| Message ID | 1411992293-7729-6-git-send-email-zhang.lyra@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Monday 29 September 2014 20:04:52 zhang.lyra@gmail.com wrote: > From: "chunyan.zhang" <chunyan.zhang@spreadtrum.com> > > Adds earlycon support for the Spreadtrum's serial. > > Signed-off-by: chunyan.zhang <chunyan.zhang@spreadtrum.com> > --- > drivers/tty/serial/Kconfig | 12 ++++++ > drivers/tty/serial/Makefile | 1 + > drivers/tty/serial/serial_sprd_early.c | 64 ++++++++++++++++++++++++++++++++ > 3 files changed, 77 insertions(+) > create mode 100644 drivers/tty/serial/serial_sprd_early.c > > diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig > index 26cec64..ede16e6 100644 > --- a/drivers/tty/serial/Kconfig > +++ b/drivers/tty/serial/Kconfig > @@ -85,6 +85,18 @@ config SERIAL_EARLYCON_ARM_SEMIHOST > with "earlycon=smh" on the kernel command line. The console is > enabled when early_param is processed. > > +config SERIAL_EARLYCON_SPRD > + bool "Early console using SPRD serial" > + depends on ARM64 > + select SERIAL_CORE > + select SERIAL_CORE_CONSOLE > + select SERIAL_EARLYCON > + help I assume you will later want to have a proper device driver for this hardware, so it would be better to make the Kconfig symbol and the file name what you are going to use in the long run, but for now only have the earlycon support included. > +static int __init serial_sprd_early_console_setup( > + struct earlycon_device *device, > + const char *opt) > +{ > + if (!device->port.membase) > + return -ENODEV; > + > + device->con->write = serial_sprd_early_write; > + return 0; > +} > +EARLYCON_DECLARE(serial_sprd, serial_sprd_early_console_setup); > +OF_EARLYCON_DECLARE(serial_sprd, "sprd,serial", > + serial_sprd_early_console_setup); > I think you should drop the EARLYCON_DECLARE() line, using OF_EARLYCON_DECLARE should be enough. Arnd
On Mon, Sep 29, 2014 at 08:04:52PM +0800, zhang.lyra@gmail.com wrote: > +config SERIAL_EARLYCON_SPRD > + bool "Early console using SPRD serial" > + depends on ARM64 This code doesn't appear to be ARM64 specific so adding an || COMPILE_TEST will allow better build time coverage for people doing generic work on the subsystem.
On Mon, Sep 29, 2014 at 8:36 AM, Arnd Bergmann <arnd@arndb.de> wrote: > On Monday 29 September 2014 20:04:52 zhang.lyra@gmail.com wrote: >> From: "chunyan.zhang" <chunyan.zhang@spreadtrum.com> >> >> Adds earlycon support for the Spreadtrum's serial. >> >> Signed-off-by: chunyan.zhang <chunyan.zhang@spreadtrum.com> >> --- >> drivers/tty/serial/Kconfig | 12 ++++++ >> drivers/tty/serial/Makefile | 1 + >> drivers/tty/serial/serial_sprd_early.c | 64 ++++++++++++++++++++++++++++++++ >> 3 files changed, 77 insertions(+) >> create mode 100644 drivers/tty/serial/serial_sprd_early.c >> >> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig >> index 26cec64..ede16e6 100644 >> --- a/drivers/tty/serial/Kconfig >> +++ b/drivers/tty/serial/Kconfig >> @@ -85,6 +85,18 @@ config SERIAL_EARLYCON_ARM_SEMIHOST >> with "earlycon=smh" on the kernel command line. The console is >> enabled when early_param is processed. >> >> +config SERIAL_EARLYCON_SPRD >> + bool "Early console using SPRD serial" >> + depends on ARM64 >> + select SERIAL_CORE >> + select SERIAL_CORE_CONSOLE >> + select SERIAL_EARLYCON >> + help > > I assume you will later want to have a proper device driver for > this hardware, so it would be better to make the Kconfig symbol > and the file name what you are going to use in the long run, but > for now only have the earlycon support included. > > >> +static int __init serial_sprd_early_console_setup( >> + struct earlycon_device *device, >> + const char *opt) >> +{ >> + if (!device->port.membase) >> + return -ENODEV; >> + >> + device->con->write = serial_sprd_early_write; >> + return 0; >> +} >> +EARLYCON_DECLARE(serial_sprd, serial_sprd_early_console_setup); >> +OF_EARLYCON_DECLARE(serial_sprd, "sprd,serial", >> + serial_sprd_early_console_setup); >> > > I think you should drop the EARLYCON_DECLARE() line, using > OF_EARLYCON_DECLARE should be enough. No, I've been telling people to put both in. The reason is you may have a bootloader or boot files (e.g PXELINUX) that only allows changing changing the command line or you want to override/extend the command line in the kernel. I'm thinking the declaration should be combined into one to do both since I'm getting tired of making this comment. Rob
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index 26cec64..ede16e6 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -85,6 +85,18 @@ config SERIAL_EARLYCON_ARM_SEMIHOST with "earlycon=smh" on the kernel command line. The console is enabled when early_param is processed. +config SERIAL_EARLYCON_SPRD + bool "Early console using SPRD serial" + depends on ARM64 + select SERIAL_CORE + select SERIAL_CORE_CONSOLE + select SERIAL_EARLYCON + help + Support for early debug console using SPRD serial. This enables + the console before standard serial driver is probed. This is enabled + with "earlycon=serial_sprd" on the kernel command line. The console is + enabled when early_param is processed. + config SERIAL_SB1250_DUART tristate "BCM1xxx on-chip DUART serial support" depends on SIBYTE_SB1xxx_SOC=y diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile index 0080cc3..3ea9edc 100644 --- a/drivers/tty/serial/Makefile +++ b/drivers/tty/serial/Makefile @@ -7,6 +7,7 @@ obj-$(CONFIG_SERIAL_21285) += 21285.o obj-$(CONFIG_SERIAL_EARLYCON) += earlycon.o obj-$(CONFIG_SERIAL_EARLYCON_ARM_SEMIHOST) += earlycon-arm-semihost.o +obj-$(CONFIG_SERIAL_EARLYCON_SPRD) += serial_sprd_early.o # These Sparc drivers have to appear before others such as 8250 # which share ttySx minor node space. Otherwise console device diff --git a/drivers/tty/serial/serial_sprd_early.c b/drivers/tty/serial/serial_sprd_early.c new file mode 100644 index 0000000..059e109 --- /dev/null +++ b/drivers/tty/serial/serial_sprd_early.c @@ -0,0 +1,64 @@ +/* + * Copyright (C) 2012 Spreadtrum Communications Inc. + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/kernel.h> +#include <linux/console.h> +#include <linux/init.h> +#include <linux/serial_core.h> +#include <linux/of.h> + +/*offset*/ +#define ARM_UART_TXD 0x0000 +#define ARM_UART_RXD 0x0004 +#define ARM_UART_STS0 0x0008 +#define ARM_UART_STS1 0x000C +#define ARM_UART_IEN 0x0010 +#define ARM_UART_ICLR 0x0014 +#define ARM_UART_CTL0 0x0018 +#define ARM_UART_CTL1 0x001C +#define ARM_UART_CTL2 0x0020 +#define ARM_UART_CLKD0 0x0024 +#define ARM_UART_CLKD1 0x0028 +#define ARM_UART_STS2 0x002C + +/*line status */ +#define UART_LSR_TX_OVER (0x1<<15) + +static void serial_sprd_putc(struct uart_port *port, int c) +{ + while (!(readl(port->membase + ARM_UART_STS0) & UART_LSR_TX_OVER)) + ; + writeb(c, port->membase + ARM_UART_TXD); +} + +static void serial_sprd_early_write(struct console *con, const char *s, + unsigned n) +{ + struct earlycon_device *dev = con->data; + + uart_console_write(&dev->port, s, n, serial_sprd_putc); +} + +static int __init serial_sprd_early_console_setup( + struct earlycon_device *device, + const char *opt) +{ + if (!device->port.membase) + return -ENODEV; + + device->con->write = serial_sprd_early_write; + return 0; +} +EARLYCON_DECLARE(serial_sprd, serial_sprd_early_console_setup); +OF_EARLYCON_DECLARE(serial_sprd, "sprd,serial", + serial_sprd_early_console_setup);