diff options
Diffstat (limited to 'Documentation/acpi')
| -rw-r--r-- | Documentation/acpi/apei/einj.txt | 107 | ||||
| -rw-r--r-- | Documentation/acpi/apei/output_format.txt | 147 | ||||
| -rw-r--r-- | Documentation/acpi/debug.txt | 148 | ||||
| -rw-r--r-- | Documentation/acpi/dsdt-override.txt | 7 | ||||
| -rw-r--r-- | Documentation/acpi/enumeration.txt | 227 | ||||
| -rw-r--r-- | Documentation/acpi/initrd_table_override.txt | 94 | ||||
| -rw-r--r-- | Documentation/acpi/method-customizing.txt | 73 | ||||
| -rw-r--r-- | Documentation/acpi/method-tracing.txt | 26 | ||||
| -rw-r--r-- | Documentation/acpi/scan_handlers.txt | 77 |
9 files changed, 906 insertions, 0 deletions
diff --git a/Documentation/acpi/apei/einj.txt b/Documentation/acpi/apei/einj.txt new file mode 100644 index 00000000..e20b6daa --- /dev/null +++ b/Documentation/acpi/apei/einj.txt @@ -0,0 +1,107 @@ + APEI Error INJection + ~~~~~~~~~~~~~~~~~~~~ + +EINJ provides a hardware error injection mechanism +It is very useful for debugging and testing of other APEI and RAS features. + +To use EINJ, make sure the following are enabled in your kernel +configuration: + +CONFIG_DEBUG_FS +CONFIG_ACPI_APEI +CONFIG_ACPI_APEI_EINJ + +The user interface of EINJ is debug file system, under the +directory apei/einj. The following files are provided. + +- available_error_type + Reading this file returns the error injection capability of the + platform, that is, which error types are supported. The error type + definition is as follow, the left field is the error type value, the + right field is error description. + + 0x00000001 Processor Correctable + 0x00000002 Processor Uncorrectable non-fatal + 0x00000004 Processor Uncorrectable fatal + 0x00000008 Memory Correctable + 0x00000010 Memory Uncorrectable non-fatal + 0x00000020 Memory Uncorrectable fatal + 0x00000040 PCI Express Correctable + 0x00000080 PCI Express Uncorrectable fatal + 0x00000100 PCI Express Uncorrectable non-fatal + 0x00000200 Platform Correctable + 0x00000400 Platform Uncorrectable non-fatal + 0x00000800 Platform Uncorrectable fatal + + The format of file contents are as above, except there are only the + available error type lines. + +- error_type + This file is used to set the error type value. The error type value + is defined in "available_error_type" description. + +- error_inject + Write any integer to this file to trigger the error + injection. Before this, please specify all necessary error + parameters. + +- param1 + This file is used to set the first error parameter value. Effect of + parameter depends on error_type specified. + +- param2 + This file is used to set the second error parameter value. Effect of + parameter depends on error_type specified. + +- notrigger + The EINJ mechanism is a two step process. First inject the error, then + perform some actions to trigger it. Setting "notrigger" to 1 skips the + trigger phase, which *may* allow the user to cause the error in some other + context by a simple access to the cpu, memory location, or device that is + the target of the error injection. Whether this actually works depends + on what operations the BIOS actually includes in the trigger phase. + +BIOS versions based in the ACPI 4.0 specification have limited options +to control where the errors are injected. Your BIOS may support an +extension (enabled with the param_extension=1 module parameter, or +boot command line einj.param_extension=1). This allows the address +and mask for memory injections to be specified by the param1 and +param2 files in apei/einj. + +BIOS versions using the ACPI 5.0 specification have more control over +the target of the injection. For processor related errors (type 0x1, +0x2 and 0x4) the APICID of the target should be provided using the +param1 file in apei/einj. For memory errors (type 0x8, 0x10 and 0x20) +the address is set using param1 with a mask in param2 (0x0 is equivalent +to all ones). For PCI express errors (type 0x40, 0x80 and 0x100) the +segment, bus, device and function are specified using param1: + + 31 24 23 16 15 11 10 8 7 0 + +-------------------------------------------------+ + | segment | bus | device | function | reserved | + +-------------------------------------------------+ + +An ACPI 5.0 BIOS may also allow vendor specific errors to be injected. +In this case a file named vendor will contain identifying information +from the BIOS that hopefully will allow an application wishing to use +the vendor specific extension to tell that they are running on a BIOS +that supports it. All vendor extensions have the 0x80000000 bit set in +error_type. A file vendor_flags controls the interpretation of param1 +and param2 (1 = PROCESSOR, 2 = MEMORY, 4 = PCI). See your BIOS vendor +documentation for details (and expect changes to this API if vendors +creativity in using this feature expands beyond our expectations). + +Example: +# cd /sys/kernel/debug/apei/einj +# cat available_error_type # See which errors can be injected +0x00000002 Processor Uncorrectable non-fatal +0x00000008 Memory Correctable +0x00000010 Memory Uncorrectable non-fatal +# echo 0x12345000 > param1 # Set memory address for injection +# echo 0xfffffffffffff000 > param2 # Mask - anywhere in this page +# echo 0x8 > error_type # Choose correctable memory error +# echo 1 > error_inject # Inject now + + +For more information about EINJ, please refer to ACPI specification +version 4.0, section 17.5 and ACPI 5.0, section 18.6. diff --git a/Documentation/acpi/apei/output_format.txt b/Documentation/acpi/apei/output_format.txt new file mode 100644 index 00000000..0c49c197 --- /dev/null +++ b/Documentation/acpi/apei/output_format.txt @@ -0,0 +1,147 @@ + APEI output format + ~~~~~~~~~~~~~~~~~~ + +APEI uses printk as hardware error reporting interface, the output +format is as follow. + +<error record> := +APEI generic hardware error status +severity: <integer>, <severity string> +section: <integer>, severity: <integer>, <severity string> +flags: <integer> +<section flags strings> +fru_id: <uuid string> +fru_text: <string> +section_type: <section type string> +<section data> + +<severity string>* := recoverable | fatal | corrected | info + +<section flags strings># := +[primary][, containment warning][, reset][, threshold exceeded]\ +[, resource not accessible][, latent error] + +<section type string> := generic processor error | memory error | \ +PCIe error | unknown, <uuid string> + +<section data> := +<generic processor section data> | <memory section data> | \ +<pcie section data> | <null> + +<generic processor section data> := +[processor_type: <integer>, <proc type string>] +[processor_isa: <integer>, <proc isa string>] +[error_type: <integer> +<proc error type strings>] +[operation: <integer>, <proc operation string>] +[flags: <integer> +<proc flags strings>] +[level: <integer>] +[version_info: <integer>] +[processor_id: <integer>] +[target_address: <integer>] +[requestor_id: <integer>] +[responder_id: <integer>] +[IP: <integer>] + +<proc type string>* := IA32/X64 | IA64 + +<proc isa string>* := IA32 | IA64 | X64 + +<processor error type strings># := +[cache error][, TLB error][, bus error][, micro-architectural error] + +<proc operation string>* := unknown or generic | data read | data write | \ +instruction execution + +<proc flags strings># := +[restartable][, precise IP][, overflow][, corrected] + +<memory section data> := +[error_status: <integer>] +[physical_address: <integer>] +[physical_address_mask: <integer>] +[node: <integer>] +[card: <integer>] +[module: <integer>] +[bank: <integer>] +[device: <integer>] +[row: <integer>] +[column: <integer>] +[bit_position: <integer>] +[requestor_id: <integer>] +[responder_id: <integer>] +[target_id: <integer>] +[error_type: <integer>, <mem error type string>] + +<mem error type string>* := +unknown | no error | single-bit ECC | multi-bit ECC | \ +single-symbol chipkill ECC | multi-symbol chipkill ECC | master abort | \ +target abort | parity error | watchdog timeout | invalid address | \ +mirror Broken | memory sparing | scrub corrected error | \ +scrub uncorrected error + +<pcie section data> := +[port_type: <integer>, <pcie port type string>] +[version: <integer>.<integer>] +[command: <integer>, status: <integer>] +[device_id: <integer>:<integer>:<integer>.<integer> +slot: <integer> +secondary_bus: <integer> +vendor_id: <integer>, device_id: <integer> +class_code: <integer>] +[serial number: <integer>, <integer>] +[bridge: secondary_status: <integer>, control: <integer>] +[aer_status: <integer>, aer_mask: <integer> +<aer status string> +[aer_uncor_severity: <integer>] +aer_layer=<aer layer string>, aer_agent=<aer agent string> +aer_tlp_header: <integer> <integer> <integer> <integer>] + +<pcie port type string>* := PCIe end point | legacy PCI end point | \ +unknown | unknown | root port | upstream switch port | \ +downstream switch port | PCIe to PCI/PCI-X bridge | \ +PCI/PCI-X to PCIe bridge | root complex integrated endpoint device | \ +root complex event collector + +if section severity is fatal or recoverable +<aer status string># := +unknown | unknown | unknown | unknown | Data Link Protocol | \ +unknown | unknown | unknown | unknown | unknown | unknown | unknown | \ +Poisoned TLP | Flow Control Protocol | Completion Timeout | \ +Completer Abort | Unexpected Completion | Receiver Overflow | \ +Malformed TLP | ECRC | Unsupported Request +else +<aer status string># := +Receiver Error | unknown | unknown | unknown | unknown | unknown | \ +Bad TLP | Bad DLLP | RELAY_NUM Rollover | unknown | unknown | unknown | \ +Replay Timer Timeout | Advisory Non-Fatal +fi + +<aer layer string> := +Physical Layer | Data Link Layer | Transaction Layer + +<aer agent string> := +Receiver ID | Requester ID | Completer ID | Transmitter ID + +Where, [] designate corresponding content is optional + +All <field string> description with * has the following format: + +field: <integer>, <field string> + +Where value of <integer> should be the position of "string" in <field +string> description. Otherwise, <field string> will be "unknown". + +All <field strings> description with # has the following format: + +field: <integer> +<field strings> + +Where each string in <fields strings> corresponding to one set bit of +<integer>. The bit position is the position of "string" in <field +strings> description. + +For more detailed explanation of every field, please refer to UEFI +specification version 2.3 or later, section Appendix N: Common +Platform Error Record. diff --git a/Documentation/acpi/debug.txt b/Documentation/acpi/debug.txt new file mode 100644 index 00000000..65bf47c4 --- /dev/null +++ b/Documentation/acpi/debug.txt @@ -0,0 +1,148 @@ + ACPI Debug Output + + +The ACPI CA, the Linux ACPI core, and some ACPI drivers can generate debug +output. This document describes how to use this facility. + +Compile-time configuration +-------------------------- + +ACPI debug output is globally enabled by CONFIG_ACPI_DEBUG. If this config +option is turned off, the debug messages are not even built into the +kernel. + +Boot- and run-time configuration +-------------------------------- + +When CONFIG_ACPI_DEBUG=y, you can select the component and level of messages +you're interested in. At boot-time, use the acpi.debug_layer and +acpi.debug_level kernel command line options. After boot, you can use the +debug_layer and debug_level files in /sys/module/acpi/parameters/ to control +the debug messages. + +debug_layer (component) +----------------------- + +The "debug_layer" is a mask that selects components of interest, e.g., a +specific driver or part of the ACPI interpreter. To build the debug_layer +bitmask, look for the "#define _COMPONENT" in an ACPI source file. + +You can set the debug_layer mask at boot-time using the acpi.debug_layer +command line argument, and you can change it after boot by writing values +to /sys/module/acpi/parameters/debug_layer. + +The possible components are defined in include/acpi/acoutput.h and +include/acpi/acpi_drivers.h. Reading /sys/module/acpi/parameters/debug_layer +shows the supported mask values, currently these: + + ACPI_UTILITIES 0x00000001 + ACPI_HARDWARE 0x00000002 + ACPI_EVENTS 0x00000004 + ACPI_TABLES 0x00000008 + ACPI_NAMESPACE 0x00000010 + ACPI_PARSER 0x00000020 + ACPI_DISPATCHER 0x00000040 + ACPI_EXECUTER 0x00000080 + ACPI_RESOURCES 0x00000100 + ACPI_CA_DEBUGGER 0x00000200 + ACPI_OS_SERVICES 0x00000400 + ACPI_CA_DISASSEMBLER 0x00000800 + ACPI_COMPILER 0x00001000 + ACPI_TOOLS 0x00002000 + ACPI_BUS_COMPONENT 0x00010000 + ACPI_AC_COMPONENT 0x00020000 + ACPI_BATTERY_COMPONENT 0x00040000 + ACPI_BUTTON_COMPONENT 0x00080000 + ACPI_SBS_COMPONENT 0x00100000 + ACPI_FAN_COMPONENT 0x00200000 + ACPI_PCI_COMPONENT 0x00400000 + ACPI_POWER_COMPONENT 0x00800000 + ACPI_CONTAINER_COMPONENT 0x01000000 + ACPI_SYSTEM_COMPONENT 0x02000000 + ACPI_THERMAL_COMPONENT 0x04000000 + ACPI_MEMORY_DEVICE_COMPONENT 0x08000000 + ACPI_VIDEO_COMPONENT 0x10000000 + ACPI_PROCESSOR_COMPONENT 0x20000000 + +debug_level +----------- + +The "debug_level" is a mask that selects different types of messages, e.g., +those related to initialization, method execution, informational messages, etc. +To build debug_level, look at the level specified in an ACPI_DEBUG_PRINT() +statement. + +The ACPI interpreter uses several different levels, but the Linux +ACPI core and ACPI drivers generally only use ACPI_LV_INFO. + +You can set the debug_level mask at boot-time using the acpi.debug_level +command line argument, and you can change it after boot by writing values +to /sys/module/acpi/parameters/debug_level. + +The possible levels are defined in include/acpi/acoutput.h. Reading +/sys/module/acpi/parameters/debug_level shows the supported mask values, +currently these: + + ACPI_LV_INIT 0x00000001 + ACPI_LV_DEBUG_OBJECT 0x00000002 + ACPI_LV_INFO 0x00000004 + ACPI_LV_INIT_NAMES 0x00000020 + ACPI_LV_PARSE 0x00000040 + ACPI_LV_LOAD 0x00000080 + ACPI_LV_DISPATCH 0x00000100 + ACPI_LV_EXEC 0x00000200 + ACPI_LV_NAMES 0x00000400 + ACPI_LV_OPREGION 0x00000800 + ACPI_LV_BFIELD 0x00001000 + ACPI_LV_TABLES 0x00002000 + ACPI_LV_VALUES 0x00004000 + ACPI_LV_OBJECTS 0x00008000 + ACPI_LV_RESOURCES 0x00010000 + ACPI_LV_USER_REQUESTS 0x00020000 + ACPI_LV_PACKAGE 0x00040000 + ACPI_LV_ALLOCATIONS 0x00100000 + ACPI_LV_FUNCTIONS 0x00200000 + ACPI_LV_OPTIMIZATIONS 0x00400000 + ACPI_LV_MUTEX 0x01000000 + ACPI_LV_THREADS 0x02000000 + ACPI_LV_IO 0x04000000 + ACPI_LV_INTERRUPTS 0x08000000 + ACPI_LV_AML_DISASSEMBLE 0x10000000 + ACPI_LV_VERBOSE_INFO 0x20000000 + ACPI_LV_FULL_TABLES 0x40000000 + ACPI_LV_EVENTS 0x80000000 + +Examples +-------- + +For example, drivers/acpi/bus.c contains this: + + #define _COMPONENT ACPI_BUS_COMPONENT + ... + ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device insertion detected\n")); + +To turn on this message, set the ACPI_BUS_COMPONENT bit in acpi.debug_layer +and the ACPI_LV_INFO bit in acpi.debug_level. (The ACPI_DEBUG_PRINT +statement uses ACPI_DB_INFO, which is macro based on the ACPI_LV_INFO +definition.) + +Enable all AML "Debug" output (stores to the Debug object while interpreting +AML) during boot: + + acpi.debug_layer=0xffffffff acpi.debug_level=0x2 + +Enable PCI and PCI interrupt routing debug messages: + + acpi.debug_layer=0x400000 acpi.debug_level=0x4 + +Enable all ACPI hardware-related messages: + + acpi.debug_layer=0x2 acpi.debug_level=0xffffffff + +Enable all ACPI_DB_INFO messages after boot: + + # echo 0x4 > /sys/module/acpi/parameters/debug_level + +Show all valid component values: + + # cat /sys/module/acpi/parameters/debug_layer diff --git a/Documentation/acpi/dsdt-override.txt b/Documentation/acpi/dsdt-override.txt new file mode 100644 index 00000000..febbb1ba --- /dev/null +++ b/Documentation/acpi/dsdt-override.txt @@ -0,0 +1,7 @@ +Linux supports a method of overriding the BIOS DSDT: + +CONFIG_ACPI_CUSTOM_DSDT builds the image into the kernel. + +When to use this method is described in detail on the +Linux/ACPI home page: +http://www.lesswatts.org/projects/acpi/overridingDSDT.php diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt new file mode 100644 index 00000000..94a65613 --- /dev/null +++ b/Documentation/acpi/enumeration.txt @@ -0,0 +1,227 @@ +ACPI based device enumeration +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +ACPI 5 introduced a set of new resources (UartTSerialBus, I2cSerialBus, +SpiSerialBus, GpioIo and GpioInt) which can be used in enumerating slave +devices behind serial bus controllers. + +In addition we are starting to see peripherals integrated in the +SoC/Chipset to appear only in ACPI namespace. These are typically devices +that are accessed through memory-mapped registers. + +In order to support this and re-use the existing drivers as much as +possible we decided to do following: + + o Devices that have no bus connector resource are represented as + platform devices. + + o Devices behind real busses where there is a connector resource + are represented as struct spi_device or struct i2c_device + (standard UARTs are not busses so there is no struct uart_device). + +As both ACPI and Device Tree represent a tree of devices (and their +resources) this implementation follows the Device Tree way as much as +possible. + +The ACPI implementation enumerates devices behind busses (platform, SPI and +I2C), creates the physical devices and binds them to their ACPI handle in +the ACPI namespace. + +This means that when ACPI_HANDLE(dev) returns non-NULL the device was +enumerated from ACPI namespace. This handle can be used to extract other +device-specific configuration. There is an example of this below. + +Platform bus support +~~~~~~~~~~~~~~~~~~~~ +Since we are using platform devices to represent devices that are not +connected to any physical bus we only need to implement a platform driver +for the device and add supported ACPI IDs. If this same IP-block is used on +some other non-ACPI platform, the driver might work out of the box or needs +some minor changes. + +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[] = { + /* ACPI IDs here */ + { } + }; + MODULE_DEVICE_TABLE(acpi, mydrv_acpi_match); + #endif + + static struct platform_driver my_driver = { + ... + .driver = { + .acpi_match_table = ACPI_PTR(mydrv_acpi_match), + }, + }; + +If the driver needs to perform more complex initialization like getting and +configuring GPIOs it can get its ACPI handle and extract this information +from ACPI tables. + +Currently the kernel is not able to automatically determine from which ACPI +device it should make the corresponding platform device so we need to add +the ACPI device explicitly to acpi_platform_device_ids list defined in +drivers/acpi/acpi_platform.c. This limitation is only for the platform +devices, SPI and I2C devices are created automatically as described below. + +SPI serial bus support +~~~~~~~~~~~~~~~~~~~~~~ +Slave devices behind SPI bus have SpiSerialBus resource attached to them. +This is extracted automatically by the SPI core and the slave devices are +enumerated once spi_register_master() is called by the bus driver. + +Here is what the ACPI namespace for a SPI slave might look like: + + Device (EEP0) + { + Name (_ADR, 1) + Name (_CID, Package() { + "ATML0025", + "AT25", + }) + ... + Method (_CRS, 0, NotSerialized) + { + SPISerialBus(1, PolarityLow, FourWireMode, 8, + ControllerInitiated, 1000000, ClockPolarityLow, + ClockPhaseFirst, "\\_SB.PCI0.SPI1",) + } + ... + +The SPI device drivers only need to add ACPI IDs in a similar way than with +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[] = { + { "AT25", 0 }, + { }, + }; + MODULE_DEVICE_TABLE(acpi, at25_acpi_match); + #endif + + static struct spi_driver at25_driver = { + .driver = { + ... + .acpi_match_table = ACPI_PTR(at25_acpi_match), + }, + }; + +Note that this driver actually needs more information like page size of the +eeprom etc. but at the time writing this there is no standard way of +passing those. One idea is to return this in _DSM method like: + + Device (EEP0) + { + ... + Method (_DSM, 4, NotSerialized) + { + Store (Package (6) + { + "byte-len", 1024, + "addr-mode", 2, + "page-size, 32 + }, Local0) + + // Check UUIDs etc. + + Return (Local0) + } + +Then the at25 SPI driver can get this configation by calling _DSM on its +ACPI handle like: + + struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL }; + struct acpi_object_list input; + acpi_status status; + + /* Fill in the input buffer */ + + status = acpi_evaluate_object(ACPI_HANDLE(&spi->dev), "_DSM", + &input, &output); + if (ACPI_FAILURE(status)) + /* Handle the error */ + + /* Extract the data here */ + + kfree(output.pointer); + +I2C serial bus support +~~~~~~~~~~~~~~~~~~~~~~ +The slaves behind I2C bus controller only need to add the ACPI IDs like +with the platform and SPI drivers. However the I2C bus controller driver +needs to call acpi_i2c_register_devices() after it has added the adapter. + +An I2C bus (controller) driver does: + + ... + ret = i2c_add_numbered_adapter(adapter); + if (ret) + /* handle error */ + + of_i2c_register_devices(adapter); + /* Enumerate the slave devices behind this bus via ACPI */ + acpi_i2c_register_devices(adapter); + +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[] = { + { "MPU3050", 0 }, + { }, + }; + MODULE_DEVICE_TABLE(acpi, mpu3050_acpi_match); + #endif + + static struct i2c_driver mpu3050_i2c_driver = { + .driver = { + .name = "mpu3050", + .owner = THIS_MODULE, + .pm = &mpu3050_pm, + .of_match_table = mpu3050_of_match, + .acpi_match_table ACPI_PTR(mpu3050_acpi_match), + }, + .probe = mpu3050_probe, + .remove = mpu3050_remove, + .id_table = mpu3050_ids, + }; + +GPIO support +~~~~~~~~~~~~ +ACPI 5 introduced two new resources to describe GPIO connections: GpioIo +and GpioInt. These resources are used be used to pass GPIO numbers used by +the device to the driver. For example: + + Method (_CRS, 0, NotSerialized) + { + Name (SBUF, ResourceTemplate() + { + GpioIo (Exclusive, PullDefault, 0x0000, 0x0000, + IoRestrictionOutputOnly, "\\_SB.PCI0.GPI0", + 0x00, ResourceConsumer,,) + { + // Pin List + 0x0055 + } + ... + + Return (SBUF) + } + } + +These GPIO numbers are controller relative and path "\\_SB.PCI0.GPI0" +specifies the path to the controller. In order to use these GPIOs in Linux +we need to translate them to the Linux GPIO numbers. + +The driver can do this by including <linux/acpi_gpio.h> and then calling +acpi_get_gpio(path, gpio). This will return the Linux GPIO number or +negative errno if there was no translation found. + +Other GpioIo parameters must be converted first by the driver to be +suitable to the gpiolib before passing them. + +In case of GpioInt resource an additional call to gpio_to_irq() must be +done before calling request_irq(). diff --git a/Documentation/acpi/initrd_table_override.txt b/Documentation/acpi/initrd_table_override.txt new file mode 100644 index 00000000..35c3f541 --- /dev/null +++ b/Documentation/acpi/initrd_table_override.txt @@ -0,0 +1,94 @@ +Overriding ACPI tables via initrd +================================= + +1) Introduction (What is this about) +2) What is this for +3) How does it work +4) References (Where to retrieve userspace tools) + +1) What is this about +--------------------- + +If the ACPI_INITRD_TABLE_OVERRIDE compile option is true, it is possible to +override nearly any ACPI table provided by the BIOS with an instrumented, +modified one. + +For a full list of ACPI tables that can be overridden, take a look at +the char *table_sigs[MAX_ACPI_SIGNATURE]; definition in drivers/acpi/osl.c +All ACPI tables iasl (Intel's ACPI compiler and disassembler) knows should +be overridable, except: + - ACPI_SIG_RSDP (has a signature of 6 bytes) + - ACPI_SIG_FACS (does not have an ordinary ACPI table header) +Both could get implemented as well. + + +2) What is this for +------------------- + +Please keep in mind that this is a debug option. +ACPI tables should not get overridden for productive use. +If BIOS ACPI tables are overridden the kernel will get tainted with the +TAINT_OVERRIDDEN_ACPI_TABLE flag. +Complain to your platform/BIOS vendor if you find a bug which is so sever +that a workaround is not accepted in the Linux kernel. + +Still, it can and should be enabled in any kernel, because: + - There is no functional change with not instrumented initrds + - It provides a powerful feature to easily debug and test ACPI BIOS table + compatibility with the Linux kernel. + + +3) How does it work +------------------- + +# Extract the machine's ACPI tables: +cd /tmp +acpidump >acpidump +acpixtract -a acpidump +# Disassemble, modify and recompile them: +iasl -d *.dat +# For example add this statement into a _PRT (PCI Routing Table) function +# of the DSDT: +Store("HELLO WORLD", debug) +iasl -sa dsdt.dsl +# Add the raw ACPI tables to an uncompressed cpio archive. +# They must be put into a /kernel/firmware/acpi directory inside the +# cpio archive. +# The uncompressed cpio archive must be the first. +# Other, typically compressed cpio archives, must be +# concatenated on top of the uncompressed one. +mkdir -p kernel/firmware/acpi +cp dsdt.aml kernel/firmware/acpi +# A maximum of: #define ACPI_OVERRIDE_TABLES 10 +# tables are currently allowed (see osl.c): +iasl -sa facp.dsl +iasl -sa ssdt1.dsl +cp facp.aml kernel/firmware/acpi +cp ssdt1.aml kernel/firmware/acpi +# Create the uncompressed cpio archive and concatenate the original initrd +# on top: +find kernel | cpio -H newc --create > /boot/instrumented_initrd +cat /boot/initrd >>/boot/instrumented_initrd +# reboot with increased acpi debug level, e.g. boot params: +acpi.debug_level=0x2 acpi.debug_layer=0xFFFFFFFF +# and check your syslog: +[ 1.268089] ACPI: PCI Interrupt Routing Table [\_SB_.PCI0._PRT] +[ 1.272091] [ACPI Debug] String [0x0B] "HELLO WORLD" + +iasl is able to disassemble and recompile quite a lot different, +also static ACPI tables. + + +4) Where to retrieve userspace tools +------------------------------------ + +iasl and acpixtract are part of Intel's ACPICA project: +http://acpica.org/ +and should be packaged by distributions (for example in the acpica package +on SUSE). + +acpidump can be found in Len Browns pmtools: +ftp://kernel.org/pub/linux/kernel/people/lenb/acpi/utils/pmtools/acpidump +This tool is also part of the acpica package on SUSE. +Alternatively, used ACPI tables can be retrieved via sysfs in latest kernels: +/sys/firmware/acpi/tables diff --git a/Documentation/acpi/method-customizing.txt b/Documentation/acpi/method-customizing.txt new file mode 100644 index 00000000..5f55373d --- /dev/null +++ b/Documentation/acpi/method-customizing.txt @@ -0,0 +1,73 @@ +Linux ACPI Custom Control Method How To +======================================= + +Written by Zhang Rui <rui.zhang@intel.com> + + +Linux supports customizing ACPI control methods at runtime. + +Users can use this to +1. override an existing method which may not work correctly, + or just for debugging purposes. +2. insert a completely new method in order to create a missing + method such as _OFF, _ON, _STA, _INI, etc. +For these cases, it is far simpler to dynamically install a single +control method rather than override the entire DSDT, because kernel +rebuild/reboot is not needed and test result can be got in minutes. + +Note: Only ACPI METHOD can be overridden, any other object types like + "Device", "OperationRegion", are not recognized. +Note: The same ACPI control method can be overridden for many times, + and it's always the latest one that used by Linux/kernel. +Note: To get the ACPI debug object output (Store (AAAA, Debug)), + please run "echo 1 > /sys/module/acpi/parameters/aml_debug_output". + +1. override an existing method + a) get the ACPI table via ACPI sysfs I/F. e.g. to get the DSDT, + just run "cat /sys/firmware/acpi/tables/DSDT > /tmp/dsdt.dat" + b) disassemble the table by running "iasl -d dsdt.dat". + c) rewrite the ASL code of the method and save it in a new file, + d) package the new file (psr.asl) to an ACPI table format. + Here is an example of a customized \_SB._AC._PSR method, + + DefinitionBlock ("", "SSDT", 1, "", "", 0x20080715) + { + External (ACON) + + Method (\_SB_.AC._PSR, 0, NotSerialized) + { + Store ("In AC _PSR", Debug) + Return (ACON) + } + } + Note that the full pathname of the method in ACPI namespace + should be used. + And remember to use "External" to declare external objects. + e) assemble the file to generate the AML code of the method. + e.g. "iasl psr.asl" (psr.aml is generated as a result) + f) mount debugfs by "mount -t debugfs none /sys/kernel/debug" + g) override the old method via the debugfs by running + "cat /tmp/psr.aml > /sys/kernel/debug/acpi/custom_method" + +2. insert a new method + This is easier than overriding an existing method. + We just need to create the ASL code of the method we want to + insert and then follow the step c) ~ g) in section 1. + +3. undo your changes + The "undo" operation is not supported for a new inserted method + right now, i.e. we can not remove a method currently. + For an overrided method, in order to undo your changes, please + save a copy of the method original ASL code in step c) section 1, + and redo step c) ~ g) to override the method with the original one. + + +Note: We can use a kernel with multiple custom ACPI method running, + But each individual write to debugfs can implement a SINGLE + method override. i.e. if we want to insert/override multiple + ACPI methods, we need to redo step c) ~ g) for multiple times. + +Note: Be aware that root can mis-use this driver to modify arbitrary + memory and gain additional rights, if root's privileges got + restricted (for example if root is not allowed to load additional + modules after boot). diff --git a/Documentation/acpi/method-tracing.txt b/Documentation/acpi/method-tracing.txt new file mode 100644 index 00000000..f6efb1ea --- /dev/null +++ b/Documentation/acpi/method-tracing.txt @@ -0,0 +1,26 @@ +/sys/module/acpi/parameters/: + +trace_method_name + The AML method name that the user wants to trace + +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. + +trace_state + The status of the tracing feature. + + "enabled" means this feature is enabled + and the AML method is traced every time it's executed. + + "1" means this feature is enabled and the AML method + will only be traced during the next execution. + + "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". diff --git a/Documentation/acpi/scan_handlers.txt b/Documentation/acpi/scan_handlers.txt new file mode 100644 index 00000000..3246ccf1 --- /dev/null +++ b/Documentation/acpi/scan_handlers.txt @@ -0,0 +1,77 @@ +ACPI Scan Handlers + +Copyright (C) 2012, Intel Corporation +Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com> + +During system initialization and ACPI-based device hot-add, the ACPI namespace +is scanned in search of device objects that generally represent various pieces +of hardware. This causes a struct acpi_device object to be created and +registered with the driver core for every device object in the ACPI namespace +and the hierarchy of those struct acpi_device objects reflects the namespace +layout (i.e. parent device objects in the namespace are represented by parent +struct acpi_device objects and analogously for their children). Those struct +acpi_device objects are referred to as "device nodes" in what follows, but they +should not be confused with struct device_node objects used by the Device Trees +parsing code (although their role is analogous to the role of those objects). + +During ACPI-based device hot-remove device nodes representing pieces of hardware +being removed are unregistered and deleted. + +The core ACPI namespace scanning code in drivers/acpi/scan.c carries out basic +initialization of device nodes, such as retrieving common configuration +information from the device objects represented by them and populating them with +appropriate data, but some of them require additional handling after they have +been registered. For example, if the given device node represents a PCI host +bridge, its registration should cause the PCI bus under that bridge to be +enumerated and PCI devices on that bus to be registered with the driver core. +Similarly, if the device node represents a PCI interrupt link, it is necessary +to configure that link so that the kernel can use it. + +Those additional configuration tasks usually depend on the type of the hardware +component represented by the given device node which can be determined on the +basis of the device node's hardware ID (HID). They are performed by objects +called ACPI scan handlers represented by the following structure: + +struct acpi_scan_handler { + const struct acpi_device_id *ids; + struct list_head list_node; + int (*attach)(struct acpi_device *dev, const struct acpi_device_id *id); + void (*detach)(struct acpi_device *dev); +}; + +where ids is the list of IDs of device nodes the given handler is supposed to +take care of, list_node is the hook to the global list of ACPI scan handlers +maintained by the ACPI core and the .attach() and .detach() callbacks are +executed, respectively, after registration of new device nodes and before +unregistration of device nodes the handler attached to previously. + +The namespace scanning function, acpi_bus_scan(), first registers all of the +device nodes in the given namespace scope with the driver core. Then, it tries +to match a scan handler against each of them using the ids arrays of the +available scan handlers. If a matching scan handler is found, its .attach() +callback is executed for the given device node. If that callback returns 1, +that means that the handler has claimed the device node and is now responsible +for carrying out any additional configuration tasks related to it. It also will +be responsible for preparing the device node for unregistration in that case. +The device node's handler field is then populated with the address of the scan +handler that has claimed it. + +If the .attach() callback returns 0, it means that the device node is not +interesting to the given scan handler and may be matched against the next scan +handler in the list. If it returns a (negative) error code, that means that +the namespace scan should be terminated due to a serious error. The error code +returned should then reflect the type of the error. + +The namespace trimming function, acpi_bus_trim(), first executes .detach() +callbacks from the scan handlers of all device nodes in the given namespace +scope (if they have scan handlers). Next, it unregisters all of the device +nodes in that scope. + +ACPI scan handlers can be added to the list maintained by the ACPI core with the +help of the acpi_scan_add_handler() function taking a pointer to the new scan +handler as an argument. The order in which scan handlers are added to the list +is the order in which they are matched against device nodes during namespace +scans. + +All scan handles must be added to the list before acpi_bus_scan() is run for the +first time and they cannot be removed from it. |