Hello Alexey Tsirlin,
The maximum allowed axi_clk frequency is 133 MHz.
I think the 104Mhz limitation may come from older versions of the EIM as that of the i.MX51 in which a note did indicated: “The maximum allowed axi_clk frequency is 133 MHz, whereas the maximum allowed BCLK frequency is 104 MHz. As a result if BCD = 0, axi_clk must be ≤104 MHz. If BCD = 1, then 133 MHz is allowed for axi_clk, resulting in a BCLK of 66.5 MHz. When the clock branch to WEIM is decreased to 104 MHz, other busses are impacted which are clocked from this source.” However, the i.MX6 BCD is fixed unlike in the i.MX51.
Regards,