* [PATCH 0/2] tty: serial: Add earlycon support to MT8173 SoC @ 2014-12-18 8:33 Eddie Huang 2014-12-18 8:33 ` [PATCH 1/2] tty: serial: 8250_mtk: Add earlycon Eddie Huang 2014-12-18 8:33 ` [PATCH 2/2] arm64: dts: Add mediatek MT8173 earlycon support Eddie Huang 0 siblings, 2 replies; 9+ messages in thread From: Eddie Huang @ 2014-12-18 8:33 UTC (permalink / raw) To: linux-arm-kernel This series add earlycon support to Mediatek MT8173 SoC. Although 8250 driver already has earlycon support, but Mediatek UART has highspeed register that not in 8250_early.c, so I port earlycon in 8250_mtk.c, and add stdout device tree support. This patchset is based on 3.18, and my basic support for Mediatek MT8173 Soc [1]. [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-December/311238.html Eddie Huang (2): tty: serial: 8250_mtk: Add earlycon arm64: dts: Add mediatek MT8173 earlycon support arch/arm64/boot/dts/mt8173-evb.dts | 4 +++- drivers/tty/serial/8250/8250_mtk.c | 33 +++++++++++++++++++++++++++++++++ 2 files changed, 36 insertions(+), 1 deletion(-) -- 1.8.1.1.dirty ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH 1/2] tty: serial: 8250_mtk: Add earlycon 2014-12-18 8:33 [PATCH 0/2] tty: serial: Add earlycon support to MT8173 SoC Eddie Huang @ 2014-12-18 8:33 ` Eddie Huang 2014-12-18 8:48 ` Matthias Brugger 2014-12-26 21:24 ` Rob Herring 2014-12-18 8:33 ` [PATCH 2/2] arm64: dts: Add mediatek MT8173 earlycon support Eddie Huang 1 sibling, 2 replies; 9+ messages in thread From: Eddie Huang @ 2014-12-18 8:33 UTC (permalink / raw) To: linux-arm-kernel Mediatek UART has highspeed register, but 8250_early.c doesn't support this, so add earlycon in 8250_mtk.c Signed-off-by: Eddie Huang <eddie.huang@mediatek.com> --- drivers/tty/serial/8250/8250_mtk.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c index de7aae5..65dd569 100644 --- a/drivers/tty/serial/8250/8250_mtk.c +++ b/drivers/tty/serial/8250/8250_mtk.c @@ -23,6 +23,7 @@ #include <linux/pm_runtime.h> #include <linux/serial_8250.h> #include <linux/serial_reg.h> +#include <linux/console.h> #include "8250.h" @@ -289,6 +290,38 @@ static struct platform_driver mtk8250_platform_driver = { }; module_platform_driver(mtk8250_platform_driver); +#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE) + +static void __init mtk8250_serial_putc(struct uart_port *port, int c) +{ + while ((readl(port->membase + (UART_LSR << 2)) & BOTH_EMPTY) != + BOTH_EMPTY) + ; + writel(c, port->membase + (UART_TX << 2)); +} + +static void __init early_mtk8250_write(struct console *console, + const char *s, unsigned int count) +{ + struct earlycon_device *dev = console->data; + + uart_console_write(&dev->port, s, count, mtk8250_serial_putc); +} + +static int __init early_mtk8250_setup(struct earlycon_device *device, + const char *options) +{ + if (!device->port.membase) + return -ENODEV; + + device->con->write = early_mtk8250_write; + + return 0; +} + +EARLYCON_DECLARE(mtk8250, early_mtk8250_setup); +OF_EARLYCON_DECLARE(mtk8250, "mediatek,mt6577-uart", early_mtk8250_setup); + MODULE_AUTHOR("Matthias Brugger"); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Mediatek 8250 serial port driver"); -- 1.8.1.1.dirty ^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH 1/2] tty: serial: 8250_mtk: Add earlycon 2014-12-18 8:33 ` [PATCH 1/2] tty: serial: 8250_mtk: Add earlycon Eddie Huang @ 2014-12-18 8:48 ` Matthias Brugger 2014-12-18 9:12 ` Arnd Bergmann 2014-12-26 21:24 ` Rob Herring 1 sibling, 1 reply; 9+ messages in thread From: Matthias Brugger @ 2014-12-18 8:48 UTC (permalink / raw) To: linux-arm-kernel 2014-12-18 9:33 GMT+01:00 Eddie Huang <eddie.huang@mediatek.com>: > Mediatek UART has highspeed register, but 8250_early.c doesn't > support this, so add earlycon in 8250_mtk.c > > Signed-off-by: Eddie Huang <eddie.huang@mediatek.com> > --- > drivers/tty/serial/8250/8250_mtk.c | 33 +++++++++++++++++++++++++++++++++ > 1 file changed, 33 insertions(+) > > diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c > index de7aae5..65dd569 100644 > --- a/drivers/tty/serial/8250/8250_mtk.c > +++ b/drivers/tty/serial/8250/8250_mtk.c > @@ -23,6 +23,7 @@ > #include <linux/pm_runtime.h> > #include <linux/serial_8250.h> > #include <linux/serial_reg.h> > +#include <linux/console.h> > > #include "8250.h" > > @@ -289,6 +290,38 @@ static struct platform_driver mtk8250_platform_driver = { > }; > module_platform_driver(mtk8250_platform_driver); > > +#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE) > + > +static void __init mtk8250_serial_putc(struct uart_port *port, int c) > +{ > + while ((readl(port->membase + (UART_LSR << 2)) & BOTH_EMPTY) != > + BOTH_EMPTY) > + ; Please delete newline before the semicolon. > + writel(c, port->membase + (UART_TX << 2)); > +} > + > +static void __init early_mtk8250_write(struct console *console, > + const char *s, unsigned int count) > +{ > + struct earlycon_device *dev = console->data; > + > + uart_console_write(&dev->port, s, count, mtk8250_serial_putc); > +} > + > +static int __init early_mtk8250_setup(struct earlycon_device *device, > + const char *options) > +{ > + if (!device->port.membase) > + return -ENODEV; > + > + device->con->write = early_mtk8250_write; > + > + return 0; > +} > + > +EARLYCON_DECLARE(mtk8250, early_mtk8250_setup); > +OF_EARLYCON_DECLARE(mtk8250, "mediatek,mt6577-uart", early_mtk8250_setup); > + > MODULE_AUTHOR("Matthias Brugger"); > MODULE_LICENSE("GPL"); > MODULE_DESCRIPTION("Mediatek 8250 serial port driver"); > -- > 1.8.1.1.dirty > -- motzblog.wordpress.com ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH 1/2] tty: serial: 8250_mtk: Add earlycon 2014-12-18 8:48 ` Matthias Brugger @ 2014-12-18 9:12 ` Arnd Bergmann 0 siblings, 0 replies; 9+ messages in thread From: Arnd Bergmann @ 2014-12-18 9:12 UTC (permalink / raw) To: linux-arm-kernel On Thursday 18 December 2014 09:48:31 Matthias Brugger wrote: > > +static void __init mtk8250_serial_putc(struct uart_port *port, int c) > > +{ > > + while ((readl(port->membase + (UART_LSR << 2)) & BOTH_EMPTY) != > > + BOTH_EMPTY) > > + ; > > Please delete newline before the semicolon. > No, that newline is best kept in there for clarity. An even better way to write this would be using cpu_relax(): while ((readl(port->membase + (UART_LSR << 2)) & BOTH_EMPTY) != BOTH_EMPTY) cpu_relax(); which the kernel convention for doing busy-loops. Arnd ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH 1/2] tty: serial: 8250_mtk: Add earlycon 2014-12-18 8:33 ` [PATCH 1/2] tty: serial: 8250_mtk: Add earlycon Eddie Huang 2014-12-18 8:48 ` Matthias Brugger @ 2014-12-26 21:24 ` Rob Herring 2014-12-29 4:24 ` Eddie Huang 1 sibling, 1 reply; 9+ messages in thread From: Rob Herring @ 2014-12-26 21:24 UTC (permalink / raw) To: linux-arm-kernel On Thu, Dec 18, 2014 at 2:33 AM, Eddie Huang <eddie.huang@mediatek.com> wrote: > Mediatek UART has highspeed register, but 8250_early.c doesn't > support this, so add earlycon in 8250_mtk.c I don't see any highspeed register setup here. More generically, aren't you just skipping any UART setup? That may be useful on other platforms with 8250s, too. With the kernel command line version, you could perhaps add a "noinit" flag. The DT case is harder, and I'm not sure how we should handle that. We could perhaps add a "stdout-path-initialized" flag to chosen. > > Signed-off-by: Eddie Huang <eddie.huang@mediatek.com> > --- > drivers/tty/serial/8250/8250_mtk.c | 33 +++++++++++++++++++++++++++++++++ > 1 file changed, 33 insertions(+) > > diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c > index de7aae5..65dd569 100644 > --- a/drivers/tty/serial/8250/8250_mtk.c > +++ b/drivers/tty/serial/8250/8250_mtk.c > @@ -23,6 +23,7 @@ > #include <linux/pm_runtime.h> > #include <linux/serial_8250.h> > #include <linux/serial_reg.h> > +#include <linux/console.h> > > #include "8250.h" > > @@ -289,6 +290,38 @@ static struct platform_driver mtk8250_platform_driver = { > }; > module_platform_driver(mtk8250_platform_driver); > > +#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE) > + > +static void __init mtk8250_serial_putc(struct uart_port *port, int c) > +{ > + while ((readl(port->membase + (UART_LSR << 2)) & BOTH_EMPTY) != > + BOTH_EMPTY) > + ; > + writel(c, port->membase + (UART_TX << 2)); > +} > + > +static void __init early_mtk8250_write(struct console *console, > + const char *s, unsigned int count) Is there a reason early_serial8250_write can't work for you other than it is currently static? Rob > +{ > + struct earlycon_device *dev = console->data; > + > + uart_console_write(&dev->port, s, count, mtk8250_serial_putc); > +} > + > +static int __init early_mtk8250_setup(struct earlycon_device *device, > + const char *options) > +{ > + if (!device->port.membase) > + return -ENODEV; > + > + device->con->write = early_mtk8250_write; > + > + return 0; > +} > + > +EARLYCON_DECLARE(mtk8250, early_mtk8250_setup); > +OF_EARLYCON_DECLARE(mtk8250, "mediatek,mt6577-uart", early_mtk8250_setup); > + > MODULE_AUTHOR("Matthias Brugger"); > MODULE_LICENSE("GPL"); > MODULE_DESCRIPTION("Mediatek 8250 serial port driver"); > -- > 1.8.1.1.dirty > ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH 1/2] tty: serial: 8250_mtk: Add earlycon 2014-12-26 21:24 ` Rob Herring @ 2014-12-29 4:24 ` Eddie Huang 2014-12-29 14:54 ` Rob Herring 2014-12-29 19:08 ` Arnd Bergmann 0 siblings, 2 replies; 9+ messages in thread From: Eddie Huang @ 2014-12-29 4:24 UTC (permalink / raw) To: linux-arm-kernel Hi Rob, On Fri, 2014-12-26 at 15:24 -0600, Rob Herring wrote: > On Thu, Dec 18, 2014 at 2:33 AM, Eddie Huang <eddie.huang@mediatek.com> wrote: > > Mediatek UART has highspeed register, but 8250_early.c doesn't > > support this, so add earlycon in 8250_mtk.c > > I don't see any highspeed register setup here. More generically, > aren't you just skipping any UART setup? That may be useful on other > platforms with 8250s, too. With the kernel command line version, you > could perhaps add a "noinit" flag. The DT case is harder, and I'm not > sure how we should handle that. We could perhaps add a > "stdout-path-initialized" flag to chosen. > Yes, I skipped UART setup same as msm_serial.c and amba-pl011.c (although they are standalone serial driver). Just like earlyprintk, I think earlycon should reuse UART setting in loader. Since some other platforms with 8250 already depend on this, it's ok to add flags to distinguish whether 8250 earlycon driver should init hw or not. As you said, add "noinit" flag is simple, but "stdout-path-initialized" need more discussion. > > > > Signed-off-by: Eddie Huang <eddie.huang@mediatek.com> > > --- > > drivers/tty/serial/8250/8250_mtk.c | 33 +++++++++++++++++++++++++++++++++ > > 1 file changed, 33 insertions(+) > > > > diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c > > index de7aae5..65dd569 100644 > > --- a/drivers/tty/serial/8250/8250_mtk.c > > +++ b/drivers/tty/serial/8250/8250_mtk.c > > @@ -23,6 +23,7 @@ > > #include <linux/pm_runtime.h> > > #include <linux/serial_8250.h> > > #include <linux/serial_reg.h> > > +#include <linux/console.h> > > > > #include "8250.h" > > > > @@ -289,6 +290,38 @@ static struct platform_driver mtk8250_platform_driver = { > > }; > > module_platform_driver(mtk8250_platform_driver); > > > > +#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE) > > + > > +static void __init mtk8250_serial_putc(struct uart_port *port, int c) > > +{ > > + while ((readl(port->membase + (UART_LSR << 2)) & BOTH_EMPTY) != > > + BOTH_EMPTY) > > + ; > > + writel(c, port->membase + (UART_TX << 2)); > > +} > > + > > +static void __init early_mtk8250_write(struct console *console, > > + const char *s, unsigned int count) > > Is there a reason early_serial8250_write can't work for you other than > it is currently static? > > Rob > The reason is only static. I want to keep 8250_early.c untouchable, all modifications in 8250_mtk.c ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH 1/2] tty: serial: 8250_mtk: Add earlycon 2014-12-29 4:24 ` Eddie Huang @ 2014-12-29 14:54 ` Rob Herring 2014-12-29 19:08 ` Arnd Bergmann 1 sibling, 0 replies; 9+ messages in thread From: Rob Herring @ 2014-12-29 14:54 UTC (permalink / raw) To: linux-arm-kernel On Sun, Dec 28, 2014 at 10:24 PM, Eddie Huang <eddie.huang@mediatek.com> wrote: > Hi Rob, > > On Fri, 2014-12-26 at 15:24 -0600, Rob Herring wrote: >> On Thu, Dec 18, 2014 at 2:33 AM, Eddie Huang <eddie.huang@mediatek.com> wrote: >> > Mediatek UART has highspeed register, but 8250_early.c doesn't >> > support this, so add earlycon in 8250_mtk.c >> >> I don't see any highspeed register setup here. More generically, >> aren't you just skipping any UART setup? That may be useful on other >> platforms with 8250s, too. With the kernel command line version, you >> could perhaps add a "noinit" flag. The DT case is harder, and I'm not >> sure how we should handle that. We could perhaps add a >> "stdout-path-initialized" flag to chosen. >> > > Yes, I skipped UART setup same as msm_serial.c and amba-pl011.c > (although they are standalone serial driver). Just like earlyprintk, I > think earlycon should reuse UART setting in loader. Since some other > platforms with 8250 already depend on this, it's ok to add flags to > distinguish whether 8250 earlycon driver should init hw or not. As you > said, add "noinit" flag is simple, but "stdout-path-initialized" need > more discussion. > >> > >> > Signed-off-by: Eddie Huang <eddie.huang@mediatek.com> >> > --- >> > drivers/tty/serial/8250/8250_mtk.c | 33 +++++++++++++++++++++++++++++++++ >> > 1 file changed, 33 insertions(+) >> > >> > diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c >> > index de7aae5..65dd569 100644 >> > --- a/drivers/tty/serial/8250/8250_mtk.c >> > +++ b/drivers/tty/serial/8250/8250_mtk.c >> > @@ -23,6 +23,7 @@ >> > #include <linux/pm_runtime.h> >> > #include <linux/serial_8250.h> >> > #include <linux/serial_reg.h> >> > +#include <linux/console.h> >> > >> > #include "8250.h" >> > >> > @@ -289,6 +290,38 @@ static struct platform_driver mtk8250_platform_driver = { >> > }; >> > module_platform_driver(mtk8250_platform_driver); >> > >> > +#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE) >> > + >> > +static void __init mtk8250_serial_putc(struct uart_port *port, int c) >> > +{ >> > + while ((readl(port->membase + (UART_LSR << 2)) & BOTH_EMPTY) != >> > + BOTH_EMPTY) >> > + ; >> > + writel(c, port->membase + (UART_TX << 2)); >> > +} >> > + >> > +static void __init early_mtk8250_write(struct console *console, >> > + const char *s, unsigned int count) >> >> Is there a reason early_serial8250_write can't work for you other than >> it is currently static? >> >> Rob >> > > The reason is only static. I want to keep 8250_early.c untouchable, all > modifications in 8250_mtk.c That is not how kernel development works. You should fix 8250_early.c to do what you need rather than duplicating code. Rob ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH 1/2] tty: serial: 8250_mtk: Add earlycon 2014-12-29 4:24 ` Eddie Huang 2014-12-29 14:54 ` Rob Herring @ 2014-12-29 19:08 ` Arnd Bergmann 1 sibling, 0 replies; 9+ messages in thread From: Arnd Bergmann @ 2014-12-29 19:08 UTC (permalink / raw) To: linux-arm-kernel On Monday 29 December 2014 12:24:56 Eddie Huang wrote: > Hi Rob, > > On Fri, 2014-12-26 at 15:24 -0600, Rob Herring wrote: > > On Thu, Dec 18, 2014 at 2:33 AM, Eddie Huang <eddie.huang@mediatek.com> wrote: > > > Mediatek UART has highspeed register, but 8250_early.c doesn't > > > support this, so add earlycon in 8250_mtk.c > > > > I don't see any highspeed register setup here. More generically, > > aren't you just skipping any UART setup? That may be useful on other > > platforms with 8250s, too. With the kernel command line version, you > > could perhaps add a "noinit" flag. The DT case is harder, and I'm not > > sure how we should handle that. We could perhaps add a > > "stdout-path-initialized" flag to chosen. > > > > Yes, I skipped UART setup same as msm_serial.c and amba-pl011.c > (although they are standalone serial driver). Just like earlyprintk, I > think earlycon should reuse UART setting in loader. Since some other > platforms with 8250 already depend on this, it's ok to add flags to > distinguish whether 8250 earlycon driver should init hw or not. As you > said, add "noinit" flag is simple, but "stdout-path-initialized" need > more discussion. It would definitely be nice to have consistent behavior, and I also think it would be good to default to noinit for the console, because that is the more likely case. Basically anything that can do debug_ll on ARM already depends on this behavior because the debug_ll infrastructure does not initialize the console before using it. I believe the same is true for powerpc udbg. Arnd ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH 2/2] arm64: dts: Add mediatek MT8173 earlycon support 2014-12-18 8:33 [PATCH 0/2] tty: serial: Add earlycon support to MT8173 SoC Eddie Huang 2014-12-18 8:33 ` [PATCH 1/2] tty: serial: 8250_mtk: Add earlycon Eddie Huang @ 2014-12-18 8:33 ` Eddie Huang 1 sibling, 0 replies; 9+ messages in thread From: Eddie Huang @ 2014-12-18 8:33 UTC (permalink / raw) To: linux-arm-kernel Add earlycon support to mediatek MT8173 evaluation board dts. Signed-off-by: Eddie Huang <eddie.huang@mediatek.com> --- arch/arm64/boot/dts/mt8173-evb.dts | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/arm64/boot/dts/mt8173-evb.dts b/arch/arm64/boot/dts/mt8173-evb.dts index b8b2621..b8802fd 100644 --- a/arch/arm64/boot/dts/mt8173-evb.dts +++ b/arch/arm64/boot/dts/mt8173-evb.dts @@ -30,5 +30,7 @@ reg = <0 0x40000000 0 0x80000000>; }; - chosen { }; + chosen { + linux,stdout-path = &uart0; + }; }; -- 1.8.1.1.dirty ^ permalink raw reply related [flat|nested] 9+ messages in thread
end of thread, other threads:[~2014-12-29 19:08 UTC | newest] Thread overview: 9+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2014-12-18 8:33 [PATCH 0/2] tty: serial: Add earlycon support to MT8173 SoC Eddie Huang 2014-12-18 8:33 ` [PATCH 1/2] tty: serial: 8250_mtk: Add earlycon Eddie Huang 2014-12-18 8:48 ` Matthias Brugger 2014-12-18 9:12 ` Arnd Bergmann 2014-12-26 21:24 ` Rob Herring 2014-12-29 4:24 ` Eddie Huang 2014-12-29 14:54 ` Rob Herring 2014-12-29 19:08 ` Arnd Bergmann 2014-12-18 8:33 ` [PATCH 2/2] arm64: dts: Add mediatek MT8173 earlycon support Eddie Huang
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