Hi, On 14/06/2021 18:42, Paul Cercueil wrote: > Hi Zhou, [ please trim ... ] >>> >> The DT documentation only mentions one memory resource. Here, you >>> >> map a second one, which is not used anywhere. I'm really confused >>> >> about what you're trying to do here. >>> >> >>> > >>> > X2000 and X2100 divide the OST into two parts. The global timer is >>> > the first part, which is still located at the address of 0x12000000, >>> > and the percpu timers are the second part, the starting address is >>> > 0x12100000, and each timer is offset by 0x100 (percpu timer0 is at >>> > 0x12100000, percpu timer1 is at 0x12100100, percpu timer2 is at >>> > 0x12100200, percpu timer3 is at 0x12100300). This one is used in >>> > line 593 of the code. >>> >>> Then you need two different DT nodes, one at each start address. >>> Either use different drivers (since the register sets are different), >>> or *if* it can be implemented cleanly in ingenic-sysost.c, different >>> compatible strings - one for the global timer and one for the percpu >>> timers. >> >> Sorry, I did not describe it clearly. Although the global timer and >> percpu timers are divided into two parts, they still belong to the same >> hardware module. The base address of the entire module is 0x12000000, >> but the control register of the global timer is not shifted. The percpu >> timers are shifted by 0x100000 as a whole (the situation here is >> similar to PDMA, which is also divided into two parts: the >> channel-related registers are not shifted, while the system >> control-related registers are shifted by 0x1000 as a whole). I think >> maybe we can follow PDMA's approach and add corresponding instructions >> in the DT documentation. This can avoid confusion caused by splitting >> different parts of the same hardware module into two nodes, and at the >> same time keep the code of the devicetree as simple and clear as >> possible. >> >> What do you think about that? > > Looking at the programming manual, these are not the same hardware > module. They are on different addresses, are functionally independent, > and are even described in different chapters of the PM; so I stick to > what I said earlier. > > Cheers, > -Paul > >> Thanks and best regards! >> >>> >>> -Paul [ ... ] -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
