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, 2 insertions, 17 deletions

diff --git a/drivers/ata/pata_pdc2027x.c b/drivers/ata/pata_pdc2027x.c
index f619c20dd192..d235c9f92d09 100644
--- a/drivers/ata/pata_pdc2027x.c
+++ b/drivers/ata/pata_pdc2027x.c
@@ -63,7 +63,7 @@ enum {
 };
 
 static int pdc2027x_init_one(struct pci_dev *pdev, const struct pci_device_id *ent);
-static void pdc2027x_error_handler(struct ata_port *ap);
+static int pdc2027x_prereset(struct ata_link *link, unsigned long deadline);
 static void pdc2027x_set_piomode(struct ata_port *ap, struct ata_device *adev);
 static void pdc2027x_set_dmamode(struct ata_port *ap, struct ata_device *adev);
 static int pdc2027x_check_atapi_dma(struct ata_queued_cmd *qc);
@@ -136,7 +136,7 @@ static struct ata_port_operations pdc2027x_pata100_ops = {
         .inherits               = &ata_bmdma_port_ops,
         .check_atapi_dma        = pdc2027x_check_atapi_dma,
         .cable_detect           = pdc2027x_cable_detect,
-        .error_handler          = pdc2027x_error_handler,
+        .prereset               = pdc2027x_prereset,
 };
 
 static struct ata_port_operations pdc2027x_pata133_ops = {
@@ -252,21 +252,6 @@ static int pdc2027x_prereset(struct ata_link *link, unsigned long deadline)
 }
 
 /**
- *      pdc2027x_error_handler - Perform reset on PATA port and classify
- *      @ap: Port to reset
- *
- *      Reset PATA phy and classify attached devices.
- *
- *      LOCKING:
- *      None (inherited from caller).
- */
-
-static void pdc2027x_error_handler(struct ata_port *ap)
-{
-        ata_bmdma_drive_eh(ap, pdc2027x_prereset, ata_std_softreset, NULL, ata_std_postreset);
-}
-
-/**
  *      pdc2720x_mode_filter    -       mode selection filter
  *      @adev: ATA device
  *      @mask: list of modes proposed