* [PATCH] tty: serial: meson: Implement earlycon support @ 2016-02-07 20:57 Andreas Färber 2016-02-08 4:22 ` Peter Hurley 0 siblings, 1 reply; 3+ messages in thread From: Andreas Färber @ 2016-02-07 20:57 UTC (permalink / raw) To: linux-arm-kernel Reuse the existing console write implementation for implementing DT-based and command-line-based earlycon support. Signed-off-by: Andreas F?rber <afaerber@suse.de> --- Documentation/kernel-parameters.txt | 6 ++++++ drivers/tty/serial/meson_uart.c | 13 +++++++++++++ 2 files changed, 19 insertions(+) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 602065c..90801ac 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1030,6 +1030,12 @@ Such letter suffixes can also be entirely omitted. the driver will use only 32-bit accessors to read/write the device registers. + meson_serial,<addr> + Start an early, polled-mode console on a meson serial + port at the specified address. The serial port must + already be setup and configured. Options are not yet + supported. + msm_serial,<addr> Start an early, polled-mode console on an msm serial port at the specified address. The serial port diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c index b12a37b..6f89567 100644 --- a/drivers/tty/serial/meson_uart.c +++ b/drivers/tty/serial/meson_uart.c @@ -548,6 +548,19 @@ static int __init meson_serial_console_init(void) } console_initcall(meson_serial_console_init); +static int __init +meson_serial_early_console_setup(struct earlycon_device *device, const char *opt) +{ + if (!device->port.membase) + return -ENODEV; + + device->con->write = meson_serial_console_write; + return 0; +} +EARLYCON_DECLARE(meson_serial, meson_serial_early_console_setup); +OF_EARLYCON_DECLARE(meson_serial, "amlogic,meson-uart", + meson_serial_early_console_setup); + #define MESON_SERIAL_CONSOLE (&meson_serial_console) #else #define MESON_SERIAL_CONSOLE NULL -- 2.6.2 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH] tty: serial: meson: Implement earlycon support 2016-02-07 20:57 [PATCH] tty: serial: meson: Implement earlycon support Andreas Färber @ 2016-02-08 4:22 ` Peter Hurley 2016-02-08 11:50 ` Andreas Färber 0 siblings, 1 reply; 3+ messages in thread From: Peter Hurley @ 2016-02-08 4:22 UTC (permalink / raw) To: linux-arm-kernel Hi Andreas, On 02/07/2016 12:57 PM, Andreas F?rber wrote: > Reuse the existing console write implementation for implementing > DT-based and command-line-based earlycon support. > > Signed-off-by: Andreas F?rber <afaerber@suse.de> > --- > Documentation/kernel-parameters.txt | 6 ++++++ > drivers/tty/serial/meson_uart.c | 13 +++++++++++++ > 2 files changed, 19 insertions(+) > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt > index 602065c..90801ac 100644 > --- a/Documentation/kernel-parameters.txt > +++ b/Documentation/kernel-parameters.txt > @@ -1030,6 +1030,12 @@ Such letter suffixes can also be entirely omitted. > the driver will use only 32-bit accessors to read/write > the device registers. > > + meson_serial,<addr> > + Start an early, polled-mode console on a meson serial > + port at the specified address. The serial port must > + already be setup and configured. Options are not yet > + supported. > + > msm_serial,<addr> > Start an early, polled-mode console on an msm serial > port at the specified address. The serial port > diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c > index b12a37b..6f89567 100644 > --- a/drivers/tty/serial/meson_uart.c > +++ b/drivers/tty/serial/meson_uart.c > @@ -548,6 +548,19 @@ static int __init meson_serial_console_init(void) > } > console_initcall(meson_serial_console_init); > > +static int __init > +meson_serial_early_console_setup(struct earlycon_device *device, const char *opt) > +{ > + if (!device->port.membase) > + return -ENODEV; > + > + device->con->write = meson_serial_console_write; meson_serial_console_write() is not appropriate for earlycon; it assumes the earlycon port is the same as the driver port (it isn't). > + return 0; > +} > +EARLYCON_DECLARE(meson_serial, meson_serial_early_console_setup); > +OF_EARLYCON_DECLARE(meson_serial, "amlogic,meson-uart", > + meson_serial_early_console_setup); With today's linux-next (or Greg's tty-next tree), it is no longer necessary to declare separate earlycon's when you want both; OF_EARLYCON_DECLARE() declares both a devicetree-enabled earlycon and automatically provides for a command line earlycon of the same name. Regards, Peter Hurley > + > #define MESON_SERIAL_CONSOLE (&meson_serial_console) > #else > #define MESON_SERIAL_CONSOLE NULL > ^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] tty: serial: meson: Implement earlycon support 2016-02-08 4:22 ` Peter Hurley @ 2016-02-08 11:50 ` Andreas Färber 0 siblings, 0 replies; 3+ messages in thread From: Andreas Färber @ 2016-02-08 11:50 UTC (permalink / raw) To: linux-arm-kernel Hi Peter, Am 08.02.2016 um 05:22 schrieb Peter Hurley: > On 02/07/2016 12:57 PM, Andreas F?rber wrote: >> Reuse the existing console write implementation for implementing >> DT-based and command-line-based earlycon support. >> >> Signed-off-by: Andreas F?rber <afaerber@suse.de> >> --- >> Documentation/kernel-parameters.txt | 6 ++++++ >> drivers/tty/serial/meson_uart.c | 13 +++++++++++++ >> 2 files changed, 19 insertions(+) >> >> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt >> index 602065c..90801ac 100644 >> --- a/Documentation/kernel-parameters.txt >> +++ b/Documentation/kernel-parameters.txt >> @@ -1030,6 +1030,12 @@ Such letter suffixes can also be entirely omitted. >> the driver will use only 32-bit accessors to read/write >> the device registers. >> >> + meson_serial,<addr> >> + Start an early, polled-mode console on a meson serial >> + port at the specified address. The serial port must >> + already be setup and configured. Options are not yet >> + supported. >> + >> msm_serial,<addr> >> Start an early, polled-mode console on an msm serial >> port at the specified address. The serial port >> diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c >> index b12a37b..6f89567 100644 >> --- a/drivers/tty/serial/meson_uart.c >> +++ b/drivers/tty/serial/meson_uart.c >> @@ -548,6 +548,19 @@ static int __init meson_serial_console_init(void) >> } >> console_initcall(meson_serial_console_init); >> >> +static int __init >> +meson_serial_early_console_setup(struct earlycon_device *device, const char *opt) >> +{ >> + if (!device->port.membase) >> + return -ENODEV; >> + >> + device->con->write = meson_serial_console_write; > > meson_serial_console_write() is not appropriate for earlycon; it assumes the > earlycon port is the same as the driver port (it isn't). Thanks for spotting that. I forgot to mention that I tested this on arm64, where there is no earlyprintk any more, seemingly successfully getting a bootconsole uart0. Using co->data instead of co->index I now get meson_serial0 instead, doh. This probably slipped though because another patch is necessary for fixing the baudrate calculation on my device. >> + return 0; >> +} >> +EARLYCON_DECLARE(meson_serial, meson_serial_early_console_setup); >> +OF_EARLYCON_DECLARE(meson_serial, "amlogic,meson-uart", >> + meson_serial_early_console_setup); > > With today's linux-next (or Greg's tty-next tree), it is no longer necessary to > declare separate earlycon's when you want both; OF_EARLYCON_DECLARE() declares > both a devicetree-enabled earlycon and automatically provides for a command line > earlycon of the same name. Thanks for the hint, it was based on linux-next from a couple days ago. Is there any guidance wrt naming? I noticed that msm uses -uart in the compatible string and _serial for earlycon, so I copied that; should it rather be meson_uart or just meson? Regards, Andreas -- SUSE Linux GmbH, Maxfeldstr. 5, 90409 N?rnberg, Germany GF: Felix Imend?rffer, Jane Smithard, Graham Norton; HRB 21284 (AG N?rnberg) ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2016-02-08 11:50 UTC | newest] Thread overview: 3+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2016-02-07 20:57 [PATCH] tty: serial: meson: Implement earlycon support Andreas Färber 2016-02-08 4:22 ` Peter Hurley 2016-02-08 11:50 ` Andreas Färber
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