libata: make reset related methods proper port operations

Currently reset methods are not specified directly in the
ata_port_operations table.  If a LLD wants to use custom reset
methods, it should construct and use a error_handler which uses those
reset methods.  It's done this way for two reasons.

First, the ops table already contained too many methods and adding
four more of them would noticeably increase the amount of necessary
boilerplate code all over low level drivers.

Second, as ->error_handler uses those reset methods, it can get
confusing.  ie. By overriding ->error_handler, those reset ops can be
made useless making layering a bit hazy.

Now that ops table uses inheritance, the first problem doesn't exist
anymore.  The second isn't completely solved but is relieved by
providing default values - most drivers can just override what it has
implemented and don't have to concern itself about higher level
callbacks.  In fact, there currently is no driver which actually
modifies error handling behavior.  Drivers which override
->error_handler just wraps the standard error handler only to prepare
the controller for EH.  I don't think making ops layering strict has
any noticeable benefit.

This patch makes ->prereset, ->softreset, ->hardreset, ->postreset and
their PMP counterparts propoer ops.  Default ops are provided in the
base ops tables and drivers are converted to override individual reset
methods instead of creating custom error_handler.

* ata_std_error_handler() doesn't use sata_std_hardreset() if SCRs
  aren't accessible.  sata_promise doesn't need to use separate
  error_handlers for PATA and SATA anymore.

* softreset is broken for sata_inic162x and sata_sx4.  As libata now
  always prefers hardreset, this doesn't really matter but the ops are
  forced to NULL using ATA_OP_NULL for documentation purpose.

* pata_hpt374 needs to use different prereset for the first and second
  PCI functions.  This used to be done by branching from
  hpt374_error_handler().  The proper way to do this is to use
  separate ops and port_info tables for each function.  Converted.

Signed-off-by: Tejun Heo <htejun@gmail.com>

1 files changed, 16 insertions, 33 deletions

diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 6223ec042c8..2a229a1d321 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -396,28 +396,21 @@ void ata_bmdma_thaw(struct ata_port *ap)
 }
 
 /**
- *	ata_bmdma_drive_eh - Perform EH with given methods for BMDMA controller
+ *	ata_bmdma_error_handler - Stock error handler for BMDMA controller
  *	@ap: port to handle error for
- *	@prereset: prereset method (can be NULL)
- *	@softreset: softreset method (can be NULL)
- *	@hardreset: hardreset method (can be NULL)
- *	@postreset: postreset method (can be NULL)
  *
- *	Handle error for ATA BMDMA controller.  It can handle both
+ *	Stock error handler for BMDMA controller.  It can handle both
  *	PATA and SATA controllers.  Many controllers should be able to
  *	use this EH as-is or with some added handling before and
  *	after.
  *
- *	This function is intended to be used for constructing
- *	->error_handler callback by low level drivers.
- *
  *	LOCKING:
  *	Kernel thread context (may sleep)
  */
-void ata_bmdma_drive_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)
+void ata_bmdma_error_handler(struct ata_port *ap)
 {
+	ata_reset_fn_t softreset = ap->ops->softreset;
+	ata_reset_fn_t hardreset = ap->ops->hardreset;
 	struct ata_queued_cmd *qc;
 	unsigned long flags;
 	int thaw = 0;
@@ -460,29 +453,19 @@ void ata_bmdma_drive_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
 		ata_eh_thaw_port(ap);
 
 	/* PIO and DMA engines have been stopped, perform recovery */
-	ata_do_eh(ap, prereset, softreset, hardreset, postreset);
-}
-
-/**
- *	ata_bmdma_error_handler - Stock error handler for BMDMA controller
- *	@ap: port to handle error for
- *
- *	Stock error handler for BMDMA controller.
- *
- *	LOCKING:
- *	Kernel thread context (may sleep)
- */
-void ata_bmdma_error_handler(struct ata_port *ap)
-{
-	ata_reset_fn_t softreset = NULL, hardreset = NULL;
 
-	if (ap->ioaddr.ctl_addr)
-		softreset = ata_std_softreset;
-	if (sata_scr_valid(&ap->link))
-		hardreset = sata_std_hardreset;
+	/* ata_std_softreset and sata_std_hardreset are inherited to
+	 * all SFF drivers from ata_sff_port_ops.  Ignore softreset if
+	 * ctl isn't accessible.  Ignore hardreset if SCR access isn't
+	 * available.
+	 */
+	if (softreset == ata_std_softreset && !ap->ioaddr.ctl_addr)
+		softreset = NULL;
+	if (hardreset == sata_std_hardreset && !sata_scr_valid(&ap->link))
+		hardreset = NULL;
 
-	ata_bmdma_drive_eh(ap, ata_std_prereset, softreset, hardreset,
-			   ata_std_postreset);
+	ata_do_eh(ap, ap->ops->prereset, softreset, hardreset,
+		  ap->ops->postreset);
 }
 
 /**