From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aneesh V Date: Thu, 15 Mar 2012 18:55:01 +0530 Subject: [U-Boot] [PATCH v4 0/6] Enable Thumb build for ARM platforms In-Reply-To: <1331227222-12419-1-git-send-email-aneesh@ti.com> References: <1331227222-12419-1-git-send-email-aneesh@ti.com> Message-ID: <4F61EDAD.6090106@ti.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Tom, Albert, Does this series look good? On Thursday 08 March 2012 10:50 PM, Aneesh V wrote: > Thumb is an alternate instruction set available in many > ARM processors. Below is a detailed description from ARM > specs: > > "The Thumb instruction set is a re-encoded subset of the > ARM instruction set. Thumb instructions execute in their > own processor state, with the architecture defining the > mechanisms required to transition between ARM and Thumb > states. The key difference is that Thumb instructions are > half the size of ARM instructions(16 bits compared with 32 > bits). Greater code density can usually be achieved by using > the Thumb instruction set in preference to the ARM instruction > set, at a cost of some reduction in performance" > > "In ARMv6T2, Thumb-2 technology is introduced. This technology > makes it possible to extend the original Thumb instruction set > with many 32-bit instructions. The range of 32-bit Thumb instructions > included in ARMv6T2 permits Thumb code to achieve performance > similar to ARM code, with code density better than that of earlier > Thumb code. From ARMv6T2, the ARM and Thumb instruction sets provide > almost identical functionality" > > This series adds Thumb support in U-Boot and enables it for > OMAP4. It also fixes issues faced while booting OMAP4 with > Thumb-2 images of U-Boot and SPL. > > Thumb mode is becoming increasingly relevant for U-Boot with > the advent of SPL. It's very important to keep SPL size smaller > considering the internal RAM size constraints on many platforms. > On OMAP4 the size reduction enables us to use SPL on secure devices > that have smaller internal RAM available for non-secure world. > > To enable support for new platforms you just need to add > CONFIG_SYS_THUMB_BUILD in your config file. > > Tool-chains tried: > 1. Sourcery G++ Lite 2010q1-202 > arm-none-linux-gnueabi-gcc (Sourcery G++ Lite 2010q1-202) 4.4.1 > GNU ld (Sourcery G++ Lite 2010q1-202) - binutils 2.19.51.20090709 > > 2. Linaro 4.6-2012.01 > arm-linux-gnueabi-gcc (crosstool-NG linaro-1.13.1-2012.01-20120125 - > Linaro GCC 2012.01) 4.6.3 20120105 (prerelease) > GNU ld (crosstool-NG linaro-1.13.1-2012.01-20120125 - Linaro GCC 2012.01) 2.22 > > Code-size reduction: > Image ARM build Thumb build % Reduction > u-boot.bin 190408 144676 24.01% > u-boot-spl.bin 33200 25096 24.40% > > Performance(timestamp just before the main loop): > ARM build Thumb build % Reduction > 898510us 878247us -2.25% > > Performance actually improved marginally for the Thumb > build, maybe because of the reduced image sizes. > > Aneesh V (6): > arm: adapt asm/linkage.h from Linux > armv7: add appropriate headers for assembly functions > ARM: enable Thumb build > armv7: Use -march=armv7-a and thereby enable Thumb-2 > omap4+: Avoid using __attribute__ ((__packed__)) > OMAP4: enable Thumb build > > README | 8 +++++ > arch/arm/config.mk | 22 +++++++++---- > arch/arm/cpu/armv7/config.mk | 7 +++- > arch/arm/cpu/armv7/mx5/lowlevel_init.S | 5 ++- > arch/arm/cpu/armv7/mx6/lowlevel_init.S | 5 ++- > arch/arm/cpu/armv7/omap-common/lowlevel_init.S | 14 ++++---- > arch/arm/cpu/armv7/omap-common/reset.S | 5 ++- > arch/arm/cpu/armv7/omap3/lowlevel_init.S | 41 ++++++++++++----------- > arch/arm/cpu/armv7/s5pc1xx/cache.S | 10 +++-- > arch/arm/cpu/armv7/s5pc1xx/reset.S | 5 ++- > arch/arm/cpu/armv7/start.S | 13 ++++--- > arch/arm/cpu/armv7/tegra2/lowlevel_init.S | 5 ++- > arch/arm/cpu/armv7/u8500/lowlevel.S | 9 +++-- > arch/arm/include/asm/arch-omap4/mux_omap4.h | 2 +- > arch/arm/include/asm/arch-omap5/mux_omap5.h | 2 +- > arch/arm/include/asm/linkage.h | 7 ++++ > include/configs/omap4_common.h | 2 + > include/linux/linkage.h | 7 +++- > 18 files changed, 106 insertions(+), 63 deletions(-) > create mode 100644 arch/arm/include/asm/linkage.h >