diff options
author | Andrii Tseglytskyi <andrii.tseglytskyi@ti.com> | 2013-05-20 22:42:08 +0000 |
---|---|---|
committer | Tom Rini <trini@ti.com> | 2013-06-10 08:43:09 -0400 |
commit | 4d0df9c1e94f32a9695be352fead3167fb5135c7 (patch) | |
tree | f1295abc801b55014db970ee1727d8ae206bc232 /arch/arm/cpu/armv7/omap5/abb.c | |
parent | a662e0c345b4cd9f4c2d51796154ad4a345a72a5 (diff) | |
download | u-boot-imx-4d0df9c1e94f32a9695be352fead3167fb5135c7.zip u-boot-imx-4d0df9c1e94f32a9695be352fead3167fb5135c7.tar.gz u-boot-imx-4d0df9c1e94f32a9695be352fead3167fb5135c7.tar.bz2 |
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>
Diffstat (limited to 'arch/arm/cpu/armv7/omap5/abb.c')
-rw-r--r-- | arch/arm/cpu/armv7/omap5/abb.c | 67 |
1 files changed, 67 insertions, 0 deletions
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; +} |