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122 lines
3.1 KiB
122 lines
3.1 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Raspberry Pi 4 firmware reset driver |
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* |
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* Copyright (C) 2020 Nicolas Saenz Julienne <[email protected]> |
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*/ |
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#include <linux/delay.h> |
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#include <linux/device.h> |
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#include <linux/module.h> |
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#include <linux/of.h> |
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#include <linux/platform_device.h> |
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#include <linux/reset-controller.h> |
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#include <soc/bcm2835/raspberrypi-firmware.h> |
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#include <dt-bindings/reset/raspberrypi,firmware-reset.h> |
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struct rpi_reset { |
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struct reset_controller_dev rcdev; |
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struct rpi_firmware *fw; |
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}; |
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static inline struct rpi_reset *to_rpi(struct reset_controller_dev *rcdev) |
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{ |
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return container_of(rcdev, struct rpi_reset, rcdev); |
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} |
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static int rpi_reset_reset(struct reset_controller_dev *rcdev, unsigned long id) |
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{ |
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struct rpi_reset *priv = to_rpi(rcdev); |
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u32 dev_addr; |
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int ret; |
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switch (id) { |
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case RASPBERRYPI_FIRMWARE_RESET_ID_USB: |
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/* |
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* The Raspberry Pi 4 gets its USB functionality from VL805, a |
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* PCIe chip that implements xHCI. After a PCI reset, VL805's |
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* firmware may either be loaded directly from an EEPROM or, if |
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* not present, by the SoC's co-processor, VideoCore. rpi's |
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* VideoCore OS contains both the non public firmware load |
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* logic and the VL805 firmware blob. This triggers the |
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* aforementioned process. |
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* |
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* The pci device address is expected is expected by the |
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* firmware encoded like this: |
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* |
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* PCI_BUS << 20 | PCI_SLOT << 15 | PCI_FUNC << 12 |
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* |
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* But since rpi's PCIe is hardwired, we know the address in |
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* advance. |
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*/ |
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dev_addr = 0x100000; |
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ret = rpi_firmware_property(priv->fw, RPI_FIRMWARE_NOTIFY_XHCI_RESET, |
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&dev_addr, sizeof(dev_addr)); |
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if (ret) |
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return ret; |
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/* Wait for vl805 to startup */ |
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usleep_range(200, 1000); |
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break; |
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default: |
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return -EINVAL; |
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} |
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return 0; |
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} |
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static const struct reset_control_ops rpi_reset_ops = { |
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.reset = rpi_reset_reset, |
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}; |
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static int rpi_reset_probe(struct platform_device *pdev) |
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{ |
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struct device *dev = &pdev->dev; |
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struct rpi_firmware *fw; |
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struct device_node *np; |
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struct rpi_reset *priv; |
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np = of_get_parent(dev->of_node); |
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if (!np) { |
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dev_err(dev, "Missing firmware node\n"); |
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return -ENOENT; |
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} |
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fw = devm_rpi_firmware_get(&pdev->dev, np); |
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of_node_put(np); |
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if (!fw) |
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return -EPROBE_DEFER; |
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priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); |
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if (!priv) |
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return -ENOMEM; |
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dev_set_drvdata(dev, priv); |
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priv->fw = fw; |
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priv->rcdev.owner = THIS_MODULE; |
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priv->rcdev.nr_resets = RASPBERRYPI_FIRMWARE_RESET_NUM_IDS; |
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priv->rcdev.ops = &rpi_reset_ops; |
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priv->rcdev.of_node = dev->of_node; |
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return devm_reset_controller_register(dev, &priv->rcdev); |
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} |
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static const struct of_device_id rpi_reset_of_match[] = { |
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{ .compatible = "raspberrypi,firmware-reset" }, |
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{ /* sentinel */ } |
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}; |
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MODULE_DEVICE_TABLE(of, rpi_reset_of_match); |
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static struct platform_driver rpi_reset_driver = { |
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.probe = rpi_reset_probe, |
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.driver = { |
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.name = "raspberrypi-reset", |
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.of_match_table = rpi_reset_of_match, |
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}, |
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}; |
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module_platform_driver(rpi_reset_driver); |
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MODULE_AUTHOR("Nicolas Saenz Julienne <[email protected]>"); |
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MODULE_DESCRIPTION("Raspberry Pi 4 firmware reset driver"); |
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MODULE_LICENSE("GPL");
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