On 05/26/2016 07:07 PM, Simon Glass wrote: > Hi Marek, > > On 26 May 2016 at 10:53, Marek Vasut <ma...@denx.de> wrote: >> On 05/26/2016 06:48 PM, Simon Glass wrote: >>> Hi Marek, >>> >>> On 26 May 2016 at 10:47, Marek Vasut <ma...@denx.de> wrote: >>>> On 05/26/2016 06:44 PM, Simon Glass wrote: >>>>> Hi Marek, >>>>> >>>>> On 26 May 2016 at 10:34, Marek Vasut <ma...@denx.de> wrote: >>>>>> On 05/26/2016 03:29 PM, Simon Glass wrote: >>>>>>> Hi Marek, >>>>>>> >>>>>>> On 25 May 2016 at 16:35, Marek Vasut <ma...@denx.de> wrote: >>>>>>>> On 05/26/2016 12:31 AM, Daniel Schwierzeck wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> Am 26.05.2016 um 00:21 schrieb Marek Vasut: >>>>>>>>>> On 05/26/2016 12:17 AM, Daniel Schwierzeck wrote: >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Am 25.05.2016 um 02:19 schrieb Marek Vasut: >>>>>>>>>>>> The Ingenic JZ47xx requires special bit (UART_EN) set in FCR >>>>>>>>>>>> register >>>>>>>>>>>> in order to work at all. Add this special case handling into the >>>>>>>>>>>> driver. >>>>>>>>>>>> >>>>>>>>>>>> Signed-off-by: Marek Vasut <ma...@denx.de> >>>>>>>>>>>> Cc: Tom Rini <tr...@konsulko.com> >>>>>>>>>>>> Cc: Simon Glass <s...@chromium.org> >>>>>>>>>>>> Cc: Daniel Schwierzeck <daniel.schwierz...@gmail.com> >>>>>>>>>>>> Cc: Paul Burton <paul.bur...@imgtec.com> >>>>>>>>>>>> --- >>>>>>>>>>>> drivers/serial/ns16550.c | 8 ++++++++ >>>>>>>>>>>> 1 file changed, 8 insertions(+) >>>>>>>>>>>> >>>>>>>>>>>> diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c >>>>>>>>>>>> index 30ba0aa..1323881 100644 >>>>>>>>>>>> --- a/drivers/serial/ns16550.c >>>>>>>>>>>> +++ b/drivers/serial/ns16550.c >>>>>>>>>>>> @@ -50,6 +50,14 @@ DECLARE_GLOBAL_DATA_PTR; >>>>>>>>>>>> #endif >>>>>>>>>>>> #endif >>>>>>>>>>>> >>>>>>>>>>>> +#ifdef CONFIG_ARCH_JZ47XX >>>>>>>>>>>> +#undef UART_FCRVAL >>>>>>>>>>>> +/* Ingenic JZ47xx SoCs require that a 'UART Module Enable' bit be >>>>>>>>>>>> set */ >>>>>>>>>>>> +#define UART_FCR_UME 0x10 >>>>>>>>>>>> +#define UART_FCRVAL (UART_FCR_FIFO_EN | UART_FCR_RXSR | \ >>>>>>>>>>>> + UART_FCR_TXSR | UART_FCR_UME) >>>>>>>>>>>> +#endif >>>>>>>>>>> >>>>>>>>>>> I think this could be added as DT property >>>>>>>>>> >>>>>>>>>> Not for SPL, which has 14 kiB size limit and it is itching to >>>>>>>>>> overflow. >>>>>>>>>> I am literally counting bytes in the SPL and removing slop from >>>>>>>>>> structures to make it fit, just barely. With the USB loader, I can >>>>>>>>>> brutalize the SPL into having extremely rudimentary UART support now >>>>>>>>>> (like printch() being the most advanced output mechanism, but you can >>>>>>>>>> only use it three times, otherwise the code won't fit and the board >>>>>>>>>> is >>>>>>>>>> eaten by demons) and this is where this patch comes into play. >>>>>>>>>> >>>>>>>>>> So yes, for full u-boot, this _should_ be part of DT. For SPL, >>>>>>>>>> please apply. >>>>>>>>>> >>>>>>>>> >>>>>>>>> ok, but wouldn't it be better to introduce an option like >>>>>>>>> CONFIG_SYS_NS16550_UME instead of using the SoC-specific >>>>>>>>> CONFIG_ARCH_JZ47XX. This driver is messed up enough ;) >>>>>>>> >>>>>>>> I was undecided between this (like the IER) and adding new ifdef (like >>>>>>>> SOC_KEYSTONE). Whichever way is fine with me. Yeah, the driver is >>>>>>>> repugnant for sure. >>>>>>>> >>>>>>>>>>>> + >>>>>>>>>>>> #ifndef CONFIG_SYS_NS16550_IER >>>>>>>>>>>> #define CONFIG_SYS_NS16550_IER 0x00 >>>>>>>>>>>> #endif /* CONFIG_SYS_NS16550_IER */ >>>>>>>>>>>> >>>>>>> >>>>>>> That way seems better to me. You should be able to add your UME flag >>>>>>> as a Kconfig for this driver, in drivers/serial/Kconfig, which >>>>>>> defaults to 0. It would be good to keep out board-specific stuff from >>>>>>> this file, as you did with OMAP1510. >>>>>> >>>>>> I'm not really sure I want to expose the CONFIG_SYS_NS16550_FCR override >>>>>> via Kconfig. The extra bits should be set via DT props >>>>>> unless there is some really good reason why that cannot be done >>>>>> (like size limitation in SPL or DT not available). >>>>>> >>>>>> I tried these approaches: >>>>>> 1) Add Kconfig option for CONFIG_SYS_NS16550_FCR , where you >>>>>> set specific byte value. This makes it hard to figure out >>>>>> which bits are set in the FCR just by looking at the value. >>>>>> 2) Add Kconfig option selected if ARCH_JZ47XX is selected and >>>>>> use that in the driver to add the extra UME bit. >>>>>> 3) Define CONFIG_SYS_NS16550_FCR in include/configs/board.h >>>>>> using the macros from ns16550.h . This makes it obvious >>>>>> which bits are set. >>>>>> >>>>>> I am undecided between 2 and 3, but inclined to go with 3. >>>>>> What do you think ? >>>>> >>>>> How about making your feature an option, like CONFIG_SYS_NS16550_UEN, >>>>> which defaults to 0, but in your case is 0x10. You can OR it into the >>>>> value. >>>> >>>> That's quite close to 1) , but then what if someone comes and wants to >>>> remove some bits from the FCR instead of adding some? >>> >>> Seems like speculative complexity to me - let's worry about it when it >>> happens! >> >> Heh, ok. But if we add Kconfig stuff, we can as well go with option 2) , >> which would only show up if JZ47XX is selected. Since this bits is >> specific to this lineup of SoCs , that makes sense in my head. What do >> you think ? > > SGTM.
No, whichever I slice it as I plumb in this, I just don't like adding this complexity only because I might sometimes use UART on this platform in SPL. I can hack that support in, but in general let's just not do it afterall to make the driver a little simple(r). I just added DM/DT support into the JZ4780 and it supports serial too with minor tweaks to the ns16550 driver and it looks much less convoluted, so I will just opt for that. -- Best regards, Marek Vasut _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
