• Tejun Heo's avatar
    libata: make reset related methods proper port operations · a1efdaba
    Tejun Heo authored
    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: default avatarTejun Heo <htejun@gmail.com>
pata_efar.c 7.78 KB