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diff --git a/Documentation/DocBook/libata.tmpl b/Documentation/DocBook/libata.tmpl new file mode 100644 index 00000000000..cf2fce7707d --- /dev/null +++ b/Documentation/DocBook/libata.tmpl @@ -0,0 +1,282 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="libataDevGuide"> + <bookinfo> + <title>libATA Developer's Guide</title> + + <authorgroup> + <author> + <firstname>Jeff</firstname> + <surname>Garzik</surname> + </author> + </authorgroup> + + <copyright> + <year>2003</year> + <holder>Jeff Garzik</holder> + </copyright> + + <legalnotice> + <para> + The contents of this file are subject to the Open + Software License version 1.1 that can be found at + <ulink url="http://www.opensource.org/licenses/osl-1.1.txt">http://www.opensource.org/licenses/osl-1.1.txt</ulink> and is included herein + by reference. + </para> + + <para> + Alternatively, the contents of this file may be used under the terms + of the GNU General Public License version 2 (the "GPL") as distributed + in the kernel source COPYING file, in which case the provisions of + the GPL are applicable instead of the above. If you wish to allow + the use of your version of this file only under the terms of the + GPL and not to allow others to use your version of this file under + the OSL, indicate your decision by deleting the provisions above and + replace them with the notice and other provisions required by the GPL. + If you do not delete the provisions above, a recipient may use your + version of this file under either the OSL or the GPL. + </para> + + </legalnotice> + </bookinfo> + +<toc></toc> + + <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). + </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> + + <chapter id="libataDriverApi"> + <title>libata Driver API</title> + <sect1> + <title>struct ata_port_operations</title> + + <programlisting> +void (*port_disable) (struct ata_port *); + </programlisting> + + <para> + Called from ata_bus_probe() and ata_bus_reset() error paths, + as well as when unregistering from the SCSI module (rmmod, hot + unplug). + </para> + + <programlisting> +void (*dev_config) (struct ata_port *, struct ata_device *); + </programlisting> + + <para> + Called after IDENTIFY [PACKET] DEVICE is issued to each device + found. Typically used to apply device-specific fixups prior to + issue of SET FEATURES - XFER MODE, and prior to operation. + </para> + + <programlisting> +void (*set_piomode) (struct ata_port *, struct ata_device *); +void (*set_dmamode) (struct ata_port *, struct ata_device *); +void (*post_set_mode) (struct ata_port *ap); + </programlisting> + + <para> + Hooks called prior to the issue of SET FEATURES - XFER MODE + command. dev->pio_mode is guaranteed to be valid when + ->set_piomode() is called, and dev->dma_mode is guaranteed to be + valid when ->set_dmamode() is called. ->post_set_mode() is + called unconditionally, after the SET FEATURES - XFER MODE + command completes successfully. + </para> + + <para> + ->set_piomode() is always called (if present), but + ->set_dma_mode() is only called if DMA is possible. + </para> + + <programlisting> +void (*tf_load) (struct ata_port *ap, struct ata_taskfile *tf); +void (*tf_read) (struct ata_port *ap, struct ata_taskfile *tf); + </programlisting> + + <para> + ->tf_load() is called to load the given taskfile into hardware + registers / DMA buffers. ->tf_read() is called to read the + hardware registers / DMA buffers, to obtain the current set of + taskfile register values. + </para> + + <programlisting> +void (*exec_command)(struct ata_port *ap, struct ata_taskfile *tf); + </programlisting> + + <para> + causes an ATA command, previously loaded with + ->tf_load(), to be initiated in hardware. + </para> + + <programlisting> +u8 (*check_status)(struct ata_port *ap); +void (*dev_select)(struct ata_port *ap, unsigned int device); + </programlisting> + + <para> + Reads the Status ATA shadow register from hardware. On some + hardware, this has the side effect of clearing the interrupt + condition. + </para> + + <programlisting> +void (*dev_select)(struct ata_port *ap, unsigned int device); + </programlisting> + + <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. + </para> + + <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. + </para> + + <programlisting> +void (*bmdma_setup) (struct ata_queued_cmd *qc); +void (*bmdma_start) (struct ata_queued_cmd *qc); + </programlisting> + + <para> + When setting up an IDE BMDMA transaction, these hooks arm + (->bmdma_setup) and fire (->bmdma_start) the hardware's DMA + engine. + </para> + + <programlisting> +void (*qc_prep) (struct ata_queued_cmd *qc); +int (*qc_issue) (struct ata_queued_cmd *qc); + </programlisting> + + <para> + Higher-level hooks, these two hooks can potentially supercede + several of the above taskfile/DMA engine hooks. ->qc_prep is + called after the buffers have been DMA-mapped, and is typically + used to populate the hardware's DMA scatter-gather table. + Most drivers use the standard ata_qc_prep() helper function, but + more advanced drivers roll their own. + </para> + <para> + ->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. + </para> + + <programlisting> +void (*eng_timeout) (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. + </para> + + <programlisting> +irqreturn_t (*irq_handler)(int, void *, struct pt_regs *); +void (*irq_clear) (struct ata_port *); + </programlisting> + + <para> + ->irq_handler is the interrupt handling routine registered with + the system, by libata. ->irq_clear is called during probe just + before the interrupt handler is registered, to be sure hardware + is quiet. + </para> + + <programlisting> +u32 (*scr_read) (struct ata_port *ap, unsigned int sc_reg); +void (*scr_write) (struct ata_port *ap, unsigned int sc_reg, + u32 val); + </programlisting> + + <para> + Read and write standard SATA phy registers. Currently only used + if ->phy_reset hook called the sata_phy_reset() helper function. + </para> + + <programlisting> +int (*port_start) (struct ata_port *ap); +void (*port_stop) (struct ata_port *ap); +void (*host_stop) (struct ata_host_set *host_set); + </programlisting> + + <para> + ->port_start() is called just after the data structures for each + port are initialized. Typically this is used to alloc per-port + DMA buffers / tables / rings, enable DMA engines, and similar + 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> + + </sect1> + </chapter> + + <chapter id="libataExt"> + <title>libata Library</title> +!Edrivers/scsi/libata-core.c + </chapter> + + <chapter id="libataInt"> + <title>libata Core Internals</title> +!Idrivers/scsi/libata-core.c + </chapter> + + <chapter id="libataScsiInt"> + <title>libata SCSI translation/emulation</title> +!Edrivers/scsi/libata-scsi.c +!Idrivers/scsi/libata-scsi.c + </chapter> + + <chapter id="PiixInt"> + <title>ata_piix Internals</title> +!Idrivers/scsi/ata_piix.c + </chapter> + + <chapter id="SILInt"> + <title>sata_sil Internals</title> +!Idrivers/scsi/sata_sil.c + </chapter> + +</book> |