cederom
Can we improve efficiency?
I'm capturing my SWD bus using a Salea USB scope to debug various issues and I notice that libSWD has a lot more bus transactions than my J-link programmer:
For example - Writing to the DHCSR register to enable debug:
C code using libSWD
// set up the DHCSR reg
int dhcsr = LIBSWD_ARM_DEBUG_DHCSR_DBGKEY |
(enable ? LIBSWD_ARM_DEBUG_DHCSR_CDEBUGEN : 0);
res = libswd_memap_write_int_32(libswdctx, LIBSWD_OPERATION_EXECUTE, LIBSWD_ARM_DEBUG_DHCSR_ADDR, 1, &dhcsr);
libSWD:
0.50693350 Operation read DebugPort CTRL/STAT 0x8D OK 0xF0000041 CSYSPWRUPACK=1, CSYSPWRUPREQ=1, CDBGPWRUPACK=1, CDBGPWRUPREQ=1, CDBGRSTACK=0, CDBGRSTREQ=0, TRNCNT=0x000, MASKLANE=0x0, WDATAERR=0, READOK=1, STICKYERR=0, STICKYCMP=0, TRNMODE=Normal, STICKYORUN=0, ORUNDETECT=1
0.50703380 Operation write AccessPort TAR 0x8B OK 0xE000EDF0
0.50708460 Operation read AccessPort TAR 0xAF OK 0x00000000
0.50716530 Operation read DebugPort RDBUFF 0xBD OK 0xE000EDF0
0.50724630 Operation write DebugPort ABORT 0x81 OK 0x0000001E ORUNERRCLR=1, WDERRCLR=1, STKERRCLR=1, STKCMPCLR=1, DAPABORT=0
0.50729995 Operation read DebugPort CTRL/STAT 0x8D OK 0xF0000041 CSYSPWRUPACK=1, CSYSPWRUPREQ=1, CDBGPWRUPACK=1, CDBGPWRUPREQ=1, CDBGRSTACK=0, CDBGRSTREQ=0, TRNCNT=0x000, MASKLANE=0x0, WDATAERR=0, READOK=1, STICKYERR=0, STICKYCMP=0, TRNMODE=Normal, STICKYORUN=0, ORUNDETECT=1
0.50740975 Operation write AccessPort TAR 0x8B OK 0xE000EDF0
0.50746895 Operation write AccessPort DRW 0xBB OK 0xA05F0001
J-Link
0.16056980 Operation write AccessPort CSW 0xA3 OK 0x23000002 DbgSwEnable=0, Prot=0x23, SPIDEN=0, Mode=0x0, TrInProg=0, DeviceEn=0, AddrInc=Auto-increment off, Size=Word (32 bits)
0.16118865 Operation write AccessPort TAR 0x8B OK 0xE000EDF0
0.16180810 Operation write AccessPort DRW 0xBB OK 0xA05F0001
so in libswd we have 8 operations where we could use 3 or even 2 (if we know CSW is already correct).
This is not really a big problem, but something we can look at in the future.
Very good poin @andrewparlane ! I did not reverse other solutions, so your input is highly welcome and appreciated! :-)
Also please note that LibSWD was first meant to be only transport layer, while DAP was supposed to be done in a separate library. I will try to come back to this idea in my https://github.com/cederom/icederom project :-)
Definitely makes sense to split hem up. My chip has two APs which makes it a bit awkward at times.
I'd love to do a bunch of tidying up and what not, but I don't really have much time to put into this. I figure creating a bunch of issues is probably the best place to start, so at least we have a list of todo items.
On 27 June 2017 at 18:06, Tomasz CEDRO [email protected] wrote:
Very good poin @andrewparlane https://github.com/andrewparlane ! I did not reverse other solutions, so your input is highly welcome and appreciated! :-)
Also please note that LibSWD was first meant to be only transport layer, while DAP was supposed to be done in a separate library. I will try to come back to this idea in my https://github.com/cederom/icederom project :-)
— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/cederom/LibSWD/issues/17#issuecomment-311499988, or mute the thread https://github.com/notifications/unsubscribe-auth/AE51Ok2ZNUzAsKOx7_vmv_4xWeDIx98qks5sIXz3gaJpZM4OHNfr .
exactly, simple list, clear TODO per issue :-)
http://www.humorsoffice.com/images/2013/08/office-humor-20130818-131112.jpg
hopefully soon I will have time and resources for those things to happen :-)
ha!
On 27 June 2017 at 19:09, Tomasz CEDRO [email protected] wrote:
exactly, simple list, clear TODO per issue :-)
http://www.humorsoffice.com/images/2013/08/office-humor- 20130818-131112.jpg
hopefully soon I will have time and resources for those things to happen :-)
— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/cederom/LibSWD/issues/17#issuecomment-311511172, or mute the thread https://github.com/notifications/unsubscribe-auth/AE51OrabOJrBsjc5DzLpY316DaPW0prZks5sIYu0gaJpZM4OHNfr .