firmware(9): extend firmware_get() by a "no warn" flag.

With the upcoming usage from LinuxKPI but also from drivers
ported natively we are seeing more probing of various
firmware (names).

Add the ability to firmware(9) to silence the
"firmware image loading/registering errors" by adding a new
firmware_get_flags() functions extending firmware_get() and
taking a flags argument as firmware_put() already does.

Requested-by:	zeising (for future LinuxKPI/DRM)
Sponsored-by:	The FreeBSD Foundation
Sponsored-by:	Rubicon Communications, LLC ("Netgate")
MFC after:	3 days
Reviewed-by:	markj
Differential Revision:	https://reviews.freebsd.org/D27413
This commit is contained in:
Bjoern A. Zeeb 2021-01-25 22:41:50 +00:00
parent bcb7f57aa2
commit 6f65b50546
3 changed files with 69 additions and 21 deletions

View File

@ -23,13 +23,14 @@
.\"
.\" $FreeBSD$
.\"
.Dd March 14, 2019
.Dd January 27, 2021
.Dt FIRMWARE 9
.Os
.Sh NAME
.Nm firmware_register ,
.Nm firmware_unregister ,
.Nm firmware_get ,
.Nm firmware_get_flags ,
.Nm firmware_put
.Nd firmware image loading and management
.Sh SYNOPSIS
@ -57,6 +58,8 @@ struct firmware {
.Fn firmware_unregister "const char *imagename"
.Ft "const struct firmware *"
.Fn firmware_get "const char *imagename"
.Ft "const struct firmware *"
.Fn firmware_get_flags "const char *imagename" "uint32_t flags"
.Ft void
.Fn firmware_put "const struct firmware *fp" "int flags"
.Sh DESCRIPTION
@ -97,7 +100,13 @@ by calling the function
.Fn firmware_get
with the
.Nm imagename
they want as an argument.
they want as an argument, or by calling
.Fn firmware_get_flags
with the
.Nm imagename
and
.Nm flags
they want as an arguments.
If a matching image is not already registered,
the firmware subsystem will try to load it using the
mechanisms specified below (typically, a kernel module
@ -134,11 +143,22 @@ if there are no pending references to the image, otherwise
it does not unregister the image and returns EBUSY.
.Pp
.Fn firmware_get
returns the requested firmware image.
and
.Fn firmware_get_flags
return the requested firmware image.
The
.Fa flags
argument may be set to
.Dv FIRMWARE_GET_NOWARN
to indicate that errors on firmware load or registration should
only be logged in case of
.Nm booverbose .
If the image is not yet registered with the system,
the function tries to load it.
the functions try to load it.
This involves the linker subsystem and disk access, so
.Fn firmware_get
or
.Fn firmware_get_flags
must not be called with any locks (except for
.Va Giant ) .
Note also that if the firmware image is loaded from a filesystem
@ -149,9 +169,11 @@ already mounted.
.Pp
On success,
.Fn firmware_get
returns a pointer to the image description and increases the reference count
and
.Fn firmware_get_flags
return a pointer to the image description and increase the reference count
for this image.
On failure, the function returns NULL.
On failure, the functions return NULL.
.Pp
.Fn firmware_put
drops a reference to a firmware image.
@ -183,10 +205,12 @@ these images in memory before calling
.Pp
When
.Fn firmware_get
or
.Fn firmware_get_flags
does not find the requested image, it tries to load it using
one of the available loading mechanisms.
At the moment, there is only one, namely
.Nm Loadable kernel modules :
.Nm Loadable kernel modules .
.Pp
A firmware image named
.Nm foo
@ -203,6 +227,8 @@ which on most systems defaults to
Note that in case a module contains multiple images,
the caller should first request a
.Fn firmware_get
or
.Fn firmware_get_flags
for the first image contained in the module, followed by requests
for the other images.
.Sh BUILDING FIRMWARE LOADABLE MODULES

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@ -238,36 +238,42 @@ firmware_unregister(const char *imagename)
return (err);
}
struct fw_loadimage {
const char *imagename;
uint32_t flags;
};
static void
loadimage(void *arg, int npending)
loadimage(void *arg, int npending __unused)
{
char *imagename = arg;
struct fw_loadimage *fwli = arg;
struct priv_fw *fp;
linker_file_t result;
int error;
error = linker_reference_module(imagename, NULL, &result);
error = linker_reference_module(fwli->imagename, NULL, &result);
if (error != 0) {
printf("%s: could not load firmware image, error %d\n",
imagename, error);
if (bootverbose || (fwli->flags & FIRMWARE_GET_NOWARN) == 0)
printf("%s: could not load firmware image, error %d\n",
fwli->imagename, error);
mtx_lock(&firmware_mtx);
goto done;
}
mtx_lock(&firmware_mtx);
fp = lookup(imagename);
fp = lookup(fwli->imagename);
if (fp == NULL || fp->file != NULL) {
mtx_unlock(&firmware_mtx);
if (fp == NULL)
printf("%s: firmware image loaded, "
"but did not register\n", imagename);
(void) linker_release_module(imagename, NULL, NULL);
"but did not register\n", fwli->imagename);
(void) linker_release_module(fwli->imagename, NULL, NULL);
mtx_lock(&firmware_mtx);
goto done;
}
fp->file = result; /* record the module identity */
done:
wakeup_one(imagename);
wakeup_one(arg);
mtx_unlock(&firmware_mtx);
}
@ -279,7 +285,7 @@ loadimage(void *arg, int npending)
* release this reference for the image to be eligible for removal/unload.
*/
const struct firmware *
firmware_get(const char *imagename)
firmware_get_flags(const char *imagename, uint32_t flags)
{
struct task fwload_task;
struct thread *td;
@ -306,11 +312,15 @@ firmware_get(const char *imagename)
* Also we must not hold any mtx's over this call which is problematic.
*/
if (!cold) {
TASK_INIT(&fwload_task, 0, loadimage, __DECONST(void *,
imagename));
struct fw_loadimage fwli;
fwli.imagename = imagename;
fwli.flags = flags;
TASK_INIT(&fwload_task, 0, loadimage, (void *)&fwli);
taskqueue_enqueue(firmware_tq, &fwload_task);
msleep(__DECONST(void *, imagename), &firmware_mtx, 0,
"fwload", 0);
PHOLD(curproc);
msleep((void *)&fwli, &firmware_mtx, 0, "fwload", 0);
PRELE(curproc);
}
/*
* After attempting to load the module, see if the image is registered.
@ -328,6 +338,13 @@ firmware_get(const char *imagename)
return &fp->fw;
}
const struct firmware *
firmware_get(const char *imagename)
{
return (firmware_get_flags(imagename, 0));
}
/*
* Release a reference to a firmware image returned by firmware_get.
* The caller may specify, with the FIRMWARE_UNLOAD flag, its desire

View File

@ -60,7 +60,12 @@ struct firmware {
const struct firmware *firmware_register(const char *,
const void *, size_t, unsigned int, const struct firmware *);
int firmware_unregister(const char *);
#define FIRMWARE_GET_NOWARN 0x0001 /* Do not warn if firmware not found. */
const struct firmware *firmware_get_flags(const char *, uint32_t flags);
const struct firmware *firmware_get(const char *);
#define FIRMWARE_UNLOAD 0x0001 /* unload if unreferenced */
void firmware_put(const struct firmware *, int);
#endif /* _SYS_FIRMWARE_H_ */