OMAP3+: introduce generic ABB support

Adaptive Body Biasing (ABB) modulates transistor bias voltages
dynamically in order to optimize switching speed versus leakage.
Adaptive Body-Bias ldos are present for some voltage domains
starting with OMAP3630. There are three modes of operation:

* Bypass - the default, it just follows the vdd voltage
* Foward Body-Bias - applies voltage bias to increase transistor
  performance at the cost of power.  Used to operate safely at high
  OPPs.
* Reverse Body-Bias - applies voltage bias to decrease leakage and
  save power.  Used to save power at lower OPPs.

Signed-off-by: Andrii Tseglytskyi <andrii.tseglytskyi@ti.com>
Acked-by: Nishanth Menon <nm@ti.com>

2 files changed, 68 insertions, 0 deletions

diff --git a/arch/arm/cpu/armv7/omap5/Makefile b/arch/arm/cpu/armv7/omap5/Makefile
index ce00e2c..6ff8dbb 100644
--- a/arch/arm/cpu/armv7/omap5/Makefile
+++ b/arch/arm/cpu/armv7/omap5/Makefile
@@ -30,6 +30,7 @@ COBJS	+= emif.o
 COBJS	+= sdram.o
 COBJS	+= prcm-regs.o
 COBJS	+= hw_data.o
+COBJS	+= abb.o
 
 SRCS	:= $(SOBJS:.o=.S) $(COBJS:.o=.c)
 OBJS	:= $(addprefix $(obj),$(COBJS) $(SOBJS))
diff --git a/arch/arm/cpu/armv7/omap5/abb.c b/arch/arm/cpu/armv7/omap5/abb.c
new file mode 100644
index 0000000..92470be
--- /dev/null
+++ b/arch/arm/cpu/armv7/omap5/abb.c
@@ -0,0 +1,67 @@
+/*
+ *
+ * Adaptive Body Bias programming sequence for OMAP5 family
+ *
+ * (C) Copyright 2013
+ * Texas Instruments, <www.ti.com>
+ *
+ * Andrii Tseglytskyi <andrii.tseglytskyi@ti.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <asm/omap_common.h>
+#include <asm/io.h>
+
+/*
+ * Setup LDOVBB for OMAP5.
+ * On OMAP5+ some ABB settings are fused. They are handled
+ * in the following way:
+ *
+ * 1. corresponding EFUSE register contains ABB enable bit
+ *    and VSET value
+ * 2. If ABB enable bit is set to 1, than ABB should be
+ *    enabled, otherwise ABB should be disabled
+ * 3. If ABB is enabled, than VSET value should be copied
+ *    to corresponding MUX control register
+ */
+s8 abb_setup_ldovbb(u32 fuse, u32 ldovbb)
+{
+	u32 vset;
+
+	/*
+	 * ABB parameters must be properly fused
+	 * otherwise ABB should be disabled
+	 */
+	vset = readl(fuse);
+	if (!(vset & OMAP5_ABB_FUSE_ENABLE_MASK))
+		return -1;
+
+	/* prepare VSET value for LDOVBB mux register */
+	vset &= OMAP5_ABB_FUSE_VSET_MASK;
+	vset >>= ffs(OMAP5_ABB_FUSE_VSET_MASK) - 1;
+	vset <<= ffs(OMAP5_ABB_LDOVBBMPU_VSET_OUT_MASK) - 1;
+	vset |= OMAP5_ABB_LDOVBBMPU_MUX_CTRL_MASK;
+
+	/* setup LDOVBB using fused value */
+	clrsetbits_le32(ldovbb,  OMAP5_ABB_LDOVBBMPU_VSET_OUT_MASK, vset);
+
+	return 0;
+}