Hi ALL:
I have a CSI camera sensor(e-CAM130_CUMI1820), it works fine。
I tried to read the CSI register.
I found that reading the register would cause the system to be crash
Such like :
$ ./devmem2 0x54080934
/dev/mem opened.
Memory mapped at address 0xb6ff3000.
[ 901.378817] Host read timeout at address 1
[ 901.640412] MSELECT error detected! status=0x1
[ 901.655149] ------------[ cut here ]------------
[ 901.669999] kernel BUG at drivers/platform/tegra/hier_ictlr/hier_ictlr.c:54!
[ 901.687494] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
[ 901.703796] Modules linked in:
[ 901.717206] CPU: 0 PID: 221 Comm: devmem2 Not tainted 3.10.40-svn458 #16
[ 901.734567] task: d9d7d040 ti: d9842000 task.ti: d9842000
[ 901.750772] PC is at tegra_hier_ictlr_irq_handler+0x38/0x40
[ 901.767257] LR is at tegra_hier_ictlr_irq_handler+0x38/0x40
[ 901.783675] pc : [] lr : [] psr: 200f0193
[ 901.783675] sp : d9843e20 ip : 00000000 fp : 00000000
[ 901.817244] r10: 00000003 r9 : 54080934 r8 : d9842000
[ 901.833299] r7 : d9843ec8 r6 : 0000009f r5 : c0bc1910 r4 : d9d81780
[ 901.850746] r3 : 00000002 r2 : c0c7b830 r1 : 200f0193 r0 : 00000022
[ 901.868317] Flags: nzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment user
[ 901.886817] Control: 10c5387d Table: 98cf406a DAC: 00000015
/////////////////////////////////////////////////////////////////////
The CSI register can be accessed when I open the Camera stream
—>
/devmem2 0x54080934
/dev/mem opened.
Memory mapped at address 0xb6fcd000.
Value at address 0x54080934 (0xb6fcd934): 0x49
Q1:
Why Graphics Host sub-system (CSI / DSI HDMI …) has this situation ?
Q2:
How do I access the CSI register without opening the Camera stream ?
thanks…