linux_dsm_epyc7002/include/linux/firmware.h
Hans de Goede e4c2c0ff00 firmware: Add new platform fallback mechanism and firmware_request_platform()
In some cases the platform's main firmware (e.g. the UEFI fw) may contain
an embedded copy of device firmware which needs to be (re)loaded into the
peripheral. Normally such firmware would be part of linux-firmware, but in
some cases this is not feasible, for 2 reasons:

1) The firmware is customized for a specific use-case of the chipset / use
with a specific hardware model, so we cannot have a single firmware file
for the chipset. E.g. touchscreen controller firmwares are compiled
specifically for the hardware model they are used with, as they are
calibrated for a specific model digitizer.

2) Despite repeated attempts we have failed to get permission to
redistribute the firmware. This is especially a problem with customized
firmwares, these get created by the chip vendor for a specific ODM and the
copyright may partially belong with the ODM, so the chip vendor cannot
give a blanket permission to distribute these.

This commit adds a new platform fallback mechanism to the firmware loader
which will try to lookup a device fw copy embedded in the platform's main
firmware if direct filesystem lookup fails.

Drivers which need such embedded fw copies can enable this fallback
mechanism by using the new firmware_request_platform() function.

Note that for now this is only supported on EFI platforms and even on
these platforms firmware_fallback_platform() only works if
CONFIG_EFI_EMBEDDED_FIRMWARE is enabled (this gets selected by drivers
which need this), in all other cases firmware_fallback_platform() simply
always returns -ENOENT.

Reported-by: Dave Olsthoorn <dave@bewaar.me>
Suggested-by: Peter Jones <pjones@redhat.com>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20200115163554.101315-5-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-20 14:54:04 +01:00

111 lines
2.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_FIRMWARE_H
#define _LINUX_FIRMWARE_H
#include <linux/types.h>
#include <linux/compiler.h>
#include <linux/gfp.h>
#define FW_ACTION_NOHOTPLUG 0
#define FW_ACTION_HOTPLUG 1
struct firmware {
size_t size;
const u8 *data;
struct page **pages;
/* firmware loader private fields */
void *priv;
};
struct module;
struct device;
struct builtin_fw {
char *name;
void *data;
unsigned long size;
};
/* We have to play tricks here much like stringify() to get the
__COUNTER__ macro to be expanded as we want it */
#define __fw_concat1(x, y) x##y
#define __fw_concat(x, y) __fw_concat1(x, y)
#define DECLARE_BUILTIN_FIRMWARE(name, blob) \
DECLARE_BUILTIN_FIRMWARE_SIZE(name, &(blob), sizeof(blob))
#define DECLARE_BUILTIN_FIRMWARE_SIZE(name, blob, size) \
static const struct builtin_fw __fw_concat(__builtin_fw,__COUNTER__) \
__used __section(.builtin_fw) = { name, blob, size }
#if defined(CONFIG_FW_LOADER) || (defined(CONFIG_FW_LOADER_MODULE) && defined(MODULE))
int request_firmware(const struct firmware **fw, const char *name,
struct device *device);
int firmware_request_nowarn(const struct firmware **fw, const char *name,
struct device *device);
int firmware_request_platform(const struct firmware **fw, const char *name,
struct device *device);
int request_firmware_nowait(
struct module *module, bool uevent,
const char *name, struct device *device, gfp_t gfp, void *context,
void (*cont)(const struct firmware *fw, void *context));
int request_firmware_direct(const struct firmware **fw, const char *name,
struct device *device);
int request_firmware_into_buf(const struct firmware **firmware_p,
const char *name, struct device *device, void *buf, size_t size);
void release_firmware(const struct firmware *fw);
#else
static inline int request_firmware(const struct firmware **fw,
const char *name,
struct device *device)
{
return -EINVAL;
}
static inline int firmware_request_nowarn(const struct firmware **fw,
const char *name,
struct device *device)
{
return -EINVAL;
}
static inline int firmware_request_platform(const struct firmware **fw,
const char *name,
struct device *device)
{
return -EINVAL;
}
static inline int request_firmware_nowait(
struct module *module, bool uevent,
const char *name, struct device *device, gfp_t gfp, void *context,
void (*cont)(const struct firmware *fw, void *context))
{
return -EINVAL;
}
static inline void release_firmware(const struct firmware *fw)
{
}
static inline int request_firmware_direct(const struct firmware **fw,
const char *name,
struct device *device)
{
return -EINVAL;
}
static inline int request_firmware_into_buf(const struct firmware **firmware_p,
const char *name, struct device *device, void *buf, size_t size)
{
return -EINVAL;
}
#endif
int firmware_request_cache(struct device *device, const char *name);
#endif