Hi Kefeng, On 5/12/2016 7:46 AM, Jon Mason wrote:
On Thu, May 12, 2016 at 2:16 AM, Kefeng Wang <wangkefeng.w...@huawei.com <mailto:wangkefeng.w...@huawei.com>> wrote: On 2016/5/12 6:56, Jon Mason wrote: > Add all of the UARTs present on NS2 and enable them in the SVK device > tree file. Also, do some magic to make sure that uart3 is discovered as > ttyS0 (as that is the console UART). > > Signed-off-by: Jon Mason <jonma...@broadcom.com <mailto:jonma...@broadcom.com>> > --- > arch/arm64/boot/dts/broadcom/ns2-svk.dts | 16 ++++++++++++++++ > arch/arm64/boot/dts/broadcom/ns2.dtsi | 30 ++++++++++++++++++++++++++++++ > 2 files changed, 46 insertions(+) > > diff --git a/arch/arm64/boot/dts/broadcom/ns2-svk.dts b/arch/arm64/boot/dts/broadcom/ns2-svk.dts > index 7cd3640..b062a44 100644 > --- a/arch/arm64/boot/dts/broadcom/ns2-svk.dts > +++ b/arch/arm64/boot/dts/broadcom/ns2-svk.dts > @@ -40,10 +40,14 @@ > > aliases { > serial0 = &uart3; > + serial1 = &uart0; > + serial2 = &uart1; > + serial3 = &uart2; > }; > > chosen { > stdout-path = "serial0:115200n8"; > + bootargs = "earlycon=uart8250,mmio32,0x66130000"; Hi Jon, I submit a patch[1], with it, we can use earlycon without option to enable early console for "snps,dw-apb-uart", could you help me to test it, thanks. Adding your change and removing the line above does not cause earlycon to work for me. Is there any additional changes necessary for this to work? Thanks, Jon
"OF_EARLYCON_DECLARE" doesn't seem to have a way to deal with DT properties? In the case of UART for NS2, it needs mmio32, configured with DT property "reg-io-width" set to 4. I don't think "OF_EARLYCON_DECLARE" is parsing that, which is likely the reason why it doesn't work for devices that required mmio32.
Thanks, Ray
