OMAP4: PRCM: move global reset function for OMAP4 to an OMAP4-specific file

Move the OMAP4 global software reset function to the OMAP4-specific
prm44xx.c file, where it belongs.  Part of the long-term process of
moving all of the direct PRCM register writes into lower-layer code.

Also add OCP barriers on OMAP2/3/4 to reduce the chance that the MPU
will continue executing while the system is supposed to be resetting
itself.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Rajendra Nayak <rnayak@ti.com>

arch/arm/mach-omap2/prm44xx.c

@@ -179,3 +179,17 @@ int omap4_prm_deassert_hardreset(void __iomem *rstctrl_reg, u8 shift)
 	return (c == MAX_MODULE_HARDRESET_WAIT) ? -EBUSY : 0;
 }
 
+void omap4_prm_global_warm_sw_reset(void)
+{
+	u32 v;
+
+	v = omap4_prm_read_inst_reg(OMAP4430_PRM_DEVICE_INST,
+				    OMAP4_RM_RSTCTRL);
+	v |= OMAP4430_RST_GLOBAL_WARM_SW_MASK;
+	omap4_prm_write_inst_reg(v, OMAP4430_PRM_DEVICE_INST,
+				 OMAP4_RM_RSTCTRL);
+
+	/* OCP barrier */
+	v = omap4_prm_read_inst_reg(OMAP4430_PRM_DEVICE_INST,
+				    OMAP4_RM_RSTCTRL);
+}