> -----Original Message----- > From: u-boot-boun...@lists.denx.de [mailto:u-boot-boun...@lists.denx.de] > On Behalf Of Lei Wen > Sent: Friday, April 01, 2011 8:04 PM > To: Wolfgang Denk > Cc: Lei Wen; u-boot@lists.denx.de > Subject: Re: [U-Boot] [PATCH] serial: ns16550: fix different reg size > access > > Hi Wolfgang, > > On Fri, Apr 1, 2011 at 10:25 PM, Wolfgang Denk <w...@denx.de> wrote: > > Dear Lei Wen, > > > > In message <AANLkTi=q-cj- > q5inqiqpeddkh1dxuar1h_5wenaes...@mail.gmail.com> you wrote: > >> > >> >> > I don't think so. You still use just a single writel() call > then. To > >> >> > leave the other bits untouched, you would have to perform a > readl() > >> >> > first, then insert one data byte, and then write it back. Your > 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? > >> > >> As I explain, if set CONFIG_SYS_NS16550_REG_SIZE to 4, and > >> set CONFIG_SYS_NS16550_MAX_REG_SIZE also to 4, then the serial_out > >> becomes writel. :) > > > > Right - which is exactly what I said, and which you denied. > > > > I give up, I have other things to do as well. > > Just a question to clarify... What your point I denied, that is really > confused me... > I think in this thread, I explain to you, my patch could recover what > original > CONFIG_SYS_NS16550_REG_SIZE means... > > Since you reject, I have nothing else to say...
Hi Lei I understood this thread correctly as- 1. ns16550 is standard IP used across several SoC and has driver in place. 2. Your specific implementation of the same IP on your specific SoC need bit9 or x register to be set to 0 to work this IP correctly on your h/w. 3. but doing in ns16550 driver may brake other implementations. (correct me if I am wrong) So what I suggest here- 1. do not disturb/touch nx16550 driver at all. 2. write a small init code in cpu.c (specific to this SoC/arch) to reset this bit only. This would be straight forward and will satisfy your need and acceptance too. Regards.. Prafulla . . _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
