1
linux/include
Tejun Heo b1c72916ab libata: implement slave_link
Explanation taken from the comment of ata_slave_link_init().

 In libata, a port contains links and a link contains devices.  There
 is single host link but if a PMP is attached to it, there can be
 multiple fan-out links.  On SATA, there's usually a single device
 connected to a link but PATA and SATA controllers emulating TF based
 interface can have two - master and slave.

 However, there are a few controllers which don't fit into this
 abstraction too well - SATA controllers which emulate TF interface
 with both master and slave devices but also have separate SCR
 register sets for each device.  These controllers need separate links
 for physical link handling (e.g. onlineness, link speed) but should
 be treated like a traditional M/S controller for everything else
 (e.g. command issue, softreset).

 slave_link is libata's way of handling this class of controllers
 without impacting core layer too much.  For anything other than
 physical link handling, the default host link is used for both master
 and slave.  For physical link handling, separate @ap->slave_link is
 used.  All dirty details are implemented inside libata core layer.
 From LLD's POV, the only difference is that prereset, hardreset and
 postreset are called once more for the slave link, so the reset
 sequence looks like the following.

 prereset(M) -> prereset(S) -> hardreset(M) -> hardreset(S) ->
 softreset(M) -> postreset(M) -> postreset(S)

 Note that softreset is called only for the master.  Softreset resets
 both M/S by definition, so SRST on master should handle both (the
 standard method will work just fine).

As slave_link excludes PMP support and only code paths which deal with
the attributes of physical link are affected, all the changes are
localized to libata.h, libata-core.c and libata-eh.c.

 * ata_is_host_link() updated so that slave_link is considered as host
   link too.

 * iterator extended to iterate over the slave_link when using the
   underbarred version.

 * force param handling updated such that devno 16 is mapped to the
   slave link/device.

 * ata_link_on/offline() updated to return the combined result from
   master and slave link.  ata_phys_link_on/offline() are the direct
   versions.

 * EH autopsy and report are performed separately for master slave
   links.  Reset is udpated to implement the above described reset
   sequence.

Except for reset update, most changes are minor, many of them just
modifying dev->link to ata_dev_phys_link(dev) or using phys online
test instead.

After this update, LLDs can take full advantage of per-dev SCR
registers by simply turning on slave link.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2008-09-29 00:25:28 -04:00
..
acpi ACPICA: Additional error checking for pathname utilities 2008-08-15 02:12:16 +02:00
asm-arm [ARM] 5191/1: ARM: remove CVS keywords 2008-08-16 20:01:18 +01:00
asm-cris Reduce brokenness of CRIS headers_install 2008-08-20 13:19:51 -07:00
asm-frv FRV: Provide ioremap_wc() for FRV 2008-08-20 13:19:52 -07:00
asm-generic warn: Turn the netdev timeout WARN_ON() into a WARN() 2008-09-16 19:39:33 -07:00
asm-m32r [PATCH] kill altroot 2008-07-26 20:53:20 -04:00
asm-m68k m68k{,nommu}: Wire up new system calls 2008-08-11 10:37:34 -07:00
asm-mips [MIPS] Fixe the definition of PTRS_PER_PGD 2008-09-24 00:26:55 +02:00
asm-mn10300 MN10300: Supply ioremap_wc() for MN10300 2008-08-20 13:19:51 -07:00
asm-parisc lib: Correct printk %pF to work on all architectures 2008-09-09 11:51:15 -07:00
asm-um [PATCH] kill altroot 2008-07-26 20:53:20 -04:00
asm-x86 x86: prevent C-states hang on AMD C1E enabled machines 2008-09-23 11:38:53 +02:00
asm-xtensa [PATCH] kill altroot 2008-07-26 20:53:20 -04:00
crypto crypto: hash - Add missing top-level functions 2008-08-13 20:08:44 +10:00
drm
keys
linux libata: implement slave_link 2008-09-29 00:25:28 -04:00
math-emu
media V4L/DVB (8610): Add suspend/resume capabilities to soc_camera. 2008-08-06 06:57:32 -03:00
mtd
net 9p: implement proper trans module refcounting and unregistration 2008-09-24 16:22:23 -05:00
pcmcia
rdma RDMA/cma: Remove padding arrays by using struct sockaddr_storage 2008-08-04 11:02:14 -07:00
rxrpc
scsi [SCSI] fix check of PQ and PDT bits for WLUNs 2008-08-29 09:19:11 -05:00
sound ALSA: ASoC: Export dapm_reg_event() fully 2008-07-29 16:00:33 +02:00
video atmel_lcdfb: add board parameter specify framebuffer memory size 2008-08-12 16:07:29 -07:00
xen
Kbuild kbuild: only one call for include/ in make headers_* 2008-07-25 22:11:44 +02:00