On Thu, 4 Sep 2014, li.xi...@freescale.com wrote: > > Subject: Re: [PATCH 2/5] Clocksource: Flextimer: Use internal clocksource > > read > > API. > > > > On Tue, 26 Aug 2014, Xiubo Li wrote: > > > > > Since the Flextimer device will be implemented in BE mode on > > > LS1 SoC, and in LE mode on Vybrid, LS2 SoCs, so here we need > > > the endianness judgment before doing the mmio. > > > > Brilliant. So for every clocksource read you take a conditional. > > > > > @@ -238,7 +243,7 @@ static int __init ftm_clocksource_init(unsigned long > > freq) > > > sched_clock_register(ftm_read_sched_clock, 16, freq / (1 << priv->ps)); > > > err = clocksource_mmio_init(priv->clksrc_base + FTM_CNT, "fsl-ftm", > > > freq / (1 << priv->ps), 300, 16, > > > - clocksource_mmio_readl_up); > > > + ftm_clocksource_read_up); > > > > What's wrong with having endianess aware clocksource_mmio functions > > and make the decision at init time? > > > > Since the FTM will be in BE mode on LS1 platform, but will be in LE mode > On LS2 platform. > > And ftm_clocksource_read_up() will adapt to this different.
You are missing the point. Why do you want a conditional in a hot path? You know at init time whether the thing is BE or LE, so you can have separate functions for BE/LE or whatever and register that with clocksource_mmio_init(). i.e. if (be) clocksource_mmio_init(....., cs_read_be); else if (le) clocksource_mmio_init(....., cs_read_le); else if (magic) clocksource_mmio_init(....., cs_read_magic); Hmm? tglx -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/