OMAP3: PRM/CM: separate CM context save/restore; remove PRM context save/restore

The OMAP3 PRM module is in the WKUP powerdomain, which is always
powered when the chip is powered, so it shouldn't be necessary to save
and restore those PRM registers.  Remove the PRM register save/restore
code, which should save several microseconds during off-mode
entry/exit, since PRM register accesses are relatively slow.

While doing so, move the CM register save/restore code into
CM-specific code.  The CM module has been distinct from the PRM module
since 2430.

This patch includes some minor changes to pm34xx.c.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Rajendra Nayak <rnayak@ti.com>
Cc: Tero Kristo <tero.kristo@nokia.com>
Cc: Kalle Jokiniemi <kalle.jokiniemi@digia.com>
Reviewed-by: Kevin Hilman <khilman@deeprootsystems.com>
Tested-by: Kevin Hilman <khilman@deeprootsystems.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Rajendra Nayak <rnayak@ti.com>

arch/arm/mach-omap2/cm2xxx_3xxx.h

@@ -128,4 +128,11 @@ extern u32 cm_clear_mod_reg_bits(u32 bits, s16 module, s16 idx);
 /* CM_IDLEST_GFX */
 #define OMAP_ST_GFX_MASK				(1 << 0)
 
+
+/* Function prototypes */
+# ifndef __ASSEMBLER__
+extern void omap3_cm_save_context(void);
+extern void omap3_cm_restore_context(void);
+# endif
+
 #endif

arch/arm/mach-omap2/pm34xx.c

@@ -424,7 +424,7 @@ void omap_sram_idle(void)
 		omap_uart_prepare_idle(1);
 		if (core_next_state == PWRDM_POWER_OFF) {
 			omap3_core_save_context();
-			omap3_prcm_save_context();
+			omap3_cm_save_context();
 		}
 	}
 
@@ -464,7 +464,7 @@ void omap_sram_idle(void)
 		core_prev_state = pwrdm_read_prev_pwrst(core_pwrdm);
 		if (core_prev_state == PWRDM_POWER_OFF) {
 			omap3_core_restore_context();
-			omap3_prcm_restore_context();
+			omap3_cm_restore_context();
 			omap3_sram_restore_context();
 			omap2_sms_restore_context();
 		}

arch/arm/mach-omap2/prm2xxx_3xxx.c

@@ -154,4 +154,3 @@ int omap2_prm_deassert_hardreset(s16 prm_mod, u8 shift)
 
 	return (c == MAX_MODULE_HARDRESET_WAIT) ? -EBUSY : 0;
 }
-

arch/arm/plat-omap/include/plat/prcm.h

@@ -31,9 +31,6 @@ int omap2_cm_wait_idlest(void __iomem *reg, u32 mask, u8 idlest,
 #define START_PADCONF_SAVE 0x2
 #define PADCONF_SAVE_DONE  0x1
 
-void omap3_prcm_save_context(void);
-void omap3_prcm_restore_context(void);
-
 u32 omap4_prm_read_bits_shift(void __iomem *reg, u32 mask);
 u32 omap4_prm_rmw_reg_bits(u32 mask, u32 bits, void __iomem *reg);