1.\" Copyright (c) 2009-2013 Alexander Motin <mav@FreeBSD.org> 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd October 22, 2013 28.Dt AHCI 4 29.Os 30.Sh NAME 31.Nm ahci 32.Nd Serial ATA Advanced Host Controller Interface driver 33.Sh SYNOPSIS 34To compile this driver into the kernel, 35place the following lines in your 36kernel configuration file: 37.Bd -ragged -offset indent 38.Cd "device pci" 39.Cd "device scbus" 40.Cd "device ahci" 41.Ed 42.Pp 43Alternatively, to load the driver as a 44module at boot time, place the following line in 45.Xr loader.conf 5 : 46.Bd -literal -offset indent 47ahci_load="YES" 48.Ed 49.Pp 50The following tunables are settable from the 51.Xr loader 8 : 52.Bl -ohang 53.It Va hint.ahci. Ns Ar X Ns Va .msi 54controls Message Signaled Interrupts (MSI) usage by the specified controller. 55.Pp 56.Bl -tag -width 4n -offset indent -compact 57.It 0 58MSI disabled; 59.It 1 60single MSI vector used, if supported; 61.It 2 62multiple MSI vectors used, if supported (default); 63.El 64.It Va hint.ahci. Ns Ar X Ns Va .ccc 65controls Command Completion Coalescing (CCC) usage by the specified controller. 66Non-zero value enables CCC and defines maximum time (in ms), request can wait 67for interrupt, if there are some more requests present on controller queue. 68CCC reduces number of context switches on systems with many parallel requests, 69but it can decrease disk performance on some workloads due to additional 70command latency. 71.It Va hint.ahci. Ns Ar X Ns Va .direct 72controls whether the driver should use direct command completion from 73interrupt thread(s), or queue them to CAM completion threads. 74Default value depends on number of MSI interrupts supported and number of 75implemented SATA ports. 76.It Va hint.ahcich. Ns Ar X Ns Va .pm_level 77controls SATA interface Power Management for the specified channel, 78allowing some power to be saved at the cost of additional command 79latency. 80Possible values: 81.Pp 82.Bl -tag -width 4n -offset indent -compact 83.It 0 84interface Power Management is disabled (default); 85.It 1 86device is allowed to initiate PM state change, host is passive; 87.It 2 88host initiates PARTIAL PM state transition every time port becomes idle; 89.It 3 90host initiates SLUMBER PM state transition every time port becomes idle. 91.It 4 92driver initiates PARTIAL PM state transition 1ms after port becomes idle; 93.It 5 94driver initiates SLUMBER PM state transition 125ms after port becomes idle. 95.El 96.Pp 97Some controllers, such as ICH8, do not implement modes 2 and 3 with NCQ used. 98Because of artificial entering latency, performance degradation in modes 994 and 5 is much smaller then in modes 2 and 3. 100.Pp 101Note that interface Power Management complicates device presence detection. 102A manual bus reset/rescan may be needed after device hot-plug, unless hardware 103implements Cold Presence Detection. 104.It Va hint.ahcich. Ns Ar X Ns Va .sata_rev 105setting to nonzero value limits maximum SATA revision (speed). 106Values 1, 2 and 3 are respectively 1.5, 3 and 6Gbps. 107.It Va hw.ahci.force 108setting to nonzero value forces driver attach to some known AHCI-capable 109chips even if they are configured for legacy IDE emulation. 110Default is 1. 111.El 112.Sh DESCRIPTION 113This driver provides the 114.Xr CAM 4 115subsystem with native access to the 116.Tn SATA 117ports of AHCI-compatible controllers. 118Each SATA port found is represented to CAM as a separate bus with one 119target, or, if HBA supports Port Multipliers, 16 targets. 120Most of the bus-management details are handled by the SATA-specific 121transport of CAM. 122Connected ATA disks are handled by the ATA protocol disk peripheral driver 123.Xr ada 4 . 124ATAPI devices are handled by the SCSI protocol peripheral drivers 125.Xr cd 4 , 126.Xr da 4 , 127.Xr sa 4 , 128etc. 129.Pp 130Driver features include support for Serial ATA and ATAPI devices, 131Port Multipliers (including FIS-based switching, when supported), 132hardware command queues (up to 32 commands per port), 133Native Command Queuing, SATA interface Power Management, device hot-plug 134and Message Signaled Interrupts. 135.Pp 136Driver supports "LED" enclosure management messages, defined by the AHCI. 137When supported by hardware, it allows to control per-port activity, locate 138and fault LEDs via the 139.Xr led 4 140API or emulated 141.Xr ses 4 142device for localization and status reporting purposes. 143Supporting AHCI controllers may transmit that information to the backplane 144controllers via SGPIO interface. 145Backplane controllers interpret received 146statuses in some way (IBPI standard) to report them using present indicators. 147.Sh HARDWARE 148The 149.Nm 150driver supports AHCI compatible controllers having PCI class 1 (mass storage), 151subclass 6 (SATA) and programming interface 1 (AHCI). 152.Pp 153Also, in cooperation with atamarvell and atajmicron drivers of ata(4), 154it supports AHCI part of legacy-PATA + AHCI-SATA combined controllers, 155such as JMicron JMB36x and Marvell 88SE61xx. 156.Sh FILES 157.Bl -tag -width /dev/led/ahcich*.locate 158.It Pa /dev/led/ahci*.*.act 159activity LED device nodes 160.It Pa /dev/led/ahci*.*.fault 161fault LED device nodes 162.It Pa /dev/led/ahci*.*.locate 163locate LED device nodes 164.El 165.Sh SEE ALSO 166.Xr ada 4 , 167.Xr ata 4 , 168.Xr cam 4 , 169.Xr cd 4 , 170.Xr da 4 , 171.Xr sa 4 , 172.Xr ses 4 173.Sh HISTORY 174The 175.Nm 176driver first appeared in 177.Fx 8.0 . 178.Sh AUTHORS 179.An Alexander Motin Aq Mt mav@FreeBSD.org 180