Hi Marek, On 26 May 2016 at 11:35, Marek Vasut <ma...@denx.de> wrote: > 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.
Even better! - Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
