[RESEND][PATCH] ARM: debug: add support for Palmchip 16550-like UART
mans at mansr.com
Wed Nov 4 07:47:26 PST 2015
Mason <slash.tmp at free.fr> writes:
> On 27/10/2015 13:57, Mans Rullgard wrote:
>> Some SoCs have a Palmchip UART with a non-standard register layout.
>> This allows the debug console to work with these.
>> Signed-off-by: Mans Rullgard <mans at mansr.com>
>> arch/arm/Kconfig.debug | 8 ++++++++
>> arch/arm/include/debug/8250.S | 12 ++++++++++++
>> 2 files changed, 20 insertions(+)
>> diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
>> index 0cfd7f9..9039fff 100644
>> --- a/arch/arm/Kconfig.debug
>> +++ b/arch/arm/Kconfig.debug
>> @@ -1597,6 +1597,14 @@ config DEBUG_UART_8250_WORD
>> DEBUG_BCM_KONA_UART || DEBUG_RK32_UART2 || \
>> +config DEBUG_UART_8250_PALMCHIP
>> + bool "8250 UART is Palmchip variant"
>> + depends on DEBUG_LL_UART_8250 || DEBUG_UART_8250
> I am 100% clueless about the UART sequence in Linux.
> There's earlyprintk, the boot console (polled?), the "full-blown"
> console (with IRQs)...
> If I want earlyprintk, I have to enable DEBUG_LL (?) so I'll have
> DEBUG_LL_UART_8250, right? There's no way to pick DEBUG_UART_8250
> in menuconfig, is there?
> So I picked the following options:
> # CONFIG_DEBUG_ICEDCC is not set
> # CONFIG_DEBUG_SEMIHOSTING is not set
> # CONFIG_DEBUG_LL_UART_PL01X is not set
> # CONFIG_DEBUG_UART_8250 is not set
> # CONFIG_DEBUG_UART_BCM63XX is not set
> # CONFIG_DEBUG_UART_8250_FLOW_CONTROL is not set
Those are the settings I use.
> I suppose I have to provide DEBUG_UART_PHYS because it needs
> the address before it can parse the DT? But how am I supposed
> to know the virtual address? Isn't that from iomap(UART_PHYS)?
The decompression code and early setup don't have that luxury.
> 'make' wouldn't let me proceed unless I gave something...
> Then I have to add earlyprintk to my boot command line, right?
> Do I need to specify more than that?
Just earlyprintk without any parameters works.
mans at mansr.com
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