On Sun, Apr 19, 2026 at 12:15:39AM +0200, Kirill A. Korinsky wrote:
> On Fri, 17 Apr 2026 20:48:35 +0200,
> Kirill A. Korinsky <[email protected]> wrote:
> >
> > bugs@,
> >
> > I'd like to share that little that I do have for now with attempt to boot
> > bsd.rd from todays snapshot at Juniper Networks SRX300 which smeels like a
> > corrupted memory:
> >
>
> No, it isn't corrupted memory.
>
> This device needs serial with 9660 only, and cn30xxuart had hardcoded
> 115200, and as soon as kernel replaces console from bootloader's 9600 to
> kernel's hardcoded 115200 garbage came.
>
> Here a patch where I read the programmed UART divisor instead and derive
> comconsrate from it, so the kernel preserves the bootloader console
> configuration.
This should be fine. This approach is usable also with old machines
where the current baud rate cannot be read from the device tree
(because the firmware does not provide the tree in the first place).
> Tested on SRX300 which boots, and does not break serial at EdgeRouter USG
> which needs 115200.
>
> Ok?
OK visa@
> Index: sys/arch/octeon/dev/cn30xxuart.c
> ===================================================================
> RCS file: /home/cvs/src/sys/arch/octeon/dev/cn30xxuart.c,v
> diff -u -p -r1.13 cn30xxuart.c
> --- sys/arch/octeon/dev/cn30xxuart.c 6 Apr 2022 18:59:27 -0000 1.13
> +++ sys/arch/octeon/dev/cn30xxuart.c 18 Apr 2026 21:35:56 -0000
> @@ -66,6 +66,7 @@ cons_decl(octuart);
>
> /* XXX: What is this used for? Removed from stand/boot/uart.c -r1.2 */
> static int delay_changed = 1;
> +static int cn30xxuart_get_divisor(void);
> int cn30xxuart_delay(void);
> void cn30xxuart_wait_txhr_empty(int);
>
> @@ -85,10 +86,16 @@ bus_space_t uartbus_tag = {
> void
> com_fdt_init_cons(void)
> {
> + int divisor;
> +
> comconsiot = &uartbus_tag;
> comconsaddr = OCTEON_UART0_BASE;
> comconsfreq = octeon_ioclock_speed();
> - comconsrate = B115200;
> + divisor = cn30xxuart_get_divisor();
> + if (divisor > 0)
> + comconsrate = comconsfreq / 16 / divisor;
> + else
> + comconsrate = TTYDEF_SPEED;
> comconscflag = (TTYDEF_CFLAG & ~(CSIZE | PARENB)) | CS8;
> }
>
> @@ -161,21 +168,30 @@ cn30xxuart_intr(void *arg)
> * Early console routines.
> */
>
> -int
> -cn30xxuart_delay(void)
> +static int
> +cn30xxuart_get_divisor(void)
> {
> int divisor;
> u_char lcr;
> - static int d = 0;
>
> - if (!delay_changed)
> - return d;
> - delay_changed = 0;
> lcr = octeon_xkphys_read_8(MIO_UART0_LCR);
> octeon_xkphys_write_8(MIO_UART0_LCR, lcr | LCR_DLAB);
> divisor = octeon_xkphys_read_8(MIO_UART0_DLL) |
> octeon_xkphys_read_8(MIO_UART0_DLH) << 8;
> octeon_xkphys_write_8(MIO_UART0_LCR, lcr);
> +
> + return divisor;
> +}
> +
> +int
> +cn30xxuart_delay(void)
> +{
> + static int d = 0;
> +
> + if (!delay_changed)
> + return d;
> + delay_changed = 0;
> + (void)cn30xxuart_get_divisor();
>
> return 10; /* return an approx delay value */
> }
>
>
>
> --
> wbr, Kirill
>
