The sifive serial driver implements earlycon support, but unless
another driver is built in that supports earlycon support it won't
be usable. Explicitly select SERIAL_EARLYCON instead.
Signed-off-by: Christoph Hellwig <[email protected]>
---
drivers/tty/serial/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 530cb966092f..6b77a72278e3 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1075,6 +1075,7 @@ config SERIAL_SIFIVE_CONSOLE
bool "Console on SiFive UART"
depends on SERIAL_SIFIVE=y
select SERIAL_CORE_CONSOLE
+ select SERIAL_EARLYCON
help
Select this option if you would like to use a SiFive UART as the
system console.
--
2.20.1
On Tue, Sep 10, 2019 at 08:57:37AM +0200, Andreas Schwab wrote:
> On Sep 10 2019, Christoph Hellwig <[email protected]> wrote:
>
> > The sifive serial driver implements earlycon support,
>
> It should probably be documented in admin-guide/kernel-parameters.txt.
How so? Wіth OF and a stdout path you just set earlycon on the
command line without any arguments and it will be found.
On Sep 10 2019, Christoph Hellwig <[email protected]> wrote:
> On Tue, Sep 10, 2019 at 08:57:37AM +0200, Andreas Schwab wrote:
>> On Sep 10 2019, Christoph Hellwig <[email protected]> wrote:
>>
>> > The sifive serial driver implements earlycon support,
>>
>> It should probably be documented in admin-guide/kernel-parameters.txt.
>
> How so? Wіth OF and a stdout path you just set earlycon on the
> command line without any arguments and it will be found.
Doesn't work for me.
[ 0.000000] Malformed early option 'earlycon'
Andreas.
--
Andreas Schwab, SUSE Labs, [email protected]
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
On Tue, Sep 10, 2019 at 10:18:15AM +0200, Andreas Schwab wrote:
> > How so? Wіth OF and a stdout path you just set earlycon on the
> > command line without any arguments and it will be found.
>
> Doesn't work for me.
>
> [ 0.000000] Malformed early option 'earlycon'
That functionality is implemented by param_setup_earlycon and
early_init_dt_scan_chosen_stdout. Check why those aren't built into
your kernel.
On Sep 10 2019, Christoph Hellwig <[email protected]> wrote:
> On Tue, Sep 10, 2019 at 10:18:15AM +0200, Andreas Schwab wrote:
>> > How so? Wіth OF and a stdout path you just set earlycon on the
>> > command line without any arguments and it will be found.
>>
>> Doesn't work for me.
>>
>> [ 0.000000] Malformed early option 'earlycon'
>
> That functionality is implemented by param_setup_earlycon and
> early_init_dt_scan_chosen_stdout. Check why those aren't built into
> your kernel.
They are.
Andreas.
--
Andreas Schwab, SUSE Labs, [email protected]
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
On Sep 10 2019, Christoph Hellwig <[email protected]> wrote:
> The sifive serial driver implements earlycon support,
It should probably be documented in admin-guide/kernel-parameters.txt.
Andreas.
--
Andreas Schwab, SUSE Labs, [email protected]
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
On Tue, 10 Sep 2019 07:36:30 PDT (-0700), Christoph Hellwig wrote:
> On Tue, Sep 10, 2019 at 10:18:15AM +0200, Andreas Schwab wrote:
>> > How so? Wіth OF and a stdout path you just set earlycon on the
>> > command line without any arguments and it will be found.
>>
>> Doesn't work for me.
>>
>> [ 0.000000] Malformed early option 'earlycon'
>
> That functionality is implemented by param_setup_earlycon and
> early_init_dt_scan_chosen_stdout. Check why those aren't built into
> your kernel.
OpenEmbedded passes "earlycon=sbi", which I can find in the doumentation. I
can't find anything about just "earlycon". I've sent a patch adding sbi to the
list of earlycon arguments.
On Fri, Sep 13, 2019 at 01:40:27PM -0700, Palmer Dabbelt wrote:
> OpenEmbedded passes "earlycon=sbi", which I can find in the doumentation.
> I can't find anything about just "earlycon". I've sent a patch adding sbi
> to the list of earlycon arguments.
earlycon without arguments is documented, although just for ARM64.
I can send a patch to update it to properly cover all DT platforms
in addition.
On Tue, 10 Sep 2019, Andreas Schwab wrote:
> On Sep 10 2019, Christoph Hellwig <[email protected]> wrote:
>
> > On Tue, Sep 10, 2019 at 08:57:37AM +0200, Andreas Schwab wrote:
> >> On Sep 10 2019, Christoph Hellwig <[email protected]> wrote:
> >>
> >> > The sifive serial driver implements earlycon support,
> >>
> >> It should probably be documented in admin-guide/kernel-parameters.txt.
> >
> > How so? Wіth OF and a stdout path you just set earlycon on the
> > command line without any arguments and it will be found.
>
> Doesn't work for me.
>
> [ 0.000000] Malformed early option 'earlycon'
Try:
earlycon=sifive,0x10010000
If it works, you should see this message on the kernel console very early
in the boot:
[ 0.000000] earlycon: sifive0 at MMIO 0x0000000010010000 (options '')
- Paul
On Mon, Sep 16, 2019 at 02:00:39PM +0200, Andreas Schwab wrote:
> > Try:
> >
> > earlycon=sifive,0x10010000
>
> That's not what Christoph wants.
Well, what I want is auto selection if the device tree uses the
stdout-path. My Kendryte DT uses that and it works like a charm. If
it doesn't work for you on the U54 board chances are that your DT
doesn't have the right settings and you have to use the line that
Paul posted.
On Tue, 10 Sep 2019, Christoph Hellwig wrote:
> The sifive serial driver implements earlycon support, but unless
> another driver is built in that supports earlycon support it won't
> be usable. Explicitly select SERIAL_EARLYCON instead.
>
> Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Paul Walmsley <[email protected]>
- Paul
On Sep 16 2019, Paul Walmsley <[email protected]> wrote:
> On Tue, 10 Sep 2019, Andreas Schwab wrote:
>
>> On Sep 10 2019, Christoph Hellwig <[email protected]> wrote:
>>
>> > On Tue, Sep 10, 2019 at 08:57:37AM +0200, Andreas Schwab wrote:
>> >> On Sep 10 2019, Christoph Hellwig <[email protected]> wrote:
>> >>
>> >> > The sifive serial driver implements earlycon support,
>> >>
>> >> It should probably be documented in admin-guide/kernel-parameters.txt.
>> >
>> > How so? Wіth OF and a stdout path you just set earlycon on the
>> > command line without any arguments and it will be found.
>>
>> Doesn't work for me.
>>
>> [ 0.000000] Malformed early option 'earlycon'
>
> Try:
>
> earlycon=sifive,0x10010000
That's not what Christoph wants.
Andreas.
--
Andreas Schwab, SUSE Labs, [email protected]
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
On Mon, Sep 16, 2019 at 05:18:57AM -0700, Paul Walmsley wrote:
> I support Christoph's plan to add generic implicit earlycon support.
I'm not planning to add it, it exist already. You just need a DT that
sets the stdout node up properly, and a earlycon driver using
OF_EARLYCON_DECLARE like the sifive uart driver.
The DT here for example works perfectly fine:
http://git.infradead.org/users/hch/riscv.git/commitdiff/f10e64873eafc68516b8884c06b9290b9887633b
On Mon, 16 Sep 2019, Andreas Schwab wrote:
> On Sep 16 2019, Paul Walmsley <[email protected]> wrote:
>
> > On Tue, 10 Sep 2019, Andreas Schwab wrote:
> >
> >> On Sep 10 2019, Christoph Hellwig <[email protected]> wrote:
> >>
> >> > On Tue, Sep 10, 2019 at 08:57:37AM +0200, Andreas Schwab wrote:
> >> >> On Sep 10 2019, Christoph Hellwig <[email protected]> wrote:
> >> >>
> >> >> > The sifive serial driver implements earlycon support,
> >> >>
> >> >> It should probably be documented in admin-guide/kernel-parameters.txt.
> >> >
> >> > How so? Wіth OF and a stdout path you just set earlycon on the
> >> > command line without any arguments and it will be found.
> >>
> >> Doesn't work for me.
> >>
> >> [ 0.000000] Malformed early option 'earlycon'
> >
> > Try:
> >
> > earlycon=sifive,0x10010000
>
> That's not what Christoph wants.
I support Christoph's plan to add generic implicit earlycon support.
In the meantime, once v5.4-rc1 is released, I'll send a patch to add a
sifive driver section to the earlycon documentation in
admin-guide/kernel-parameters.txt. Thanks for the (earlier) suggestion.
- Paul
On Sep 16 2019, Palmer Dabbelt <[email protected]> wrote:
> On Sun, 15 Sep 2019 23:42:53 PDT (-0700), Christoph Hellwig wrote:
>> On Fri, Sep 13, 2019 at 01:40:27PM -0700, Palmer Dabbelt wrote:
>>> OpenEmbedded passes "earlycon=sbi", which I can find in the doumentation.
>>> I can't find anything about just "earlycon". I've sent a patch adding sbi
>>> to the list of earlycon arguments.
>>
>> earlycon without arguments is documented, although just for ARM64.
>> I can send a patch to update it to properly cover all DT platforms
>> in addition.
>
> Thanks. I've kind of lost track of the thread, but assuming that does the
> "automatically pick an earlycon" stuff then that's probably what we should
> be using in the distros.
Except that it doesn't work.
Andreas.
--
Andreas Schwab, SUSE Labs, [email protected]
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
On Sun, 15 Sep 2019 23:42:53 PDT (-0700), Christoph Hellwig wrote:
> On Fri, Sep 13, 2019 at 01:40:27PM -0700, Palmer Dabbelt wrote:
>> OpenEmbedded passes "earlycon=sbi", which I can find in the doumentation.
>> I can't find anything about just "earlycon". I've sent a patch adding sbi
>> to the list of earlycon arguments.
>
> earlycon without arguments is documented, although just for ARM64.
> I can send a patch to update it to properly cover all DT platforms
> in addition.
Thanks. I've kind of lost track of the thread, but assuming that does the
"automatically pick an earlycon" stuff then that's probably what we should be
using in the distros.
On Mon, 16 Sep 2019 12:40:10 PDT (-0700), [email protected] wrote:
> On Sep 16 2019, Palmer Dabbelt <[email protected]> wrote:
>
>> On Sun, 15 Sep 2019 23:42:53 PDT (-0700), Christoph Hellwig wrote:
>>> On Fri, Sep 13, 2019 at 01:40:27PM -0700, Palmer Dabbelt wrote:
>>>> OpenEmbedded passes "earlycon=sbi", which I can find in the doumentation.
>>>> I can't find anything about just "earlycon". I've sent a patch adding sbi
>>>> to the list of earlycon arguments.
>>>
>>> earlycon without arguments is documented, although just for ARM64.
>>> I can send a patch to update it to properly cover all DT platforms
>>> in addition.
>>
>> Thanks. I've kind of lost track of the thread, but assuming that does the
>> "automatically pick an earlycon" stuff then that's probably what we should
>> be using in the distros.
>
> Except that it doesn't work.
Sorry, once again I've lost track of the thread.
The code looks generic. The device tree in arch/riscv for the HiFive Unleashed
doesn't have a stdout-path set, which if I understand correctly is used by the
automatic earlycon stuff to pick a console. I gave this a quick test on QEMU,
which finds a 16550 earlycon for me. I use openembedded's qemuriscv64 target,
the following diff to make sure I'm getting an earlycon
diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
index 5cd8c36c8fcc..61290714bbcb 100644
--- a/drivers/tty/serial/8250/8250_early.c
+++ b/drivers/tty/serial/8250/8250_early.c
@@ -106,6 +106,7 @@ static void early_serial8250_write(struct console *console,
struct earlycon_device *device = console->data;
struct uart_port *port = &device->port;
+ uart_console_write(port, "_e_", 3, serial_putc);
uart_console_write(port, s, count, serial_putc);
}
and run this command line
/home/palmer/work/linux/openembedded-riscv64/build/tmp-glibc/work/x86_64-linux/qemu-helper-native/1.0-r1/recipe-sysroot-native/usr/bin/qemu-system-riscv64 -device virtio-net-device,netdev=net0,mac=52:54:00:12:35:02 -netdev user,id=net0,hostfwd=tcp::2222-:22,hostfwd=tcp::2323-:23,tftp=/home/palmer/work/linux/openembedded-riscv64/build/tmp-glibc/deploy/images/qemuriscv64 -drive id=disk0,file=/home/palmer/work/linux/openembedded-riscv64/build/tmp-glibc/deploy/images/qemuriscv64/core-image-full-cmdline-qemuriscv64-20190711162644.rootfs.ext4,if=none,format=raw -device virtio-blk-device,drive=disk0 -object rng-random,filename=/dev/urandom,id=rng0 -device virtio-rng-device,rng=rng0 -show-cursor -monitor null -device loader,file=/home/palmer/work/linux/linux/arch/riscv/boot/Image,addr=0x80200000 -nographic -machine virt -m 512 -serial mon:stdio -serial null -kernel /home/palmer/work/linux/openembedded-riscv64/build/tmp-glibc/deploy/images/qemuriscv64/fw_jump.elf -append 'root=/dev/vda rw highres=off console=ttyS0 mem=512M ip=dhcp earlycon '
which gives me some early stuff and then some non-early stuff
_e_[ 0.407579] printk: console [ttyS0] disabled
_e_[ 0.409205] 10000000.uart: ttyS0 at MMIO 0x10000000 (irq = 10, base_baud = 230400) is a 16550A
[ 0.410720] printk: console [ttyS0] enabled
_e_[ 0.410720] printk: console [ttyS0] enabled
[ 0.411391] printk: bootconsole [ns16550a0] disabled
_e_[ 0.411391] printk: bootconsole [ns16550a0] disabled
[ 0.420664] [drm] radeon kernel modesetting enabled.
[ 0.428086] random: fast init done
[ 0.429331] random: crng init done
[ 0.440678] loop: module loaded
[ 0.447607] virtio_blk virtio1: [vda] 262830 512-byte logical blocks (135 MB/128 MiB)
[ 0.469483] libphy: Fixed MDIO Bus: probed
If you don't have something like "/chosen/stdout-path = &uart0;" in your device
tree, then that's probably the issue. Here's where it's set in Christoph's
k210:
http://git.infradead.org/users/hch/riscv.git/blob/f10e64873eafc68516b8884c06b9290b9887633b:/arch/riscv/boot/dts/kendryte/kd210.dts#l20
but we don't set it for the HiFive Unleashed. I'd call that a bug, something
like this
diff --git a/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts b/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
index 93d68cbd64fe..6d0ec76d93fe 100644
--- a/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
+++ b/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
@@ -13,6 +13,7 @@
compatible = "sifive,hifive-unleashed-a00", "sifive,fu540-c000";
chosen {
+ stdout-path = &uart0;
};
cpus {
should fix it. LMK if I've misunderstood something.
On Sep 16 2019, Palmer Dabbelt <[email protected]> wrote:
> but we don't set it for the HiFive Unleashed. I'd call that a bug,
> something like this
>
> diff --git a/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts b/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
> index 93d68cbd64fe..6d0ec76d93fe 100644
> --- a/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
> +++ b/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
> @@ -13,6 +13,7 @@
> compatible = "sifive,hifive-unleashed-a00", "sifive,fu540-c000";
>
> chosen {
> + stdout-path = &uart0;
> };
>
> cpus {
>
> should fix it. LMK if I've misunderstood something.
If that's how it's supposed to work, ok. Other platforms add it in
u-boot.
Andreas.
--
Andreas Schwab, SUSE Labs, [email protected]
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
On Mon, 2019-09-16 at 14:38 -0700, Palmer Dabbelt wrote:
> On Mon, 16 Sep 2019 12:40:10 PDT (-0700), [email protected] wrote:
> > On Sep 16 2019, Palmer Dabbelt <[email protected]> wrote:
> >
> > > On Sun, 15 Sep 2019 23:42:53 PDT (-0700), Christoph Hellwig
> > > wrote:
> > > > On Fri, Sep 13, 2019 at 01:40:27PM -0700, Palmer Dabbelt wrote:
> > > > > OpenEmbedded passes "earlycon=sbi", which I can find in the
> > > > > doumentation.
> > > > > I can't find anything about just "earlycon". I've sent a
> > > > > patch adding sbi
> > > > > to the list of earlycon arguments.
> > > >
> > > > earlycon without arguments is documented, although just for
> > > > ARM64.
> > > > I can send a patch to update it to properly cover all DT
> > > > platforms
> > > > in addition.
> > >
> > > Thanks. I've kind of lost track of the thread, but assuming that
> > > does the
> > > "automatically pick an earlycon" stuff then that's probably what
> > > we should
> > > be using in the distros.
> >
> > Except that it doesn't work.
>
> Sorry, once again I've lost track of the thread.
>
> The code looks generic. The device tree in arch/riscv for the HiFive
> Unleashed
> doesn't have a stdout-path set, which if I understand correctly is
> used by the
> automatic earlycon stuff to pick a console. I gave this a quick test
> on QEMU,
> which finds a 16550 earlycon for me. I use openembedded's
> qemuriscv64 target,
> the following diff to make sure I'm getting an earlycon
>
> diff --git a/drivers/tty/serial/8250/8250_early.c
> b/drivers/tty/serial/8250/8250_early.c
> index 5cd8c36c8fcc..61290714bbcb 100644
> --- a/drivers/tty/serial/8250/8250_early.c
> +++ b/drivers/tty/serial/8250/8250_early.c
> @@ -106,6 +106,7 @@ static void early_serial8250_write(struct console
> *console,
> struct earlycon_device *device = console->data;
> struct uart_port *port = &device->port;
>
> + uart_console_write(port, "_e_", 3, serial_putc);
> uart_console_write(port, s, count, serial_putc);
> }
>
> and run this command line
>
> /home/palmer/work/linux/openembedded-riscv64/build/tmp-
> glibc/work/x86_64-linux/qemu-helper-native/1.0-r1/recipe-sysroot-
> native/usr/bin/qemu-system-riscv64 -device virtio-net-
> device,netdev=net0,mac=52:54:00:12:35:02 -netdev
> user,id=net0,hostfwd=tcp::2222-:22,hostfwd=tcp::2323-
> :23,tftp=/home/palmer/work/linux/openembedded-riscv64/build/tmp-
> glibc/deploy/images/qemuriscv64 -drive
> id=disk0,file=/home/palmer/work/linux/openembedded-riscv64/build/tmp-
> glibc/deploy/images/qemuriscv64/core-image-full-cmdline-qemuriscv64-
> 20190711162644.rootfs.ext4,if=none,format=raw -device virtio-blk-
> device,drive=disk0 -object rng-random,filename=/dev/urandom,id=rng0
> -device virtio-rng-device,rng=rng0 -show-cursor -monitor null -device
> loader,file=/home/palmer/work/linux/linux/arch/riscv/boot/Image,addr=
> 0x80200000 -nographic -machine virt -m 512 -serial mon:stdio
> -serial null -kernel /home/palmer/work/linux/openembedded-
> riscv64/build/tmp-glibc/deploy/images/qemuriscv64/fw_jump.elf -append
> 'root=/dev/vda rw highres=off console=ttyS0 mem=512M ip=dhcp
> earlycon '
>
> which gives me some early stuff and then some non-early stuff
>
> _e_[ 0.407579] printk: console [ttyS0] disabled
> _e_[ 0.409205] 10000000.uart: ttyS0 at MMIO 0x10000000 (irq = 10,
> base_baud = 230400) is a 16550A
> [ 0.410720] printk: console [ttyS0] enabled
> _e_[ 0.410720] printk: console [ttyS0] enabled
> [ 0.411391] printk: bootconsole [ns16550a0] disabled
> _e_[ 0.411391] printk: bootconsole [ns16550a0] disabled
> [ 0.420664] [drm] radeon kernel modesetting enabled.
> [ 0.428086] random: fast init done
> [ 0.429331] random: crng init done
> [ 0.440678] loop: module loaded
> [ 0.447607] virtio_blk virtio1: [vda] 262830 512-byte logical
> blocks (135 MB/128 MiB)
> [ 0.469483] libphy: Fixed MDIO Bus: probed
>
> If you don't have something like "/chosen/stdout-path = &uart0;" in
> your device
> tree, then that's probably the issue. Here's where it's set in
> Christoph's
> k210:
>
>
> http://git.infradead.org/users/hch/riscv.git/blob/f10e64873eafc68516b8884c06b9290b9887633b:/arch/riscv/boot/dts/kendryte/kd210.dts#l20
>
> but we don't set it for the HiFive Unleashed. I'd call that a bug,
> something
> like this
>
> diff --git a/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
> b/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
> index 93d68cbd64fe..6d0ec76d93fe 100644
> --- a/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
> +++ b/arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts
> @@ -13,6 +13,7 @@
> compatible = "sifive,hifive-unleashed-a00", "sifive,fu540-
> c000";
>
> chosen {
> + stdout-path = &uart0;
> };
>
> cpus {
>
> should fix it. LMK if I've misunderstood something.
>
OpenSBI already adds this node to DT for U-Boot serial console.
I have tested that just adding "earlycon" to the commandline works as
long as you are using OpenSBI and SERIAL_EARLYCON is enabled.
If this entry can be added to dt residing in kernel, we can remove the
code that adds the "stdout-path" from OpenSBI.
> _______________________________________________
> linux-riscv mailing list
> [email protected]
> http://lists.infradead.org/mailman/listinfo/linux-riscv
--
Regards,
Atish