提交 31760463 编写于 作者: L Linus Torvalds
...@@ -14,7 +14,7 @@ ...@@ -14,7 +14,7 @@
</authorgroup> </authorgroup>
<copyright> <copyright>
<year>2003</year> <year>2003-2005</year>
<holder>Jeff Garzik</holder> <holder>Jeff Garzik</holder>
</copyright> </copyright>
...@@ -44,30 +44,38 @@ ...@@ -44,30 +44,38 @@
<toc></toc> <toc></toc>
<chapter id="libataThanks"> <chapter id="libataIntroduction">
<title>Thanks</title> <title>Introduction</title>
<para> <para>
The bulk of the ATA knowledge comes thanks to long conversations with libATA is a library used inside the Linux kernel to support ATA host
Andre Hedrick (www.linux-ide.org). 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>
<para> <para>
Thanks to Alan Cox for pointing out similarities This Guide documents the libATA driver API, library functions, library
between SATA and SCSI, and in general for motivation to hack on internals, and a couple sample ATA low-level drivers.
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> </para>
</chapter> </chapter>
<chapter id="libataDriverApi"> <chapter id="libataDriverApi">
<title>libata Driver API</title> <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> <sect1>
<title>struct ata_port_operations</title> <title>struct ata_port_operations</title>
<sect2><title>Disable ATA port</title>
<programlisting> <programlisting>
void (*port_disable) (struct ata_port *); void (*port_disable) (struct ata_port *);
</programlisting> </programlisting>
...@@ -78,6 +86,9 @@ void (*port_disable) (struct ata_port *); ...@@ -78,6 +86,9 @@ void (*port_disable) (struct ata_port *);
unplug). unplug).
</para> </para>
</sect2>
<sect2><title>Post-IDENTIFY device configuration</title>
<programlisting> <programlisting>
void (*dev_config) (struct ata_port *, struct ata_device *); void (*dev_config) (struct ata_port *, struct ata_device *);
</programlisting> </programlisting>
...@@ -88,6 +99,9 @@ void (*dev_config) (struct ata_port *, struct ata_device *); ...@@ -88,6 +99,9 @@ void (*dev_config) (struct ata_port *, struct ata_device *);
issue of SET FEATURES - XFER MODE, and prior to operation. issue of SET FEATURES - XFER MODE, and prior to operation.
</para> </para>
</sect2>
<sect2><title>Set PIO/DMA mode</title>
<programlisting> <programlisting>
void (*set_piomode) (struct ata_port *, struct ata_device *); void (*set_piomode) (struct ata_port *, struct ata_device *);
void (*set_dmamode) (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); ...@@ -108,6 +122,9 @@ void (*post_set_mode) (struct ata_port *ap);
->set_dma_mode() is only called if DMA is possible. ->set_dma_mode() is only called if DMA is possible.
</para> </para>
</sect2>
<sect2><title>Taskfile read/write</title>
<programlisting> <programlisting>
void (*tf_load) (struct ata_port *ap, struct ata_taskfile *tf); void (*tf_load) (struct ata_port *ap, struct ata_taskfile *tf);
void (*tf_read) (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); ...@@ -120,6 +137,9 @@ void (*tf_read) (struct ata_port *ap, struct ata_taskfile *tf);
taskfile register values. taskfile register values.
</para> </para>
</sect2>
<sect2><title>ATA command execute</title>
<programlisting> <programlisting>
void (*exec_command)(struct ata_port *ap, struct ata_taskfile *tf); void (*exec_command)(struct ata_port *ap, struct ata_taskfile *tf);
</programlisting> </programlisting>
...@@ -129,17 +149,37 @@ void (*exec_command)(struct ata_port *ap, struct ata_taskfile *tf); ...@@ -129,17 +149,37 @@ void (*exec_command)(struct ata_port *ap, struct ata_taskfile *tf);
->tf_load(), to be initiated in hardware. ->tf_load(), to be initiated in hardware.
</para> </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> <programlisting>
u8 (*check_status)(struct ata_port *ap); 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> </programlisting>
<para> <para>
Reads the Status ATA shadow register from hardware. On some Reads the Status/AltStatus/Error ATA shadow register from
hardware, this has the side effect of clearing the interrupt hardware. On some hardware, reading the Status register has
condition. the side effect of clearing the interrupt condition.
</para> </para>
</sect2>
<sect2><title>Select ATA device on bus</title>
<programlisting> <programlisting>
void (*dev_select)(struct ata_port *ap, unsigned int device); void (*dev_select)(struct ata_port *ap, unsigned int device);
</programlisting> </programlisting>
...@@ -147,9 +187,13 @@ void (*dev_select)(struct ata_port *ap, unsigned int device); ...@@ -147,9 +187,13 @@ void (*dev_select)(struct ata_port *ap, unsigned int device);
<para> <para>
Issues the low-level hardware command(s) that causes one of N Issues the low-level hardware command(s) that causes one of N
hardware devices to be considered 'selected' (active and 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> </para>
</sect2>
<sect2><title>Reset ATA bus</title>
<programlisting> <programlisting>
void (*phy_reset) (struct ata_port *ap); void (*phy_reset) (struct ata_port *ap);
</programlisting> </programlisting>
...@@ -162,17 +206,31 @@ void (*phy_reset) (struct ata_port *ap); ...@@ -162,17 +206,31 @@ void (*phy_reset) (struct ata_port *ap);
functions ata_bus_reset() or sata_phy_reset() for this hook. functions ata_bus_reset() or sata_phy_reset() for this hook.
</para> </para>
</sect2>
<sect2><title>Control PCI IDE BMDMA engine</title>
<programlisting> <programlisting>
void (*bmdma_setup) (struct ata_queued_cmd *qc); void (*bmdma_setup) (struct ata_queued_cmd *qc);
void (*bmdma_start) (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> </programlisting>
<para> <para>
When setting up an IDE BMDMA transaction, these hooks arm When setting up an IDE BMDMA transaction, these hooks arm
(->bmdma_setup) and fire (->bmdma_start) the hardware's DMA (->bmdma_setup), fire (->bmdma_start), and halt (->bmdma_stop)
engine. the hardware's DMA engine. ->bmdma_status is used to read the standard
PCI IDE DMA Status register.
</para> </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> <programlisting>
void (*qc_prep) (struct ata_queued_cmd *qc); void (*qc_prep) (struct ata_queued_cmd *qc);
int (*qc_issue) (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); ...@@ -190,20 +248,26 @@ int (*qc_issue) (struct ata_queued_cmd *qc);
->qc_issue is used to make a command active, once the hardware ->qc_issue is used to make a command active, once the hardware
and S/G tables have been prepared. IDE BMDMA drivers use the and S/G tables have been prepared. IDE BMDMA drivers use the
helper function ata_qc_issue_prot() for taskfile protocol-based helper function ata_qc_issue_prot() for taskfile protocol-based
dispatch. More advanced drivers roll their own ->qc_issue dispatch. More advanced drivers implement their own ->qc_issue.
implementation, using this as the "issue new ATA command to
hardware" hook.
</para> </para>
</sect2>
<sect2><title>Timeout (error) handling</title>
<programlisting> <programlisting>
void (*eng_timeout) (struct ata_port *ap); void (*eng_timeout) (struct ata_port *ap);
</programlisting> </programlisting>
<para> <para>
This is a high level error handling function, called from the 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> </para>
</sect2>
<sect2><title>Hardware interrupt handling</title>
<programlisting> <programlisting>
irqreturn_t (*irq_handler)(int, void *, struct pt_regs *); irqreturn_t (*irq_handler)(int, void *, struct pt_regs *);
void (*irq_clear) (struct ata_port *); void (*irq_clear) (struct ata_port *);
...@@ -216,6 +280,9 @@ void (*irq_clear) (struct ata_port *); ...@@ -216,6 +280,9 @@ void (*irq_clear) (struct ata_port *);
is quiet. is quiet.
</para> </para>
</sect2>
<sect2><title>SATA phy read/write</title>
<programlisting> <programlisting>
u32 (*scr_read) (struct ata_port *ap, unsigned int sc_reg); u32 (*scr_read) (struct ata_port *ap, unsigned int sc_reg);
void (*scr_write) (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, ...@@ -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. if ->phy_reset hook called the sata_phy_reset() helper function.
</para> </para>
</sect2>
<sect2><title>Init and shutdown</title>
<programlisting> <programlisting>
int (*port_start) (struct ata_port *ap); int (*port_start) (struct ata_port *ap);
void (*port_stop) (struct ata_port *ap); void (*port_stop) (struct ata_port *ap);
...@@ -240,15 +310,17 @@ void (*host_stop) (struct ata_host_set *host_set); ...@@ -240,15 +310,17 @@ void (*host_stop) (struct ata_host_set *host_set);
tasks. tasks.
</para> </para>
<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 ->port_stop() is called after ->host_stop(). It's sole function
is to release DMA/memory resources, now that they are no longer is to release DMA/memory resources, now that they are no longer
actively being used. actively being used.
</para> </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> </sect1>
</chapter> </chapter>
...@@ -279,4 +351,24 @@ void (*host_stop) (struct ata_host_set *host_set); ...@@ -279,4 +351,24 @@ void (*host_stop) (struct ata_host_set *host_set);
!Idrivers/scsi/sata_sil.c !Idrivers/scsi/sata_sil.c
</chapter> </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> </book>
...@@ -665,15 +665,6 @@ static int piix_init_one (struct pci_dev *pdev, const struct pci_device_id *ent) ...@@ -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); return ata_pci_init_one(pdev, port_info, n_ports);
} }
/**
* piix_init -
*
* LOCKING:
*
* RETURNS:
*
*/
static int __init piix_init(void) static int __init piix_init(void)
{ {
int rc; int rc;
...@@ -689,13 +680,6 @@ static int __init piix_init(void) ...@@ -689,13 +680,6 @@ static int __init piix_init(void)
return 0; return 0;
} }
/**
* piix_exit -
*
* LOCKING:
*
*/
static void __exit piix_exit(void) static void __exit piix_exit(void)
{ {
pci_unregister_driver(&piix_pci_driver); pci_unregister_driver(&piix_pci_driver);
......
此差异已折叠。
...@@ -947,7 +947,7 @@ unsigned int ata_scsiop_inq_83(struct ata_scsi_args *args, u8 *rbuf, ...@@ -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. * @args: device IDENTIFY data / SCSI command of interest.
* @rbuf: Response buffer, to which simulated SCSI cmd output is sent. * @rbuf: Response buffer, to which simulated SCSI cmd output is sent.
* @buflen: Response buffer length. * @buflen: Response buffer length.
......
...@@ -467,12 +467,34 @@ static inline u8 ata_chk_status(struct ata_port *ap) ...@@ -467,12 +467,34 @@ static inline u8 ata_chk_status(struct ata_port *ap)
return ap->ops->check_status(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) static inline void ata_pause(struct ata_port *ap)
{ {
ata_altstatus(ap); ata_altstatus(ap);
ndelay(400); 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, static inline u8 ata_busy_wait(struct ata_port *ap, unsigned int bits,
unsigned int max) unsigned int max)
{ {
...@@ -487,6 +509,18 @@ static inline u8 ata_busy_wait(struct ata_port *ap, unsigned int bits, ...@@ -487,6 +509,18 @@ static inline u8 ata_busy_wait(struct ata_port *ap, unsigned int bits,
return status; 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) static inline u8 ata_wait_idle(struct ata_port *ap)
{ {
u8 status = ata_busy_wait(ap, ATA_BUSY | ATA_DRQ, 1000); 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 ...@@ -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; 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) static inline u8 ata_irq_on(struct ata_port *ap)
{ {
struct ata_ioports *ioaddr = &ap->ioaddr; struct ata_ioports *ioaddr = &ap->ioaddr;
...@@ -544,6 +590,18 @@ static inline u8 ata_irq_on(struct ata_port *ap) ...@@ -544,6 +590,18 @@ static inline u8 ata_irq_on(struct ata_port *ap)
return tmp; 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) 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; unsigned int bits = chk_drq ? ATA_BUSY | ATA_DRQ : ATA_BUSY;
......
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