Hang system when access to BAR0, SV HARD IP CORE AVMM DMA

Good afternoon colleagues

Help me to understand

1) Launched PCIE HARD IP 256-bit AVMM DMA

2) Trying to run the dma controller

3) I am writing data in a bar0 from Linux

4) As soon as I call the iowrite32 35 times, the system freezes. At the same time, after each entry, I try to read the data and get 0xFFFFFF

Please tell me what could be the problem?

c++ driver code

init_chrdev(..)
pci_enable_device(..)
request_mem_region(
                                            pci_resource_start(_device, 0), 
                                            pci_resource_len(_device, 0), 
                                            ALTERA_DMA_DRIVER_NAME
                                         )
pci_iomap (...)
pci_enable_msi(...)
iowrite32 (
                      cpu_to_le32(tmp_rand), 
                      (u32 *)(_dev_data_ptr->bar[0]) + i
                    );

Also, if my driver is loaded, I need to contact any utility to pci (lspci for example), the system immediately hangs

Under windows the same

Thank you in advance