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libata: more doc updates

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Document recently-added ata_port_operations hooks.

Fill several doc stubs in libata-core.c.
This commit is contained in:
Jeff Garzik 2005-05-30 15:41:05 -04:00
parent 07dd39b9f6
commit 780a87f718
2 changed files with 84 additions and 33 deletions
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60
Documentation/DocBook/libata.tmpl
View file

@ -14,7 +14,7 @@
</authorgroup>
<copyright>
<year>2003</year>
<year>2003-2005</year>
<holder>Jeff Garzik</holder>
</copyright>
@ -145,14 +145,25 @@ void (*exec_command)(struct ata_port *ap, struct ata_taskfile *tf);
</para>
<programlisting>
u8 (*check_status)(struct ata_port *ap);
void (*dev_select)(struct ata_port *ap, unsigned int device);
int (*check_atapi_dma) (struct ata_queued_cmd *qc);
</programlisting>
<para>
Reads the Status ATA shadow register from hardware. On some
hardware, this has the side effect of clearing the interrupt
condition.
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);
u8 (*check_altstatus)(struct ata_port *ap);
u8 (*check_err)(struct ata_port *ap);
</programlisting>
<para>
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.
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>
<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>
@ -215,8 +233,10 @@ void (*eng_timeout) (struct ata_port *ap);
</programlisting>
<para>
This is a high level error handling function, called from the
error handling thread, when a command times out.
This is a high level error handling function, called from the
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>

57
drivers/scsi/libata-core.c
View file

@ -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)
*/