On Sat 2020-12-19 23:38:25, Martin Blumenstingl wrote: > Hi Pavel, > > On Sat, Dec 19, 2020 at 10:51 PM Pavel Machek <pavel@xxxxxx> wrote: > [...] > > I can't say I like this one: > > > > > > > clk_configs->m250_mux.reg = dwmac->regs + PRG_ETH0; > > > - clk_configs->m250_mux.shift = PRG_ETH0_CLK_M250_SEL_SHIFT; > > > - clk_configs->m250_mux.mask = PRG_ETH0_CLK_M250_SEL_MASK; > > > + clk_configs->m250_mux.shift = __ffs(PRG_ETH0_CLK_M250_SEL_MASK); > > > > It replaces constant with computation done at runtime; compiler can't > > optimize it as __ffs is implemented with asm(). > what do you suggest to use instead? > personally I don't see a problem because this is only called once at > driver probe time. I believe canonical solution is version before this patch, just with fixed values.... I mean yes, computation at runtime is not end of the world, but it is both slower and needs more code space... Best regards, Pavel -- http://www.livejournal.com/~pavelmachek
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