Dear Lei Wen, In message <[email protected]> you wrote: > > >> I think my code also could handle this. They only could set the > >> CONFIG_SYS_NS16550_REG_SIZE =A0to be 1 > >> and CONFIG_SYS_NS16550_MAX_REG_SIZE to be 4. Then > >> the other bits is untouched by this driver. > > > > I don't think so. You still use just a single writel() call then. =A0To > > leave the other bits untouched, you would have to perform a readl() > > first, then insert one data byte, and then write it back. =A0Your patch > > does not do that. > > My original patch is like below, so where it call writel?... > +#elif (CONFIG_SYS_NS16550_REG_SIZE == 1) || (CONFIG_SYS_NS16550_REG_SIZE == > -1) > +#ifdef CONFIG_SYS_NS16550_PORT_MAPPED > +#define serial_out(x, y) outb(x, y) > +#define serial_in(y) inb(y) > +#else > +#define serial_out(x, y) writeb(x, y) > +#define serial_in(y) readb(y)
If you use writeb() [as the current driver would do as well}, then how do you expect to set this bit 8 (which is in the next byte) to 0 as you claim you have to? Either I don't understand what you want, or you don't understand how the ns16550 driver works. I can see no shortcomings in the existent driver, thus no need to make it more complicated than it already is. Best regards, Wolfgang Denk -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: [email protected] Time is a drug. Too much of it kills you. - Terry Pratchett, _Small Gods_ _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
