AML(2) AML(2)
NAME
amltag, amlval, amlint, amllen, amlnew, amlinit, amlexit,
amlload, amlwalk, amleval, amlenum, amltake, amldrop - ACPI
machine language interpreter
SYNOPSIS
#include <u.h>
#include <libc.h>
#include <aml.h>
int amltag(void *);
void* amlval(void *);
uvlong amlint(void *);
int amllen(void *);
void* amlnew(char tag, int len);
void amlinit(void);
void amlexit(void);
int amlload(uchar *data, int len);
void* amlwalk(void *dot, char *name);
int amleval(void *dot, char *fmt, ...);
void amlenum(void *dot, char *seg, int (*proc)(void *, void *), void *arg);
void amltake(void *);
void amldrop(void *);
void* amlroot;
int amldebug;
uvlong amlintmask;
DESCRIPTION
The aml library implements an interpreter for the ACPI
machine language byte code.
amlinit() amlexit()
The interpreter runtime state is initialized by calling
amlinit and frees all the resources when amlexit is
called. The runtime state consists of objects orga-
nized in a global namespace. The name object referred
to by amlroot is the root of that namespace.
The width of integers is defined by the global variable
amlintmask, which should be initialized to 0xFFFFFFFF for
DSDT revision <= 1 or 0xFFFFFFFFFFFFFFFF for revision >= 2.
amlload(data,len)
Amlload populates the namespace with objects parsed
from the definition block of len byte size read from
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AML(2) AML(2)
data. The pc kernel provides access to the ACPI tables
through the /dev/acpitbls file (see arch(3) for further
details).
amltag(p)
Objects are dynamically allocated and typed and are
passed as void* pointers. The type tag of an object can
be determined with the amltag function. The following
table shows the defined tags and ther underlying type:
/*
* b uchar* buffer amllen() returns number of bytes
* s char* string amllen() is strlen()
* n char* undefined name amllen() is strlen()
* i uvlong* integer
* p void** package amllen() is # of elements
* r void* region
* f void* field
* u void* bufferfield
* N void* name
* R void* reference
*/
amlwalk(dot,name)
Amlwalk takes a path string (relative to dot) in name
and returns the final name object of the walk; or nil
if not found.
amlenum(dot,seg,proc,arg)
Amlenum recursively enumerates all child name objects
of dot that have seg as name; or any name if seg is
nil; calling proc for each one passing dot. When proc
returns zero, enumeration will continue recursively
down for the current dot.
amlval(p)
Amlval returns the value of a name, reference or field
object. Calling amlval on any other object yields the
same object.
amllen(p)
Amllen is defined for variable length objects like
buffers, strings and packages. For strings, the number
of characters (not including the terminating null byte)
is returned. For buffers, the size of the buffer in
bytes is returned. For packages (arrays), the number
of elements is returned. For any other object types,
the return value is undefined.
amlint(p)
Amlint returns the integer value of an object. For
strings, the string is interpreted as an hexadecimal
number. For buffers and buffer fields, the binary value
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AML(2) AML(2)
is returned. Integers just return their value. Any
other object types yield zero.
amlnew(tag,len)
Integer, buffer, string and package objects can be cre-
ated with the amlnew function. The tag specific defini-
tion of the len parameter is the same as in amllen (see
above).
amleval(dot,fmt,...)
Amleval evaluates the name object dot. For method eval-
uation, the fmt string parameter describes the argu-
ments passed to the evaluated method. Each character in
fmt represents a tag for an method argument taken from
the variable argument list of amleval and passed to the
method. The fmt tags I, i and s take uvlong, int and
char* from the variable argument list and create object
copies to be passed. The tags b, p and * take void*
from the variable argument list and pass them as
objects by reference (without conversion or copies).
The last variable argument is a pointer to the result
object location. When the last parameter is nil the
result is discarded.
amltake(p) amldrop(p)
Objects returned by amlval, amleval and amlnew are sub-
ject to garbage collection during method evaluation
unless previously maked to be excluded from collection
with amltake. To remark an object for collection,
amldrop needs be called. Objects stay valid as long as
they are reachable from amlroot.
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AML(2) AML(2)
The aml library can be linked into userspace programs and
the kernel which have different means of hardware access and
memory constraints.
The Amlio data structure defines access to a hardware space.
enum {
MemSpace = 0x00,
IoSpace = 0x01,
PcicfgSpace = 0x02,
EbctlSpace = 0x03,
SmbusSpace = 0x04,
CmosSpace = 0x05,
PcibarSpace = 0x06,
IpmiSpace = 0x07,
};
typedef struct Amlio Amlio;
struct Amlio
{
int space;
uvlong off;
uvlong len;
void *name;
uchar *va;
void *aux;
int (*read)(Amlio *io, void *data, int len, int off);
int (*write)(Amlio *io, void *data, int len, int off);
};
The members space, off, len and name are initialized by the
interpreter and describe the I/O region it needs access to.
For memory regions, va can to be set to the virtual address
mapping base by the mapping function. The interpreter will
call the read and write function pointers with a relative
offset to the regions base offset. The aux pointer can be
used freely by the map function to attach its own resources
to the I/O region and allows it to free these resources on
amlunmapio.
amlmapio(io) amlunmapio(io)
The interpreter calls amlmapio with a Amlio data struc-
ture that is to be filled out. When finished, the
interpreter calls amlunmapio with the same data struc-
ture to allow freeing resources.
amldelay(µs)
Amldelay is called by the interpreter with the number
of microseconds to sleep.
amlalloc(n) amlfree(p)
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AML(2) AML(2)
Amlalloc and amlfree can be optionally defined to con-
trol dynamic memory allocation providing a way to limit
or pool the memory allocated by acpi. If not provided,
the library will use the functions defined in malloc(2)
for dynamic allocation.
SOURCE
/sys/src/libaml
SEE ALSO
arch(3)
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