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? Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
