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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#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 intrpi_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; } } 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; } else if (ret == -ETIMEDOUT) { WARN_ONCE(1, "Firmware transaction 0x%08x timeout", buf[2]); }
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 voidrpi_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 voidrpi_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_obj(*fw); 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 = 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");