Re: [PATCH 06/14] ARM: kirkwood: convert uart0 to devicetree.

On Thu, Mar 08, 2012 at 02:31:39PM -0700, Grant Likely wrote:

On Wed, Mar 07, 2012 at 02:27:23PM -0500, Jason wrote:

quoted

On Wed, Mar 07, 2012 at 06:31:31PM +0000, Arnd Bergmann wrote:

quoted

On Wednesday 07 March 2012, Jason Cooper wrote:

quoted

+       serial@f1012000 {
+               compatible = "ns16550a";
+               reg = <0xf1012000 0xff>;
+               reg-shift = <2>;
+               interrupts = <33>;
+               clock-frequency = <200000000>;
+       };

I just noticed that the length here should be inclusive, i.e. 0x100 not 0xff.
This is different from the way we define resources in Linux.

Grrr.  Now I'm getting frustrated.  I'm trying to boot without
earlyprintk.  Evidently, something is wrong with the above, because the
device boots all the way up (blinky lights come on), but I get no
messages after the usual "Uncompressing Linux... done, booting the
kernel."

Here's my most recent attempt:

I see that you've resolved your problem, but some comments below on the
device node:

quoted

        serial@f1012000 {
                device_type = "serial";

Never use device_type.  It should only ever appear in the memory node, and
I plan to remove it from there too.

quoted

                compatible = "ns16550a";
                reg = <0xf1012000 0x100>; /*phys addr*/
                virt-reg = <0xfed12000>;  /*virt addr*/

Don't use virt-reg.  Nothing in the kernel uses it and the kernel will
make it's own decision about virtual address mapping.

quoted

                reg-shift = <2>;
                reg-io-width = <1>;

1 is the default for reg-io-width.  No need to have this property.  It
should only be used if the device requires 32 bit accesses.

quoted

                interrupts = <33>;
                current-speed = <115200>;
                interrupt-parent = <&intc>;
                clock-frequency = <200000000>;
        };

Thanks, Grant.  I reverted all of those changes once I found the root of
my problem.

thx,

Jason.