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The current delay loop calculation is still from revision 1 of flashrom, and since then it had a logic bug which caused all delays to be twice as long as intended. Fix the delay duration. Protect against delay loop overflows. Detect a non-working delay loop. Change the delay loop itself to ensure clever compiler optimizers won't eliminate it (as happens with clang/llvm in the current code). Some people suggested machine-specific asm, but the empty asm statement with the loop counter as register/memory input has the benefit of being perfectly cross-platform and working in gcc and clang. If time goes backwards (catastrophical NTP time difference, manual time change), timing measurements were shot because the new-old time subtraction yielded negative numbers which weren't handled correctly because the variable is unsigned. Work around that issue (a fix is mathematically impossible). If time goes forward too fast, pick the biggest possible timing measurement with a guaranteed overflow avoidance for all timing calculations. Check four times if the calculated timing is at most 10% too fast. This addresses OS scheduler interactions, e.g. being scheduled out during measurement which inflates measurements. If the timing looks like garbage, recalculate the timer values up to four times before giving up. Avoid division by zero in rare cases where timing measurements for a 250 ms delay returned 0 us elapsed. Corresponding to flashrom svn r990. Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net> Acked-by: Maciej Pijanka <maciej.pijanka@gmail.com>
------------------------------------------------------------------------------- flashrom README ------------------------------------------------------------------------------- flashrom is a utility for detecting, reading, writing, verifying and erasing flash chips. It is often used to flash BIOS/EFI/coreboot/firmware images in-system using a supported mainboard, but it also supports flashing of network cards (NICs), SATA controller cards, and other external devices which can program flash chips. It supports a wide range of DIP32, PLCC32, DIP8, SO8/SOIC8, TSOP32, and TSOP40 chips, which use various protocols such as LPC, FWH, parallel flash, or SPI. Please see the flashrom(8) manpage. Packaging --------- To package flashrom and remove dependencies on subversion, either use make export or make tarball make export will export all flashrom files from the subversion repository at revision BASE into a directory named $EXPORTDIR/flashrom-$VERSION-r$SVNREVISION and will additionally modify the Makefile in that directory to contain the svn revision of the exported tree. make tarball will simply tar up the result of make export and gzip compress it. The snapshot tarballs are the result of make tarball and require no further processing. Build Instructions ------------------ To build flashrom you need to install the following packages or ports: Linux et al: * pciutils / libpci * pciutils-devel / pciutils-dev / libpci-dev * zlib-devel / zlib1g-dev (needed if libpci was compiled with libz support) On FreeBSD, you need the following ports: * devel/gmake * devel/libpci To compile on Linux, use: make To compile on FreeBSD, use: gmake To compile on Nexenta, use: make To compile on Solaris, use: gmake LDFLAGS="-L$pathtolibpci" CC="gcc -I$pathtopciheaders" CFLAGS=-O2 To compile on NetBSD or DragonFly BSD, use: ln -s /usr/pkg/include/pciutils pci gmake CPPFLAGS=-I. LDFLAGS="-L/usr/pkg/lib -Wl,-rpath-link,/usr/pkg/lib" To compile and run on Darwin/Mac OS X: Install DirectIO from coresystems GmbH. DirectIO is available at http://www.coresystems.de/en/directio. To cross-compile on Linux for DOS: Get RPMs of the cross compiler from the DJGPP site and install them: djcross-binutils-2.19.1-10ap.i386.rpm djcross-gcc-tools-4.4.1-1ap.i686.rpm djcross-gcc-4.3.2-8ap.i686.rpm Download pciutils 3.1.5 and apply http://assembler.cz/flashrom/pciutils.patch Download and compile http://assembler.cz/flashrom/libgetopt/ Compile pciutils, see README.DJGPP for instructions. Enter the flashrom directory. ../libpci should contain pciutils source and binaries. ../libgetopt should contain getopt.a from libgetopt. Run either (change settings where appropriate) make CC=i586-pc-msdosdjgpp-gcc STRIP=i586-pc-msdosdjgpp-strip OS_ARCH=DOS or (above settings hardcoded) make djgpp-dos You might have to add WARNERROR=no to the make command line. To run flashrom.exe, download http://clio.rice.edu/djgpp/csdpmi7b.zip and make sure CWSDPMI.EXE is in the current directory. Installation ------------ In order to install flashrom and the manpage into /usr/local, type: make install For installation in a different directory use DESTDIR, e.g. like this: make DESTDIR=/usr install If you have insufficient permissions for the destination directory, use sudo by adding sudo in front of the commands above. Contact ------- The official flashrom website is: http://www.flashrom.org/ The IRC channel is #flashrom at irc.freenode.net The mailing list address is flashrom@flashrom.org