel */ }
		};
		MODULE_DEVICE_TABLE(of, rpi_reset_of_match);

		static struct platform_driver rpi_reset_driver = {
		.probe = rpi_reset_probe,
		.driver = {
		.name = "raspberrypi-reset",
		.of_match_table = rpi_reset_of_match,
		},
		};
		module_platform_driver(rpi_reset_driver);

		MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de>");
		MODULE_DESCRIPTION("Raspberry Pi 4 firmware reset driver");
		MODULE_LICENSE("GPL");