Separate the parallel scsi knowledge out of the core of the XPT, and

modularize it so that new transports can be created.

Add a transport for SATA

Add a periph+protocol layer for ATA

Add a driver for AHCI-compliant hardware.

Add a maxio field to CAM so that drivers can advertise their max
I/O capability.  Modify various drivers so that they are insulated
from the value of MAXPHYS.

The new ATA/SATA code supports AHCI-compliant hardware, and will override
the classic ATA driver if it is loaded as a module at boot time or compiled
into the kernel.  The stack now support NCQ (tagged queueing) for increased
performance on modern SATA drives.  It also supports port multipliers.

ATA drives are accessed via 'ada' device nodes.  ATAPI drives are
accessed via 'cd' device nodes.  They can all be enumerated and manipulated
via camcontrol, just like SCSI drives.  SCSI commands are not translated to
their ATA equivalents; ATA native commands are used throughout the entire
stack, including camcontrol.  See the camcontrol manpage for further
details.  Testing this code may require that you update your fstab, and
possibly modify your BIOS to enable AHCI functionality, if available.

This code is very experimental at the moment.  The userland ABI/API has
changed, so applications will need to be recompiled.  It may change
further in the near future.  The 'ada' device name may also change as
more infrastructure is completed in this project.  The goal is to
eventually put all CAM busses and devices until newbus, allowing for
interesting topology and management options.

Few functional changes will be seen with existing SCSI/SAS/FC drivers,
though the userland ABI has still changed.  In the future, transports
specific modules for SAS and FC may appear in order to better support
the topologies and capabilities of these technologies.

The modularization of CAM and the addition of the ATA/SATA modules is
meant to break CAM out of the mold of being specific to SCSI, letting it
grow to be a framework for arbitrary transports and protocols.  It also
allows drivers to be written to support discrete hardware without
jeopardizing the stability of non-related hardware.  While only an AHCI
driver is provided now, a Silicon Image driver is also in the works.
Drivers for ICH1-4, ICH5-6, PIIX, classic IDE, and any other hardware
is possible and encouraged.  Help with new transports is also encouraged.

Submitted by:	scottl, mav
Approved by:	re

2 files changed, 133 insertions, 0 deletions

diff --git a/share/man/man4/Makefile b/share/man/man4/Makefile
index 488d69f..b56d117 100644
--- a/share/man/man4/Makefile
+++ b/share/man/man4/Makefile
@@ -23,6 +23,7 @@ MAN=	aac.4 \
 	aha.4 \
 	ahb.4 \
 	ahc.4 \
+	ahci.4 \
 	ahd.4 \
 	aio.4 \
 	alc.4 \
diff --git a/share/man/man4/ahci.4 b/share/man/man4/ahci.4
new file mode 100644
index 0000000..aa89bb7
--- /dev/null
+++ b/share/man/man4/ahci.4
@@ -0,0 +1,132 @@
+.\" Copyright (c) 2009 Alexander Motin <mav@FreeBSD.org>
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. The name of the author may not be used to endorse or promote products
+.\"    derived from this software without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd June 26, 2009
+.Dt AHCI 4
+.Os
+.Sh NAME
+.Nm ahci
+.Nd Serial ATA Advanced Host Controller Interface driver
+.Sh SYNOPSIS
+To compile this driver into the kernel,
+place the following lines in your
+kernel configuration file:
+.Bd -ragged -offset indent
+.Cd "device pci"
+.Cd "device scbus"
+.Cd "device ahci"
+.Ed
+.Pp
+Alternatively, to load the driver as a
+module at boot time, place the following line in
+.Xr loader.conf 5 :
+.Bd -literal -offset indent
+ahci_load="YES"
+.Ed
+.Pp
+The following tunables are settable from the loader:
+.Bl -ohang
+.It Va hint.ahci.X.msi
+controls Message Signaled Interrupts (MSI) usage by the specified controller
+.Bl -tag -compact
+.It 0
+MSI disabled;
+.It 1
+single MSI vector used, if supported (default);
+.It 2
+multiple MSI vectors used, if supported;
+.El
+.It Va hint.ahcich.X.pm_level
+controls SATA interface Power Management for specified channel,
+allowing some power to be saved at the cost of additional command
+latency.
+Possible values:
+.Bl -tag -compact
+.It 0
+interface Power Management is disabled (default);
+.It 1
+device is allowed to initiate PM state change, host is passive;
+.It 2
+host initiates PARTIAL PM state transition every time port becomes idle;
+.It 3
+host initiates SLUMBER PM state transition every time port becomes idle.
+.El
+Note that interface Power Management is not compatible with
+device presence detection.
+You will have to reset bus manually on device hot-plug.
+.It Va hint.ahcich.X.sata_rev
+setting to nonzero value limits maximum SATA revision (speed).
+Values 1, 2 and 3 are respectively 1.5, 3 and 6Gbps.
+.El
+.Sh DESCRIPTION
+This driver provides the CAM subsystem with native access to the
+.Tn SATA
+ports of AHCI-compatible controllers.
+Each SATA port found is represented to CAM as a separate bus with one
+target, or, if HBA supports Port Multipliers, 15 targets.
+Most of the bus-management details are handled by the SATA-specific 
+transport of CAM.
+Connected ATA disks are handled by the ATA protocol disk peripheral driver
+.Xr ada 4 .
+ATAPI devices are handled by the SCSI protocol peripheral drivers
+.Xr cd 4 ,
+.Xr da 4 ,
+.Xr sa 4 ,
+etc.
+.Pp
+Driver features include support for Serial ATA and ATAPI devices,
+Port Multipliers, hardware command queues (up to 32 commands per port),
+Native Command Queuing, SATA interface Power Management, device hot-plug
+and Message Signaled Interrupts.
+.Pp
+The Port Multiplier FIS Based Switching feature added in the AHCI 1.2
+specification, which is required for effective parallel operation of devices
+behind Port Multipliers, is not yet supported.
+.Pp
+AHCI hardware is also supported by ataahci driver from
+.Xr ata 4
+subsystem. If both drivers are loaded at the same time, this one will be
+given precedence as the more functional of the two.
+.Sh HARDWARE
+The
+.Nm
+driver supports AHCI compatible controllers having PCI class 1 (mass storage),
+subclass 6 (SATA) and programming interface 1 (AHCI).
+.Sh SEE ALSO
+.Xr ada 4 ,
+.Xr cd 4 ,
+.Xr da 4 ,
+.Xr sa 4 ,
+.Xr scsi 4 ,
+.Xr ata 4
+.Sh HISTORY
+The
+.Nm
+driver first appeared in
+.Fx 8.0 .
+.Sh AUTHORS
+.An Alexander Motin Aq mav@FreeBSD.org .