| Message ID | 20221123-serial-clk-v3-0-49c516980ae0@chromium.org |
|---|---|
| Headers | show |
| Series | earlycon: Let users set the clock frequency | expand |
Hi Jiri is there something else that I am missing here? Thanks! On Thu, 24 Nov 2022 at 13:39, Ricardo Ribalda <ribalda@chromium.org> wrote: > > 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 a5f380584cda..3a0c88419b6c 100644 > --- a/drivers/tty/serial/earlycon.c > +++ b/drivers/tty/serial/earlycon.c > @@ -120,7 +120,13 @@ static int __init parse_options(struct earlycon_device *device, char *options) > } > > if (options) { > + char *uartclk; > + > device->baud = simple_strtoul(options, NULL, 0); > + uartclk = strchr(options, ','); > + if (uartclk && kstrtouint(uartclk + 1, 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); > @@ -139,7 +145,8 @@ 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
On 24. 11. 22, 13:39, Ricardo Ribalda wrote: > 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> Reviewed-by: Jiri Slaby <jirislaby@kernel.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 a5f380584cda..3a0c88419b6c 100644 > --- a/drivers/tty/serial/earlycon.c > +++ b/drivers/tty/serial/earlycon.c > @@ -120,7 +120,13 @@ static int __init parse_options(struct earlycon_device *device, char *options) > } > > if (options) { > + char *uartclk; > + > device->baud = simple_strtoul(options, NULL, 0); > + uartclk = strchr(options, ','); > + if (uartclk && kstrtouint(uartclk + 1, 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); > @@ -139,7 +145,8 @@ 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); > >
On Fri, Dec 02, 2022 at 06:24:19PM +0100, Ricardo Ribalda wrote: > Hi Jiri > > is there something else that I am missing here? Sorry, been busy with other reviews. I will queue this up after 6.2-rc1 is out, thanks. greg k-h
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 v3: - Revert patch to use kstrtouint for baudrate - Parse the number not the ,number (Thanks Jiri :) ) - Add optional patch to increase the options size - Link to v2: https://lore.kernel.org/r/20221123-serial-clk-v2-0-9c03ce8940d8@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: Let users set the clock frequency earlycon: Increase options size Documentation/admin-guide/kernel-parameters.txt | 12 +++++++----- drivers/tty/serial/earlycon.c | 9 ++++++++- include/linux/serial_core.h | 2 +- 3 files changed, 16 insertions(+), 7 deletions(-) --- base-commit: 4312098baf37ee17a8350725e6e0d0e8590252d4 change-id: 20221123-serial-clk-85db701ada57 Best regards,