NAME
sdahci – AHCI (Advanced Host Controller Interface) SATA (Serial ATA) storage device drivers

SYNOPSIS
bind –a #S /dev
/dev/sdctl
/dev/sd
En/ctl
/dev/sd
En/raw
/dev/sd
En/data
...

DESCRIPTION
The sdahci driver provides access to AHCI devices via the sd(3) interface. The AHCI programming interface supports up to 32 hot–swappable ATAPI or hard disk–like devices per controller. The legacy IDE interface provided by sdata.c supports up to four drives which are not hot–swappable. Controller drive letters are assigned from E onward.

AHCI controllers are detected automatically. Currently Intel and AMD controllers are detected. Intel controllers need to have AHCI enabled in the BIOS. For ich parts this typically means enabling enhanced mode and AHCI. For ESB (Enterprise South Bridge) –based parts, only enhanced mode needs to be enabled. Intel ich9–based AHCI does not support hot swapping and drives must be connected to the lowest–numbered free port.

The top level control file, /dev/sdctl, supports the following control messages for sdahci:
iahci debug     Toggle debug messages. Default is off.
iahci idprint   Toggle printing of drive identification messages. Default is on. Prints short messages when a drive is identified or removed.
iahci aprint    Print verbose ATAPI debugging messages. Default is off.

The device–level ctl file supports:
flushcache     Send the ATA/ATAPI FLUSH CACHE command (0xe7 or 0xea). This command may take up to 60 seconds to complete.
identify       Send the ATA/ATAPI IDENTIFY DEVICE command (0xec). If device information has changed, the new size, features and serial will be noted. If changed, I/O on existing file descriptors will result in the error string media or partition has changed.
mode speed      Change the connection speed to one of auto, satai or sataii.
nop           Send the ATA NOP command (0) if the device supports it. Per standard, the result is always an error.
smart          Send the ATA/ATAPI SMART RETURN STATUS command (0xda). This will fail unless SMART is enabled on the drive.
smartdisable   Disable SMART on the drive. SMART is a persistent property of the drive.
smartenable    Enable SMART on the drive.
state state     Force a transition to the named state. The states are:
null        ignored (may only be reached manually);
missing     not detected;
new         powered down or newly discovered;
ready       ready for commands;
reset       being reset gently;
portreset   being fully reset;
offline     device failed portreset (a port reset will be attempted periodically).

For devices present at boot, the transition is from state new to state ready.

SOURCE
/sys/src/9/pc/sdiahci.c

SEE ALSO
sd(3)
http://download.intel.com/technology/serialata/pdf/rev1_2.pdf.

BUGS
None of enclosure management, LED control and port multipliers are supported.

ATAPI devices may not be reset when they have outstanding commands.