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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123// 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 = devm_rpi_firmware_get(&pdev->dev, 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");