OMAP4: PRCM: add OMAP4-specific accessor/mutator functions

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: Paul Walmsley <paul@pwsan.com>
Cc: Benoît Cousson <b-cousson@ti.com>
Cc: Rajendra Nayak <rnayak@ti.com>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/prcm_mpu44xx.h b/arch/arm/mach-omap2/prcm_mpu44xx.h
index 80e00c16d36..e5190e99fd9 100644
--- a/arch/arm/mach-omap2/prcm_mpu44xx.h
+++ b/arch/arm/mach-omap2/prcm_mpu44xx.h
@@ -88,4 +88,12 @@
 #define OMAP4_CM_CPU1_CLKSTCTRL_OFFSET			0x0018
 #define OMAP4430_CM_CPU1_CLKSTCTRL			OMAP44XX_PRCM_MPU_REGADDR(OMAP4430_PRCM_MPU_CPU1_INST, 0x0018)
 
+/* Function prototypes */
+# ifndef __ASSEMBLER__
+extern u32 omap4_prcm_mpu_read_inst_reg(s16 inst, u16 idx);
+extern void omap4_prcm_mpu_write_inst_reg(u32 val, s16 inst, u16 idx);
+extern u32 omap4_prcm_mpu_rmw_inst_reg_bits(u32 mask, u32 bits, s16 inst,
+					    s16 idx);
+# endif
+
 #endif