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Commit 780a87f7 authored by Jeff Garzik's avatar Jeff Garzik
Browse files

libata: more doc updates 

Document recently-added ata_port_operations hooks.

Fill several doc stubs in libata-core.c.
parent 07dd39b9

Documentation/DocBook/libata.tmpl

+39 −19
Original line number Diff line number Diff line
@@ -14,7 +14,7 @@ 
  </authorgroup>



  <copyright>

   <year>2003</year>

   <year>2003-2005</year>

   <holder>Jeff Garzik</holder>

  </copyright>
@@ -144,15 +144,26 @@ void (*exec_command)(struct ata_port *ap, struct ata_taskfile *tf); 
	->tf_load(), to be initiated in hardware.

	</para>



	<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>



	<programlisting>

u8   (*check_status)(struct ata_port *ap);

void (*dev_select)(struct ata_port *ap, unsigned int device);

u8   (*check_altstatus)(struct ata_port *ap);

u8   (*check_err)(struct ata_port *ap);

	</programlisting>



	<para>

	Reads the Status ATA shadow register from hardware.  On some

	hardware, this has the side effect of clearing the interrupt

	condition.

	Reads the Status/AltStatus/Error ATA shadow register from

	hardware.  On some hardware, reading the Status register has

	the side effect of clearing the interrupt condition.

	</para>



	<programlisting>
@@ -162,7 +173,8 @@ void (*dev_select)(struct ata_port *ap, unsigned int device); 
	<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.

	available for use) on the ATA bus.  This generally has no

meaning on FIS-based devices.

	</para>



	<programlisting>
@@ -180,12 +192,20 @@ void (*phy_reset) (struct ata_port *ap); 
	<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) and fire (->bmdma_start) the hardware's DMA

	engine.

(->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>



	<programlisting>
@@ -205,9 +225,7 @@ int (*qc_issue) (struct ata_queued_cmd *qc); 
	->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 roll their own ->qc_issue

	implementation, using this as the "issue new ATA command to

	hardware" hook.

	dispatch.  More advanced drivers implement their own ->qc_issue.

	</para>



	<programlisting>
@@ -216,7 +234,9 @@ void (*eng_timeout) (struct ata_port *ap); 


	<para>

This is a high level error handling function, called from the

	error handling thread, when a command times out.

error handling thread, when a command times out.  Most newer

hardware will implement its own error handling code here.  IDE BMDMA

drivers may use the helper function ata_eng_timeout().

	</para>



	<programlisting>
@@ -255,15 +275,15 @@ void (*host_stop) (struct ata_host_set *host_set); 
	tasks.  

	</para>

	<para>

	->host_stop() is called when the rmmod or hot unplug process

	begins.  The hook must stop all hardware interrupts, DMA

	engines, etc.

	</para>

	<para>

	->port_stop() is called after ->host_stop().  It's sole function

	is to release DMA/memory resources, now that they are no longer

	actively being used.

	</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.

	</para>



     </sect1>

  </chapter>

drivers/scsi/libata-core.c

+44 −13
Original line number Diff line number Diff line
@@ -1241,10 +1241,14 @@ void ata_port_probe(struct ata_port *ap) 
}



/**

 *	__sata_phy_reset -

 *	@ap:

 *	__sata_phy_reset - Wake/reset a low-level SATA PHY

 *	@ap: SATA port associated with target SATA PHY.

 *

 *	LOCKING:

 *	This function issues commands to standard SATA Sxxx

 *	PHY registers, to wake up the phy (and device), and

 *	clear any reset condition.

 *

 *	LOCKING: None.  Serialized during ata_bus_probe().

 *

 */

void __sata_phy_reset(struct ata_port *ap)
@@ -1289,10 +1293,13 @@ void __sata_phy_reset(struct ata_port *ap) 
}



/**

 *	__sata_phy_reset -

 *	@ap:

 *	sata_phy_reset - Reset SATA bus.

 *	@ap: SATA port associated with target SATA PHY.

 *

 *	LOCKING:

 *	This function resets the SATA bus, and then probes

 *	the bus for devices.

 *

 *	LOCKING: None.  Serialized during ata_bus_probe().

 *

 */

void sata_phy_reset(struct ata_port *ap)
@@ -1304,10 +1311,16 @@ void sata_phy_reset(struct ata_port *ap) 
}



/**

 *	ata_port_disable -

 *	@ap:

 *	ata_port_disable - Disable port.

 *	@ap: Port to be disabled.

 *

 *	LOCKING:

 *	Modify @ap data structure such that the system

 *	thinks that the entire port is disabled, and should

 *	never attempt to probe or communicate with devices

 *	on this port.

 *

 *	LOCKING: host_set lock, or some other form of

 *	serialization.

 */



void ata_port_disable(struct ata_port *ap)
@@ -1416,7 +1429,9 @@ static void ata_host_set_dma(struct ata_port *ap, u8 xfer_mode, 
 *	ata_set_mode - Program timings and issue SET FEATURES - XFER

 *	@ap: port on which timings will be programmed

 *

 *	LOCKING:

 *	Set ATA device disk transfer mode (PIO3, UDMA6, etc.).

 *

 *	LOCKING: None.  Serialized during ata_bus_probe().

 *

 */

static void ata_set_mode(struct ata_port *ap)
@@ -1467,7 +1482,10 @@ err_out: 
 *	@tmout_pat: impatience timeout

 *	@tmout: overall timeout

 *

 *	LOCKING:

 *	Sleep until ATA Status register bit BSY clears,

 *	or a timeout occurs.

 *

 *	LOCKING: None.

 *

 */
@@ -1556,7 +1574,7 @@ static void ata_bus_post_reset(struct ata_port *ap, unsigned int devmask) 
 *	ata_bus_edd -

 *	@ap:

 *

 *	LOCKING:

 *	LOCKING: None.  Serialized during ata_bus_probe().

 *

 */
@@ -1909,7 +1927,10 @@ static int ata_choose_xfer_mode(struct ata_port *ap, 
 *	@ap: Port associated with device @dev

 *	@dev: Device to which command will be sent

 *

 *	LOCKING:

 *	Issue SET FEATURES - XFER MODE command to device @dev

 *	on port @ap.

 *

 *	LOCKING: None.  Serialized during ata_bus_probe().

 */



static void ata_dev_set_xfermode(struct ata_port *ap, struct ata_device *dev)
@@ -1981,7 +2002,11 @@ static void ata_sg_clean(struct ata_queued_cmd *qc) 
 *	ata_fill_sg - Fill PCI IDE PRD table

 *	@qc: Metadata associated with taskfile to be transferred

 *

 *	Fill PCI IDE PRD (scatter-gather) table with segments

 *	associated with the current disk command.

 *

 *	LOCKING:

 *	spin_lock_irqsave(host_set lock)

 *

 */

static void ata_fill_sg(struct ata_queued_cmd *qc)
@@ -2028,6 +2053,10 @@ static void ata_fill_sg(struct ata_queued_cmd *qc) 
 *	ata_check_atapi_dma - Check whether ATAPI DMA can be supported

 *	@qc: Metadata associated with taskfile to check

 *

 *	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.

 *

 *	LOCKING:

 *	RETURNS: 0 when ATAPI DMA can be used

 *               nonzero otherwise
@@ -2046,6 +2075,8 @@ int ata_check_atapi_dma(struct ata_queued_cmd *qc) 
 *	ata_qc_prep - Prepare taskfile for submission

 *	@qc: Metadata associated with taskfile to be prepared

 *

 *	Prepare ATA taskfile for submission.

 *

 *	LOCKING:

 *	spin_lock_irqsave(host_set lock)

 */