We are having T1022 based customized board with DDR4, one of the IFC chip select CS3 is connected to a FPGA device via GASIC mode. The write transaction to IFC controller in GASIC mode is working properly. The read transaction on IFC via GASIC is having issue, the cycle doesn't terminate properly.
As per our observation- on initiating the read transaction to the IFC controller in GASIC mode, the address cycles floats properly on the IFC bus and RD/BSY is properly asserted by end point device. On receiving the data , the CS assertion takes extra delay due to which cycle doesn't terminate properly resulting in machine check error in kernel.
I am attaching in this thread -
*complete dump of IFC bus registers
* Scope image of the Ready/Busy and CS behavior [Blue is ready busy , Yellow is CS]
*images of ila - read GASIC, then write GASIC , read_gasic_after_write in GASIC
kernel trace after read in linux-
[ 3840.277389] Machine check in kernel mode.
[ 3840.280095] Caused by (from MCSR=a000): Load Error Report
[ 3840.284188] Guarded Load Error Report
[ 3840.286542] Oops: Machine check, sig: 7 [#1]
[ 3840.289502] SMP NR_CPUS=8 CoreNet Generic
[ 3840.292205] Modules linked in: linux_user_bde(O) linux_kernel_bde(O) ext4 jbd2
[ 3840.298143] CPU: 0 PID: 1467 Comm: util_t10xx-32b Tainted: G O 4.1.8-rt8 #1
[ 3840.304929] task: e84e72d0 ti: e855a000 task.ti: e855a000
[ 3840.309018] **bleep**: 10000a34 LR: 100009ec CTR: 0fee03a0
[ 3840.312674] REGS: e855bf10 TRAP: 0204 Tainted: G O (4.1.8-rt8)
[ 3840.318590] MSR: 0002d002 <CE,EE,PR,ME> CR: 28000482 XER: 20000000
[ 3840.323657] DEAR: b7a01000 ESR: 00000000
GPR00: 100009ec bfcb7fd0 b7a074c0 00000000 b7a02000 b7a02000 00000000 00000000
GPR08: 00000001 b7a01000 b7a01000 ffffffff 28000488 10019268 10100000 00000000
GPR16: 00000000 100fda04 100fd9f4 10100000 00000000 42222482 10100000 00000000
GPR24: 10117980 00000000 00000000 0000000f ffe00000 0000000f ffe00000 bfcb7fd0
[ 3840.354627] **bleep** [10000a34] 0x10000a34
[ 3840.356979] LR [100009ec] 0x100009ec
[ 3840.359242] Call Trace:
[ 3840.360382] ---[ end trace 0b333fe9569ae18b ]---
