On 2 October 2017 at 09:41, marekzmyslowski marekzmyslowski@poczta.onet.pl wrote:
Hello Mathieu,
I'm trying to use CSAL for DragonBoard. The fisrt thing there is rom_init. According to the docs, the rom that needs to be mmaped is 0x800000. Is there any way to check if the power domain or clock turned om?
There is no way to check from user space. When using the CSAL people will typically connect to the board using a Dstream (or another Jtag solution). That typically switch on the power domain and the required clock, given the initialisation script for the board has done that correctly.
The dragonboard is popular and ubiquitous, it shouldn't be hard to find a Jtag init script on the internet somewhere. If you don't have a Jtag you can read the Jtag init script for that board and enact the same operations by mmap'ing memory areas and flipping bits.
Regards Marek
W dniu 2017-10-02 16:50:08 użytkownik Mathieu Poirier mathieu.poirier@linaro.org napisał:
On 2 October 2017 at 02:15, marekzmyslowski marekzmyslowski@poczta.onet.pl wrote:
Hello,
I'm trying to get access to Qualcomm Debug Subsystem on my DragonBoard 410c by using the mmap. Just want to read data available in DQSS_DAPROM. However when I try to do that, the system is rebooting. Any idea why I can't do that?
int size = 4096; off_t addr_to_map = 0x00800000; //according to docs this is an address of QDSS_DAPROM
int mem_fd = open("/dev/mem", O_RDWR); localv = mmap(0, size, PROT_READ, MAP_SHARED, mem_fd, addr_to_map); printf ("mmap completed %p.\n", localv); tab = (unsigned int *)localv; printf ("%u\n", tab[0]);
Result of my application execution: mmap completed 0x7fa29f0000.[ 484.585864] Synchronous External Abort: synchronous external abort (0x92000010) at 0x0000007fa29f0000
This is usually an indication the memory area you are trying to reach is not accessible - either the power domain hasn't been switched on or the clock(s) aren't enabled. Is there a device driver specific to the DQSS_DAPROM?
Regards Marek
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