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authorJeff Garzik <jeff@garzik.org>2006-06-13 20:27:03 -0400
committerJeff Garzik <jeff@garzik.org>2006-06-13 20:27:03 -0400
commitbf717b11aec20965d48dea36dea3eea18a75d18c (patch)
tree4e2d1051910cc983d689c6b4ce86eb497e6667cf /Documentation
parentf0eb62b81dd16bfc4034916418c3406ba20011e1 (diff)
[libata] Update docs to reflect current driver API
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/DocBook/libata.tmpl104
1 files changed, 80 insertions, 24 deletions
diff --git a/Documentation/DocBook/libata.tmpl b/Documentation/DocBook/libata.tmpl
index f869b03929d..e97c3231454 100644
--- a/Documentation/DocBook/libata.tmpl
+++ b/Documentation/DocBook/libata.tmpl
@@ -169,6 +169,22 @@ void (*tf_read) (struct ata_port *ap, struct ata_taskfile *tf);
</sect2>
+ <sect2><title>PIO data read/write</title>
+ <programlisting>
+void (*data_xfer) (struct ata_device *, unsigned char *, unsigned int, int);
+ </programlisting>
+
+ <para>
+All bmdma-style drivers must implement this hook. This is the low-level
+operation that actually copies the data bytes during a PIO data
+transfer.
+Typically the driver
+will choose one of ata_pio_data_xfer_noirq(), ata_pio_data_xfer(), or
+ata_mmio_data_xfer().
+ </para>
+
+ </sect2>
+
<sect2><title>ATA command execute</title>
<programlisting>
void (*exec_command)(struct ata_port *ap, struct ata_taskfile *tf);
@@ -204,11 +220,10 @@ command.
<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
+ Reads the Status/AltStatus ATA shadow register from
hardware. On some hardware, reading the Status register has
the side effect of clearing the interrupt condition.
Most drivers for taskfile-based hardware use
@@ -269,23 +284,6 @@ void (*set_mode) (struct ata_port *ap);
</sect2>
- <sect2><title>Reset ATA bus</title>
- <programlisting>
-void (*phy_reset) (struct ata_port *ap);
- </programlisting>
-
- <para>
- The very first step in the probe phase. Actions vary depending
- on the bus type, typically. After waking up the device and probing
- for device presence (PATA and SATA), typically a soft reset
- (SRST) will be performed. Drivers typically use the helper
- functions ata_bus_reset() or sata_phy_reset() for this hook.
- Many SATA drivers use sata_phy_reset() or call it from within
- their own phy_reset() functions.
- </para>
-
- </sect2>
-
<sect2><title>Control PCI IDE BMDMA engine</title>
<programlisting>
void (*bmdma_setup) (struct ata_queued_cmd *qc);
@@ -354,16 +352,74 @@ int (*qc_issue) (struct ata_queued_cmd *qc);
</sect2>
- <sect2><title>Timeout (error) handling</title>
+ <sect2><title>Exception and probe handling (EH)</title>
<programlisting>
void (*eng_timeout) (struct ata_port *ap);
+void (*phy_reset) (struct ata_port *ap);
+ </programlisting>
+
+ <para>
+Deprecated. Use ->error_handler() instead.
+ </para>
+
+ <programlisting>
+void (*freeze) (struct ata_port *ap);
+void (*thaw) (struct ata_port *ap);
+ </programlisting>
+
+ <para>
+ata_port_freeze() is called when HSM violations or some other
+condition disrupts normal operation of the port. A frozen port
+is not allowed to perform any operation until the port is
+thawed, which usually follows a successful reset.
+ </para>
+
+ <para>
+The optional ->freeze() callback can be used for freezing the port
+hardware-wise (e.g. mask interrupt and stop DMA engine). If a
+port cannot be frozen hardware-wise, the interrupt handler
+must ack and clear interrupts unconditionally while the port
+is frozen.
+ </para>
+ <para>
+The optional ->thaw() callback is called to perform the opposite of ->freeze():
+prepare the port for normal operation once again. Unmask interrupts,
+start DMA engine, etc.
+ </para>
+
+ <programlisting>
+void (*error_handler) (struct ata_port *ap);
+ </programlisting>
+
+ <para>
+->error_handler() is a driver's hook into probe, hotplug, and recovery
+and other exceptional conditions. The primary responsibility of an
+implementation is to call ata_do_eh() or ata_bmdma_drive_eh() with a set
+of EH hooks as arguments:
+ </para>
+
+ <para>
+'prereset' hook (may be NULL) is called during an EH reset, before any other actions
+are taken.
+ </para>
+
+ <para>
+'postreset' hook (may be NULL) is called after the EH reset is performed. Based on
+existing conditions, severity of the problem, and hardware capabilities,
+ </para>
+
+ <para>
+Either 'softreset' (may be NULL) or 'hardreset' (may be NULL) will be
+called to perform the low-level EH reset.
+ </para>
+
+ <programlisting>
+void (*post_internal_cmd) (struct ata_queued_cmd *qc);
</programlisting>
<para>
-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().
+Perform any hardware-specific actions necessary to finish processing
+after executing a probe-time or EH-time command via ata_exec_internal().
</para>
</sect2>