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authorAlan Cox <alan@lxorguk.ukuu.org.uk>2006-03-27 12:58:20 -0500
committerJeff Garzik <jeff@garzik.org>2006-03-29 19:30:28 -0500
commit5444a6f405618706eddbe1605ef8533b1b655764 (patch)
tree9265a1e65563add47a9fe5f1ddae44d6dd0742e3 /Documentation/DocBook
parent692785e798f341c057ff976c35a3d86ad5af8ac6 (diff)
[PATCH] libata: Simplex and other mode filtering logic
Add a field to the host_set called 'flags' (was host_set_flags changed to suit Jeff) Add a simplex_claimed field so we can remember who owns the DMA channel Add a ->mode_filter() hook to allow drivers to filter modes Add docs for mode_filter and set_mode Filter according to simplex state Filter cable in core This provides the needed framework to support all the mode rules found in the PATA world. The simplex filter deals with 'to spec' simplex DMA systems found in older chips. The cable filter avoids duplicating the same rules in each chip driver with PATA. Finally the mode filter is neccessary because drive/chip combinations have errata that forbid certain modes with some drives or types of ATA object. Drive speed setup remains per channel for now and the filters now use the framework Tejun put into place which cleans them up a lot from the older libata-pata patches. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
Diffstat (limited to 'Documentation/DocBook')
-rw-r--r--Documentation/DocBook/libata.tmpl47
1 files changed, 43 insertions, 4 deletions
diff --git a/Documentation/DocBook/libata.tmpl b/Documentation/DocBook/libata.tmpl
index d260d92089ad..5bcbb6ee3bc0 100644
--- a/Documentation/DocBook/libata.tmpl
+++ b/Documentation/DocBook/libata.tmpl
@@ -120,14 +120,27 @@ void (*dev_config) (struct ata_port *, struct ata_device *);
120 <programlisting> 120 <programlisting>
121void (*set_piomode) (struct ata_port *, struct ata_device *); 121void (*set_piomode) (struct ata_port *, struct ata_device *);
122void (*set_dmamode) (struct ata_port *, struct ata_device *); 122void (*set_dmamode) (struct ata_port *, struct ata_device *);
123void (*post_set_mode) (struct ata_port *ap); 123void (*post_set_mode) (struct ata_port *);
124unsigned int (*mode_filter) (struct ata_port *, struct ata_device *, unsigned int);
124 </programlisting> 125 </programlisting>
125 126
126 <para> 127 <para>
127 Hooks called prior to the issue of SET FEATURES - XFER MODE 128 Hooks called prior to the issue of SET FEATURES - XFER MODE
128 command. dev->pio_mode is guaranteed to be valid when 129 command. The optional ->mode_filter() hook is called when libata
129 ->set_piomode() is called, and dev->dma_mode is guaranteed to be 130 has built a mask of the possible modes. This is passed to the
130 valid when ->set_dmamode() is called. ->post_set_mode() is 131 ->mode_filter() function which should return a mask of valid modes
132 after filtering those unsuitable due to hardware limits. It is not
133 valid to use this interface to add modes.
134 </para>
135 <para>
136 dev->pio_mode and dev->dma_mode are guaranteed to be valid when
137 ->set_piomode() and when ->set_dmamode() is called. The timings for
138 any other drive sharing the cable will also be valid at this point.
139 That is the library records the decisions for the modes of each
140 drive on a channel before it attempts to set any of them.
141 </para>
142 <para>
143 ->post_set_mode() is
131 called unconditionally, after the SET FEATURES - XFER MODE 144 called unconditionally, after the SET FEATURES - XFER MODE
132 command completes successfully. 145 command completes successfully.
133 </para> 146 </para>
@@ -230,6 +243,32 @@ void (*dev_select)(struct ata_port *ap, unsigned int device);
230 243
231 </sect2> 244 </sect2>
232 245
246 <sect2><title>Private tuning method</title>
247 <programlisting>
248void (*set_mode) (struct ata_port *ap);
249 </programlisting>
250
251 <para>
252 By default libata performs drive and controller tuning in
253 accordance with the ATA timing rules and also applies blacklists
254 and cable limits. Some controllers need special handling and have
255 custom tuning rules, typically raid controllers that use ATA
256 commands but do not actually do drive timing.
257 </para>
258
259 <warning>
260 <para>
261 This hook should not be used to replace the standard controller
262 tuning logic when a controller has quirks. Replacing the default
263 tuning logic in that case would bypass handling for drive and
264 bridge quirks that may be important to data reliability. If a
265 controller needs to filter the mode selection it should use the
266 mode_filter hook instead.
267 </para>
268 </warning>
269
270 </sect2>
271
233 <sect2><title>Reset ATA bus</title> 272 <sect2><title>Reset ATA bus</title>
234 <programlisting> 273 <programlisting>
235void (*phy_reset) (struct ata_port *ap); 274void (*phy_reset) (struct ata_port *ap);