Messages in this thread | | | Date | Tue, 25 Sep 2012 17:40:07 +0200 | From | Matthieu CASTET <> | Subject | Re: [PATCH v2] hvc_dcc : add support to armv4 and armv5 core |
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Stephen Boyd a écrit : > On 8/31/2012 4:47 AM, Matthieu CASTET wrote: >> Signed-off-by: Matthieu Castet <matthieu.castet@parrot.com> > > Please consider adding some sort of commit text. Does this add some new > feature I may want on some downstream distro kernel? > ok > > It's unfortunate that the main logic is duplicated. I wonder if we could > push the runtime decision slightly lower into the accessor functions > instead and make some new functions dcc_tx_busy() and dcc_rx_busy() or > something. Then these loops stay the same. see my previous mail
>> +static inline char __dcc_getchar(void) >> +{ >> + char c; >> + >> + asm __volatile__ ("mrc p14, 0, %0, c1, c0 @ read comms data reg" >> + : "=r" (c)); >> + > > Do you see any multiple character inputs? I think you may need an isb > here similar to the v6/7 code and in the putchar as well. I don't see multiple character. On armv5 isb is only a memory barrier (__asm__ __volatile__ ("" : : : "memory")) and it may be not need for dcc operation.
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