// SPDX-License-Identifier: GPL-2.0
/*
* Defines interfaces for interacting with the Raspberry Pi firmware's
* property channel.
*
* Copyright © 2015 Broadcom
*/
#include <linux/dma-mapping.h>
#include <linux/kref.h>
#include <linux/mailbox_client.h>
#include <linux/mailbox_controller.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <soc/bcm2835/raspberrypi-firmware.h>
#define MBOX_MSG(chan, data28) (((data28) & ~0xf) | ((chan) & 0xf))
#define MBOX_CHAN(msg) ((msg) & 0xf)
#define MBOX_DATA28(msg) ((msg) & ~0xf)
#define MBOX_CHAN_PROPERTY 8
static struct platform_device *rpi_hwmon;
static struct platform_device *rpi_clk;
struct rpi_firmware {
struct mbox_client cl;
struct mbox_chan *chan; /* The property channel. */
struct completion c;
u32 enabled;
struct kref consumers;
};
static DEFINE_MUTEX(transaction_lock);
static void response_callback(struct mbox_client *cl, void *msg)
{
struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl);
complete(&fw->c);
}
/*
* Sends a request to the firmware through the BCM2835 mailbox driver,
* and synchronously waits for the reply.
*/
static int
rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)
{
u32 message = MBOX_MSG(chan, data);
int ret;
WARN_ON(data & 0xf);
mutex_lock(&transaction_lock);
reinit_completion(&fw->c);
ret = mbox_send_message(fw->chan, &message);
if (ret >= 0) {
if (wait_for_completion_timeout(&fw->c, HZ)) {
ret = 0;
} else {
ret = -ETIMEDOUT;
WARN_ONCE(1, "Firmware transaction timeout");
}
} else {
dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
}
mutex_unlock(&transaction_lock);
return ret;
}
/**
* rpi_firmware_property_list - Submit firmware property list
* @fw: Pointer to firmware structure from rpi_firmware_get().
* @data: Buffer holding tags.
* @tag_size: Size of tags buffer.
*
* Submits a set of concatenated tags to the VPU firmware through the
* mailbox property interface.
*
* The buffer header and the ending tag are added by this function and
* don't need to be supplied, just the actual tags for your operation.
* See struct rpi_firmware_property_tag_header for the per-tag
* structure.
*/
int rpi_firmware_property_list(struct rpi_firmware *fw,
void *data, size_t tag_size)
{
size_t size = tag_size + 12;
u32 *buf;
dma_addr_t bus_addr;
int ret;
/* Packets are processed a dword at a time. */
if (size & 3)
return -EINVAL;
buf = dma_alloc_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size),
&bus_addr, GFP_ATOMIC);
if (!buf)
return -ENOMEM;
/* The firmware will error out without parsing in this case. */
WARN_ON(size >= 1024 * 1024);
buf[0] = size;
buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
memcpy(&buf[2], data, tag_size);
buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
wmb();
ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);
rmb();
memcpy(data, &buf[2], tag_size);
if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
/*
* The tag name here might not be the one causing the
* error, if there were multiple tags in the request.
* But single-tag is the most common, so go with it.
*/
dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
buf[2], buf[1]);
ret = -EINVAL;
}
dma_free_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size), buf, bus_addr);
return ret;
}
EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
/**
* rpi_firmware_property - Submit single firmware property
* @fw: Pointer to firmware structure from rpi_firmware_get().
* @tag: One of enum_mbox_property_tag.
* @tag_data: Tag data buffer.
* @buf_size: Buffer size.
*
* Submits a single tag to the VPU firmware through the mailbox
* property interface.
*
* This is a convenience wrapper around
* rpi_firmware_property_list() to avoid some of the
* boilerplate in property calls.
*/
int rpi_firmware_property(struct rpi_firmware *fw,
u32 tag, void *tag_data, size_t buf_size)
{
struct rpi_firmware_property_tag_header *header;
int ret;
/* Some mailboxes can use over 1k bytes. Rather than checking
* size and using stack or kmalloc depending on requirements,
* just use kmalloc. Mailboxes don't get called enough to worry
* too much about the time taken in the allocation.
*/
void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL);
if (!data)
return -ENOMEM;
header = data;
header->tag = tag;
header->buf_size = buf_size;
header->req_resp_size = 0;
memcpy(data + sizeof(*header), tag_data, buf_size);
ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header));
memcpy(tag_data, data + sizeof(*header), buf_size);
kfree(data);
return ret;
}
EXPORT_SYMBOL_GPL(rpi_firmware_property);
static void
rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
{
time64_t date_and_time;
u32 packet;
int ret = rpi_firmware_property(fw,
RPI_FIRMWARE_GET_FIRMWARE_REVISION,
&packet, sizeof(packet));
if (ret)
return;
/* This is not compatible with y2038 */
date_and_time = packet;
dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time);
}
static void
rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
{
u32 packet;
int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,
&packet, sizeof(packet));
if (ret)
return;
rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",
-1, NULL, 0);
}
static void rpi_register_clk_driver(struct device *dev)
{
struct device_node *firmware;
/*
* Earlier DTs don't have a node for the firmware clocks but
* rely on us creating a platform device by hand. If we do
* have a node for the firmware clocks, just bail out here.
*/
firmware = of_get_compatible_child(dev->of_node,
"raspberrypi,firmware-clocks");
if (firmware) {
of_node_put(firmware);
return;
}
rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",
-1, NULL, 0);
}
unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id)
{
struct rpi_firmware_clk_rate_request msg =
RPI_FIRMWARE_CLK_RATE_REQUEST(id);
int ret;
ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_MAX_CLOCK_RATE,
&msg, sizeof(msg));
if (ret)
/*
* If our firmware doesn't support that operation, or fails, we
* assume the maximum clock rate is absolute maximum we can
* store over our type.
*/
return UINT_MAX;
return le32_to_cpu(msg.rate);
}
EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate);
static void rpi_firmware_delete(struct kref *kref)
{
struct rpi_firmware *fw = container_of(kref, struct rpi_firmware,
consumers);
mbox_free_channel(fw->chan);
kfree(fw);
}
void rpi_firmware_put(struct rpi_firmware *fw)
{
kref_put(&fw->consumers, rpi_firmware_delete);
}
EXPORT_SYMBOL_GPL(rpi_firmware_put);
static void devm_rpi_firmware_put(void *data)
{
struct rpi_firmware *fw = data;
rpi_firmware_put(fw);
}
static int rpi_firmware_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct rpi_firmware *fw;
/*
* Memory will be freed by rpi_firmware_delete() once all users have
* released their firmware handles. Don't use devm_kzalloc() here.
*/
fw = kzalloc(sizeof(*fw), GFP_KERNEL);
if (!fw)
return -ENOMEM;
fw->cl.dev = dev;
fw->cl.rx_callback = response_callback;
fw->cl.tx_block = true;
fw->chan = mbox_request_channel(&fw->cl, 0);
if (IS_ERR(fw->chan)) {
int ret = PTR_ERR(fw->chan);
kfree(fw);
return dev_err_probe(dev, ret, "Failed to get mbox channel\n");
}
init_completion(&fw->c);
kref_init(&fw->consumers);
platform_set_drvdata(pdev, fw);
rpi_firmware_print_firmware_revision(fw);
rpi_register_hwmon_driver(dev, fw);
rpi_register_clk_driver(dev);
return 0;
}
static void rpi_firmware_shutdown(struct platform_device *pdev)
{
struct rpi_firmware *fw = platform_get_drvdata(pdev);
if (!fw)
return;
rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
}
static void rpi_firmware_remove(struct platform_device *pdev)
{
struct rpi_firmware *fw = platform_get_drvdata(pdev);
platform_device_unregister(rpi_hwmon);
rpi_hwmon = NULL;
platform_device_unregister(rpi_clk);
rpi_clk = NULL;
rpi_firmware_put(fw);
}
static const struct of_device_id rpi_firmware_of_match[] = {
{ .compatible = "raspberrypi,bcm2835-firmware", },
{},
};
MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
struct device_node *rpi_firmware_find_node(void)
{
return of_find_matching_node(NULL, rpi_firmware_of_match);
}
EXPORT_SYMBOL_GPL(rpi_firmware_find_node);
/**
* rpi_firmware_get - Get pointer to rpi_firmware structure.
* @firmware_node: Pointer to the firmware Device Tree node.
*
* The reference to rpi_firmware has to be released with rpi_firmware_put().
*
* Returns NULL is the firmware device is not ready.
*/
struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
{
struct platform_device *pdev = of_find_device_by_node(firmware_node);
struct rpi_firmware *fw;
if (!pdev)
return NULL;
fw = platform_get_drvdata(pdev);
if (!fw)
goto err_put_device;
if (!kref_get_unless_zero(&fw->consumers))
goto err_put_device;
put_device(&pdev->dev);
return fw;
err_put_device:
put_device(&pdev->dev);
return NULL;
}
EXPORT_SYMBOL_GPL(rpi_firmware_get);
/**
* devm_rpi_firmware_get - Get pointer to rpi_firmware structure.
* @dev: The firmware device structure
* @firmware_node: Pointer to the firmware Device Tree node.
*
* Returns NULL is the firmware device is not ready.
*/
struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
struct device_node *firmware_node)
{
struct rpi_firmware *fw;
fw = rpi_firmware_get(firmware_node);
if (!fw)
return NULL;
if (devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw))
return NULL;
return fw;
}
EXPORT_SYMBOL_GPL(devm_rpi_firmware_get);
static struct platform_driver rpi_firmware_driver = {
.driver = {
.name = "raspberrypi-firmware",
.of_match_table = rpi_firmware_of_match,
},
.probe = rpi_firmware_probe,
.shutdown = rpi_firmware_shutdown,
.remove_new = rpi_firmware_remove,
};
module_platform_driver(rpi_firmware_driver);
MODULE_AUTHOR("Eric Anholt <[email protected]>");
MODULE_DESCRIPTION("Raspberry Pi firmware driver");
MODULE_LICENSE("GPL v2");
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