mirror of
https://github.com/torvalds/linux.git
synced 2024-11-14 16:12:02 +00:00
abffc82aae
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. Introduce a reset controller capable of interfacing with RPi4's co-processor that models these firmware initialization routines as reset lines. Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Link: https://lore.kernel.org/r/20200629161845.6021-3-nsaenzjulienne@suse.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
123 lines
3.1 KiB
C
123 lines
3.1 KiB
C
// 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");
|