• Paul Walmsley's avatar
    OMAP4: PRCM: add OMAP4-specific accessor/mutator functions · 2ace831f
    Paul Walmsley authored
    In some ways, the OMAP4 PRCM register layout is quite different than
    the OMAP2/3 PRCM register layout.  For example, on OMAP2/3, from a
    register layout point of view, all CM instances were located in the CM
    subsystem, and all PRM instances were located in the PRM subsystem.
    OMAP4 changes this.  Now, for example, some CM instances, such as
    WKUP_CM and EMU_CM, are located in the system PRM subsystem.  And a
    "local PRCM" exists for the MPU - this PRCM combines registers that
    would normally appear in both CM and PRM instances, but uses its own
    register layout which matches neither the OMAP2/3 PRCM layout nor the
    OMAP4 PRCM layout.
    
    To try to deal with this, introduce some new functions, omap4_cminst*
    and omap4_prminst*.  The former is to be used when writing to a CM
    instance register (no matter what subsystem or hardware module it
    exists in), and the latter, similarly, with PRM instance registers.
    To determine which "PRCM partition" to write to, the functions take a
    PRCM instance ID argument.  Subsequent patches add these partition IDs
    to the OMAP4 powerdomain and clockdomain definitions.
    
    As far as I can see, there's really no good way to handle these types
    of register access inconsistencies.  This patch seemed like the least
    bad approach.
    
    Moving forward, the long-term goal is to remove all direct PRCM
    register access from the PM code.  PRCM register access should go
    through layers such as the powerdomain and clockdomain code that can
    hide the details of how to interact with the specific hardware
    variant.
    
    While here, rename cm4xxx.c to cm44xx.c to match the naming convention
    of the other OMAP4 PRCM files.
    
    Thanks to Santosh Shilimkar <santosh.shilimkar@ti.com>, Rajendra Nayak
    <rnayak@ti.com>, and Benoît Cousson <b-cousson@ti.com> for some comments.
    Signed-off-by: default avatarPaul Walmsley <paul@pwsan.com>
    Cc: Benoît Cousson <b-cousson@ti.com>
    Cc: Rajendra Nayak <rnayak@ti.com>
    Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
    2ace831f
prminst44xx.c 1.76 KB