Re: [PATCH v6 5/5] drivers/tty/serial: add LiteUART driver

Mateusz Holenko
2020-06-04T08:25:49Z

On Thu, Jun 4, 2020 at 9:57 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Thu, Jun 04, 2020 at 09:16:25AM +0200, Mateusz Holenko wrote:
> > On Wed, May 27, 2020 at 6:27 PM Mateusz Holenko <mholenko@antmicro.com> wrote:
> > >
> > > From: Filip Kokosinski <fkokosinski@antmicro.com>
> > >
> > > This commit adds driver for the FPGA-based LiteUART serial controller
> > > from LiteX SoC builder.
> > >
> > > The current implementation supports LiteUART configured
> > > for 32 bit data width and 8 bit CSR bus width.
> > >
> > > It does not support IRQ.
> > >
> > > Signed-off-by: Filip Kokosinski <fkokosinski@antmicro.com>
> > > Signed-off-by: Mateusz Holenko <mholenko@antmicro.com>
> > > ---
> > >
> > > Notes:
> > > Changes in v6:
> > > - LiteUART ports now stored in xArray
> > > - removed PORT_LITEUART
> > > - fixed formatting
> > > - removed some unnecessary defines
> > >
> > > No changes in v5.
> > >
> > > Changes in v4:
> > > - fixed copyright header
> > > - removed a wrong dependency on UARTLITE from Kconfig
> > > - added a dependency on LITEX_SOC_CONTROLLER to LITEUART in Kconfig
> > >
> > > Changes in v3:
> > > - aliases made optional
> > > - used litex_get_reg/litex_set_reg functions instead of macros
> > > - SERIAL_LITEUART_NR_PORTS renamed to SERIAL_LITEUART_MAX_PORTS
> > > - PORT_LITEUART changed from 122 to 123
> > > - added dependency on LITEX_SOC_CONTROLLER
> > > - patch number changed from 4 to 5
> > >
> > > No changes in v2.
> > >
> > > MAINTAINERS | 1 +
> > > drivers/tty/serial/Kconfig | 31 +++
> > > drivers/tty/serial/Makefile | 1 +
> > > drivers/tty/serial/liteuart.c | 404 ++++++++++++++++++++++++++++++++++
> > > 4 files changed, 437 insertions(+)
> > > create mode 100644 drivers/tty/serial/liteuart.c
> > >
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index 51d2d6a61fb0..d855fe807833 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -9846,6 +9846,7 @@ M: Mateusz Holenko <mholenko@antmicro.com>
> > > S: Maintained
> > > F: Documentation/devicetree/bindings/*/litex,*.yaml
> > > F: drivers/soc/litex/litex_soc_ctrl.c
> > > +F: drivers/tty/serial/liteuart.c
> > > F: include/linux/litex.h
> > >
> > > LIVE PATCHING
> > > diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> > > index adf9e80e7dc9..17aaf0afb27a 100644
> > > --- a/drivers/tty/serial/Kconfig
> > > +++ b/drivers/tty/serial/Kconfig
> > > @@ -1562,6 +1562,37 @@ config SERIAL_MILBEAUT_USIO_CONSOLE
> > > receives all kernel messages and warnings and which allows logins in
> > > single user mode).
> > >
> > > +config SERIAL_LITEUART
> > > + tristate "LiteUART serial port support"
> > > + depends on HAS_IOMEM
> > > + depends on OF || COMPILE_TEST
> > > + depends on LITEX_SOC_CONTROLLER
> > > + select SERIAL_CORE
> > > + help
> > > + This driver is for the FPGA-based LiteUART serial controller from LiteX
> > > + SoC builder.
> > > +
> > > + Say 'Y' here if you wish to use the LiteUART serial controller.
> > > + Otherwise, say 'N'.
> > > +
> > > +config SERIAL_LITEUART_MAX_PORTS
> > > + int "Maximum number of LiteUART ports"
> > > + depends on SERIAL_LITEUART
> > > + default "1"
> > > + help
> > > + Set this to the maximum number of serial ports you want the driver
> > > + to support.
> > > +
> > > +config SERIAL_LITEUART_CONSOLE
> > > + bool "LiteUART serial port console support"
> > > + depends on SERIAL_LITEUART=y
> > > + select SERIAL_CORE_CONSOLE
> > > + help
> > > + Say 'Y' here if you wish to use the FPGA-based LiteUART serial controller
> > > + from LiteX SoC builder as the system console (the system console is the
> > > + device which receives all kernel messages and warnings and which allows
> > > + logins in single user mode). Otherwise, say 'N'.
> > > +
> > > endmenu
> > >
> > > config SERIAL_MCTRL_GPIO
> > > diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
> > > index d056ee6cca33..9f8ba419ff3b 100644
> > > --- a/drivers/tty/serial/Makefile
> > > +++ b/drivers/tty/serial/Makefile
> > > @@ -89,6 +89,7 @@ obj-$(CONFIG_SERIAL_OWL) += owl-uart.o
> > > obj-$(CONFIG_SERIAL_RDA) += rda-uart.o
> > > obj-$(CONFIG_SERIAL_MILBEAUT_USIO) += milbeaut_usio.o
> > > obj-$(CONFIG_SERIAL_SIFIVE) += sifive.o
> > > +obj-$(CONFIG_SERIAL_LITEUART) += liteuart.o
> > >
> > > # GPIOLIB helpers for modem control lines
> > > obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o
> > > diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c
> > > new file mode 100644
> > > index 000000000000..22b7612c13ca
> > > --- /dev/null
> > > +++ b/drivers/tty/serial/liteuart.c
> > > @@ -0,0 +1,404 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * LiteUART serial controller (LiteX) Driver
> > > + *
> > > + * Copyright (C) 2019-2020 Antmicro <www.antmicro.com>
> > > + */
> > > +
> > > +#include <linux/console.h>
> > > +#include <linux/module.h>
> > > +#include <linux/of.h>
> > > +#include <linux/of_address.h>
> > > +#include <linux/of_platform.h>
> > > +#include <linux/serial.h>
> > > +#include <linux/serial_core.h>
> > > +#include <linux/timer.h>
> > > +#include <linux/tty_flip.h>
> > > +#include <linux/litex.h>
> > > +#include <linux/xarray.h>
> >
> > kbuild test robot reported problems with this patch, namely: implicit
> > declaration of function 'kzalloc'
> > This is caused by the missing include directive. When I was testing it
> > I must have missed the warning, but the compilation succeeded and the
> > resulting binary worked fine on HW (LiteX/mor1kx platform).
> > The fix is a simple one-liner, adding a new include:
> >
> > +#include <linux/slab.h>
> >
> > Since this is a very small fix and does not modify the actual code of
> > the driver I want to wait for more feedback on all patches in the
> > series before resubmitting, in order to limit traffic on the list.
> > Or should I generate the next version and resend the whole patchset
> > with this single fix, as otherwise it won't be reviewed at all?
>
> Please fix up and resend. We can't do anything until after 5.8-rc1 is
> out anyway...
>
> thanks,
>
> greg k-h

Sure, thanks for the prompt response!

Best,
Mateusz Hołenko

--
Mateusz Holenko
Antmicro Ltd | www.antmicro.com
Roosevelta 22, 60-829 Poznan, Poland