On Wed, Dec 4, 2013 at 5:01 AM, Ezequiel Garcia
[off-list ref] wrote:

On Thu, Nov 28, 2013 at 04:53:37PM -0300, Ezequiel Garcia wrote:

quoted

On Thu, Nov 28, 2013 at 04:47:20PM -0300, Ezequiel Garcia wrote:

quoted

quoted

Changing the console port by setting "console=ttyS1,115200" gives this:

[..]
Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
dw-apb-uart d0012000.serial: Couldn't set LCR to 191
dw-apb-uart d0012000.serial: Couldn't set LCR to 191
dw-apb-uart d0012000.serial: Couldn't set LCR to 224
dw-apb-uart d0012000.serial: Couldn't set LCR to 224
d0012000.serial: ttyS0 at MMIO 0xd0012000 (irq = 17, base_baud = 15625000) is a 16550A
dw-apb-uart d0012100.serial: Couldn't set LCR to 191
dw-apb-uart d0012100.serial: Couldn't set LCR to 191
dw-apb-uart d0012100.serial: Couldn't set LCR to 224
dw-apb-uart d0012100.serial: Couldn't set LCR to 224
d0012100.serial: ttyS1 at MMIO 0xd0012100 (irq = 18, base_baud = 15625000) is a 16550A
console [ttyS1] enabled
dw-apb-uart d0012200.serial: Couldn't set LCR to 191
dw-apb-uart d0012200.serial: Couldn't set LCR to 191
dw-apb-uart d0012200.serial: Couldn't set LCR to 224
dw-apb-uart d0012200.serial: Couldn't set LCR to 224
d0012200.serial: ttyS2 at MMIO 0xd0012200 (irq = 31, base_baud = 15625000) is a 16550A
dw-apb-uart d0012300.serial: Couldn't set LCR to 191
dw-apb-uart d0012300.serial: Couldn't set LCR to 191
dw-apb-uart d0012300.serial: Couldn't set LCR to 224
dw-apb-uart d0012300.serial: Couldn't set LCR to 224
d0012300.serial: ttyS3 at MMIO 0xd0012300 (irq = 32, base_baud = 15625000) is a 16550A

So we get the "Couldn't set" message in all four ports.

Tim: Any ideas?

And another thing: the weird output on the console looks related to the
early boot console. If I enable 'earlyprintk' on ttyS0 but set the console
on ttyS1, this is what I get on ttyS0:

bootconsole [earlycon0] enabled
[..]
Kernel command line: earlyprintk console=ttyS1,115200 root=/dev/nfs rw nfsroot=192.168.0.45:/opt/buildrootfs,v3, ip=192.168.0.159:192.168.0.45:192.168.0.1:255.255.255.0:develboard:eth0:on rootwait
[..]
Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
???????????????????????????????????????????????
Welcome to Buildroot
buildroot login:

Hope this helps you understand what's going on...

Gentle ping?

Any ideas about those weird characters?

If there was just one weird character, I would say it was an
indication that hardware rejected a write to LCR and then software
wrote the lower 8 bits of the baud into DLL which happens to live at
the same address offset as RBR.  However, there are a bunch of them
here so it is less clear.

It would be really helpful to get any extra information that you can
about the Synopsys IP in your SoC.  If it configured with
UART_ADD_ENCODED_PARAMS = 1, there should be a UART configuration ID
register at offset 0xF4.  Could you try reading that back?  This
register has information about the FIFO size and a few more things.

Also, I am curious what LCR value the hardware reports when the driver
fails update it.  Perhaps you can amend the error message to include
p->serial_in(p, UART_LCR) too?

-Tim