Re: [PATCH 0/3] serial: sh-sci: Clock handling improvements

[Yoshinori Sato <ysato@users.sourceforge.jp>]

On Mon, 20 Dec 2021 19:29:24 +0900,
Rob Landley wrote:
> 
> On 12/19/21 4:53 AM, Geert Uytterhoeven wrote:
> >> By the way, did you ever figure out how to get the first serial port to work on
> >> qemu so qemu-system-sh4 doesn't have to "-serial null -serial mon:stdio" to get
> >> a serial console?
> > 
> > Nope, same as last time you asked ;-)
> 
> Well it had been a couple years, you never know...
> 
> > However, upon a fresh look at linux/arch/sh/boards/mach-r2d/setup.c,
> > I noticed something I missed before: the SCI port is not available
> > as a UART, as it is used to talk SPI to an RTC.

Yes.
R2D plus serial port connected SuperI/O UART. It not cpu on-chip SCI.
It is not possible to check SCI with the standard version of qemu-system-sh4.
There is SCI emulation, so you can change it to connect to the qemu serial port.

> /* Single Epson RTC-9701JE attached on CS0 */
> 
> Huh. That does explain the CONFIG_RTC_DRV_R9701=y in rts7751r2d*_defconfig.
> (And also SPI SPI_SH_SCI MFD_SM501 RTC_CLASS and RTC_DRV_SH RTC_HCTOSYS which
> I've never gotten connected to QEMU.)

SPI_SH_SCI using SCI pin like GPIO.
qemu-system-sh4 is not support this.

> > So that means qemu
> > has the hardware description wrong?
> 
> It would be nice if qemu-system-sh4 grew an RTC. Looks like Sato-san and Magnus
> Damm are the qemu-system-sh4 maintainers? (cc'd)
> 
> Thanks,
> 
> Rob

-- 
Yosinori Sato