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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: Samuel Holland <samuel@sholland.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Samuel Holland 2018-01-24 19:41:16 -06:00 committed by Greg Kroah-Hartman
parent 093a89d4c2
commit 570d30c282
4 changed files with 157 additions and 19 deletions
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2
drivers/firmware/google/coreboot_table-acpi.c
View File

@ -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)

2
drivers/firmware/google/coreboot_table-of.c
View File

@ -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)

123
drivers/firmware/google/coreboot_table.c
View File

@ -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)
{
ptr_header = ptr;
int i, ret;
void *ptr_entry;
struct coreboot_device *device;
struct coreboot_table_entry entry;
struct coreboot_table_header header;
return 0;
ptr_header = ptr;
memcpy_fromio(&header, ptr_header, sizeof(header));
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;
}

49
drivers/firmware/google/coreboot_table.h
View File

@ -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);