linux-stable/drivers/base/firmware_loader/firmware.h
Luis Chamberlain 48d09e9787 firmware_loader: formalize built-in firmware API
Formalize the built-in firmware with a proper API. This can later
be used by other callers where all they need is built-in firmware.

We export the firmware_request_builtin() call for now only
under the TEST_FIRMWARE symbol namespace as there are no
direct modular users for it. If they pop up they are free
to export it generally. Built-in code always gets access to
the callers and we'll demonstrate a hidden user which has been
lurking in the kernel for a while and the reason why using a
proper API was better long term.

Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20211021155843.1969401-2-mcgrof@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-22 14:13:44 +02:00

183 lines
5.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __FIRMWARE_LOADER_H
#define __FIRMWARE_LOADER_H
#include <linux/bitops.h>
#include <linux/firmware.h>
#include <linux/types.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/completion.h>
#include <generated/utsrelease.h>
/**
* enum fw_opt - options to control firmware loading behaviour
*
* @FW_OPT_UEVENT: Enables the fallback mechanism to send a kobject uevent
* when the firmware is not found. Userspace is in charge to load the
* firmware using the sysfs loading facility.
* @FW_OPT_NOWAIT: Used to describe the firmware request is asynchronous.
* @FW_OPT_USERHELPER: Enable the fallback mechanism, in case the direct
* filesystem lookup fails at finding the firmware. For details refer to
* firmware_fallback_sysfs().
* @FW_OPT_NO_WARN: Quiet, avoid printing warning messages.
* @FW_OPT_NOCACHE: Disables firmware caching. Firmware caching is used to
* cache the firmware upon suspend, so that upon resume races against the
* firmware file lookup on storage is avoided. Used for calls where the
* file may be too big, or where the driver takes charge of its own
* firmware caching mechanism.
* @FW_OPT_NOFALLBACK_SYSFS: Disable the sysfs fallback mechanism. Takes
* precedence over &FW_OPT_UEVENT and &FW_OPT_USERHELPER.
* @FW_OPT_FALLBACK_PLATFORM: Enable fallback to device fw copy embedded in
* the platform's main firmware. If both this fallback and the sysfs
* fallback are enabled, then this fallback will be tried first.
* @FW_OPT_PARTIAL: Allow partial read of firmware instead of needing to read
* entire file.
*/
enum fw_opt {
FW_OPT_UEVENT = BIT(0),
FW_OPT_NOWAIT = BIT(1),
FW_OPT_USERHELPER = BIT(2),
FW_OPT_NO_WARN = BIT(3),
FW_OPT_NOCACHE = BIT(4),
FW_OPT_NOFALLBACK_SYSFS = BIT(5),
FW_OPT_FALLBACK_PLATFORM = BIT(6),
FW_OPT_PARTIAL = BIT(7),
};
enum fw_status {
FW_STATUS_UNKNOWN,
FW_STATUS_LOADING,
FW_STATUS_DONE,
FW_STATUS_ABORTED,
};
/*
* Concurrent request_firmware() for the same firmware need to be
* serialized. struct fw_state is simple state machine which hold the
* state of the firmware loading.
*/
struct fw_state {
struct completion completion;
enum fw_status status;
};
struct fw_priv {
struct kref ref;
struct list_head list;
struct firmware_cache *fwc;
struct fw_state fw_st;
void *data;
size_t size;
size_t allocated_size;
size_t offset;
u32 opt_flags;
#ifdef CONFIG_FW_LOADER_PAGED_BUF
bool is_paged_buf;
struct page **pages;
int nr_pages;
int page_array_size;
#endif
#ifdef CONFIG_FW_LOADER_USER_HELPER
bool need_uevent;
struct list_head pending_list;
#endif
const char *fw_name;
};
extern struct mutex fw_lock;
static inline bool __fw_state_check(struct fw_priv *fw_priv,
enum fw_status status)
{
struct fw_state *fw_st = &fw_priv->fw_st;
return fw_st->status == status;
}
static inline int __fw_state_wait_common(struct fw_priv *fw_priv, long timeout)
{
struct fw_state *fw_st = &fw_priv->fw_st;
long ret;
ret = wait_for_completion_killable_timeout(&fw_st->completion, timeout);
if (ret != 0 && fw_st->status == FW_STATUS_ABORTED)
return -ENOENT;
if (!ret)
return -ETIMEDOUT;
return ret < 0 ? ret : 0;
}
static inline void __fw_state_set(struct fw_priv *fw_priv,
enum fw_status status)
{
struct fw_state *fw_st = &fw_priv->fw_st;
WRITE_ONCE(fw_st->status, status);
if (status == FW_STATUS_DONE || status == FW_STATUS_ABORTED) {
#ifdef CONFIG_FW_LOADER_USER_HELPER
/*
* Doing this here ensures that the fw_priv is deleted from
* the pending list in all abort/done paths.
*/
list_del_init(&fw_priv->pending_list);
#endif
complete_all(&fw_st->completion);
}
}
static inline void fw_state_aborted(struct fw_priv *fw_priv)
{
__fw_state_set(fw_priv, FW_STATUS_ABORTED);
}
static inline bool fw_state_is_aborted(struct fw_priv *fw_priv)
{
return __fw_state_check(fw_priv, FW_STATUS_ABORTED);
}
static inline void fw_state_start(struct fw_priv *fw_priv)
{
__fw_state_set(fw_priv, FW_STATUS_LOADING);
}
static inline void fw_state_done(struct fw_priv *fw_priv)
{
__fw_state_set(fw_priv, FW_STATUS_DONE);
}
int assign_fw(struct firmware *fw, struct device *device);
#ifdef CONFIG_FW_LOADER
bool firmware_is_builtin(const struct firmware *fw);
bool firmware_request_builtin_buf(struct firmware *fw, const char *name,
void *buf, size_t size);
#else /* module case */
static inline bool firmware_is_builtin(const struct firmware *fw)
{
return false;
}
static inline bool firmware_request_builtin_buf(struct firmware *fw,
const char *name,
void *buf, size_t size)
{
return false;
}
#endif
#ifdef CONFIG_FW_LOADER_PAGED_BUF
void fw_free_paged_buf(struct fw_priv *fw_priv);
int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed);
int fw_map_paged_buf(struct fw_priv *fw_priv);
bool fw_is_paged_buf(struct fw_priv *fw_priv);
#else
static inline void fw_free_paged_buf(struct fw_priv *fw_priv) {}
static inline int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed) { return -ENXIO; }
static inline int fw_map_paged_buf(struct fw_priv *fw_priv) { return -ENXIO; }
static inline bool fw_is_paged_buf(struct fw_priv *fw_priv) { return false; }
#endif
#endif /* __FIRMWARE_LOADER_H */