提交 bf717b11 编写于 作者: J Jeff Garzik

[libata] Update docs to reflect current driver API

上级 f0eb62b8
...@@ -169,6 +169,22 @@ void (*tf_read) (struct ata_port *ap, struct ata_taskfile *tf); ...@@ -169,6 +169,22 @@ void (*tf_read) (struct ata_port *ap, struct ata_taskfile *tf);
</sect2> </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> <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);
...@@ -204,11 +220,10 @@ command. ...@@ -204,11 +220,10 @@ command.
<programlisting> <programlisting>
u8 (*check_status)(struct ata_port *ap); u8 (*check_status)(struct ata_port *ap);
u8 (*check_altstatus)(struct ata_port *ap); u8 (*check_altstatus)(struct ata_port *ap);
u8 (*check_err)(struct ata_port *ap);
</programlisting> </programlisting>
<para> <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 hardware. On some hardware, reading the Status register has
the side effect of clearing the interrupt condition. the side effect of clearing the interrupt condition.
Most drivers for taskfile-based hardware use Most drivers for taskfile-based hardware use
...@@ -269,23 +284,6 @@ void (*set_mode) (struct ata_port *ap); ...@@ -269,23 +284,6 @@ void (*set_mode) (struct ata_port *ap);
</sect2> </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> <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);
...@@ -354,16 +352,74 @@ int (*qc_issue) (struct ata_queued_cmd *qc); ...@@ -354,16 +352,74 @@ int (*qc_issue) (struct ata_queued_cmd *qc);
</sect2> </sect2>
<sect2><title>Timeout (error) handling</title> <sect2><title>Exception and probe handling (EH)</title>
<programlisting> <programlisting>
void (*eng_timeout) (struct ata_port *ap); 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> </programlisting>
<para> <para>
This is a high level error handling function, called from the Perform any hardware-specific actions necessary to finish processing
error handling thread, when a command times out. Most newer after executing a probe-time or EH-time command via ata_exec_internal().
hardware will implement its own error handling code here. IDE BMDMA
drivers may use the helper function ata_eng_timeout().
</para> </para>
</sect2> </sect2>
......
...@@ -3496,7 +3496,7 @@ void swap_buf_le16(u16 *buf, unsigned int buf_words) ...@@ -3496,7 +3496,7 @@ void swap_buf_le16(u16 *buf, unsigned int buf_words)
/** /**
* ata_mmio_data_xfer - Transfer data by MMIO * ata_mmio_data_xfer - Transfer data by MMIO
* @dev: device for this I/O * @adev: device for this I/O
* @buf: data buffer * @buf: data buffer
* @buflen: buffer length * @buflen: buffer length
* @write_data: read/write * @write_data: read/write
......
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