linux/drivers/firmware/raspberrypi.c
Eric Anholt 4e3d60656a ARM: bcm2835: Add the Raspberry Pi firmware driver
This gives us a function for making mailbox property channel requests
of the firmware, which is most notable in that it will let us get and
set clock rates.

Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
2015-10-14 15:30:06 -07:00

261 lines
6.6 KiB
C

/*
* Defines interfaces for interacting wtih the Raspberry Pi firmware's
* property channel.
*
* Copyright © 2015 Broadcom
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/dma-mapping.h>
#include <linux/mailbox_client.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/platform_device.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
struct rpi_firmware {
struct mbox_client cl;
struct mbox_chan *chan; /* The property channel. */
struct completion c;
u32 enabled;
};
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) {
wait_for_completion(&fw->c);
ret = 0;
} 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->cl.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->cl.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)
{
/* Single tags are very small (generally 8 bytes), so the
* stack should be safe.
*/
u8 data[buf_size + sizeof(struct rpi_firmware_property_tag_header)];
struct rpi_firmware_property_tag_header *header =
(struct rpi_firmware_property_tag_header *)data;
int ret;
header->tag = tag;
header->buf_size = buf_size;
header->req_resp_size = 0;
memcpy(data + sizeof(struct rpi_firmware_property_tag_header),
tag_data, buf_size);
ret = rpi_firmware_property_list(fw, &data, sizeof(data));
memcpy(tag_data,
data + sizeof(struct rpi_firmware_property_tag_header),
buf_size);
return ret;
}
EXPORT_SYMBOL_GPL(rpi_firmware_property);
static void
rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
{
u32 packet;
int ret = rpi_firmware_property(fw,
RPI_FIRMWARE_GET_FIRMWARE_REVISION,
&packet, sizeof(packet));
if (ret == 0) {
struct tm tm;
time_to_tm(packet, 0, &tm);
dev_info(fw->cl.dev,
"Attached to firmware from %04ld-%02d-%02d %02d:%02d\n",
tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
tm.tm_hour, tm.tm_min);
}
}
static int rpi_firmware_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct rpi_firmware *fw;
fw = devm_kzalloc(dev, 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);
if (ret != -EPROBE_DEFER)
dev_err(dev, "Failed to get mbox channel: %d\n", ret);
return ret;
}
init_completion(&fw->c);
platform_set_drvdata(pdev, fw);
rpi_firmware_print_firmware_revision(fw);
return 0;
}
static int rpi_firmware_remove(struct platform_device *pdev)
{
struct rpi_firmware *fw = platform_get_drvdata(pdev);
mbox_free_channel(fw->chan);
return 0;
}
/**
* rpi_firmware_get - Get pointer to rpi_firmware structure.
* @firmware_node: Pointer to the firmware Device Tree node.
*
* 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);
if (!pdev)
return NULL;
return platform_get_drvdata(pdev);
}
EXPORT_SYMBOL_GPL(rpi_firmware_get);
static const struct of_device_id rpi_firmware_of_match[] = {
{ .compatible = "raspberrypi,bcm2835-firmware", },
{},
};
MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
static struct platform_driver rpi_firmware_driver = {
.driver = {
.name = "raspberrypi-firmware",
.of_match_table = rpi_firmware_of_match,
},
.probe = rpi_firmware_probe,
.remove = rpi_firmware_remove,
};
module_platform_driver(rpi_firmware_driver);
MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
MODULE_DESCRIPTION("Raspberry Pi firmware driver");
MODULE_LICENSE("GPL v2");