Am 17.05.2016 um 18:00 schrieb Simon Glass: > Hi Paul, > > On 17 May 2016 at 09:58, Paul Burton <paul.bur...@imgtec.com> wrote: >> On Tue, May 17, 2016 at 09:54:21AM -0600, Simon Glass wrote: >>>>>>> diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c >>>>>>> index 28da9dd..e58e6aa 100644 >>>>>>> --- a/drivers/serial/ns16550.c >>>>>>> +++ b/drivers/serial/ns16550.c >>>>>>> @@ -100,7 +100,11 @@ static void ns16550_writeb(NS16550_t port, int >>>>>>> offset, int value) >>>>>>> unsigned char *addr; >>>>>>> >>>>>>> offset *= 1 << plat->reg_shift; >>>>>>> +#ifdef CONFIG_SYS_NS16550_PORT_MAPPED >>>>>>> + addr = (unsigned char *)plat->base + offset; >>>>>>> +#else >>>>>>> addr = map_physmem(plat->base, 0, MAP_NOCACHE) + offset; >>>>>>> +#endif >>>>>> >>>>>> Please don't add CONFIG #ifdefs in these functions. Perhaps it needs >>>>>> to be another parameter? Possibly a flag. But with driver-model we >>>>>> need to be able to support both options in the core code. >>>>> >>>>> Hi Simon, >>>>> >>>>> Are you sure systems rely on using I/O ports with map_physmem? The only >>>>> other systems that define CONFIG_SYS_NS16550_PORT_MAPPED are x86 ones, >>>>> in include/configs/x86-common.h, and so far as I can tell they don't use >>>>> device model which suggests this code has simply been untested before. I >>>>> don't see why you would use map_physmem on an I/O port address that is >>>>> then going to be passed to inb/outb & I think the code here is simply >>>>> wrong to do so. >>>> >>>> the current code looks wrong. serial_in_shift() is expanded to inb() >>>> in case of CONFIG_SYS_NS16550_PORT_MAPPED and to >>>> in_le32()/in_be32()/readl()/readb() otherwise. Only in the latter case >>>> a map_physmem() is required and should be done in serial_in_shift() >>>> itself or preferrably only once in >>>> ns16550_serial_ofdata_to_platdata(). >>>> >>>> I think the correct approach would be the following: >>> >>> This is better I think. But how about adding a device tree binding to >>> select I/O access? In principle each device might have its own >>> settings. >> >> Note that's what I worked towards last time I had a crack at this, but >> it just expanded into an attempt to tackle the mess that is ns16550.c & >> rather lost sight of the original goal of making Malta work. >> >> https://patchwork.ozlabs.org/patch/575643/ >> https://patchwork.ozlabs.org/patch/577194/ > > Yes it is tricky. What do you think about the suggestions above?
for now we should only fix the broken port-based I/O. Additional DT bindings could be added later. I'd like to merge the DM support on MIPS Malta in this merge window ;) -- - Daniel
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