Index: Documentation/DocBook/libata.tmpl
===================================================================
--- ad2516671b031a8e0b3f9a656a16c13c3f03d61c/Documentation/DocBook/libata.tmpl (mode:100644)
+++ f2de8c9152ca956aaaaad57ddbe9fc373d4b39d7/Documentation/DocBook/libata.tmpl (mode:100644)
@@ -14,7 +14,7 @@
</authorgroup>
<copyright>
- <year>2003</year>
+ <year>2003-2005</year>
<holder>Jeff Garzik</holder>
</copyright>
@@ -44,22 +44,17 @@
<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<->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>
@@ -130,14 +125,25 @@
</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>
@@ -147,7 +153,8 @@
<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>
@@ -165,12 +172,20 @@
<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>
@@ -190,9 +205,7 @@
->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>
@@ -200,8 +213,10 @@
</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>
@@ -240,15 +255,15 @@
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>
@@ -279,4 +294,24 @@
!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>
Index: drivers/scsi/ata_piix.c
===================================================================
--- ad2516671b031a8e0b3f9a656a16c13c3f03d61c/drivers/scsi/ata_piix.c (mode:100644)
+++ f2de8c9152ca956aaaaad57ddbe9fc373d4b39d7/drivers/scsi/ata_piix.c (mode:100644)
@@ -663,15 +663,6 @@
return ata_pci_init_one(pdev, port_info, n_ports);
}
-/**
- * piix_init -
- *
- * LOCKING:
- *
- * RETURNS:
- *
- */
-
static int __init piix_init(void)
{
int rc;
@@ -687,13 +678,6 @@
return 0;
}
-/**
- * piix_exit -
- *
- * LOCKING:
- *
- */
-
static void __exit piix_exit(void)
{
pci_unregister_driver(&piix_pci_driver);
Index: drivers/scsi/libata-core.c
===================================================================
--- ad2516671b031a8e0b3f9a656a16c13c3f03d61c/drivers/scsi/libata-core.c (mode:100644)
+++ f2de8c9152ca956aaaaad57ddbe9fc373d4b39d7/drivers/scsi/libata-core.c (mode:100644)
@@ -1190,7 +1190,12 @@
* 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 +1234,14 @@
}
/**
- * 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 +1250,15 @@
}
/**
- * __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 +1303,14 @@
}
/**
- * __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 +1322,16 @@
}
/**
- * 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 +1440,10 @@
* 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 +1494,10 @@
* @tmout_pat: impatience timeout
* @tmout: overall timeout
*
- * LOCKING:
+ * Sleep until ATA Status register bit BSY clears,
+ * or a timeout occurs.
+ *
+ * LOCKING: None.
*
*/
@@ -1553,10 +1583,14 @@
}
/**
- * 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 +1667,8 @@
* 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 +1910,11 @@
* @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 +1947,11 @@
* @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 +1989,13 @@
}
/**
- * 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 +2026,11 @@
* 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 +2077,13 @@
* 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 +2101,8 @@
* 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 +2114,19 @@
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)
+ */
+
void ata_sg_init_one(struct ata_queued_cmd *qc, void *buf, unsigned int buflen)
{
struct scatterlist *sg;
@@ -2074,6 +2144,20 @@
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)
+ */
+
void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
unsigned int n_elem)
{
@@ -2083,14 +2167,16 @@
}
/**
- * 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 +2201,16 @@
}
/**
- * 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 +2240,7 @@
* @ap:
*
* LOCKING:
+ * None. (executing in kernel thread context)
*
* RETURNS:
*
@@ -2198,6 +2288,7 @@
* @ap:
*
* LOCKING:
+ * None. (executing in kernel thread context)
*/
static void ata_pio_complete (struct ata_port *ap)
@@ -2415,6 +2506,7 @@
* @ap:
*
* LOCKING:
+ * None. (executing in kernel thread context)
*/
static void ata_pio_block(struct ata_port *ap)
@@ -2583,6 +2675,7 @@
* transaction completed successfully.
*
* LOCKING:
+ * Inherited from SCSI layer (none, can sleep)
*/
static void ata_qc_timeout(struct ata_queued_cmd *qc)
@@ -2692,6 +2785,7 @@
* @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 +2811,7 @@
* @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 +2876,7 @@
* in case something prevents using it.
*
* LOCKING:
+ * spin_lock_irqsave(host_set lock)
*
*/
void ata_qc_free(struct ata_queued_cmd *qc)
@@ -2794,9 +2890,13 @@
/**
* 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)
*
*/
@@ -3203,13 +3303,18 @@
/**
* 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.
*
*/
@@ -3350,7 +3455,11 @@
* @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.
*
*/
@@ -3405,9 +3514,13 @@
* @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.
*
*/
@@ -3440,12 +3553,22 @@
}
/**
- * 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).
*
*/
@@ -3724,6 +3847,7 @@
* Inherited from PCI layer (may sleep).
*
* RETURNS:
+ * Zero on success, negative on errno-based value on error.
*
*/
@@ -3943,15 +4067,6 @@
#endif /* CONFIG_PCI */
-/**
- * ata_init -
- *
- * LOCKING:
- *
- * RETURNS:
- *
- */
-
static int __init ata_init(void)
{
ata_wq = create_workqueue("ata");
Index: drivers/scsi/libata-scsi.c
===================================================================
--- ad2516671b031a8e0b3f9a656a16c13c3f03d61c/drivers/scsi/libata-scsi.c (mode:100644)
+++ f2de8c9152ca956aaaaad57ddbe9fc373d4b39d7/drivers/scsi/libata-scsi.c (mode:100644)
@@ -947,7 +947,7 @@
}
/**
- * 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.