在2023年11月23日十一月 下午4:07，Thomas Bogendoerfer写道： > On Thu, Nov 23, 2023 at 03:07:09PM +0000, Jiaxun Yang wrote: >> [...] > > the problem with all 32bit unmapped segments is their limitations in > size. But there is always room to try to use unmapped and fall back > to mapped, if it doesn't work. But I doubt anybody is going to > implement that. Yep, I guess fallback should be implemented for ioremap_cache as well. > >> >> AFAIK for Loongson DMI is located at cached memory so using ioremap_uc >> >> blindly will cause inconsistency. >> > >> > why ? >> >> Firmware sometimes does not flush those tables from cache back to memory. >> For Loongson systems (as well as most MTI systems) cache is enabled by >> firmware. > > kernel flushes all caches on startup, so there shouldn't be a problem. Actually dmi_setup() is called before cpu_cache_init(). Thanks > > Thomas. > > -- > Crap can work. Given enough thrust pigs will fly, but it's not necessarily a > good idea. [ RFC1925, 2.3 ] -- - Jiaxun
