forked from Minki/linux
libata: more doc updates
Document recently-added ata_port_operations hooks. Fill several doc stubs in libata-core.c.
This commit is contained in:
Jeff Garzik
parent
07dd39b9f6
commit
780a87f718
@ -14,7 +14,7 @@
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</authorgroup>
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<copyright>
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<year>2003</year>
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<year>2003-2005</year>
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<holder>Jeff Garzik</holder>
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</copyright>
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@ -145,14 +145,25 @@ void (*exec_command)(struct ata_port *ap, struct ata_taskfile *tf);
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</para>
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<programlisting>
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u8 (*check_status)(struct ata_port *ap);
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void (*dev_select)(struct ata_port *ap, unsigned int device);
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int (*check_atapi_dma) (struct ata_queued_cmd *qc);
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</programlisting>
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<para>
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Reads the Status ATA shadow register from hardware. On some
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hardware, this has the side effect of clearing the interrupt
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condition.
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Allow low-level driver to filter ATA PACKET commands, returning a status
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indicating whether or not it is OK to use DMA for the supplied PACKET
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command.
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</para>
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<programlisting>
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u8 (*check_status)(struct ata_port *ap);
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u8 (*check_altstatus)(struct ata_port *ap);
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u8 (*check_err)(struct ata_port *ap);
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</programlisting>
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<para>
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Reads the Status/AltStatus/Error ATA shadow register from
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hardware. On some hardware, reading the Status register has
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the side effect of clearing the interrupt condition.
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</para>
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<programlisting>
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@ -162,7 +173,8 @@ void (*dev_select)(struct ata_port *ap, unsigned int device);
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<para>
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Issues the low-level hardware command(s) that causes one of N
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hardware devices to be considered 'selected' (active and
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available for use) on the ATA bus.
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available for use) on the ATA bus. This generally has no
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meaning on FIS-based devices.
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</para>
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<programlisting>
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@ -180,12 +192,20 @@ void (*phy_reset) (struct ata_port *ap);
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<programlisting>
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void (*bmdma_setup) (struct ata_queued_cmd *qc);
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void (*bmdma_start) (struct ata_queued_cmd *qc);
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void (*bmdma_stop) (struct ata_port *ap);
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u8 (*bmdma_status) (struct ata_port *ap);
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</programlisting>
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<para>
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When setting up an IDE BMDMA transaction, these hooks arm
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(->bmdma_setup) and fire (->bmdma_start) the hardware's DMA
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engine.
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When setting up an IDE BMDMA transaction, these hooks arm
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(->bmdma_setup), fire (->bmdma_start), and halt (->bmdma_stop)
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the hardware's DMA engine. ->bmdma_status is used to read the standard
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PCI IDE DMA Status register.
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</para>
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<para>
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These hooks are typically either no-ops, or simply not implemented, in
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FIS-based drivers.
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</para>
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<programlisting>
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@ -205,9 +225,7 @@ int (*qc_issue) (struct ata_queued_cmd *qc);
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->qc_issue is used to make a command active, once the hardware
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and S/G tables have been prepared. IDE BMDMA drivers use the
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helper function ata_qc_issue_prot() for taskfile protocol-based
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dispatch. More advanced drivers roll their own ->qc_issue
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implementation, using this as the "issue new ATA command to
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hardware" hook.
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dispatch. More advanced drivers implement their own ->qc_issue.
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</para>
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<programlisting>
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@ -215,8 +233,10 @@ void (*eng_timeout) (struct ata_port *ap);
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</programlisting>
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<para>
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This is a high level error handling function, called from the
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error handling thread, when a command times out.
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This is a high level error handling function, called from the
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error handling thread, when a command times out. Most newer
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hardware will implement its own error handling code here. IDE BMDMA
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drivers may use the helper function ata_eng_timeout().
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</para>
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<programlisting>
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@ -255,15 +275,15 @@ void (*host_stop) (struct ata_host_set *host_set);
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tasks.
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</para>
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<para>
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->host_stop() is called when the rmmod or hot unplug process
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begins. The hook must stop all hardware interrupts, DMA
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engines, etc.
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</para>
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<para>
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->port_stop() is called after ->host_stop(). It's sole function
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is to release DMA/memory resources, now that they are no longer
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actively being used.
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</para>
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<para>
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->host_stop() is called after all ->port_stop() calls
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have completed. The hook must finalize hardware shutdown, release DMA
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and other resources, etc.
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</para>
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</sect1>
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</chapter>
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@ -1241,10 +1241,14 @@ void ata_port_probe(struct ata_port *ap)
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}
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/**
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* __sata_phy_reset -
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* @ap:
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* __sata_phy_reset - Wake/reset a low-level SATA PHY
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* @ap: SATA port associated with target SATA PHY.
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*
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* LOCKING:
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* This function issues commands to standard SATA Sxxx
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* PHY registers, to wake up the phy (and device), and
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* clear any reset condition.
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*
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* LOCKING: None. Serialized during ata_bus_probe().
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*
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*/
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void __sata_phy_reset(struct ata_port *ap)
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@ -1289,10 +1293,13 @@ void __sata_phy_reset(struct ata_port *ap)
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}
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/**
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* __sata_phy_reset -
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* @ap:
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* sata_phy_reset - Reset SATA bus.
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* @ap: SATA port associated with target SATA PHY.
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*
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* LOCKING:
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* This function resets the SATA bus, and then probes
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* the bus for devices.
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*
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* LOCKING: None. Serialized during ata_bus_probe().
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*
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*/
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void sata_phy_reset(struct ata_port *ap)
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@ -1304,10 +1311,16 @@ void sata_phy_reset(struct ata_port *ap)
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}
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/**
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* ata_port_disable -
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* @ap:
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* ata_port_disable - Disable port.
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* @ap: Port to be disabled.
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*
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* LOCKING:
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* Modify @ap data structure such that the system
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* thinks that the entire port is disabled, and should
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* never attempt to probe or communicate with devices
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* on this port.
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*
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* LOCKING: host_set lock, or some other form of
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* serialization.
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*/
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void ata_port_disable(struct ata_port *ap)
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@ -1416,7 +1429,9 @@ static void ata_host_set_dma(struct ata_port *ap, u8 xfer_mode,
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* ata_set_mode - Program timings and issue SET FEATURES - XFER
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* @ap: port on which timings will be programmed
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*
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* LOCKING:
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* Set ATA device disk transfer mode (PIO3, UDMA6, etc.).
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*
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* LOCKING: None. Serialized during ata_bus_probe().
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*
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*/
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static void ata_set_mode(struct ata_port *ap)
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@ -1467,7 +1482,10 @@ err_out:
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* @tmout_pat: impatience timeout
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* @tmout: overall timeout
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*
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* LOCKING:
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* Sleep until ATA Status register bit BSY clears,
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* or a timeout occurs.
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*
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* LOCKING: None.
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*
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*/
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@ -1556,7 +1574,7 @@ static void ata_bus_post_reset(struct ata_port *ap, unsigned int devmask)
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* ata_bus_edd -
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* @ap:
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*
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* LOCKING:
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* LOCKING: None. Serialized during ata_bus_probe().
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*
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*/
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@ -1909,7 +1927,10 @@ static int ata_choose_xfer_mode(struct ata_port *ap,
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* @ap: Port associated with device @dev
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* @dev: Device to which command will be sent
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*
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* LOCKING:
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* Issue SET FEATURES - XFER MODE command to device @dev
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* on port @ap.
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*
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* LOCKING: None. Serialized during ata_bus_probe().
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*/
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static void ata_dev_set_xfermode(struct ata_port *ap, struct ata_device *dev)
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@ -1981,7 +2002,11 @@ static void ata_sg_clean(struct ata_queued_cmd *qc)
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* ata_fill_sg - Fill PCI IDE PRD table
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* @qc: Metadata associated with taskfile to be transferred
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*
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* Fill PCI IDE PRD (scatter-gather) table with segments
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* associated with the current disk command.
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*
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* LOCKING:
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* spin_lock_irqsave(host_set lock)
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*
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*/
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static void ata_fill_sg(struct ata_queued_cmd *qc)
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@ -2028,6 +2053,10 @@ static void ata_fill_sg(struct ata_queued_cmd *qc)
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* ata_check_atapi_dma - Check whether ATAPI DMA can be supported
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* @qc: Metadata associated with taskfile to check
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*
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* Allow low-level driver to filter ATA PACKET commands, returning
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* a status indicating whether or not it is OK to use DMA for the
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* supplied PACKET command.
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*
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* LOCKING:
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* RETURNS: 0 when ATAPI DMA can be used
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* nonzero otherwise
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@ -2046,6 +2075,8 @@ int ata_check_atapi_dma(struct ata_queued_cmd *qc)
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* ata_qc_prep - Prepare taskfile for submission
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* @qc: Metadata associated with taskfile to be prepared
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*
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* Prepare ATA taskfile for submission.
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*
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* LOCKING:
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* spin_lock_irqsave(host_set lock)
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*/
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