libata-pmp: implement Port Multiplier support

Implement Port Multiplier support.  To support PMP, a LLDD has to
supply ops->pmp_read() and pmp_write().  If non-null, ->pmp_attach and
->pmp_detach are called on PMP attach and detach, respectively.

->pmp_read/write() can be called while the port is frozen, so they
must be implemented by polling.  This patch supplies several helpers
to ease ->pmp_read/write() implementation.

Also, irq_handler and error_handler must be PMP aware.  Most of PMP
aware EH can be done by calling ata_pmp_do_eh() with appropriate
methods.  PMP EH uses separate set of reset methods and this patch
implements standard prereset, hardreset and postreset methods.

This patch only implements PMP support.  The next patch will integrate
PMP into the reset of libata and thus enable PMP support.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/ata/Makefile b/drivers/ata/Makefile
index 56bf13cbd198..7e937519a930 100644
--- a/drivers/ata/Makefile
+++ b/drivers/ata/Makefile
@@ -71,5 +71,6 @@ obj-$(CONFIG_ATA_GENERIC)	+= ata_generic.o
 # Should be last libata driver
 obj-$(CONFIG_PATA_LEGACY)       += pata_legacy.o
 
-libata-objs     := libata-core.o libata-scsi.o libata-sff.o libata-eh.o
+libata-objs     := libata-core.o libata-scsi.o libata-sff.o libata-eh.o \
+                   libata-pmp.o
 libata-$(CONFIG_ATA_ACPI)       += libata-acpi.o