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Commit 31760463 authored by Linus Torvalds's avatar Linus Torvalds
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Merge of 'docs' branch from 

	rsync://rsync.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev
parents 0fd56f67 d7aaf481
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Documentation/DocBook/libata.tmpl
View file @ 31760463
......@@ -14,7 +14,7 @@
</authorgroup>
<copyright>
<year>2003</year>
<year>2003-2005</year>
<holder>Jeff Garzik</holder>
</copyright>
......@@ -44,30 +44,38 @@
<toc></toc>
<chapter id="libataThanks">
<title>Thanks</title>
<chapter id="libataIntroduction">
<title>Introduction</title>
<para>
The bulk of the ATA knowledge comes thanks to long conversations with
Andre Hedrick (www.linux-ide.org).
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>
Thanks to Alan Cox for pointing out similarities
between SATA and SCSI, and in general for motivation to hack on
libata.
</para>
<para>
libata's device detection
method, ata_pio_devchk, and in general all the early probing was
based on extensive study of Hale Landis's probe/reset code in his
ATADRVR driver (www.ata-atapi.com).
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>
......@@ -78,6 +86,9 @@ void (*port_disable) (struct ata_port *);
unplug).
</para>
</sect2>
<sect2><title>Post-IDENTIFY device configuration</title>
<programlisting>
void (*dev_config) (struct ata_port *, struct ata_device *);
</programlisting>
......@@ -88,6 +99,9 @@ void (*dev_config) (struct ata_port *, struct ata_device *);
issue of SET FEATURES - XFER MODE, and prior to operation.
</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 *);
......@@ -108,6 +122,9 @@ void (*post_set_mode) (struct ata_port *ap);
->set_dma_mode() is only called if DMA is possible.
</para>
</sect2>
<sect2><title>Taskfile read/write</title>
<programlisting>
void (*tf_load) (struct ata_port *ap, struct ata_taskfile *tf);
void (*tf_read) (struct ata_port *ap, struct ata_taskfile *tf);
......@@ -120,6 +137,9 @@ void (*tf_read) (struct ata_port *ap, struct ata_taskfile *tf);
taskfile register values.
</para>
</sect2>
<sect2><title>ATA command execute</title>
<programlisting>
void (*exec_command)(struct ata_port *ap, struct ata_taskfile *tf);
</programlisting>
......@@ -129,17 +149,37 @@ void (*exec_command)(struct ata_port *ap, struct ata_taskfile *tf);
->tf_load(), to be initiated in hardware.
</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>
</sect2>
<sect2><title>Read specific ATA shadow registers</title>
<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>
</sect2>
<sect2><title>Select ATA device on bus</title>
<programlisting>
void (*dev_select)(struct ata_port *ap, unsigned int device);
</programlisting>
......@@ -147,9 +187,13 @@ 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>
</sect2>
<sect2><title>Reset ATA bus</title>
<programlisting>
void (*phy_reset) (struct ata_port *ap);
</programlisting>
......@@ -162,17 +206,31 @@ void (*phy_reset) (struct ata_port *ap);
functions ata_bus_reset() or sata_phy_reset() for this hook.
</para>
</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) 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>
</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);
......@@ -190,20 +248,26 @@ 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>
</sect2>
<sect2><title>Timeout (error) handling</title>
<programlisting>
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>
</sect2>
<sect2><title>Hardware interrupt handling</title>
<programlisting>
irqreturn_t (*irq_handler)(int, void *, struct pt_regs *);
void (*irq_clear) (struct ata_port *);
......@@ -216,6 +280,9 @@ void (*irq_clear) (struct ata_port *);
is quiet.
</para>
</sect2>
<sect2><title>SATA phy read/write</title>
<programlisting>
u32 (*scr_read) (struct ata_port *ap, unsigned int sc_reg);
void (*scr_write) (struct ata_port *ap, unsigned int sc_reg,
......@@ -227,6 +294,9 @@ void (*scr_write) (struct ata_port *ap, unsigned int sc_reg,
if ->phy_reset hook called the sata_phy_reset() helper function.
</para>
</sect2>
<sect2><title>Init and shutdown</title>
<programlisting>
int (*port_start) (struct ata_port *ap);
void (*port_stop) (struct ata_port *ap);
......@@ -240,15 +310,17 @@ 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>
</sect2>
</sect1>
</chapter>
......@@ -279,4 +351,24 @@ void (*host_stop) (struct ata_host_set *host_set);
!Idrivers/scsi/sata_sil.c
</chapter>
<chapter id="libataThanks">
<title>Thanks</title>
<para>
The bulk of the ATA knowledge comes thanks to long conversations with
Andre Hedrick (www.linux-ide.org), and long hours pondering the ATA
and SCSI specifications.
</para>
<para>
Thanks to Alan Cox for pointing out similarities
between SATA and SCSI, and in general for motivation to hack on
libata.
</para>
<para>
libata's device detection
method, ata_pio_devchk, and in general all the early probing was
based on extensive study of Hale Landis's probe/reset code in his
ATADRVR driver (www.ata-atapi.com).
</para>
</chapter>
</book>
drivers/scsi/ata_piix.c
View file @ 31760463
......@@ -665,15 +665,6 @@ static int piix_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
return ata_pci_init_one(pdev, port_info, n_ports);
}
/**
* piix_init -
*
* LOCKING:
*
* RETURNS:
*
*/
static int __init piix_init(void)
{
int rc;
......@@ -689,13 +680,6 @@ static int __init piix_init(void)
return 0;
}
/**
* piix_exit -
*
* LOCKING:
*
*/
static void __exit piix_exit(void)
{
pci_unregister_driver(&piix_pci_driver);
......
drivers/scsi/libata-core.c
View file @ 31760463
......@@ -186,6 +186,28 @@ static void ata_tf_load_mmio(struct ata_port *ap, struct ata_taskfile *tf)
ata_wait_idle(ap);
}
/**
* ata_tf_load - send taskfile registers to host controller
* @ap: Port to which output is sent
* @tf: ATA taskfile register set
*
* Outputs ATA taskfile to standard ATA host controller using MMIO
* or PIO as indicated by the ATA_FLAG_MMIO flag.
* Writes the control, feature, nsect, lbal, lbam, and lbah registers.
* Optionally (ATA_TFLAG_LBA48) writes hob_feature, hob_nsect,
* hob_lbal, hob_lbam, and hob_lbah.
*
* This function waits for idle (!BUSY and !DRQ) after writing
* registers. If the control register has a new value, this
* function also waits for idle after writing control and before
* writing the remaining registers.
*
* May be used as the tf_load() entry in ata_port_operations.
*
* LOCKING:
* Inherited from caller.
*/
void ata_tf_load(struct ata_port *ap, struct ata_taskfile *tf)
{
if (ap->flags & ATA_FLAG_MMIO)
......@@ -195,11 +217,11 @@ void ata_tf_load(struct ata_port *ap, struct ata_taskfile *tf)
}
/**
* ata_exec_command - issue ATA command to host controller
* ata_exec_command_pio - issue ATA command to host controller
* @ap: port to which command is being issued
* @tf: ATA taskfile register set
*
* Issues PIO/MMIO write to ATA command register, with proper
* Issues PIO write to ATA command register, with proper
* synchronization with interrupt handler / other threads.
*
* LOCKING:
......@@ -235,6 +257,18 @@ static void ata_exec_command_mmio(struct ata_port *ap, struct ata_taskfile *tf)
ata_pause(ap);
}
/**
* ata_exec_command - issue ATA command to host controller
* @ap: port to which command is being issued
* @tf: ATA taskfile register set
*
* Issues PIO/MMIO write to ATA command register, with proper
* synchronization with interrupt handler / other threads.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
void ata_exec_command(struct ata_port *ap, struct ata_taskfile *tf)
{
if (ap->flags & ATA_FLAG_MMIO)
......@@ -305,7 +339,7 @@ void ata_tf_to_host_nolock(struct ata_port *ap, struct ata_taskfile *tf)
}
/**
* ata_tf_read - input device's ATA taskfile shadow registers
* ata_tf_read_pio - input device's ATA taskfile shadow registers
* @ap: Port from which input is read
* @tf: ATA taskfile register set for storing input
*
......@@ -368,6 +402,23 @@ static void ata_tf_read_mmio(struct ata_port *ap, struct ata_taskfile *tf)
}
}
/**
* ata_tf_read - input device's ATA taskfile shadow registers
* @ap: Port from which input is read
* @tf: ATA taskfile register set for storing input
*
* Reads ATA taskfile registers for currently-selected device
* into @tf.
*
* Reads nsect, lbal, lbam, lbah, and device. If ATA_TFLAG_LBA48
* is set, also reads the hob registers.
*
* May be used as the tf_read() entry in ata_port_operations.
*
* LOCKING:
* Inherited from caller.
*/
void ata_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
{
if (ap->flags & ATA_FLAG_MMIO)
......@@ -381,7 +432,7 @@ void ata_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
* @ap: port where the device is
*
* Reads ATA taskfile status register for currently-selected device
* and return it's value. This also clears pending interrupts
* and return its value. This also clears pending interrupts
* from this device
*
* LOCKING:
......@@ -397,7 +448,7 @@ static u8 ata_check_status_pio(struct ata_port *ap)
* @ap: port where the device is
*
* Reads ATA taskfile status register for currently-selected device
* via MMIO and return it's value. This also clears pending interrupts
* via MMIO and return its value. This also clears pending interrupts
* from this device
*
* LOCKING:
......@@ -408,6 +459,20 @@ static u8 ata_check_status_mmio(struct ata_port *ap)
return readb((void __iomem *) ap->ioaddr.status_addr);
}
/**
* ata_check_status - Read device status reg & clear interrupt
* @ap: port where the device is
*
* Reads ATA taskfile status register for currently-selected device
* and return its value. This also clears pending interrupts
* from this device
*
* May be used as the check_status() entry in ata_port_operations.
*
* LOCKING:
* Inherited from caller.
*/
u8 ata_check_status(struct ata_port *ap)
{
if (ap->flags & ATA_FLAG_MMIO)
......@@ -415,6 +480,20 @@ u8 ata_check_status(struct ata_port *ap)
return ata_check_status_pio(ap);
}
/**
* ata_altstatus - Read device alternate status reg
* @ap: port where the device is
*
* Reads ATA taskfile alternate status register for
* currently-selected device and return its value.
*
* Note: may NOT be used as the check_altstatus() entry in
* ata_port_operations.
*
* LOCKING:
* Inherited from caller.
*/
u8 ata_altstatus(struct ata_port *ap)
{
if (ap->ops->check_altstatus)
......@@ -425,6 +504,20 @@ u8 ata_altstatus(struct ata_port *ap)
return inb(ap->ioaddr.altstatus_addr);
}
/**
* ata_chk_err - Read device error reg
* @ap: port where the device is
*
* Reads ATA taskfile error register for
* currently-selected device and return its value.
*
* Note: may NOT be used as the check_err() entry in
* ata_port_operations.
*
* LOCKING:
* Inherited from caller.
*/
u8 ata_chk_err(struct ata_port *ap)
{
if (ap->ops->check_err)
......@@ -873,10 +966,24 @@ void ata_dev_id_string(u16 *id, unsigned char *s,
}
}
/**
* ata_noop_dev_select - Select device 0/1 on ATA bus
* @ap: ATA channel to manipulate
* @device: ATA device (numbered from zero) to select
*
* This function performs no actual function.
*
* May be used as the dev_select() entry in ata_port_operations.
*
* LOCKING:
* caller.
*/
void ata_noop_dev_select (struct ata_port *ap, unsigned int device)
{
}
/**
* ata_std_dev_select - Select device 0/1 on ATA bus
* @ap: ATA channel to manipulate
......@@ -884,7 +991,9 @@ void ata_noop_dev_select (struct ata_port *ap, unsigned int device)
*
* Use the method defined in the ATA specification to
* make either device 0, or device 1, active on the
* ATA channel.
* ATA channel. Works with both PIO and MMIO.
*
* May be used as the dev_select() entry in ata_port_operations.
*
* LOCKING:
* caller.
......@@ -1190,7 +1299,12 @@ static void ata_dev_identify(struct ata_port *ap, unsigned int device)
* ata_bus_probe - Reset and probe ATA bus
* @ap: Bus to probe
*
* Master ATA bus probing function. Initiates a hardware-dependent
* bus reset, then attempts to identify any devices found on
* the bus.
*
* LOCKING:
* PCI/etc. bus probe sem.
*
* RETURNS:
* Zero on success, non-zero on error.
......@@ -1229,10 +1343,14 @@ static int ata_bus_probe(struct ata_port *ap)
}
/**
* ata_port_probe -
* @ap:
* ata_port_probe - Mark port as enabled
* @ap: Port for which we indicate enablement
*
* LOCKING:
* Modify @ap data structure such that the system
* thinks that the entire port is enabled.
*
* LOCKING: host_set lock, or some other form of
* serialization.
*/
void ata_port_probe(struct ata_port *ap)
......@@ -1241,10 +1359,15 @@ 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.
*
* This function issues commands to standard SATA Sxxx
* PHY registers, to wake up the phy (and device), and
* clear any reset condition.
*
* LOCKING:
* PCI/etc. bus probe sem.
*
*/
void __sata_phy_reset(struct ata_port *ap)
......@@ -1289,10 +1412,14 @@ 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.
*
* This function resets the SATA bus, and then probes
* the bus for devices.
*
* LOCKING:
* PCI/etc. bus probe sem.
*
*/
void sata_phy_reset(struct ata_port *ap)
......@@ -1304,10 +1431,16 @@ 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 +1549,10 @@ 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
*
* Set ATA device disk transfer mode (PIO3, UDMA6, etc.).
*
* LOCKING:
* PCI/etc. bus probe sem.
*
*/
static void ata_set_mode(struct ata_port *ap)
......@@ -1467,7 +1603,10 @@ static void ata_set_mode(struct ata_port *ap)
* @tmout_pat: impatience timeout
* @tmout: overall timeout
*
* LOCKING:
* Sleep until ATA Status register bit BSY clears,
* or a timeout occurs.
*
* LOCKING: None.
*
*/
......@@ -1553,10 +1692,14 @@ static void ata_bus_post_reset(struct ata_port *ap, unsigned int devmask)
}
/**
* ata_bus_edd -
* @ap:
* ata_bus_edd - Issue EXECUTE DEVICE DIAGNOSTIC command.
* @ap: Port to reset and probe
*
* Use the EXECUTE DEVICE DIAGNOSTIC command to reset and
* probe the bus. Not often used these days.
*
* LOCKING:
* PCI/etc. bus probe sem.
*
*/
......@@ -1633,8 +1776,8 @@ static unsigned int ata_bus_softreset(struct ata_port *ap,
* the device is ATA or ATAPI.
*
* LOCKING:
* Inherited from caller. Some functions called by this function
* obtain the host_set lock.
* PCI/etc. bus probe sem.
* Obtains host_set lock.
*
* SIDE EFFECTS:
* Sets ATA_FLAG_PORT_DISABLED if bus reset fails.
......@@ -1876,7 +2019,11 @@ static int fgb(u32 bitmap)
* @xfer_mode_out: (output) SET FEATURES - XFER MODE code
* @xfer_shift_out: (output) bit shift that selects this mode
*
* Based on host and device capabilities, determine the
* maximum transfer mode that is amenable to all.
*
* LOCKING:
* PCI/etc. bus probe sem.
*
* RETURNS:
* Zero on success, negative on error.
......@@ -1909,7 +2056,11 @@ static int ata_choose_xfer_mode(struct ata_port *ap,
* @ap: Port associated with device @dev
* @dev: Device to which command will be sent
*
* Issue SET FEATURES - XFER MODE command to device @dev
* on port @ap.
*
* LOCKING:
* PCI/etc. bus probe sem.
*/
static void ata_dev_set_xfermode(struct ata_port *ap, struct ata_device *dev)
......@@ -1947,10 +2098,13 @@ static void ata_dev_set_xfermode(struct ata_port *ap, struct ata_device *dev)
}
/**
* ata_sg_clean -
* @qc:
* ata_sg_clean - Unmap DMA memory associated with command
* @qc: Command containing DMA memory to be released
*
* Unmap all mapped DMA memory associated with this command.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
static void ata_sg_clean(struct ata_queued_cmd *qc)
......@@ -1981,7 +2135,11 @@ 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)
......@@ -2028,7 +2186,13 @@ 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:
* spin_lock_irqsave(host_set lock)
*
* RETURNS: 0 when ATAPI DMA can be used
* nonzero otherwise
*/
......@@ -2046,6 +2210,8 @@ 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)
*/
......@@ -2057,6 +2223,32 @@ void ata_qc_prep(struct ata_queued_cmd *qc)
ata_fill_sg(qc);
}
/**
* ata_sg_init_one - Associate command with memory buffer
* @qc: Command to be associated
* @buf: Memory buffer
* @buflen: Length of memory buffer, in bytes.
*
* Initialize the data-related elements of queued_cmd @qc
* to point to a single memory buffer, @buf of byte length @buflen.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
/**
* ata_sg_init_one - Prepare a one-entry scatter-gather list.
* @qc: Queued command
* @buf: transfer buffer
* @buflen: length of buf
*
* Builds a single-entry scatter-gather list to initiate a
* transfer utilizing the specified buffer.
*
* LOCKING:
*/
void ata_sg_init_one(struct ata_queued_cmd *qc, void *buf, unsigned int buflen)
{
struct scatterlist *sg;
......@@ -2074,6 +2266,32 @@ void ata_sg_init_one(struct ata_queued_cmd *qc, void *buf, unsigned int buflen)
sg->length = buflen;
}
/**
* ata_sg_init - Associate command with scatter-gather table.
* @qc: Command to be associated
* @sg: Scatter-gather table.
* @n_elem: Number of elements in s/g table.
*
* Initialize the data-related elements of queued_cmd @qc
* to point to a scatter-gather table @sg, containing @n_elem
* elements.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
/**
* ata_sg_init - Assign a scatter gather list to a queued command
* @qc: Queued command
* @sg: Scatter-gather list
* @n_elem: length of sg list
*
* Attaches a scatter-gather list to a queued command.
*
* LOCKING:
*/
void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
unsigned int n_elem)
{
......@@ -2083,14 +2301,16 @@ void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
}
/**
* ata_sg_setup_one -
* @qc:
* ata_sg_setup_one - DMA-map the memory buffer associated with a command.
* @qc: Command with memory buffer to be mapped.
*
* DMA-map the memory buffer associated with queued_cmd @qc.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*
* RETURNS:
*
* Zero on success, negative on error.
*/
static int ata_sg_setup_one(struct ata_queued_cmd *qc)
......@@ -2115,13 +2335,16 @@ static int ata_sg_setup_one(struct ata_queued_cmd *qc)
}
/**
* ata_sg_setup -
* @qc:
* ata_sg_setup - DMA-map the scatter-gather table associated with a command.
* @qc: Command with scatter-gather table to be mapped.
*
* DMA-map the scatter-gather table associated with queued_cmd @qc.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*
* RETURNS:
* Zero on success, negative on error.
*
*/
......@@ -2151,6 +2374,7 @@ static int ata_sg_setup(struct ata_queued_cmd *qc)
* @ap:
*
* LOCKING:
* None. (executing in kernel thread context)
*
* RETURNS:
*
......@@ -2198,6 +2422,7 @@ static unsigned long ata_pio_poll(struct ata_port *ap)
* @ap:
*
* LOCKING:
* None. (executing in kernel thread context)
*/
static void ata_pio_complete (struct ata_port *ap)
......@@ -2240,6 +2465,18 @@ static void ata_pio_complete (struct ata_port *ap)
ata_qc_complete(qc, drv_stat);
}
/**
* swap_buf_le16 -
* @buf: Buffer to swap
* @buf_words: Number of 16-bit words in buffer.
*
* Swap halves of 16-bit words if needed to convert from
* little-endian byte order to native cpu byte order, or
* vice-versa.
*
* LOCKING:
*/
void swap_buf_le16(u16 *buf, unsigned int buf_words)
{
#ifdef __BIG_ENDIAN
......@@ -2415,6 +2652,7 @@ static void atapi_pio_bytes(struct ata_queued_cmd *qc)
* @ap:
*
* LOCKING:
* None. (executing in kernel thread context)
*/
static void ata_pio_block(struct ata_port *ap)
......@@ -2583,6 +2821,7 @@ static void atapi_request_sense(struct ata_port *ap, struct ata_device *dev,
* transaction completed successfully.
*
* LOCKING:
* Inherited from SCSI layer (none, can sleep)
*/
static void ata_qc_timeout(struct ata_queued_cmd *qc)
......@@ -2692,6 +2931,7 @@ void ata_eng_timeout(struct ata_port *ap)
* @dev: Device from whom we request an available command structure
*
* LOCKING:
* None.
*/
static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap)
......@@ -2717,6 +2957,7 @@ static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap)
* @dev: Device from whom we request an available command structure
*
* LOCKING:
* None.
*/
struct ata_queued_cmd *ata_qc_new_init(struct ata_port *ap,
......@@ -2781,6 +3022,7 @@ static void __ata_qc_complete(struct ata_queued_cmd *qc)
* in case something prevents using it.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*
*/
void ata_qc_free(struct ata_queued_cmd *qc)
......@@ -2794,9 +3036,13 @@ void ata_qc_free(struct ata_queued_cmd *qc)
/**
* ata_qc_complete - Complete an active ATA command
* @qc: Command to complete
* @drv_stat: ATA status register contents
* @drv_stat: ATA Status register contents
*
* Indicate to the mid and upper layers that an ATA
* command has completed, with either an ok or not-ok status.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*
*/
......@@ -2892,6 +3138,7 @@ int ata_qc_issue(struct ata_queued_cmd *qc)
return -1;
}
/**
* ata_qc_issue_prot - issue taskfile to device in proto-dependent manner
* @qc: command to issue to device
......@@ -2901,6 +3148,8 @@ int ata_qc_issue(struct ata_queued_cmd *qc)
* classes called "protocols", and issuing each type of protocol
* is slightly different.
*
* May be used as the qc_issue() entry in ata_port_operations.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*
......@@ -2958,7 +3207,7 @@ int ata_qc_issue_prot(struct ata_queued_cmd *qc)
}
/**
* ata_bmdma_setup - Set up PCI IDE BMDMA transaction
* ata_bmdma_setup_mmio - Set up PCI IDE BMDMA transaction
* @qc: Info associated with this ATA transaction.
*
* LOCKING:
......@@ -3065,6 +3314,18 @@ static void ata_bmdma_start_pio (struct ata_queued_cmd *qc)
ap->ioaddr.bmdma_addr + ATA_DMA_CMD);
}
/**
* ata_bmdma_start - Start a PCI IDE BMDMA transaction
* @qc: Info associated with this ATA transaction.
*
* Writes the ATA_DMA_START flag to the DMA command register.
*
* May be used as the bmdma_start() entry in ata_port_operations.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
void ata_bmdma_start(struct ata_queued_cmd *qc)
{
if (qc->ap->flags & ATA_FLAG_MMIO)
......@@ -3073,6 +3334,20 @@ void ata_bmdma_start(struct ata_queued_cmd *qc)
ata_bmdma_start_pio(qc);
}
/**
* ata_bmdma_setup - Set up PCI IDE BMDMA transaction
* @qc: Info associated with this ATA transaction.
*
* Writes address of PRD table to device's PRD Table Address
* register, sets the DMA control register, and calls
* ops->exec_command() to start the transfer.
*
* May be used as the bmdma_setup() entry in ata_port_operations.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
void ata_bmdma_setup(struct ata_queued_cmd *qc)
{
if (qc->ap->flags & ATA_FLAG_MMIO)
......@@ -3081,6 +3356,19 @@ void ata_bmdma_setup(struct ata_queued_cmd *qc)
ata_bmdma_setup_pio(qc);
}
/**
* ata_bmdma_irq_clear - Clear PCI IDE BMDMA interrupt.
* @ap: Port associated with this ATA transaction.
*
* Clear interrupt and error flags in DMA status register.
*
* May be used as the irq_clear() entry in ata_port_operations.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
void ata_bmdma_irq_clear(struct ata_port *ap)
{
if (ap->flags & ATA_FLAG_MMIO) {
......@@ -3093,6 +3381,19 @@ void ata_bmdma_irq_clear(struct ata_port *ap)
}
/**
* ata_bmdma_status - Read PCI IDE BMDMA status
* @ap: Port associated with this ATA transaction.
*
* Read and return BMDMA status register.
*
* May be used as the bmdma_status() entry in ata_port_operations.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
u8 ata_bmdma_status(struct ata_port *ap)
{
u8 host_stat;
......@@ -3104,6 +3405,19 @@ u8 ata_bmdma_status(struct ata_port *ap)
return host_stat;
}
/**
* ata_bmdma_stop - Stop PCI IDE BMDMA transfer
* @ap: Port associated with this ATA transaction.
*
* Clears the ATA_DMA_START flag in the dma control register
*
* May be used as the bmdma_stop() entry in ata_port_operations.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
void ata_bmdma_stop(struct ata_port *ap)
{
if (ap->flags & ATA_FLAG_MMIO) {
......@@ -3203,13 +3517,18 @@ inline unsigned int ata_host_intr (struct ata_port *ap,
/**
* ata_interrupt - Default ATA host interrupt handler
* @irq: irq line
* @dev_instance: pointer to our host information structure
* @irq: irq line (unused)
* @dev_instance: pointer to our ata_host_set information structure
* @regs: unused
*
* Default interrupt handler for PCI IDE devices. Calls
* ata_host_intr() for each port that is not disabled.
*
* LOCKING:
* Obtains host_set lock during operation.
*
* RETURNS:
* IRQ_NONE or IRQ_HANDLED.
*
*/
......@@ -3302,6 +3621,19 @@ static void atapi_packet_task(void *_data)
ata_qc_complete(qc, ATA_ERR);
}
/**
* ata_port_start - Set port up for dma.
* @ap: Port to initialize
*
* Called just after data structures for each port are
* initialized. Allocates space for PRD table.
*
* May be used as the port_start() entry in ata_port_operations.
*
* LOCKING:
*/
int ata_port_start (struct ata_port *ap)
{
struct device *dev = ap->host_set->dev;
......@@ -3315,6 +3647,18 @@ int ata_port_start (struct ata_port *ap)
return 0;
}
/**
* ata_port_stop - Undo ata_port_start()
* @ap: Port to shut down
*
* Frees the PRD table.
*
* May be used as the port_stop() entry in ata_port_operations.
*
* LOCKING:
*/
void ata_port_stop (struct ata_port *ap)
{
struct device *dev = ap->host_set->dev;
......@@ -3357,7 +3701,11 @@ static void ata_host_remove(struct ata_port *ap, unsigned int do_unregister)
* @ent: Probe information provided by low-level driver
* @port_no: Port number associated with this ata_port
*
* Initialize a new ata_port structure, and its associated
* scsi_host.
*
* LOCKING:
* Inherited from caller.
*
*/
......@@ -3412,9 +3760,13 @@ static void ata_host_init(struct ata_port *ap, struct Scsi_Host *host,
* @host_set: Collections of ports to which we add
* @port_no: Port number associated with this host
*
* Attach low-level ATA driver to system.
*
* LOCKING:
* PCI/etc. bus probe sem.
*
* RETURNS:
* New ata_port on success, for NULL on error.
*
*/
......@@ -3447,12 +3799,22 @@ static struct ata_port * ata_host_add(struct ata_probe_ent *ent,
}
/**
* ata_device_add -
* @ent:
* ata_device_add - Register hardware device with ATA and SCSI layers
* @ent: Probe information describing hardware device to be registered
*
* This function processes the information provided in the probe
* information struct @ent, allocates the necessary ATA and SCSI
* host information structures, initializes them, and registers
* everything with requisite kernel subsystems.
*
* This function requests irqs, probes the ATA bus, and probes
* the SCSI bus.
*
* LOCKING:
* PCI/etc. bus probe sem.
*
* RETURNS:
* Number of ports registered. Zero on error (no ports registered).
*
*/
......@@ -3604,7 +3966,15 @@ int ata_scsi_release(struct Scsi_Host *host)
/**
* ata_std_ports - initialize ioaddr with standard port offsets.
* @ioaddr: IO address structure to be initialized
*
* Utility function which initializes data_addr, error_addr,
* feature_addr, nsect_addr, lbal_addr, lbam_addr, lbah_addr,
* device_addr, status_addr, and command_addr to standard offsets
* relative to cmd_addr.
*
* Does not set ctl_addr, altstatus_addr, bmdma_addr, or scr_addr.
*/
void ata_std_ports(struct ata_ioports *ioaddr)
{
ioaddr->data_addr = ioaddr->cmd_addr + ATA_REG_DATA;
......@@ -3646,6 +4016,20 @@ ata_probe_ent_alloc(struct device *dev, struct ata_port_info *port)
return probe_ent;
}
/**
* ata_pci_init_native_mode - Initialize native-mode driver
* @pdev: pci device to be initialized
* @port: array[2] of pointers to port info structures.
*
* Utility function which allocates and initializes an
* ata_probe_ent structure for a standard dual-port
* PIO-based IDE controller. The returned ata_probe_ent
* structure can be passed to ata_device_add(). The returned
* ata_probe_ent structure should then be freed with kfree().
*/
#ifdef CONFIG_PCI
struct ata_probe_ent *
ata_pci_init_native_mode(struct pci_dev *pdev, struct ata_port_info **port)
......@@ -3727,10 +4111,19 @@ ata_pci_init_legacy_mode(struct pci_dev *pdev, struct ata_port_info **port,
* @port_info: Information from low-level host driver
* @n_ports: Number of ports attached to host controller
*
* This is a helper function which can be called from a driver's
* xxx_init_one() probe function if the hardware uses traditional
* IDE taskfile registers.
*
* This function calls pci_enable_device(), reserves its register
* regions, sets the dma mask, enables bus master mode, and calls
* ata_device_add()
*
* LOCKING:
* Inherited from PCI layer (may sleep).
*
* RETURNS:
* Zero on success, negative on errno-based value on error.
*
*/
......@@ -3949,15 +4342,6 @@ int pci_test_config_bits(struct pci_dev *pdev, struct pci_bits *bits)
#endif /* CONFIG_PCI */
/**
* ata_init -
*
* LOCKING:
*
* RETURNS:
*
*/
static int __init ata_init(void)
{
ata_wq = create_workqueue("ata");
......
drivers/scsi/libata-scsi.c
View file @ 31760463
......@@ -947,7 +947,7 @@ unsigned int ata_scsiop_inq_83(struct ata_scsi_args *args, u8 *rbuf,
}
/**
* ata_scsiop_noop -
* ata_scsiop_noop - Command handler that simply returns success.
* @args: device IDENTIFY data / SCSI command of interest.
* @rbuf: Response buffer, to which simulated SCSI cmd output is sent.
* @buflen: Response buffer length.
......
include/linux/libata.h
View file @ 31760463
......@@ -467,12 +467,34 @@ static inline u8 ata_chk_status(struct ata_port *ap)
return ap->ops->check_status(ap);
}
/**
* ata_pause - Flush writes and pause 400 nanoseconds.
* @ap: Port to wait for.
*
* LOCKING:
* Inherited from caller.
*/
static inline void ata_pause(struct ata_port *ap)
{
ata_altstatus(ap);
ndelay(400);
}
/**
* ata_busy_wait - Wait for a port status register
* @ap: Port to wait for.
*
* Waits up to max*10 microseconds for the selected bits in the port's
* status register to be cleared.
* Returns final value of status register.
*
* LOCKING:
* Inherited from caller.
*/
static inline u8 ata_busy_wait(struct ata_port *ap, unsigned int bits,
unsigned int max)
{
......@@ -487,6 +509,18 @@ static inline u8 ata_busy_wait(struct ata_port *ap, unsigned int bits,
return status;
}
/**
* ata_wait_idle - Wait for a port to be idle.
* @ap: Port to wait for.
*
* Waits up to 10ms for port's BUSY and DRQ signals to clear.
* Returns final value of status register.
*
* LOCKING:
* Inherited from caller.
*/
static inline u8 ata_wait_idle(struct ata_port *ap)
{
u8 status = ata_busy_wait(ap, ATA_BUSY | ATA_DRQ, 1000);
......@@ -525,6 +559,18 @@ static inline void ata_tf_init(struct ata_port *ap, struct ata_taskfile *tf, uns
tf->device = ATA_DEVICE_OBS | ATA_DEV1;
}
/**
* ata_irq_on - Enable interrupts on a port.
* @ap: Port on which interrupts are enabled.
*
* Enable interrupts on a legacy IDE device using MMIO or PIO,
* wait for idle, clear any pending interrupts.
*
* LOCKING:
* Inherited from caller.
*/
static inline u8 ata_irq_on(struct ata_port *ap)
{
struct ata_ioports *ioaddr = &ap->ioaddr;
......@@ -544,6 +590,18 @@ static inline u8 ata_irq_on(struct ata_port *ap)
return tmp;
}
/**
* ata_irq_ack - Acknowledge a device interrupt.
* @ap: Port on which interrupts are enabled.
*
* Wait up to 10 ms for legacy IDE device to become idle (BUSY
* or BUSY+DRQ clear). Obtain dma status and port status from
* device. Clear the interrupt. Return port status.
*
* LOCKING:
*/
static inline u8 ata_irq_ack(struct ata_port *ap, unsigned int chk_drq)
{
unsigned int bits = chk_drq ? ATA_BUSY | ATA_DRQ : ATA_BUSY;
......
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