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.
The application of FBB/RBB technique is determined for each unique device in some process nodes, whereas, they are mandated on other process nodes.
OMAP5 silicon requires ABB to be properly configured on early boot stage. The following patch series adds generic ABB configuration and enables it for OMAP5 silicons.
v02: series contains minor comments fixes.
v03: series contains: - clearing pending ABB interrupts before beginning of ABB configuration. - clearing ABB "setup" and "control" registers before beginning of ABB configuration. - removing superfluous wait on ABB "in transition" done status.
Andrii Tseglytskyi (2): OMAP3+: introduce generic ABB support OMAP5: add ABB setup for MPU voltage domain
arch/arm/cpu/armv7/omap-common/Makefile | 1 + arch/arm/cpu/armv7/omap-common/abb.c | 137 ++++++++++++++++++++++++ arch/arm/cpu/armv7/omap-common/clocks-common.c | 9 ++ arch/arm/cpu/armv7/omap5/Makefile | 1 + arch/arm/cpu/armv7/omap5/abb.c | 67 ++++++++++++ arch/arm/cpu/armv7/omap5/prcm-regs.c | 7 ++ arch/arm/include/asm/arch-omap3/omap3.h | 7 ++ arch/arm/include/asm/arch-omap4/omap.h | 7 ++ arch/arm/include/asm/arch-omap5/omap.h | 13 +++ arch/arm/include/asm/omap_common.h | 22 ++++ 10 files changed, 271 insertions(+) create mode 100644 arch/arm/cpu/armv7/omap-common/abb.c create mode 100644 arch/arm/cpu/armv7/omap5/abb.c