On Thu, Jan 22, 2015 at 7:02 PM, Julien Grall <julien.gr...@linaro.org> wrote: > On 22/01/15 16:55, Oleksandr Tyshchenko wrote: >> On Thu, Jan 22, 2015 at 6:49 PM, Julien Grall <julien.gr...@linaro.org> >> wrote: >>> On 22/01/15 16:44, Oleksandr Tyshchenko wrote: >>>> I understand, then I will implement local delay func in uart driver >>>> based on READ_SYSREG64(CNTPCT_EL0). >>> >>> Unless I miss something, udelay should work in your case even if the >>> xen_init_time is not called. >> Unfortunately, no. If I understand correctly the var "cpu_khz" (used >> in ticks_to_ns()) is initialized in init_xen_time(). > > Hrm, right. I looked too quickly to the function. > > I don't like the idea to use READ_SYSREG64(CNTPCT_EL0) in the UART drivers. > > Does the udelay necessary here? If yes, maybe we should either split the > xen_init_time in 2 parts or create a udelay_tick function to use when > timer is not set. > > I'm not sure what is the best one. > > Regards, > > -- > Julien Grall
According to the TRM for this family we need to add delay after changing baudrate before continuing init sequence. I tried without udelay and it is worked fine. But, if the TRM says we need to follow this. -- Oleksandr Tyshchenko | Embedded Dev GlobalLogic www.globallogic.com _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
