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e4c2c0ff00
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>
153 lines
4.3 KiB
C
153 lines
4.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __FIRMWARE_LOADER_H
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#define __FIRMWARE_LOADER_H
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#include <linux/bitops.h>
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#include <linux/firmware.h>
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#include <linux/types.h>
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#include <linux/kref.h>
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#include <linux/list.h>
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#include <linux/completion.h>
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#include <generated/utsrelease.h>
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/**
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* enum fw_opt - options to control firmware loading behaviour
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*
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* @FW_OPT_UEVENT: Enables the fallback mechanism to send a kobject uevent
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* when the firmware is not found. Userspace is in charge to load the
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* firmware using the sysfs loading facility.
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* @FW_OPT_NOWAIT: Used to describe the firmware request is asynchronous.
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* @FW_OPT_USERHELPER: Enable the fallback mechanism, in case the direct
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* filesystem lookup fails at finding the firmware. For details refer to
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* firmware_fallback_sysfs().
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* @FW_OPT_NO_WARN: Quiet, avoid printing warning messages.
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* @FW_OPT_NOCACHE: Disables firmware caching. Firmware caching is used to
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* cache the firmware upon suspend, so that upon resume races against the
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* firmware file lookup on storage is avoided. Used for calls where the
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* file may be too big, or where the driver takes charge of its own
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* firmware caching mechanism.
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* @FW_OPT_NOFALLBACK_SYSFS: Disable the sysfs fallback mechanism. Takes
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* precedence over &FW_OPT_UEVENT and &FW_OPT_USERHELPER.
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* @FW_OPT_FALLBACK_PLATFORM: Enable fallback to device fw copy embedded in
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* the platform's main firmware. If both this fallback and the sysfs
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* fallback are enabled, then this fallback will be tried first.
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*/
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enum fw_opt {
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FW_OPT_UEVENT = BIT(0),
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FW_OPT_NOWAIT = BIT(1),
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FW_OPT_USERHELPER = BIT(2),
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FW_OPT_NO_WARN = BIT(3),
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FW_OPT_NOCACHE = BIT(4),
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FW_OPT_NOFALLBACK_SYSFS = BIT(5),
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FW_OPT_FALLBACK_PLATFORM = BIT(6),
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};
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enum fw_status {
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FW_STATUS_UNKNOWN,
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FW_STATUS_LOADING,
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FW_STATUS_DONE,
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FW_STATUS_ABORTED,
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};
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/*
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* Concurrent request_firmware() for the same firmware need to be
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* serialized. struct fw_state is simple state machine which hold the
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* state of the firmware loading.
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*/
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struct fw_state {
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struct completion completion;
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enum fw_status status;
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};
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struct fw_priv {
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struct kref ref;
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struct list_head list;
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struct firmware_cache *fwc;
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struct fw_state fw_st;
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void *data;
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size_t size;
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size_t allocated_size;
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#ifdef CONFIG_FW_LOADER_PAGED_BUF
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bool is_paged_buf;
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struct page **pages;
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int nr_pages;
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int page_array_size;
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#endif
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#ifdef CONFIG_FW_LOADER_USER_HELPER
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bool need_uevent;
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struct list_head pending_list;
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#endif
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const char *fw_name;
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};
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extern struct mutex fw_lock;
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static inline bool __fw_state_check(struct fw_priv *fw_priv,
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enum fw_status status)
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{
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struct fw_state *fw_st = &fw_priv->fw_st;
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return fw_st->status == status;
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}
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static inline int __fw_state_wait_common(struct fw_priv *fw_priv, long timeout)
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{
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struct fw_state *fw_st = &fw_priv->fw_st;
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long ret;
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ret = wait_for_completion_killable_timeout(&fw_st->completion, timeout);
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if (ret != 0 && fw_st->status == FW_STATUS_ABORTED)
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return -ENOENT;
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if (!ret)
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return -ETIMEDOUT;
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return ret < 0 ? ret : 0;
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}
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static inline void __fw_state_set(struct fw_priv *fw_priv,
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enum fw_status status)
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{
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struct fw_state *fw_st = &fw_priv->fw_st;
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WRITE_ONCE(fw_st->status, status);
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if (status == FW_STATUS_DONE || status == FW_STATUS_ABORTED)
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complete_all(&fw_st->completion);
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}
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static inline void fw_state_aborted(struct fw_priv *fw_priv)
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{
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__fw_state_set(fw_priv, FW_STATUS_ABORTED);
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}
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static inline bool fw_state_is_aborted(struct fw_priv *fw_priv)
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{
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return __fw_state_check(fw_priv, FW_STATUS_ABORTED);
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}
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static inline void fw_state_start(struct fw_priv *fw_priv)
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{
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__fw_state_set(fw_priv, FW_STATUS_LOADING);
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}
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static inline void fw_state_done(struct fw_priv *fw_priv)
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{
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__fw_state_set(fw_priv, FW_STATUS_DONE);
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}
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int assign_fw(struct firmware *fw, struct device *device,
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enum fw_opt opt_flags);
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#ifdef CONFIG_FW_LOADER_PAGED_BUF
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void fw_free_paged_buf(struct fw_priv *fw_priv);
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int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed);
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int fw_map_paged_buf(struct fw_priv *fw_priv);
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#else
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static inline void fw_free_paged_buf(struct fw_priv *fw_priv) {}
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static inline int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed) { return -ENXIO; }
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static inline int fw_map_paged_buf(struct fw_priv *fw_priv) { return -ENXIO; }
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#endif
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#endif /* __FIRMWARE_LOADER_H */
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