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Commit 570d30c2 authored by Samuel Holland's avatar Samuel Holland Committed by Greg Kroah-Hartman
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firmware: coreboot: Expose the coreboot table as a bus 



This simplifies creating device drivers for hardware or information
described in the coreboot table. It also avoids needing to search
through the table every time a driver is loaded.

Signed-off-by: default avatarSamuel Holland <samuel@sholland.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 093a89d4

drivers/firmware/google/coreboot_table-acpi.c

+1 −1
Original line number Diff line number Diff line
@@ -53,7 +53,7 @@ static int coreboot_table_acpi_probe(struct platform_device *pdev) 
	if (!ptr)

		return -ENOMEM;



	return coreboot_table_init(ptr);

	return coreboot_table_init(&pdev->dev, ptr);

}



static int coreboot_table_acpi_remove(struct platform_device *pdev)

drivers/firmware/google/coreboot_table-of.c

+1 −1
Original line number Diff line number Diff line
@@ -34,7 +34,7 @@ static int coreboot_table_of_probe(struct platform_device *pdev) 
	if (!ptr)

		return -ENOMEM;



	return coreboot_table_init(ptr);

	return coreboot_table_init(&pdev->dev, ptr);

}



static int coreboot_table_of_remove(struct platform_device *pdev)

drivers/firmware/google/coreboot_table.c

+114 −7
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
 * Module providing coreboot table access.

 *

 * Copyright 2017 Google Inc.

 * Copyright 2017 Samuel Holland <samuel@sholland.org>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License v2.0 as published by
@@ -15,21 +16,87 @@ 
 * GNU General Public License for more details.

 */



#include <linux/device.h>

#include <linux/err.h>

#include <linux/init.h>

#include <linux/io.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/slab.h>



#include "coreboot_table.h"



struct coreboot_table_entry {

	u32 tag;

	u32 size;

};

#define CB_DEV(d) container_of(d, struct coreboot_device, dev)

#define CB_DRV(d) container_of(d, struct coreboot_driver, drv)



static struct coreboot_table_header __iomem *ptr_header;



static int coreboot_bus_match(struct device *dev, struct device_driver *drv)

{

	struct coreboot_device *device = CB_DEV(dev);

	struct coreboot_driver *driver = CB_DRV(drv);



	return device->entry.tag == driver->tag;

}



static int coreboot_bus_probe(struct device *dev)

{

	int ret = -ENODEV;

	struct coreboot_device *device = CB_DEV(dev);

	struct coreboot_driver *driver = CB_DRV(dev->driver);



	if (driver->probe)

		ret = driver->probe(device);



	return ret;

}



static int coreboot_bus_remove(struct device *dev)

{

	int ret = 0;

	struct coreboot_device *device = CB_DEV(dev);

	struct coreboot_driver *driver = CB_DRV(dev->driver);



	if (driver->remove)

		ret = driver->remove(device);



	return ret;

}



static struct bus_type coreboot_bus_type = {

	.name		= "coreboot",

	.match		= coreboot_bus_match,

	.probe		= coreboot_bus_probe,

	.remove		= coreboot_bus_remove,

};



static int __init coreboot_bus_init(void)

{

	return bus_register(&coreboot_bus_type);

}

module_init(coreboot_bus_init);



static void coreboot_device_release(struct device *dev)

{

	struct coreboot_device *device = CB_DEV(dev);



	kfree(device);

}



int coreboot_driver_register(struct coreboot_driver *driver)

{

	driver->drv.bus = &coreboot_bus_type;



	return driver_register(&driver->drv);

}

EXPORT_SYMBOL(coreboot_driver_register);



void coreboot_driver_unregister(struct coreboot_driver *driver)

{

	driver_unregister(&driver->drv);

}

EXPORT_SYMBOL(coreboot_driver_unregister);



/*

 * This function parses the coreboot table for an entry that contains the base

 * address of the given entry tag. The coreboot table consists of a header
@@ -73,18 +140,58 @@ int coreboot_table_find(int tag, void *data, size_t data_size) 
}

EXPORT_SYMBOL(coreboot_table_find);



int coreboot_table_init(void __iomem *ptr)

int coreboot_table_init(struct device *dev, void __iomem *ptr)

{

	int i, ret;

	void *ptr_entry;

	struct coreboot_device *device;

	struct coreboot_table_entry entry;

	struct coreboot_table_header header;



	ptr_header = ptr;

	memcpy_fromio(&header, ptr_header, sizeof(header));



	return 0;

	if (strncmp(header.signature, "LBIO", sizeof(header.signature))) {

		pr_warn("coreboot_table: coreboot table missing or corrupt!\n");

		return -ENODEV;

	}



	ptr_entry = (void *)ptr_header + header.header_bytes;

	for (i = 0; i < header.table_entries; i++) {

		memcpy_fromio(&entry, ptr_entry, sizeof(entry));



		device = kzalloc(sizeof(struct device) + entry.size, GFP_KERNEL);

		if (!device) {

			ret = -ENOMEM;

			break;

		}



		dev_set_name(&device->dev, "coreboot%d", i);

		device->dev.parent = dev;

		device->dev.bus = &coreboot_bus_type;

		device->dev.release = coreboot_device_release;

		memcpy_fromio(&device->entry, ptr_entry, entry.size);



		ret = device_register(&device->dev);

		if (ret) {

			put_device(&device->dev);

			break;

		}



		ptr_entry += entry.size;

	}



	return ret;

}

EXPORT_SYMBOL(coreboot_table_init);



int coreboot_table_exit(void)

{

	if (ptr_header)

	if (ptr_header) {

		bus_unregister(&coreboot_bus_type);

		iounmap(ptr_header);

		ptr_header = NULL;

	}



	return 0;

}

drivers/firmware/google/coreboot_table.h

+40 −9
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
 * Internal header for coreboot table access.

 *

 * Copyright 2017 Google Inc.

 * Copyright 2017 Samuel Holland <samuel@sholland.org>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License v2.0 as published by
@@ -20,14 +21,6 @@ 


#include <linux/io.h>



/* List of coreboot entry structures that is used */

struct lb_cbmem_ref {

	uint32_t tag;

	uint32_t size;



	uint64_t cbmem_addr;

};



/* Coreboot table header structure */

struct coreboot_table_header {

	char signature[4];
@@ -38,11 +31,49 @@ struct coreboot_table_header { 
	u32 table_entries;

};



/* List of coreboot entry structures that is used */

/* Generic */

struct coreboot_table_entry {

	u32 tag;

	u32 size;

};



/* Points to a CBMEM entry */

struct lb_cbmem_ref {

	u32 tag;

	u32 size;



	u64 cbmem_addr;

};



/* A device, additionally with information from coreboot. */

struct coreboot_device {

	struct device dev;

	union {

		struct coreboot_table_entry entry;

		struct lb_cbmem_ref cbmem_ref;

	};

};



/* A driver for handling devices described in coreboot tables. */

struct coreboot_driver {

	int (*probe)(struct coreboot_device *);

	int (*remove)(struct coreboot_device *);

	struct device_driver drv;

	u32 tag;

};



/* Register a driver that uses the data from a coreboot table. */

int coreboot_driver_register(struct coreboot_driver *driver);



/* Unregister a driver that uses the data from a coreboot table. */

void coreboot_driver_unregister(struct coreboot_driver *driver);



/* Retrieve coreboot table entry with tag *tag* and copy it to data */

int coreboot_table_find(int tag, void *data, size_t data_size);



/* Initialize coreboot table module given a pointer to iomem */

int coreboot_table_init(void __iomem *ptr);

int coreboot_table_init(struct device *dev, void __iomem *ptr);



/* Cleanup coreboot table module */

int coreboot_table_exit(void);