* [PATCH v2 0/2] earlycon: Let users set the clock frequency
@ 2022-11-24 10:02 Ricardo Ribalda
2022-11-24 10:02 ` [PATCH v2 1/2] earlycon: Replace simple_strtoul with kstrtouint Ricardo Ribalda
2022-11-24 10:02 ` [PATCH v2 2/2] earlycon: Let users set the clock frequency Ricardo Ribalda
0 siblings, 2 replies; 5+ messages in thread
From: Ricardo Ribalda @ 2022-11-24 10:02 UTC (permalink / raw)
To: Greg Kroah-Hartman, Jiri Slaby, Jonathan Corbet
Cc: Ricardo Ribalda, linux-doc, linux-serial, linux-kernel
Some platforms, namely AMD Picasso, use non standard uart clocks (48M),
witch makes it impossible to use with earlycon.
Let the user select its own frequency.
To: Jonathan Corbet <corbet@lwn.net>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Jiri Slaby <jirislaby@kernel.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
Changes in v2:
- Add a patch to fix handling of baudrate
- Use kstrtouint instead of simple_strtoul
- Link to v1: https://lore.kernel.org/r/20221123-serial-clk-v1-0-1f0554a46ad1@chromium.org
---
Ricardo Ribalda (2):
earlycon: Replace simple_strtoul with kstrtouint
earlycon: Let users set the clock frequency
Documentation/admin-guide/kernel-parameters.txt | 12 +++++++-----
drivers/tty/serial/earlycon.c | 17 ++++++++++++++---
2 files changed, 21 insertions(+), 8 deletions(-)
---
base-commit: 4312098baf37ee17a8350725e6e0d0e8590252d4
change-id: 20221123-serial-clk-85db701ada57
Best regards,
--
Ricardo Ribalda <ribalda@chromium.org>
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v2 1/2] earlycon: Replace simple_strtoul with kstrtouint
2022-11-24 10:02 [PATCH v2 0/2] earlycon: Let users set the clock frequency Ricardo Ribalda
@ 2022-11-24 10:02 ` Ricardo Ribalda
2022-11-24 10:02 ` [PATCH v2 2/2] earlycon: Let users set the clock frequency Ricardo Ribalda
1 sibling, 0 replies; 5+ messages in thread
From: Ricardo Ribalda @ 2022-11-24 10:02 UTC (permalink / raw)
To: Greg Kroah-Hartman, Jiri Slaby, Jonathan Corbet
Cc: Ricardo Ribalda, linux-doc, linux-serial, linux-kernel
Baud rate is declared as unsigned integer. Use the right function.
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
index a5f380584cda..5b73da9487b1 100644
--- a/drivers/tty/serial/earlycon.c
+++ b/drivers/tty/serial/earlycon.c
@@ -120,7 +120,9 @@ static int __init parse_options(struct earlycon_device *device, char *options)
}
if (options) {
- device->baud = simple_strtoul(options, NULL, 0);
+ if (kstrtouint(options, 0, &device->baud) < 0)
+ pr_warn("[%s] unsupported earlycon baud rate option\n",
+ options);
length = min(strcspn(options, " ") + 1,
(size_t)(sizeof(device->options)));
strscpy(device->options, options, length);
@@ -303,7 +305,9 @@ int __init of_setup_earlycon(const struct earlycon_id *match,
port->uartclk = be32_to_cpu(*val);
if (options) {
- early_console_dev.baud = simple_strtoul(options, NULL, 0);
+ if (kstrtouint(options, 0, &early_console_dev.baud) < 0)
+ pr_warn("[%s] unsupported earlycon baud rate options\n",
+ options);
strscpy(early_console_dev.options, options,
sizeof(early_console_dev.options));
}
--
b4 0.11.0-dev-d93f8
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v2 2/2] earlycon: Let users set the clock frequency
2022-11-24 10:02 [PATCH v2 0/2] earlycon: Let users set the clock frequency Ricardo Ribalda
2022-11-24 10:02 ` [PATCH v2 1/2] earlycon: Replace simple_strtoul with kstrtouint Ricardo Ribalda
@ 2022-11-24 10:02 ` Ricardo Ribalda
2022-11-24 11:19 ` Jiri Slaby
1 sibling, 1 reply; 5+ messages in thread
From: Ricardo Ribalda @ 2022-11-24 10:02 UTC (permalink / raw)
To: Greg Kroah-Hartman, Jiri Slaby, Jonathan Corbet
Cc: Ricardo Ribalda, linux-doc, linux-serial, linux-kernel
Some platforms, namely AMD Picasso, use non standard uart clocks (48M),
witch makes it impossible to use with earlycon.
Let the user select its own frequency.
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a465d5242774..9efb6c3b0486 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1182,10 +1182,10 @@
specified, the serial port must already be setup and
configured.
- uart[8250],io,<addr>[,options]
- uart[8250],mmio,<addr>[,options]
- uart[8250],mmio32,<addr>[,options]
- uart[8250],mmio32be,<addr>[,options]
+ uart[8250],io,<addr>[,options[,uartclk]]
+ uart[8250],mmio,<addr>[,options[,uartclk]]
+ uart[8250],mmio32,<addr>[,options[,uartclk]]
+ uart[8250],mmio32be,<addr>[,options[,uartclk]]
uart[8250],0x<addr>[,options]
Start an early, polled-mode console on the 8250/16550
UART at the specified I/O port or MMIO address.
@@ -1194,7 +1194,9 @@
If none of [io|mmio|mmio32|mmio32be], <addr> is assumed
to be equivalent to 'mmio'. 'options' are specified
in the same format described for "console=ttyS<n>"; if
- unspecified, the h/w is not initialized.
+ unspecified, the h/w is not initialized. 'uartclk' is
+ the uart clock frequency; if unspecified, it is set
+ to 'BASE_BAUD' * 16.
pl011,<addr>
pl011,mmio32,<addr>
diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
index 5b73da9487b1..2db92d36351b 100644
--- a/drivers/tty/serial/earlycon.c
+++ b/drivers/tty/serial/earlycon.c
@@ -120,9 +120,15 @@ static int __init parse_options(struct earlycon_device *device, char *options)
}
if (options) {
+ char *uartclk;
+
if (kstrtouint(options, 0, &device->baud) < 0)
pr_warn("[%s] unsupported earlycon baud rate option\n",
options);
+ uartclk = strchr(options, ',');
+ if (uartclk && kstrtouint(uartclk, 0, &port->uartclk) < 0)
+ pr_warn("[%s] unsupported earlycon uart clkrate option\n",
+ options);
length = min(strcspn(options, " ") + 1,
(size_t)(sizeof(device->options)));
strscpy(device->options, options, length);
@@ -141,7 +147,8 @@ static int __init register_earlycon(char *buf, const struct earlycon_id *match)
buf = NULL;
spin_lock_init(&port->lock);
- port->uartclk = BASE_BAUD * 16;
+ if (!port->uartclk)
+ port->uartclk = BASE_BAUD * 16;
if (port->mapbase)
port->membase = earlycon_map(port->mapbase, 64);
--
b4 0.11.0-dev-d93f8
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v2 2/2] earlycon: Let users set the clock frequency
2022-11-24 10:02 ` [PATCH v2 2/2] earlycon: Let users set the clock frequency Ricardo Ribalda
@ 2022-11-24 11:19 ` Jiri Slaby
2022-11-24 12:10 ` Ricardo Ribalda
0 siblings, 1 reply; 5+ messages in thread
From: Jiri Slaby @ 2022-11-24 11:19 UTC (permalink / raw)
To: Ricardo Ribalda, Greg Kroah-Hartman, Jonathan Corbet
Cc: linux-doc, linux-serial, linux-kernel
Hi,
On 24. 11. 22, 11:02, Ricardo Ribalda wrote:
...
> --- a/drivers/tty/serial/earlycon.c
> +++ b/drivers/tty/serial/earlycon.c
> @@ -120,9 +120,15 @@ static int __init parse_options(struct earlycon_device *device, char *options)
> }
>
> if (options) {
> + char *uartclk;
> +
> if (kstrtouint(options, 0, &device->baud) < 0)
> pr_warn("[%s] unsupported earlycon baud rate option\n",
> options);
IMO this won't work if there is a comma in options (i.e. your new
clkrate param). kstrtouint will return -EINVAL in that case.
> + uartclk = strchr(options, ',');
> + if (uartclk && kstrtouint(uartclk, 0, &port->uartclk) < 0)
You are giving ",number" to kstrtouint, right? That won't work either ;).
regards,
--
js
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2 2/2] earlycon: Let users set the clock frequency
2022-11-24 11:19 ` Jiri Slaby
@ 2022-11-24 12:10 ` Ricardo Ribalda
0 siblings, 0 replies; 5+ messages in thread
From: Ricardo Ribalda @ 2022-11-24 12:10 UTC (permalink / raw)
To: Jiri Slaby
Cc: Greg Kroah-Hartman, Jonathan Corbet, linux-doc, linux-serial,
linux-kernel
On Thu, 24 Nov 2022 at 12:19, Jiri Slaby <jirislaby@kernel.org> wrote:
>
> Hi,
>
> On 24. 11. 22, 11:02, Ricardo Ribalda wrote:
> ...
> > --- a/drivers/tty/serial/earlycon.c
> > +++ b/drivers/tty/serial/earlycon.c
> > @@ -120,9 +120,15 @@ static int __init parse_options(struct earlycon_device *device, char *options)
> > }
> >
> > if (options) {
> > + char *uartclk;
> > +
> > if (kstrtouint(options, 0, &device->baud) < 0)
> > pr_warn("[%s] unsupported earlycon baud rate option\n",
> > options);
>
> IMO this won't work if there is a comma in options (i.e. your new
> clkrate param). kstrtouint will return -EINVAL in that case.
>
> > + uartclk = strchr(options, ',');
> > + if (uartclk && kstrtouint(uartclk, 0, &port->uartclk) < 0)
>
> You are giving ",number" to kstrtouint, right? That won't work either ;).
The fun thing is that it worked because it fell back to the acpi
parameters :). Will send a v3
Thanks!
>
> regards,
> --
> js
>
--
Ricardo Ribalda
^ permalink raw reply [flat|nested] 5+ messages in thread
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