docs-rst: convert libata book to ReST

Use pandoc to convert documentation to ReST by calling
Documentation/sphinx/tmplcvt script.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

2 files changed, 1 insertions, 1626 deletions

diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile
index 2f767e30b59e..abe71345160b 100644
--- a/Documentation/DocBook/Makefile
+++ b/Documentation/DocBook/Makefile
@@ -9,7 +9,7 @@
 DOCBOOKS := z8530book.xml  \
 	    networking.xml \
 	    lsm.xml \
-	    libata.xml mtdnand.xml librs.xml rapidio.xml \
+	    mtdnand.xml librs.xml rapidio.xml \
 	    s390-drivers.xml scsi.xml \
 	    sh.xml w1.xml
 
diff --git a/Documentation/DocBook/libata.tmpl b/Documentation/DocBook/libata.tmpl
deleted file mode 100644
index 0320910b866d..000000000000
--- a/Documentation/DocBook/libata.tmpl
+++ /dev/null
@@ -1,1625 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
-	"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
-
-<book id="libataDevGuide">
- <bookinfo>
-  <title>libATA Developer's Guide</title>
-  
-  <authorgroup>
-   <author>
-    <firstname>Jeff</firstname>
-    <surname>Garzik</surname>
-   </author>
-  </authorgroup>
-
-  <copyright>
-   <year>2003-2006</year>
-   <holder>Jeff Garzik</holder>
-  </copyright>
-
-  <legalnotice>
-   <para>
-   The contents of this file are subject to the Open
-   Software License version 1.1 that can be found at
-   <ulink url="http://fedoraproject.org/wiki/Licensing:OSL1.1">http://fedoraproject.org/wiki/Licensing:OSL1.1</ulink>
-   and is included herein by reference.
-   </para>
-
-   <para>
-   Alternatively, the contents of this file may be used under the terms
-   of the GNU General Public License version 2 (the "GPL") as distributed
-   in the kernel source COPYING file, in which case the provisions of
-   the GPL are applicable instead of the above.  If you wish to allow
-   the use of your version of this file only under the terms of the
-   GPL and not to allow others to use your version of this file under
-   the OSL, indicate your decision by deleting the provisions above and
-   replace them with the notice and other provisions required by the GPL.
-   If you do not delete the provisions above, a recipient may use your
-   version of this file under either the OSL or the GPL.
-   </para>
-
-  </legalnotice>
- </bookinfo>
-
-<toc></toc>
-
-  <chapter id="libataIntroduction">
-     <title>Introduction</title>
-  <para>
-  libATA is a library used inside the Linux kernel to support ATA host
-  controllers and devices.  libATA provides an ATA driver API, class
-  transports for ATA and ATAPI devices, and SCSI&lt;-&gt;ATA translation
-  for ATA devices according to the T10 SAT specification.
-  </para>
-  <para>
-  This Guide documents the libATA driver API, library functions, library
-  internals, and a couple sample ATA low-level drivers.
-  </para>
-  </chapter>
-
-  <chapter id="libataDriverApi">
-     <title>libata Driver API</title>
-     <para>
-     struct ata_port_operations is defined for every low-level libata
-     hardware driver, and it controls how the low-level driver
-     interfaces with the ATA and SCSI layers.
-     </para>
-     <para>
-     FIS-based drivers will hook into the system with ->qc_prep() and
-     ->qc_issue() high-level hooks.  Hardware which behaves in a manner
-     similar to PCI IDE hardware may utilize several generic helpers,
-     defining at a bare minimum the bus I/O addresses of the ATA shadow
-     register blocks.
-     </para>
-     <sect1>
-        <title>struct ata_port_operations</title>
-
-	<sect2><title>Disable ATA port</title>
-	<programlisting>
-void (*port_disable) (struct ata_port *);
-	</programlisting>
-
-	<para>
-	Called from ata_bus_probe() error path, as well as when
-	unregistering from the SCSI module (rmmod, hot unplug).
-	This function should do whatever needs to be done to take the
-	port out of use.  In most cases, ata_port_disable() can be used
-	as this hook.
-	</para>
-	<para>
-	Called from ata_bus_probe() on a failed probe.
-	Called from ata_scsi_release().
-	</para>
-
-	</sect2>
-
-	<sect2><title>Post-IDENTIFY device configuration</title>
-	<programlisting>
-void (*dev_config) (struct ata_port *, struct ata_device *);
-	</programlisting>
-
-	<para>
-	Called after IDENTIFY [PACKET] DEVICE is issued to each device
-	found.  Typically used to apply device-specific fixups prior to
-	issue of SET FEATURES - XFER MODE, and prior to operation.
-	</para>
-	<para>
-	This entry may be specified as NULL in ata_port_operations.
-	</para>
-
-	</sect2>
-
-	<sect2><title>Set PIO/DMA mode</title>
-	<programlisting>
-void (*set_piomode) (struct ata_port *, struct ata_device *);
-void (*set_dmamode) (struct ata_port *, struct ata_device *);
-void (*post_set_mode) (struct ata_port *);
-unsigned int (*mode_filter) (struct ata_port *, struct ata_device *, unsigned int);
-	</programlisting>
-
-	<para>
-	Hooks called prior to the issue of SET FEATURES - XFER MODE
-	command.  The optional ->mode_filter() hook is called when libata
-	has built a mask of the possible modes. This is passed to the 
-	->mode_filter() function which should return a mask of valid modes
-	after filtering those unsuitable due to hardware limits. It is not
-	valid to use this interface to add modes.
-	</para>
-	<para>
-	dev->pio_mode and dev->dma_mode are guaranteed to be valid when
-	->set_piomode() and when ->set_dmamode() is called. The timings for
-	any other drive sharing the cable will also be valid at this point.
-	That is the library records the decisions for the modes of each
-	drive on a channel before it attempts to set any of them.
-	</para>
-	<para>
-	->post_set_mode() is
-	called unconditionally, after the SET FEATURES - XFER MODE
-	command completes successfully.
-	</para>
-
-	<para>
-	->set_piomode() is always called (if present), but
-	->set_dma_mode() is only called if DMA is possible.
-	</para>
-
-	</sect2>
-
-	<sect2><title>Taskfile read/write</title>
-	<programlisting>
-void (*sff_tf_load) (struct ata_port *ap, struct ata_taskfile *tf);
-void (*sff_tf_read) (struct ata_port *ap, struct ata_taskfile *tf);
-	</programlisting>
-
-	<para>
-	->tf_load() is called to load the given taskfile into hardware
-	registers / DMA buffers.  ->tf_read() is called to read the
-	hardware registers / DMA buffers, to obtain the current set of
-	taskfile register values.
-	Most drivers for taskfile-based hardware (PIO or MMIO) use
-	ata_sff_tf_load() and ata_sff_tf_read() for these hooks.
-	</para>
-
-	</sect2>
-
-	<sect2><title>PIO data read/write</title>
-	<programlisting>
-void (*sff_data_xfer) (struct ata_device *, unsigned char *, unsigned int, int);
-	</programlisting>
-
-	<para>
-All bmdma-style drivers must implement this hook.  This is the low-level
-operation that actually copies the data bytes during a PIO data
-transfer.
-Typically the driver will choose one of ata_sff_data_xfer_noirq(),
-ata_sff_data_xfer(), or ata_sff_data_xfer32().
-	</para>
-
-	</sect2>
-
-	<sect2><title>ATA command execute</title>
-	<programlisting>
-void (*sff_exec_command)(struct ata_port *ap, struct ata_taskfile *tf);
-	</programlisting>
-
-	<para>
-	causes an ATA command, previously loaded with
-	->tf_load(), to be initiated in hardware.
-	Most drivers for taskfile-based hardware use ata_sff_exec_command()
-	for this hook.
-	</para>
-
-	</sect2>
-
-	<sect2><title>Per-cmd ATAPI DMA capabilities filter</title>
-	<programlisting>
-int (*check_atapi_dma) (struct ata_queued_cmd *qc);
-	</programlisting>
-
-	<para>
-Allow low-level driver to filter ATA PACKET commands, returning a status
-indicating whether or not it is OK to use DMA for the supplied PACKET
-command.
-	</para>
-	<para>
-	This hook may be specified as NULL, in which case libata will
-	assume that atapi dma can be supported.
-	</para>
-
-	</sect2>
-
-	<sect2><title>Read specific ATA shadow registers</title>
-	<programlisting>
-u8   (*sff_check_status)(struct ata_port *ap);
-u8   (*sff_check_altstatus)(struct ata_port *ap);
-	</programlisting>
-
-	<para>
-	Reads the Status/AltStatus ATA shadow register from
-	hardware.  On some hardware, reading the Status register has
-	the side effect of clearing the interrupt condition.
-	Most drivers for taskfile-based hardware use
-	ata_sff_check_status() for this hook.
-	</para>
-
-	</sect2>
-
-	<sect2><title>Write specific ATA shadow register</title>
-	<programlisting>
-void (*sff_set_devctl)(struct ata_port *ap, u8 ctl);
-	</programlisting>
-
-	<para>
-	Write the device control ATA shadow register to the hardware.
-	Most drivers don't need to define this.
-	</para>
-
-	</sect2>
-
-	<sect2><title>Select ATA device on bus</title>
-	<programlisting>
-void (*sff_dev_select)(struct ata_port *ap, unsigned int device);
-	</programlisting>
-
-	<para>
-	Issues the low-level hardware command(s) that causes one of N
-	hardware devices to be considered 'selected' (active and
-	available for use) on the ATA bus.  This generally has no
-	meaning on FIS-based devices.
-	</para>
-	<para>
-	Most drivers for taskfile-based hardware use
-	ata_sff_dev_select() for this hook.
-	</para>
-
-	</sect2>
-
-	<sect2><title>Private tuning method</title>
-	<programlisting>
-void (*set_mode) (struct ata_port *ap);
-	</programlisting>
-
-	<para>
-	By default libata performs drive and controller tuning in
-	accordance with the ATA timing rules and also applies blacklists
-	and cable limits. Some controllers need special handling and have
-	custom tuning rules, typically raid controllers that use ATA
-	commands but do not actually do drive timing.
-	</para>
-
-	<warning>
-	<para>
-	This hook should not be used to replace the standard controller
-	tuning logic when a controller has quirks. Replacing the default
-	tuning logic in that case would bypass handling for drive and
-	bridge quirks that may be important to data reliability. If a
-	controller needs to filter the mode selection it should use the
-	mode_filter hook instead.
-	</para>
-	</warning>
-
-	</sect2>
-
-	<sect2><title>Control PCI IDE BMDMA engine</title>
-	<programlisting>
-void (*bmdma_setup) (struct ata_queued_cmd *qc);
-void (*bmdma_start) (struct ata_queued_cmd *qc);
-void (*bmdma_stop) (struct ata_port *ap);
-u8   (*bmdma_status) (struct ata_port *ap);
-	</programlisting>
-
-	<para>
-When setting up an IDE BMDMA transaction, these hooks arm
-(->bmdma_setup), fire (->bmdma_start), and halt (->bmdma_stop)
-the hardware's DMA engine.  ->bmdma_status is used to read the standard
-PCI IDE DMA Status register.
-	</para>
-
-	<para>
-These hooks are typically either no-ops, or simply not implemented, in
-FIS-based drivers.
-	</para>
-	<para>
-Most legacy IDE drivers use ata_bmdma_setup() for the bmdma_setup()
-hook.  ata_bmdma_setup() will write the pointer to the PRD table to
-the IDE PRD Table Address register, enable DMA in the DMA Command
-register, and call exec_command() to begin the transfer.
-	</para>
-	<para>
-Most legacy IDE drivers use ata_bmdma_start() for the bmdma_start()
-hook.  ata_bmdma_start() will write the ATA_DMA_START flag to the DMA
-Command register.
-	</para>
-	<para>
-Many legacy IDE drivers use ata_bmdma_stop() for the bmdma_stop()
-hook.  ata_bmdma_stop() clears the ATA_DMA_START flag in the DMA
-command register.
-	</para>
-	<para>
-Many legacy IDE drivers use ata_bmdma_status() as the bmdma_status() hook.
-	</para>
-
-	</sect2>
-
-	<sect2><title>High-level taskfile hooks</title>
-	<programlisting>
-void (*qc_prep) (struct ata_queued_cmd *qc);
-int (*qc_issue) (struct ata_queued_cmd *qc);
-	</programlisting>
-
-	<para>
-	Higher-level hooks, these two hooks can potentially supercede
-	several of the above taskfile/DMA engine hooks.  ->qc_prep is
-	called after the buffers have been DMA-mapped, and is typically
-	used to populate the hardware's DMA scatter-gather table.
-	Most drivers use the standard ata_qc_prep() helper function, but
-	more advanced drivers roll their own.
-	</para>
-	<para>
-	->qc_issue is used to make a command active, once the hardware
-	and S/G tables have been prepared.  IDE BMDMA drivers use the
-	helper function ata_qc_issue_prot() for taskfile protocol-based
-	dispatch.  More advanced drivers implement their own ->qc_issue.
-	</para>
-	<para>
-	ata_qc_issue_prot() calls ->tf_load(), ->bmdma_setup(), and
-	->bmdma_start() as necessary to initiate a transfer.
-	</para>
-
-	</sect2>
-
-	<sect2><title>Exception and probe handling (EH)</title>
-	<programlisting>
-void (*eng_timeout) (struct ata_port *ap);
-void (*phy_reset) (struct ata_port *ap);
-	</programlisting>
-
-	<para>
-Deprecated.  Use ->error_handler() instead.
-	</para>
-
-	<programlisting>
-void (*freeze) (struct ata_port *ap);
-void (*thaw) (struct ata_port *ap);
-	</programlisting>
-
-	<para>
-ata_port_freeze() is called when HSM violations or some other
-condition disrupts normal operation of the port.  A frozen port
-is not allowed to perform any operation until the port is
-thawed, which usually follows a successful reset.
-	</para>
-
-	<para>
-The optional ->freeze() callback can be used for freezing the port
-hardware-wise (e.g. mask interrupt and stop DMA engine).  If a
-port cannot be frozen hardware-wise, the interrupt handler
-must ack and clear interrupts unconditionally while the port
-is frozen.
-	</para>
-	<para>
-The optional ->thaw() callback is called to perform the opposite of ->freeze():
-prepare the port for normal operation once again.  Unmask interrupts,
-start DMA engine, etc.
-	</para>
-
-	<programlisting>
-void (*error_handler) (struct ata_port *ap);
-	</programlisting>
-
-	<para>
-->error_handler() is a driver's hook into probe, hotplug, and recovery
-and other exceptional conditions.  The primary responsibility of an
-implementation is to call ata_do_eh() or ata_bmdma_drive_eh() with a set
-of EH hooks as arguments:
-	</para>
-
-	<para>
-'prereset' hook (may be NULL) is called during an EH reset, before any other actions
-are taken.
-	</para>
-
-	<para>
-'postreset' hook (may be NULL) is called after the EH reset is performed.  Based on
-existing conditions, severity of the problem, and hardware capabilities,
-	</para>
-
-	<para>
-Either 'softreset' (may be NULL) or 'hardreset' (may be NULL) will be
-called to perform the low-level EH reset.
-	</para>
-
-	<programlisting>
-void (*post_internal_cmd) (struct ata_queued_cmd *qc);
-	</programlisting>
-
-	<para>
-Perform any hardware-specific actions necessary to finish processing
-after executing a probe-time or EH-time command via ata_exec_internal().
-	</para>
-
-	</sect2>
-
-	<sect2><title>Hardware interrupt handling</title>
-	<programlisting>
-irqreturn_t (*irq_handler)(int, void *, struct pt_regs *);
-void (*irq_clear) (struct ata_port *);
-	</programlisting>
-
-	<para>
-	->irq_handler is the interrupt handling routine registered with
-	the system, by libata.  ->irq_clear is called during probe just
-	before the interrupt handler is registered, to be sure hardware
-	is quiet.
-	</para>
-	<para>
-	The second argument, dev_instance, should be cast to a pointer
-	to struct ata_host_set.
-	</para>
-	<para>
-	Most legacy IDE drivers use ata_sff_interrupt() for the
-	irq_handler hook, which scans all ports in the host_set,
-	determines which queued command was active (if any), and calls
-	ata_sff_host_intr(ap,qc).
-	</para>
-	<para>
-	Most legacy IDE drivers use ata_sff_irq_clear() for the
-	irq_clear() hook, which simply clears the interrupt and error
-	flags in the DMA status register.
-	</para>
-
-	</sect2>
-
-	<sect2><title>SATA phy read/write</title>
-	<programlisting>
-int (*scr_read) (struct ata_port *ap, unsigned int sc_reg,
-		 u32 *val);
-int (*scr_write) (struct ata_port *ap, unsigned int sc_reg,
-                   u32 val);
-	</programlisting>
-
-	<para>
-	Read and write standard SATA phy registers.  Currently only used
-	if ->phy_reset hook called the sata_phy_reset() helper function.
-	sc_reg is one of SCR_STATUS, SCR_CONTROL, SCR_ERROR, or SCR_ACTIVE.
-	</para>
-
-	</sect2>
-
-	<sect2><title>Init and shutdown</title>
-	<programlisting>
-int (*port_start) (struct ata_port *ap);
-void (*port_stop) (struct ata_port *ap);
-void (*host_stop) (struct ata_host_set *host_set);
-	</programlisting>
-
-	<para>
-	->port_start() is called just after the data structures for each
-	port are initialized.  Typically this is used to alloc per-port
-	DMA buffers / tables / rings, enable DMA engines, and similar
-	tasks.  Some drivers also use this entry point as a chance to
-	allocate driver-private memory for ap->private_data.
-	</para>
-	<para>
-	Many drivers use ata_port_start() as this hook or call
-	it from their own port_start() hooks.  ata_port_start()
-	allocates space for a legacy IDE PRD table and returns.
-	</para>
-	<para>
-	->port_stop() is called after ->host_stop().  Its sole function
-	is to release DMA/memory resources, now that they are no longer
-	actively being used.  Many drivers also free driver-private
-	data from port at this time.
-	</para>
-	<para>
-	->host_stop() is called after all ->port_stop() calls
-have completed.  The hook must finalize hardware shutdown, release DMA
-and other resources, etc.
-	This hook may be specified as NULL, in which case it is not called.
-	</para>
-
-	</sect2>
-
-     </sect1>
-  </chapter>
-
-  <chapter id="libataEH">
-        <title>Error handling</title>
-
-	<para>
-	This chapter describes how errors are handled under libata.
-	Readers are advised to read SCSI EH
-	(Documentation/scsi/scsi_eh.txt) and ATA exceptions doc first.
-	</para>
-
-	<sect1><title>Origins of commands</title>
-	<para>
-	In libata, a command is represented with struct ata_queued_cmd
-	or qc.  qc's are preallocated during port initialization and
-	repetitively used for command executions.  Currently only one
-	qc is allocated per port but yet-to-be-merged NCQ branch
-	allocates one for each tag and maps each qc to NCQ tag 1-to-1.
-	</para>
-	<para>
-	libata commands can originate from two sources - libata itself
-	and SCSI midlayer.  libata internal commands are used for
-	initialization and error handling.  All normal blk requests
-	and commands for SCSI emulation are passed as SCSI commands
-	through queuecommand callback of SCSI host template.
-	</para>
-	</sect1>
-
-	<sect1><title>How commands are issued</title>
-
-	<variablelist>
-
-	<varlistentry><term>Internal commands</term>
-	<listitem>
-	<para>
-	First, qc is allocated and initialized using
-	ata_qc_new_init().  Although ata_qc_new_init() doesn't
-	implement any wait or retry mechanism when qc is not
-	available, internal commands are currently issued only during
-	initialization and error recovery, so no other command is
-	active and allocation is guaranteed to succeed.
-	</para>
-	<para>
-	Once allocated qc's taskfile is initialized for the command to
-	be executed.  qc currently has two mechanisms to notify
-	completion.  One is via qc->complete_fn() callback and the
-	other is completion qc->waiting.  qc->complete_fn() callback
-	is the asynchronous path used by normal SCSI translated
-	commands and qc->waiting is the synchronous (issuer sleeps in
-	process context) path used by internal commands.
-	</para>
-	<para>
-	Once initialization is complete, host_set lock is acquired
-	and the qc is issued.
-	</para>
-	</listitem>
-	</varlistentry>
-
-	<varlistentry><term>SCSI commands</term>
-	<listitem>
-	<para>
-	All libata drivers use ata_scsi_queuecmd() as
-	hostt->queuecommand callback.  scmds can either be simulated
-	or translated.  No qc is involved in processing a simulated
-	scmd.  The result is computed right away and the scmd is
-	completed.
-	</para>
-	<para>
-	For a translated scmd, ata_qc_new_init() is invoked to
-	allocate a qc and the scmd is translated into the qc.  SCSI
-	midlayer's completion notification function pointer is stored
-	into qc->scsidone.
-	</para>
-	<para>
-	qc->complete_fn() callback is used for completion
-	notification.  ATA commands use ata_scsi_qc_complete() while
-	ATAPI commands use atapi_qc_complete().  Both functions end up
-	calling qc->scsidone to notify upper layer when the qc is
-	finished.  After translation is completed, the qc is issued
-	with ata_qc_issue().
-	</para>
-	<para>
-	Note that SCSI midlayer invokes hostt->queuecommand while
-	holding host_set lock, so all above occur while holding
-	host_set lock.
-	</para>
-	</listitem>
-	</varlistentry>
-
-	</variablelist>
-	</sect1>
-
-	<sect1><title>How commands are processed</title>
-	<para>
-	Depending on which protocol and which controller are used,
-	commands are processed differently.  For the purpose of
-	discussion, a controller which uses taskfile interface and all
-	standard callbacks is assumed.
-	</para>
-	<para>
-	Currently 6 ATA command protocols are used.  They can be
-	sorted into the following four categories according to how
-	they are processed.
-	</para>
-
-	<variablelist>
-	   <varlistentry><term>ATA NO DATA or DMA</term>
-	   <listitem>
-	   <para>
-	   ATA_PROT_NODATA and ATA_PROT_DMA fall into this category.
-	   These types of commands don't require any software
-	   intervention once issued.  Device will raise interrupt on
-	   completion.
-	   </para>
-	   </listitem>
-	   </varlistentry>
-
-	   <varlistentry><term>ATA PIO</term>
-	   <listitem>
-	   <para>
-	   ATA_PROT_PIO is in this category.  libata currently
-	   implements PIO with polling.  ATA_NIEN bit is set to turn
-	   off interrupt and pio_task on ata_wq performs polling and
-	   IO.
-	   </para>
-	   </listitem>
-	   </varlistentry>
-
-	   <varlistentry><term>ATAPI NODATA or DMA</term>
-	   <listitem>
-	   <para>
-	   ATA_PROT_ATAPI_NODATA and ATA_PROT_ATAPI_DMA are in this
-	   category.  packet_task is used to poll BSY bit after
-	   issuing PACKET command.  Once BSY is turned off by the
-	   device, packet_task transfers CDB and hands off processing
-	   to interrupt handler.
-	   </para>
-	   </listitem>
-	   </varlistentry>
-
-	   <varlistentry><term>ATAPI PIO</term>
-	   <listitem>
-	   <para>
-	   ATA_PROT_ATAPI is in this category.  ATA_NIEN bit is set
-	   and, as in ATAPI NODATA or DMA, packet_task submits cdb.
-	   However, after submitting cdb, further processing (data
-	   transfer) is handed off to pio_task.
-	   </para>
-	   </listitem>
-	   </varlistentry>
-	</variablelist>
-        </sect1>
-
-	<sect1><title>How commands are completed</title>
-	<para>
-	Once issued, all qc's are either completed with
-	ata_qc_complete() or time out.  For commands which are handled
-	by interrupts, ata_host_intr() invokes ata_qc_complete(), and,
-	for PIO tasks, pio_task invokes ata_qc_complete().  In error
-	cases, packet_task may also complete commands.
-	</para>
-	<para>
-	ata_qc_complete() does the following.
-	</para>
-
-	<orderedlist>
-
-	<listitem>
-	<para>
-	DMA memory is unmapped.
-	</para>
-	</listitem>
-
-	<listitem>
-	<para>
-	ATA_QCFLAG_ACTIVE is cleared from qc->flags.
-	</para>
-	</listitem>
-
-	<listitem>
-	<para>
-	qc->complete_fn() callback is invoked.  If the return value of
-	the callback is not zero.  Completion is short circuited and
-	ata_qc_complete() returns.
-	</para>
-	</listitem>
-
-	<listitem>
-	<para>
-	__ata_qc_complete() is called, which does
-	   <orderedlist>
-
-	   <listitem>
-	   <para>
-	   qc->flags is cleared to zero.
-	   </para>
-	   </listitem>
-
-	   <listitem>
-	   <para>
-	   ap->active_tag and qc->tag are poisoned.
-	   </para>
-	   </listitem>
-
-	   <listitem>
-	   <para>
-	   qc->waiting is cleared &amp; completed (in that order).
-	   </para>
-	   </listitem>
-
-	   <listitem>
-	   <para>
-	   qc is deallocated by clearing appropriate bit in ap->qactive.
-	   </para>
-	   </listitem>
-
-	   </orderedlist>
-	</para>
-	</listitem>
-
-	</orderedlist>
-
-	<para>
-	So, it basically notifies upper layer and deallocates qc.  One
-	exception is short-circuit path in #3 which is used by
-	atapi_qc_complete().
-	</para>
-	<para>
-	For all non-ATAPI commands, whether it fails or not, almost
-	the same code path is taken and very little error handling
-	takes place.  A qc is completed with success status if it
-	succeeded, with failed status otherwise.
-	</para>
-	<para>
-	However, failed ATAPI commands require more handling as
-	REQUEST SENSE is needed to acquire sense data.  If an ATAPI
-	command fails, ata_qc_complete() is invoked with error status,
-	which in turn invokes atapi_qc_complete() via
-	qc->complete_fn() callback.
-	</para>
-	<para>
-	This makes atapi_qc_complete() set scmd->result to
-	SAM_STAT_CHECK_CONDITION, complete the scmd and return 1.  As
-	the sense data is empty but scmd->result is CHECK CONDITION,
-	SCSI midlayer will invoke EH for the scmd, and returning 1
-	makes ata_qc_complete() to return without deallocating the qc.
-	This leads us to ata_scsi_error() with partially completed qc.
-	</para>
-
-	</sect1>
-
-	<sect1><title>ata_scsi_error()</title>
-	<para>
-	ata_scsi_error() is the current transportt->eh_strategy_handler()
-	for libata.  As discussed above, this will be entered in two
-	cases - timeout and ATAPI error completion.  This function
-	calls low level libata driver's eng_timeout() callback, the
-	standard callback for which is ata_eng_timeout().  It checks
-	if a qc is active and calls ata_qc_timeout() on the qc if so.
-	Actual error handling occurs in ata_qc_timeout().
-	</para>
-	<para>
-	If EH is invoked for timeout, ata_qc_timeout() stops BMDMA and
-	completes the qc.  Note that as we're currently in EH, we
-	cannot call scsi_done.  As described in SCSI EH doc, a
-	recovered scmd should be either retried with
-	scsi_queue_insert() or finished with scsi_finish_command().
-	Here, we override qc->scsidone with scsi_finish_command() and
-	calls ata_qc_complete().
-	</para>
-	<para>
-	If EH is invoked due to a failed ATAPI qc, the qc here is
-	completed but not deallocated.  The purpose of this
-	half-completion is to use the qc as place holder to make EH
-	code reach this place.  This is a bit hackish, but it works.
-	</para>
-	<para>
-	Once control reaches here, the qc is deallocated by invoking
-	__ata_qc_complete() explicitly.  Then, internal qc for REQUEST
-	SENSE is issued.  Once sense data is acquired, scmd is
-	finished by directly invoking scsi_finish_command() on the
-	scmd.  Note that as we already have completed and deallocated
-	the qc which was associated with the scmd, we don't need
-	to/cannot call ata_qc_complete() again.
-	</para>
-
-	</sect1>
-
-	<sect1><title>Problems with the current EH</title>
-
-	<itemizedlist>
-
-	<listitem>
-	<para>
-	Error representation is too crude.  Currently any and all
-	error conditions are represented with ATA STATUS and ERROR
-	registers.  Errors which aren't ATA device errors are treated
-	as ATA device errors by setting ATA_ERR bit.  Better error
-	descriptor which can properly represent ATA and other
-	errors/exceptions is needed.
-	</para>
-	</listitem>
-
-	<listitem>
-	<para>
-	When handling timeouts, no action is taken to make device
-	forget about the timed out command and ready for new commands.
-	</para>
-	</listitem>
-
-	<listitem>
-	<para>
-	EH handling via ata_scsi_error() is not properly protected
-	from usual command processing.  On EH entrance, the device is
-	not in quiescent state.  Timed out commands may succeed or
-	fail any time.  pio_task and atapi_task may still be running.
-	</para>
-	</listitem>
-
-	<listitem>
-	<para>
-	Too weak error recovery.  Devices / controllers causing HSM
-	mismatch errors and other errors quite often require reset to
-	return to known state.  Also, advanced error handling is
-	necessary to support features like NCQ and hotplug.
-	</para>
-	</listitem>
-
-	<listitem>
-	<para>
-	ATA errors are directly handled in the interrupt handler and
-	PIO errors in pio_task.  This is problematic for advanced
-	error handling for the following reasons.
-	</para>
-	<para>
-	First, advanced error handling often requires context and
-	internal qc execution.
-	</para>
-	<para>
-	Second, even a simple failure (say, CRC error) needs
-	information gathering and could trigger complex error handling
-	(say, resetting &amp; reconfiguring).  Having multiple code
-	paths to gather information, enter EH and trigger actions
-	makes life painful.
-	</para>
-	<para>
-	Third, scattered EH code makes implementing low level drivers
-	difficult.  Low level drivers override libata callbacks.  If
-	EH is scattered over several places, each affected callbacks
-	should perform its part of error handling.  This can be error
-	prone and painful.
-	</para>
-	</listitem>
-
-	</itemizedlist>
-	</sect1>
-  </chapter>
-
-  <chapter id="libataExt">
-     <title>libata Library</title>
-!Edrivers/ata/libata-core.c
-  </chapter>
-
-  <chapter id="libataInt">
-     <title>libata Core Internals</title>
-!Idrivers/ata/libata-core.c
-  </chapter>
-
-  <chapter id="libataScsiInt">
-     <title>libata SCSI translation/emulation</title>
-!Edrivers/ata/libata-scsi.c
-!Idrivers/ata/libata-scsi.c
-  </chapter>
-
-  <chapter id="ataExceptions">
-     <title>ATA errors and exceptions</title>
-
-  <para>
-  This chapter tries to identify what error/exception conditions exist
-  for ATA/ATAPI devices and describe how they should be handled in
-  implementation-neutral way.
-  </para>
-
-  <para>
-  The term 'error' is used to describe conditions where either an
-  explicit error condition is reported from device or a command has
-  timed out.
-  </para>
-
-  <para>
-  The term 'exception' is either used to describe exceptional
-  conditions which are not errors (say, power or hotplug events), or
-  to describe both errors and non-error exceptional conditions.  Where
-  explicit distinction between error and exception is necessary, the
-  term 'non-error exception' is used.
-  </para>
-
-  <sect1 id="excat">
-     <title>Exception categories</title>
-     <para>
-     Exceptions are described primarily with respect to legacy
-     taskfile + bus master IDE interface.  If a controller provides
-     other better mechanism for error reporting, mapping those into
-     categories described below shouldn't be difficult.
-     </para>
-
-     <para>
-     In the following sections, two recovery actions - reset and
-     reconfiguring transport - are mentioned.  These are described
-     further in <xref linkend="exrec"/>.
-     </para>
-
-     <sect2 id="excatHSMviolation">
-        <title>HSM violation</title>
-        <para>
-        This error is indicated when STATUS value doesn't match HSM
-        requirement during issuing or execution any ATA/ATAPI command.
-        </para>
-
-	<itemizedlist>
-	<title>Examples</title>
-
-        <listitem>
-	<para>
-	ATA_STATUS doesn't contain !BSY &amp;&amp; DRDY &amp;&amp; !DRQ while trying
-	to issue a command.
-        </para>
-	</listitem>
-
-        <listitem>
-	<para>
-	!BSY &amp;&amp; !DRQ during PIO data transfer.
-        </para>
-	</listitem>
-
-        <listitem>
-	<para>
-	DRQ on command completion.
-        </para>
-	</listitem>
-
-        <listitem>
-	<para>
-	!BSY &amp;&amp; ERR after CDB transfer starts but before the
-        last byte of CDB is transferred.  ATA/ATAPI standard states
-        that &quot;The device shall not terminate the PACKET command
-        with an error before the last byte of the command packet has
-        been written&quot; in the error outputs description of PACKET
-        command and the state diagram doesn't include such
-        transitions.
-	</para>
-	</listitem>
-
-	</itemizedlist>
-
-	<para>
-	In these cases, HSM is violated and not much information
-	regarding the error can be acquired from STATUS or ERROR
-	register.  IOW, this error can be anything - driver bug,
-	faulty device, controller and/or cable.
-	</para>
-
-	<para>
-	As HSM is violated, reset is necessary to restore known state.
-	Reconfiguring transport for lower speed might be helpful too
-	as transmission errors sometimes cause this kind of errors.
-	</para>
-     </sect2>
-     
-     <sect2 id="excatDevErr">
-        <title>ATA/ATAPI device error (non-NCQ / non-CHECK CONDITION)</titl