SATA AHCI Disk Controller

AHCI Driver for OS/2 Introduction ============ OS2AHCI is an AHCI driver for OS/2. It supports both ATA and ATAPI devices in a single driver. An ATAPI/CDROM filter driver is only required if you want to read/write CD-DA (audio) format CDs. Copyrights and License ====================== (c) Copyright IBM Corporation 1990,2000. All rights reserved. Copyright (c) 2011 thi.guten Software Development Copyright (c) 2011 Mensys B.V. Copyright (c) 2013-2021 David Azarewicz Authors: Christian Mueller, Markus Thielen Parts copied from/inspired by the Linux AHCI driver; those parts are (c) Linux AHCI/ATA maintainers. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA The OS2AHCI.ADD Driver Software is a derivative work of the IBM DDK. Binary programs and documentation for the OS2AHCI.ADD Driver Software are licensed to and distributed by Arca Noae, LLC. The source code can be retrieved from http://svn.netlabs.org. In compliance to the GNU General Public License, the source code can of course be modified/compiled to run on other products as long as modifications will also be published as outlined in the GNU GPL. Please note that builds other than the official binary delivered by the Arca Noae web site are not officially supported. Getting Support and Reporting Problems ====================================== For more information and to report problems please visit: https://www.arcanoae.com and click on SUPPORT. Or go directly to the AHCI support wiki at: https://www.arcanoae.com/wiki/ahci/ Driver Command Line Options =========================== Global Options Option Description ----------------------------------------------------------------------------- /A:n Set adapter to n for adapter-specific options (default = -1, all adapters) /F Force the use of the HW write cache when using NCQ commands; see "Native Command Queuing" below for further explanation (default = off) /G:<vendor>:<device> Add generic PCI ID to list of supported AHCI adapters (e.g. /G:8086:2829) /I Ignore current adapter if no port has been specified. Otherwise, ignore the current port on the current adapter. /P:n Set port to n for port-specific options (default = -1, all ports) /R Reset ports during initialization (default = on) Can be turned off with /!R, however, when the [Intel] AHCI controller was found to be initialized by the BIOS in SATA mode, ports will always be reset even when /!R is specified /T Perform thorough PCI ID scan; default = on, can be turned off with /!T to perform only a PCI class scan /U Check for usable disks and mark disks that are not usable as unavailable for normal OS/2 operations. To be usable a disk must be an MBR disk or wiped. (default = on) Can be turned off with /!U. /V Display informational messages during boot. Debugging options (may only be available in debug builds) Option Description ----------------------------------------------------------------------------- /B:<baud> Initialize the COM port to the specified baud rate. Allowable baud values are: 300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, and 115200. /B has no effect if /C is not also specified. If /B is not specified, the COM port is not initialized. For example, if you are using the kernel debugger, the kernel debugger initializes the COM port so you should not use this switch. /COM:<n> Set debug COM port base address. Values for n can be: 1 = COM1 2 = COM2 a hex value (COM port base address) COM1=3f8, COM2=2f8 The default is 0. If set to 0 then no output goes to the COM port. /DEBUG:<n> Sets debug mask /W Allows the debug buffer to wrap when full. Port-specific Options Option Description ----------------------------------------------------------------------------- /S Enable SCSI emulation for ATAPI units (default = on) SCSI emulation is required for tools like cdrecord. /N Enable NCQ (Native Command Queuing) for hard disks (default = off) /LS Set link speed (default = 0): 0 = maximum, 1 = limit to generation 1 2 = limit to generation 2 3 = limit to generation 3 /LP Set link power management (default = 0): 0 = full power management, 1 = transitions to "partial slumber state" disabled, 2 = transitions to "slumber state" disabled, 3 = transitions to both partial and slumber states disabled /4 Force track size to be 56 sectors regardless of the reported disk geometry to optimize partition boundaries for hard disks with 4096 byte sectors. Port-specific options depend on the currently active adapter and port selector (/A and /P). Those selectors are -1 per default which means "all" adapters/ports. The scope can be reduced by limiting it to an adapter (/A) or an adapter and a port (/A and /P). The scope can be reset by setting the corresponding option back to -1. For example: BASEDEV=OS2AHCI.ADD /N /A:0 /P:5 /!N /A:1 /P:-1 /!N This has the following effect: - Enable NCQ for all hard disks - Disable NCQ for hard disk on adapter #0, port #5 - Disable NCQ for all hard disks on adapter #1 Another example: BASEDEV=OS2AHCI.ADD /A:0 /P:0 /I Means to ignore the disk plugged into port 0 on adapeter 0. Native Command Queuing ====================== Native Command Queuing (NCQ) is a feature which allows sending multiple I/O requests to hard disks before waiting for any of the requests to complete, much like Tagged Command Queuing for SCSI devices. This allows the disks to reorder I/O requests to minimize head movements, resulting in improved performance when executing random I/Os. In practice, this will be most noticeable when multiple programs request I/O services to different parts of the disk -- a single program typically won't queue up I/O's but instead will wait for each I/O to complete (with the exception of programs like database servers). While we believe NCQ will work with the majority of controllers and hard disks, it's currently turned off by default until we have more feedback from OS/2 users. In order to turn on NCQ, just add the command line option "/N" to OS2AHCI.ADD. NCQ and HW Caches ----------------- In NCQ mode, OS2AHCI supports a request flag which allows upstream code (e.g. file systems) to force writes to go directly to the disk instead of being buffered in the HW disk cache. However, at least JFS doesn't support this flag properly which effectively disables the HW disk cache for write operations across the board, resulting in a substantial performance loss. In order to prevent OS2AHCI from disabling the HW cache when so requested by upstream code, please use the command line option "/F". This may, of course, result in data loss in case of power failures but apparently this was the situation with previous IDE drivers as well thus shouldn't make much difference in the field. The JFS code also seems to imply that this flag has never been widely supported by [IDE] drivers; otherwise, the JFS developers should have stumbled over the performance loss a long time ago and fixed the code. NOTES: - Without NCQ, OS2AHCI behaves like former IDE drivers, i.e. the HW cache will always be enabled (on modern disks). - When suspending, rebooting or shutting down, OS2AHCI always flushes the HW disk cache regardless of the "/F" or "/N" command line options. Interoperability With IDE Drivers ================================= There are three kinds of IDE/ATA/SATA controllers: 1. Older controllers (IDE or SATA) without AHCI support This kind of controller will only be recognized by IDE drivers (IBM1S506.ADD or DANIS506.ADD). 2. AHCI-capable controllers which supports IDE/SATA interfaces This kind of controller will work with IDE or AHCI drivers and it's up to the user to decide which driver to use. 3. AHCI-only controllers This kind of controller will only be recognized by OS2AHCI. If there's a mix of controllers of types 1 and 3, both an IDE and an AHCI driver will be required. If type 2 controllers are involved, it's up to the user to decide which driver to use. Both DANIS506.ADD and OS2AHCI.ADD will verify whether another driver has already allocated the corresponding adapter, thus the only decision to take for mixed configurations is whether type-2 controllers should be handled by DANIS506.ADD or OS2AHCI.ADD and this can be done by having the desired driver's BASEDEV statement coming first in CONFIG.SYS. NOTE: Older versions of DANIS506.ADD did not verify whether the resources of a particular adapter were already allocated by another driver. DANIS506.ADD 1.8.8 or later is required for this to work. When using earlier versions of DANIS506.ADD, the options "/A:x /I" will be required to tell DANIS506.ADD to ignore adapters to be driven by OS2AHCI.ADD. The same applies to IBM1S506.ADD Mixed Controller Example ------------------------ Assume a DELL D630 or a Thinkpad T60. The hard disk is attached to the SATA/AHCI controller of the ICH-7 hub while the CDROM is attached to the PATA IDE controller. This allows two different configurations: 1. Drive HDD and CDROM via DANIS506.ADD 2. Drive HDD via OS2AHCI.ADD and CDROM via DANIS506.ADD OS2AHCI.ADD can't drive the CDROM because it's attached to a PATA IDE controller which doesn't support AHCI. - If OS2AHCI.ADD comes first in CONFIG.SYS, it will take over the SATA/AHCI controller and drive the HDD. DANIS506.ADD will take care of the PATA/IDE controller for the CDROM. - If DANIS506.ADD comes first in CONFIG.SYS, it will take over both the SATA/AHCI and the PATA/IDE controller and OS2AHCI.ADD will silently exit. Advantages of AHCI ------------------ The interfaces provided by the various [Intel] controllers could be summarized like this (the term ATA as driver interface being a bit of our own invention): - Intel PIIX: IDE (I/O registers) and ATA (taskfile) - Intel ICH6: IDE (I/O registers), ATA (taskfile) and SATA (FIS, vendor-specific) - Intel ICH7: IDE (I/O registers), ATA (taskfile), SATA (FIS, vendor-specific) and AHCI (FIS) - Intel PCH: AHCI (FIS) Taskfiles are regions in memory with ATA commands which the IDE/ATA controller can read and process autonomously. FIS (Frame Information Structures) are pretty much the same but they are specific to the SATA communication protocol on the serial link. The most important FIS type for AHCI drivers is the H2D (host to device) FIS which basically contains the ATA command to be executed. The big advantage of AHCI controllers, apart from being vendor-neutral, is that they take care of a lot of things which previous-generation drivers like DANIS506 would have to do step by step. For example, in order to send an ATAPI command, DANIS506 would have to do the following: * Send ATA "PACKET" command to device (via IDE registers, ATA taskfiles or SATA FIS) * Wait until device signals via interrupt it's ready for the ATAPI command * Send ATAPI command to device via PIO * Wait until device signals via interrupt it's ready to transfer data * Send/Receive any data that might come along with the ATAPI command via PIO, or wait for DMA transfer to complete * Wait until device signals via interrupt that command and data transfer have completed For OS2AHCI, the same operation looks like this: * Fill in AHCI command header, FIS with ATA "PACKET" command and the ATAPI command * Tell port engine to process the command * Wait until controller signals via interrupt that command and data transfer have completed The AHCI controller automatically takes care of all underlying bits and pieces. OS2AHCI doesn't even have to know whether a particular message is sent via PIO or DMA because this is handled by the AHCI controller, too. And the whole concept of PIO and DMA is only relevant between AHCI controller and the device -- all transfers between OS2AHCI and the AHCI controller are always done via DMA. SMART Support ============= Starting with version 1.22, OS2AHCI supports the IOCTL interface required by existing SMART monitoring tools. Beware that the IBM version of smartctl.exe is hard-coded to open the character device named "IBMS506$" so it will not work with OS2AHCI. You must use a version that allows specifying ahci devices. NOTES: - The IOCTL interface for SMART is based on the idea of IDE controllers with a master and a slave drive. OS2AHCI maps all devices (ATA or ATAPI) sequentially to this pattern. If, for example, you have 4 hard disks and one CDROM attached to a single controller on ports 1, 2, 5, 7, and 11, SMART tools will see 3 controllers as follows: - controller 0, master: HD on port 1 - controller 0, slave: HD on port 2 - controller 1, master: HD on port 5 - controller 1, slave: HD on port 7 - controller 2, master: CDROM on port 11 - The DSKSP_GEN_GET_COUNTERS interface is currently unsupported; calls to the corresponding IOCTL will return 0 for all counters. SMART counters are not affected by this limitation, i.e. SMART tools will be able to report counters from the physical disk; this limitation only affects the software counters maintained by ADD drivers which do support the DSKSP_GEN_GET_COUNTERS IOCTL request. Known Issues and Limitations ============================ Hot swap is not supported. Port expanders are not supported. Only one drive per port is allowed. Manual Installation =================== - Copy the driver file, OS2AHCI.ADD, to \OS2\BOOT on your boot disk. - Add the following line to CONFIG.SYS: BASEDEV=OS2AHCI.ADD Building The Driver ------------------- The toolchain required for compilation consists of: - The MiniDDK or an updated DDK (You must have a DDK license to build this driver.) - Open Watcom version 1.9 or later - The Drv32 kit. (You must have a DDK license to use the Drv32 kit.) Define DDK, WATCOM, and DRV32KIT in the environment. Use "wmake" or "wmake -a" to build the driver. See _build.cmd. Change Log ========== v.2.08 20-Feb-2021 - David Azarewicz Corrected RM ADD handle and unit. Changed the internal implementation of /U to accomodate gpt filter. Added support for 48/64 bit LBA operations. Added test for non-aligned SG list element. v.2.07 19-May-2019 - David Azarewicz Fixed hardware failure recovery to arm ctx hook in watchdog timer.