[libata] Update docs to reflect current driver API

This commit is contained in:
Jeff Garzik 2006-06-13 20:27:03 -04:00
parent f0eb62b81d
commit bf717b11ae
2 changed files with 81 additions and 25 deletions

View file

@ -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>
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().
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>
Perform any hardware-specific actions necessary to finish processing
after executing a probe-time or EH-time command via ata_exec_internal().
</para>
</sect2>

View file

@ -3496,7 +3496,7 @@ void swap_buf_le16(u16 *buf, unsigned int buf_words)
/**
* ata_mmio_data_xfer - Transfer data by MMIO
* @dev: device for this I/O
* @adev: device for this I/O
* @buf: data buffer
* @buflen: buffer length
* @write_data: read/write