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-rw-r--r--kernel/Documentation/acpi/enumeration.txt68
-rw-r--r--kernel/Documentation/acpi/i2c-muxes.txt58
-rw-r--r--kernel/Documentation/acpi/method-tracing.txt204
3 files changed, 305 insertions, 25 deletions
diff --git a/kernel/Documentation/acpi/enumeration.txt b/kernel/Documentation/acpi/enumeration.txt
index 15dfce708..a91ec5af5 100644
--- a/kernel/Documentation/acpi/enumeration.txt
+++ b/kernel/Documentation/acpi/enumeration.txt
@@ -42,7 +42,7 @@ Adding ACPI support for an existing driver should be pretty
straightforward. Here is the simplest example:
#ifdef CONFIG_ACPI
- static struct acpi_device_id mydrv_acpi_match[] = {
+ static const struct acpi_device_id mydrv_acpi_match[] = {
/* ACPI IDs here */
{ }
};
@@ -166,7 +166,7 @@ the platform device drivers. Below is an example where we add ACPI support
to at25 SPI eeprom driver (this is meant for the above ACPI snippet):
#ifdef CONFIG_ACPI
- static struct acpi_device_id at25_acpi_match[] = {
+ static const struct acpi_device_id at25_acpi_match[] = {
{ "AT25", 0 },
{ },
};
@@ -230,7 +230,7 @@ Below is an example of how to add ACPI support to the existing mpu3050
input driver:
#ifdef CONFIG_ACPI
- static struct acpi_device_id mpu3050_acpi_match[] = {
+ static const struct acpi_device_id mpu3050_acpi_match[] = {
{ "MPU3050", 0 },
{ },
};
@@ -347,15 +347,71 @@ For the first case, the MFD drivers do not need to do anything. The
resulting child platform device will have its ACPI_COMPANION() set to point
to the parent device.
-If the ACPI namespace has a device that we can match using an ACPI id,
-the id should be set like:
+If the ACPI namespace has a device that we can match using an ACPI id or ACPI
+adr, the cell should be set like:
+
+ static struct mfd_cell_acpi_match my_subdevice_cell_acpi_match = {
+ .pnpid = "XYZ0001",
+ .adr = 0,
+ };
static struct mfd_cell my_subdevice_cell = {
.name = "my_subdevice",
/* set the resources relative to the parent */
- .acpi_pnpid = "XYZ0001",
+ .acpi_match = &my_subdevice_cell_acpi_match,
};
The ACPI id "XYZ0001" is then used to lookup an ACPI device directly under
the MFD device and if found, that ACPI companion device is bound to the
resulting child platform device.
+
+Device Tree namespace link device ID
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The Device Tree protocol uses device indentification based on the "compatible"
+property whose value is a string or an array of strings recognized as device
+identifiers by drivers and the driver core. The set of all those strings may be
+regarded as a device indentification namespace analogous to the ACPI/PNP device
+ID namespace. Consequently, in principle it should not be necessary to allocate
+a new (and arguably redundant) ACPI/PNP device ID for a devices with an existing
+identification string in the Device Tree (DT) namespace, especially if that ID
+is only needed to indicate that a given device is compatible with another one,
+presumably having a matching driver in the kernel already.
+
+In ACPI, the device identification object called _CID (Compatible ID) is used to
+list the IDs of devices the given one is compatible with, but those IDs must
+belong to one of the namespaces prescribed by the ACPI specification (see
+Section 6.1.2 of ACPI 6.0 for details) and the DT namespace is not one of them.
+Moreover, the specification mandates that either a _HID or an _ADR identificaion
+object be present for all ACPI objects representing devices (Section 6.1 of ACPI
+6.0). For non-enumerable bus types that object must be _HID and its value must
+be a device ID from one of the namespaces prescribed by the specification too.
+
+The special DT namespace link device ID, PRP0001, provides a means to use the
+existing DT-compatible device identification in ACPI and to satisfy the above
+requirements following from the ACPI specification at the same time. Namely,
+if PRP0001 is returned by _HID, the ACPI subsystem will look for the
+"compatible" property in the device object's _DSD and will use the value of that
+property to identify the corresponding device in analogy with the original DT
+device identification algorithm. If the "compatible" property is not present
+or its value is not valid, the device will not be enumerated by the ACPI
+subsystem. Otherwise, it will be enumerated automatically as a platform device
+(except when an I2C or SPI link from the device to its parent is present, in
+which case the ACPI core will leave the device enumeration to the parent's
+driver) and the identification strings from the "compatible" property value will
+be used to find a driver for the device along with the device IDs listed by _CID
+(if present).
+
+Analogously, if PRP0001 is present in the list of device IDs returned by _CID,
+the identification strings listed by the "compatible" property value (if present
+and valid) will be used to look for a driver matching the device, but in that
+case their relative priority with respect to the other device IDs listed by
+_HID and _CID depends on the position of PRP0001 in the _CID return package.
+Specifically, the device IDs returned by _HID and preceding PRP0001 in the _CID
+return package will be checked first. Also in that case the bus type the device
+will be enumerated to depends on the device ID returned by _HID.
+
+It is valid to define device objects with a _HID returning PRP0001 and without
+the "compatible" property in the _DSD or a _CID as long as one of their
+ancestors provides a _DSD with a valid "compatible" property. Such device
+objects are then simply regarded as additional "blocks" providing hierarchical
+configuration information to the driver of the composite ancestor device.
diff --git a/kernel/Documentation/acpi/i2c-muxes.txt b/kernel/Documentation/acpi/i2c-muxes.txt
new file mode 100644
index 000000000..9fcc4f0b8
--- /dev/null
+++ b/kernel/Documentation/acpi/i2c-muxes.txt
@@ -0,0 +1,58 @@
+ACPI I2C Muxes
+--------------
+
+Describing an I2C device hierarchy that includes I2C muxes requires an ACPI
+Device () scope per mux channel.
+
+Consider this topology:
+
++------+ +------+
+| SMB1 |-->| MUX0 |--CH00--> i2c client A (0x50)
+| | | 0x70 |--CH01--> i2c client B (0x50)
++------+ +------+
+
+which corresponds to the following ASL:
+
+Device (SMB1)
+{
+ Name (_HID, ...)
+ Device (MUX0)
+ {
+ Name (_HID, ...)
+ Name (_CRS, ResourceTemplate () {
+ I2cSerialBus (0x70, ControllerInitiated, I2C_SPEED,
+ AddressingMode7Bit, "^SMB1", 0x00,
+ ResourceConsumer,,)
+ }
+
+ Device (CH00)
+ {
+ Name (_ADR, 0)
+
+ Device (CLIA)
+ {
+ Name (_HID, ...)
+ Name (_CRS, ResourceTemplate () {
+ I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED,
+ AddressingMode7Bit, "^CH00", 0x00,
+ ResourceConsumer,,)
+ }
+ }
+ }
+
+ Device (CH01)
+ {
+ Name (_ADR, 1)
+
+ Device (CLIB)
+ {
+ Name (_HID, ...)
+ Name (_CRS, ResourceTemplate () {
+ I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED,
+ AddressingMode7Bit, "^CH01", 0x00,
+ ResourceConsumer,,)
+ }
+ }
+ }
+ }
+}
diff --git a/kernel/Documentation/acpi/method-tracing.txt b/kernel/Documentation/acpi/method-tracing.txt
index f6efb1ea5..c2505eefc 100644
--- a/kernel/Documentation/acpi/method-tracing.txt
+++ b/kernel/Documentation/acpi/method-tracing.txt
@@ -1,26 +1,192 @@
-/sys/module/acpi/parameters/:
+ACPICA Trace Facility
-trace_method_name
- The AML method name that the user wants to trace
+Copyright (C) 2015, Intel Corporation
+Author: Lv Zheng <lv.zheng@intel.com>
-trace_debug_layer
- The temporary debug_layer used when tracing the method.
- Using 0xffffffff by default if it is 0.
-trace_debug_level
- The temporary debug_level used when tracing the method.
- Using 0x00ffffff by default if it is 0.
+Abstract:
-trace_state
- The status of the tracing feature.
+This document describes the functions and the interfaces of the method
+tracing facility.
+
+1. Functionalities and usage examples:
+
+ ACPICA provides method tracing capability. And two functions are
+ currently implemented using this capability.
+
+ A. Log reducer
+ ACPICA subsystem provides debugging outputs when CONFIG_ACPI_DEBUG is
+ enabled. The debugging messages which are deployed via
+ ACPI_DEBUG_PRINT() macro can be reduced at 2 levels - per-component
+ level (known as debug layer, configured via
+ /sys/module/acpi/parameters/debug_layer) and per-type level (known as
+ debug level, configured via /sys/module/acpi/parameters/debug_level).
+
+ But when the particular layer/level is applied to the control method
+ evaluations, the quantity of the debugging outputs may still be too
+ large to be put into the kernel log buffer. The idea thus is worked out
+ to only enable the particular debug layer/level (normally more detailed)
+ logs when the control method evaluation is started, and disable the
+ detailed logging when the control method evaluation is stopped.
+
+ The following command examples illustrate the usage of the "log reducer"
+ functionality:
+ a. Filter out the debug layer/level matched logs when control methods
+ are being evaluated:
+ # cd /sys/module/acpi/parameters
+ # echo "0xXXXXXXXX" > trace_debug_layer
+ # echo "0xYYYYYYYY" > trace_debug_level
+ # echo "enable" > trace_state
+ b. Filter out the debug layer/level matched logs when the specified
+ control method is being evaluated:
+ # cd /sys/module/acpi/parameters
+ # echo "0xXXXXXXXX" > trace_debug_layer
+ # echo "0xYYYYYYYY" > trace_debug_level
+ # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
+ # echo "method" > /sys/module/acpi/parameters/trace_state
+ c. Filter out the debug layer/level matched logs when the specified
+ control method is being evaluated for the first time:
+ # cd /sys/module/acpi/parameters
+ # echo "0xXXXXXXXX" > trace_debug_layer
+ # echo "0xYYYYYYYY" > trace_debug_level
+ # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
+ # echo "method-once" > /sys/module/acpi/parameters/trace_state
+ Where:
+ 0xXXXXXXXX/0xYYYYYYYY: Refer to Documentation/acpi/debug.txt for
+ possible debug layer/level masking values.
+ \PPPP.AAAA.TTTT.HHHH: Full path of a control method that can be found
+ in the ACPI namespace. It needn't be an entry
+ of a control method evaluation.
+
+ B. AML tracer
+
+ There are special log entries added by the method tracing facility at
+ the "trace points" the AML interpreter starts/stops to execute a control
+ method, or an AML opcode. Note that the format of the log entries are
+ subject to change:
+ [ 0.186427] exdebug-0398 ex_trace_point : Method Begin [0xf58394d8:\_SB.PCI0.LPCB.ECOK] execution.
+ [ 0.186630] exdebug-0398 ex_trace_point : Opcode Begin [0xf5905c88:If] execution.
+ [ 0.186820] exdebug-0398 ex_trace_point : Opcode Begin [0xf5905cc0:LEqual] execution.
+ [ 0.187010] exdebug-0398 ex_trace_point : Opcode Begin [0xf5905a20:-NamePath-] execution.
+ [ 0.187214] exdebug-0398 ex_trace_point : Opcode End [0xf5905a20:-NamePath-] execution.
+ [ 0.187407] exdebug-0398 ex_trace_point : Opcode Begin [0xf5905f60:One] execution.
+ [ 0.187594] exdebug-0398 ex_trace_point : Opcode End [0xf5905f60:One] execution.
+ [ 0.187789] exdebug-0398 ex_trace_point : Opcode End [0xf5905cc0:LEqual] execution.
+ [ 0.187980] exdebug-0398 ex_trace_point : Opcode Begin [0xf5905cc0:Return] execution.
+ [ 0.188146] exdebug-0398 ex_trace_point : Opcode Begin [0xf5905f60:One] execution.
+ [ 0.188334] exdebug-0398 ex_trace_point : Opcode End [0xf5905f60:One] execution.
+ [ 0.188524] exdebug-0398 ex_trace_point : Opcode End [0xf5905cc0:Return] execution.
+ [ 0.188712] exdebug-0398 ex_trace_point : Opcode End [0xf5905c88:If] execution.
+ [ 0.188903] exdebug-0398 ex_trace_point : Method End [0xf58394d8:\_SB.PCI0.LPCB.ECOK] execution.
- "enabled" means this feature is enabled
- and the AML method is traced every time it's executed.
+ Developers can utilize these special log entries to track the AML
+ interpretion, thus can aid issue debugging and performance tuning. Note
+ that, as the "AML tracer" logs are implemented via ACPI_DEBUG_PRINT()
+ macro, CONFIG_ACPI_DEBUG is also required to be enabled for enabling
+ "AML tracer" logs.
- "1" means this feature is enabled and the AML method
- will only be traced during the next execution.
+ The following command examples illustrate the usage of the "AML tracer"
+ functionality:
+ a. Filter out the method start/stop "AML tracer" logs when control
+ methods are being evaluated:
+ # cd /sys/module/acpi/parameters
+ # echo "0x80" > trace_debug_layer
+ # echo "0x10" > trace_debug_level
+ # echo "enable" > trace_state
+ b. Filter out the method start/stop "AML tracer" when the specified
+ control method is being evaluated:
+ # cd /sys/module/acpi/parameters
+ # echo "0x80" > trace_debug_layer
+ # echo "0x10" > trace_debug_level
+ # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
+ # echo "method" > trace_state
+ c. Filter out the method start/stop "AML tracer" logs when the specified
+ control method is being evaluated for the first time:
+ # cd /sys/module/acpi/parameters
+ # echo "0x80" > trace_debug_layer
+ # echo "0x10" > trace_debug_level
+ # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
+ # echo "method-once" > trace_state
+ d. Filter out the method/opcode start/stop "AML tracer" when the
+ specified control method is being evaluated:
+ # cd /sys/module/acpi/parameters
+ # echo "0x80" > trace_debug_layer
+ # echo "0x10" > trace_debug_level
+ # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
+ # echo "opcode" > trace_state
+ e. Filter out the method/opcode start/stop "AML tracer" when the
+ specified control method is being evaluated for the first time:
+ # cd /sys/module/acpi/parameters
+ # echo "0x80" > trace_debug_layer
+ # echo "0x10" > trace_debug_level
+ # echo "\PPPP.AAAA.TTTT.HHHH" > trace_method_name
+ # echo "opcode-opcode" > trace_state
- "disabled" means this feature is disabled.
- Users can enable/disable this debug tracing feature by
- "echo string > /sys/module/acpi/parameters/trace_state".
- "string" should be one of "enable", "disable" and "1".
+ Note that all above method tracing facility related module parameters can
+ be used as the boot parameters, for example:
+ acpi.trace_debug_layer=0x80 acpi.trace_debug_level=0x10 \
+ acpi.trace_method_name=\_SB.LID0._LID acpi.trace_state=opcode-once
+
+2. Interface descriptions:
+
+ All method tracing functions can be configured via ACPI module
+ parameters that are accessible at /sys/module/acpi/parameters/:
+
+ trace_method_name
+ The full path of the AML method that the user wants to trace.
+ Note that the full path shouldn't contain the trailing "_"s in its
+ name segments but may contain "\" to form an absolute path.
+
+ trace_debug_layer
+ The temporary debug_layer used when the tracing feature is enabled.
+ Using ACPI_EXECUTER (0x80) by default, which is the debug_layer
+ used to match all "AML tracer" logs.
+
+ trace_debug_level
+ The temporary debug_level used when the tracing feature is enabled.
+ Using ACPI_LV_TRACE_POINT (0x10) by default, which is the
+ debug_level used to match all "AML tracer" logs.
+
+ trace_state
+ The status of the tracing feature.
+ Users can enable/disable this debug tracing feature by executing
+ the following command:
+ # echo string > /sys/module/acpi/parameters/trace_state
+ Where "string" should be one of the followings:
+ "disable"
+ Disable the method tracing feature.
+ "enable"
+ Enable the method tracing feature.
+ ACPICA debugging messages matching
+ "trace_debug_layer/trace_debug_level" during any method
+ execution will be logged.
+ "method"
+ Enable the method tracing feature.
+ ACPICA debugging messages matching
+ "trace_debug_layer/trace_debug_level" during method execution
+ of "trace_method_name" will be logged.
+ "method-once"
+ Enable the method tracing feature.
+ ACPICA debugging messages matching
+ "trace_debug_layer/trace_debug_level" during method execution
+ of "trace_method_name" will be logged only once.
+ "opcode"
+ Enable the method tracing feature.
+ ACPICA debugging messages matching
+ "trace_debug_layer/trace_debug_level" during method/opcode
+ execution of "trace_method_name" will be logged.
+ "opcode-once"
+ Enable the method tracing feature.
+ ACPICA debugging messages matching
+ "trace_debug_layer/trace_debug_level" during method/opcode
+ execution of "trace_method_name" will be logged only once.
+ Note that, the difference between the "enable" and other feature
+ enabling options are:
+ 1. When "enable" is specified, since
+ "trace_debug_layer/trace_debug_level" shall apply to all control
+ method evaluations, after configuring "trace_state" to "enable",
+ "trace_method_name" will be reset to NULL.
+ 2. When "method/opcode" is specified, if
+ "trace_method_name" is NULL when "trace_state" is configured to
+ these options, the "trace_debug_layer/trace_debug_level" will
+ apply to all control method evaluations.