1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __FIRMWARE_LOADER_H
3 #define __FIRMWARE_LOADER_H
4 
5 #include <linux/bitops.h>
6 #include <linux/firmware.h>
7 #include <linux/types.h>
8 #include <linux/kref.h>
9 #include <linux/list.h>
10 #include <linux/completion.h>
11 
12 #include <generated/utsrelease.h>
13 
14 /**
15  * enum fw_opt - options to control firmware loading behaviour
16  *
17  * @FW_OPT_UEVENT: Enables the fallback mechanism to send a kobject uevent
18  *	when the firmware is not found. Userspace is in charge to load the
19  *	firmware using the sysfs loading facility.
20  * @FW_OPT_NOWAIT: Used to describe the firmware request is asynchronous.
21  * @FW_OPT_USERHELPER: Enable the fallback mechanism, in case the direct
22  *	filesystem lookup fails at finding the firmware.  For details refer to
23  *	firmware_fallback_sysfs().
24  * @FW_OPT_NO_WARN: Quiet, avoid printing warning messages.
25  * @FW_OPT_NOCACHE: Disables firmware caching. Firmware caching is used to
26  *	cache the firmware upon suspend, so that upon resume races against the
27  *	firmware file lookup on storage is avoided. Used for calls where the
28  *	file may be too big, or where the driver takes charge of its own
29  *	firmware caching mechanism.
30  * @FW_OPT_NOFALLBACK_SYSFS: Disable the sysfs fallback mechanism. Takes
31  *	precedence over &FW_OPT_UEVENT and &FW_OPT_USERHELPER.
32  * @FW_OPT_FALLBACK_PLATFORM: Enable fallback to device fw copy embedded in
33  *	the platform's main firmware. If both this fallback and the sysfs
34  *      fallback are enabled, then this fallback will be tried first.
35  * @FW_OPT_PARTIAL: Allow partial read of firmware instead of needing to read
36  *	entire file.
37  */
38 enum fw_opt {
39 	FW_OPT_UEVENT			= BIT(0),
40 	FW_OPT_NOWAIT			= BIT(1),
41 	FW_OPT_USERHELPER		= BIT(2),
42 	FW_OPT_NO_WARN			= BIT(3),
43 	FW_OPT_NOCACHE			= BIT(4),
44 	FW_OPT_NOFALLBACK_SYSFS		= BIT(5),
45 	FW_OPT_FALLBACK_PLATFORM	= BIT(6),
46 	FW_OPT_PARTIAL			= BIT(7),
47 };
48 
49 enum fw_status {
50 	FW_STATUS_UNKNOWN,
51 	FW_STATUS_LOADING,
52 	FW_STATUS_DONE,
53 	FW_STATUS_ABORTED,
54 };
55 
56 /*
57  * Concurrent request_firmware() for the same firmware need to be
58  * serialized.  struct fw_state is simple state machine which hold the
59  * state of the firmware loading.
60  */
61 struct fw_state {
62 	struct completion completion;
63 	enum fw_status status;
64 };
65 
66 struct fw_priv {
67 	struct kref ref;
68 	struct list_head list;
69 	struct firmware_cache *fwc;
70 	struct fw_state fw_st;
71 	void *data;
72 	size_t size;
73 	size_t allocated_size;
74 	size_t offset;
75 	u32 opt_flags;
76 #ifdef CONFIG_FW_LOADER_PAGED_BUF
77 	bool is_paged_buf;
78 	struct page **pages;
79 	int nr_pages;
80 	int page_array_size;
81 #endif
82 #ifdef CONFIG_FW_LOADER_USER_HELPER
83 	bool need_uevent;
84 	struct list_head pending_list;
85 #endif
86 	const char *fw_name;
87 };
88 
89 extern struct mutex fw_lock;
90 
91 static inline bool __fw_state_check(struct fw_priv *fw_priv,
92 				    enum fw_status status)
93 {
94 	struct fw_state *fw_st = &fw_priv->fw_st;
95 
96 	return fw_st->status == status;
97 }
98 
99 static inline int __fw_state_wait_common(struct fw_priv *fw_priv, long timeout)
100 {
101 	struct fw_state *fw_st = &fw_priv->fw_st;
102 	long ret;
103 
104 	ret = wait_for_completion_killable_timeout(&fw_st->completion, timeout);
105 	if (ret != 0 && fw_st->status == FW_STATUS_ABORTED)
106 		return -ENOENT;
107 	if (!ret)
108 		return -ETIMEDOUT;
109 
110 	return ret < 0 ? ret : 0;
111 }
112 
113 static inline void __fw_state_set(struct fw_priv *fw_priv,
114 				  enum fw_status status)
115 {
116 	struct fw_state *fw_st = &fw_priv->fw_st;
117 
118 	WRITE_ONCE(fw_st->status, status);
119 
120 	if (status == FW_STATUS_DONE || status == FW_STATUS_ABORTED) {
121 #ifdef CONFIG_FW_LOADER_USER_HELPER
122 		/*
123 		 * Doing this here ensures that the fw_priv is deleted from
124 		 * the pending list in all abort/done paths.
125 		 */
126 		list_del_init(&fw_priv->pending_list);
127 #endif
128 		complete_all(&fw_st->completion);
129 	}
130 }
131 
132 static inline void fw_state_aborted(struct fw_priv *fw_priv)
133 {
134 	__fw_state_set(fw_priv, FW_STATUS_ABORTED);
135 }
136 
137 static inline bool fw_state_is_aborted(struct fw_priv *fw_priv)
138 {
139 	return __fw_state_check(fw_priv, FW_STATUS_ABORTED);
140 }
141 
142 static inline void fw_state_start(struct fw_priv *fw_priv)
143 {
144 	__fw_state_set(fw_priv, FW_STATUS_LOADING);
145 }
146 
147 static inline void fw_state_done(struct fw_priv *fw_priv)
148 {
149 	__fw_state_set(fw_priv, FW_STATUS_DONE);
150 }
151 
152 int assign_fw(struct firmware *fw, struct device *device);
153 
154 #ifdef CONFIG_FW_LOADER_PAGED_BUF
155 void fw_free_paged_buf(struct fw_priv *fw_priv);
156 int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed);
157 int fw_map_paged_buf(struct fw_priv *fw_priv);
158 bool fw_is_paged_buf(struct fw_priv *fw_priv);
159 #else
160 static inline void fw_free_paged_buf(struct fw_priv *fw_priv) {}
161 static inline int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed) { return -ENXIO; }
162 static inline int fw_map_paged_buf(struct fw_priv *fw_priv) { return -ENXIO; }
163 static inline bool fw_is_paged_buf(struct fw_priv *fw_priv) { return false; }
164 #endif
165 
166 #endif /* __FIRMWARE_LOADER_H */
167