-----Original Message----- From: u-boot-bounces@lists.denx.de [mailto:u-boot-bounces@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 wd@denx.de wrote:
Dear Lei Wen,
In message <AANLkTi=q-cj-
Q5iNqiQpEddkH1DxUAR1H_5wenaES7bE@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 . .