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, 19 insertions, 0 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index f9ed198e4fc..3cfdb5f6762 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -945,6 +945,25 @@ extern unsigned long ata_pci_default_filter(struct ata_device *, unsigned long);
 #endif /* CONFIG_PCI */
 
 /*
+ * PMP
+ */
+extern void sata_pmp_read_init_tf(struct ata_taskfile *tf,
+				  struct ata_device *dev, int pmp, int reg);
+extern u32 sata_pmp_read_val(const struct ata_taskfile *tf);
+extern void sata_pmp_write_init_tf(struct ata_taskfile *tf,
+				   struct ata_device *dev,
+				   int pmp, int reg, u32 val);
+extern int sata_pmp_std_prereset(struct ata_link *link, unsigned long deadline);
+extern int sata_pmp_std_hardreset(struct ata_link *link, unsigned int *class,
+				  unsigned long deadline);
+extern void sata_pmp_std_postreset(struct ata_link *link, unsigned int *class);
+extern void sata_pmp_do_eh(struct ata_port *ap,
+		ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
+		ata_reset_fn_t hardreset, ata_postreset_fn_t postreset,
+		ata_prereset_fn_t pmp_prereset, ata_reset_fn_t pmp_softreset,
+		ata_reset_fn_t pmp_hardreset, ata_postreset_fn_t pmp_postreset);
+
+/*
  * EH
  */
 extern void ata_eng_timeout(struct ata_port *ap);