Hi,
Looking through your log, I see similar corruptions with DSR. Bit 30 is a
reserved bit and should always be 0. The top nibble should always be 0x8, but
your log shows it is sometimes as 0x8 and sometimes as 0xc:
Debug: 63059 35535 xtensa.c:2094 xtensa_poll(): [plmp.smcu] DSR has changed:
was **0xc000c000** now 0x8020c010
This likely implies a timing issue since it affects both DDR and DSR.
Corroborating this, there are some WAIT responses to some DAP transactions,
which should usually not occur:
**Info : 103551 58863 adi_v5_jtag.c:558 jtagdp_overrun_check(): DAP transaction
stalled (WAIT) - slowing down and resending**
I'm guessing the APB interface behind your DAP is running too slowly. Do you
have any JTAG components in your system upstream of the Xtensa or the DAP?
Xtensa JTAG systems require a 1:4 ratio between JTCK and core clock.
I would recommend trying some extremely slow JLink speeds and see if that makes
any difference. If that does not help, perhaps capturing the transport
signals on a logic analyzer for the DAP WAIT status may shed some light on this.
BTW, I'm assuming your Coresight HW is ADIv5, not ADIv6. IIRC the reply width
differs between the two versions.
Thanks,
--ian
---
**[tickets:#445] openocd with xtensa core problem(about debug data reg)**
**Status:** new
**Milestone:** 0.11.0
**Created:** Fri Dec 06, 2024 05:30 AM UTC by vitocichen
**Last Updated:** Fri Dec 06, 2024 12:23 PM UTC
**Owner:** nobody
HI,
I am debugging xtensa core using openocd tool. The connection relationship of
my system is as follows:
<< jlink--->coresight dap--->APB_AP(ap_num=0)----->xtensa core0/1/2 >>
The gdb tool I use is xt-gdb, but I find that the values of my pc registers,
a0-a15,ar0-ar15, etc. are strange during reuse, their highest bit bit31 is
always 1, bit30 is always 0, but this value is wrong.
I finally found that openocd had a problem when reading and writing the DDR
(debug data reg) register, in order to better explain the phenomenon.
I've added a test function in openocd source, in the SRC/target/xtensa/xtensa.
C I added a test function, the code is as follows:
/************************************************************************************/
void ddr_test(struct target target)
{
struct xtensa xtensa = target_to_xtensa(target);
uint8_t a3_buf[4]={0};
LOG_DEBUG("***ddr test******");
xtensa_queue_dbg_reg_write(xtensa, XDMREG_DDR, 0x12345678);
xtensa_queue_dbg_reg_read(xtensa, XDMREG_DDR,a3_buf);
LOG_DEBUG("A3[0]=%X",a3_buf[0]);
LOG_DEBUG("A3[1]=%X",a3_buf[1]);
LOG_DEBUG("A3[2]=%X",a3_buf[2]);
LOG_DEBUG("A3[3]=%X",a3_buf[3]);
xtensa_queue_dbg_reg_write(xtensa, XDMREG_DDR, 0);
xtensa_queue_dbg_reg_read(xtensa, XDMREG_DDR,a3_buf);
LOG_DEBUG("A3[0]=%X",a3_buf[0]);
LOG_DEBUG("A3[1]=%X",a3_buf[1]);
LOG_DEBUG("A3[2]=%X",a3_buf[2]);
LOG_DEBUG("A3[3]=%X",a3_buf[3]);
xtensa_queue_dbg_reg_write(xtensa, XDMREG_DDR, 0x5a5a8080);
xtensa_queue_dbg_reg_read(xtensa, XDMREG_DDR,a3_buf);
LOG_DEBUG("A3[0]=%X",a3_buf[0]);
LOG_DEBUG("A3[1]=%X",a3_buf[1]);
LOG_DEBUG("A3[2]=%X",a3_buf[2]);
LOG_DEBUG("A3[3]=%X",a3_buf[3]);
}
/************************************************************************************/
I put the above test function in a lot of event locations like
xtensa_halt/xtensa_resume/xtensa_prepare_resume and other places.
Then I found that the DDR test always fails, bit31 is always 1, bit30 is always
0, such as the above result:
0x12345678----->0x82345678 0x0---->0x8000000 0x5a5a8080--->9a5a8080
I tried to modify the speed of jlink can not improve this, below is my cfg
file, can you help me find out the reason?
Here is my cfg file:
/************************************xxxx.cfg************************************************/
adapter driver jlink
adapter serial 601012352
transport select jtag
gdb_port 20005
bindto 0.0.0.0
source [find mem_helper.tcl]
set _CHIPNAME plmp
set _CPU0NAME smcu
set _CPU1NAME pmcu
set _TARGETNAME_0 $_CHIPNAME.$_CPU0NAME
set _TARGETNAME_1 $_CHIPNAME.$_CPU1NAME
set _CPUTAPID 0x6ba00477
source [find target/swj-dp.tcl]
swj_newdap $_CHIPNAME tap -irlen 4 -expected-id $_CPUTAPID
dap create $_CHIPNAME.dap -chain-position $_CHIPNAME.tap
target create $_CHIPNAME.axi mem_ap -dap $_CHIPNAME.dap -ap-num 1
target create $_TARGETNAME_0 xtensa -dap $_CHIPNAME.dap -ap-num 0 -coreid 1
-dbgbase 0x0108000
source [find target/xtensa-core-lx7.cfg]
target create $_TARGETNAME_1 xtensa -dap $_CHIPNAME.dap -ap-num 0 -coreid 2
-dbgbase 0x010c000
source [find target/xtensa-core-lx7.cfg]
---
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