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Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver

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On Wednesday, August 24, 2016 11:57:08 PM CEST Arnd Bergmann wrote:
> > I'm not familiar with those classifications, but from what I can tell,
> > BE32 describes it correctly. I'll see if I can get someone to verify
> > this. Is there a reason it's not widely used anymore? Perhaps
> > something related to supporting misaligned word-sized loads/stores?
> 
> The main problem I see is that you can't easily use MMIO registers that
> are not 32-bit wide -- you end up having to flip not just the register
> contents but also the lower bits of the address in order to reach
> the right contents of the register.
> 

Actually there is a much more serious problem with BE32/LE32 mode:
doing unaligned access to RAM is a huge pain at the HW level,
and also when emulating it in the kernel on CPUs that require
aligned access. In ARM THUMB2 mode, you can even have unaligned
32-bit instructions.

	Arnd

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Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-08-24 18:50 +0200
  Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Rich Felker <dalias@libc.org> - 2016-08-24 19:50 +0200
    Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Marc Zyngier <marc.zyngier@arm.com> - 2016-08-24 21:10 +0200
      Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Rich Felker <dalias@libc.org> - 2016-08-24 21:30 +0200
        Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Mark Rutland <mark.rutland@arm.com> - 2016-08-25 00:30 +0200
    Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Arnd Bergmann <arnd@arndb.de> - 2016-08-24 22:10 +0200
      Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Rich Felker <dalias@libc.org> - 2016-08-24 23:00 +0200
        Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Mark Rutland <mark.rutland@arm.com> - 2016-08-24 23:30 +0200
          Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Rich Felker <dalias@libc.org> - 2016-08-24 23:50 +0200
            Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Arnd Bergmann <arnd@arndb.de> - 2016-08-25 00:10 +0200
              Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Arnd Bergmann <arnd@arndb.de> - 2016-08-25 12:30 +0200
            Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Mark Rutland <mark.rutland@arm.com> - 2016-08-25 01:00 +0200
    Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource  driver Thomas Gleixner <tglx@linutronix.de> - 2016-08-25 10:20 +0200
      Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Rich Felker <dalias@libc.org> - 2016-08-25 17:00 +0200
        Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource  driver Thomas Gleixner <tglx@linutronix.de> - 2016-08-25 17:50 +0200
          Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Rich Felker <dalias@libc.org> - 2016-08-25 19:50 +0200
        Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Mark Rutland <mark.rutland@arm.com> - 2016-08-25 18:50 +0200
          Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Mark Rutland <mark.rutland@arm.com> - 2016-08-25 20:30 +0200
            Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Rich Felker <dalias@libc.org> - 2016-08-25 21:30 +0200
          Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Rich Felker <dalias@libc.org> - 2016-08-25 20:30 +0200
    Re: [PATCH v6 2/2] clocksource: add J-Core timer/clocksource driver Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-08-26 11:10 +0200

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