* [PATCH] serial: 8250_uniphier: add earlycon support
@ 2015-10-22 8:39 Masahiro Yamada
2015-10-28 15:21 ` Peter Hurley
0 siblings, 1 reply; 4+ messages in thread
From: Masahiro Yamada @ 2015-10-22 8:39 UTC (permalink / raw)
To: linux-serial
Cc: Peter Hurley, Masahiro Yamada, Jiri Slaby, linux-kernel,
Greg Kroah-Hartman, linux-arm-kernel
This reuses the code of drivers/tty/serial/8250/8250_early.c except
- Overwrite device->port.iotype and device->port.regshift for
UPIO_MEM32 because of_setup_earlycon() has set them for UPIO_MEM.
- Set device->baud to zero to prevent early8250_setup() from
initializing the divisor register because port->uartclk does not
match the frequency expected by this hardware.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---
drivers/tty/serial/8250/8250_uniphier.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/drivers/tty/serial/8250/8250_uniphier.c b/drivers/tty/serial/8250/8250_uniphier.c
index 245edbb..c1075c5 100644
--- a/drivers/tty/serial/8250/8250_uniphier.c
+++ b/drivers/tty/serial/8250/8250_uniphier.c
@@ -13,6 +13,7 @@
*/
#include <linux/clk.h>
+#include <linux/console.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
@@ -34,6 +35,29 @@ struct uniphier8250_priv {
spinlock_t atomic_write_lock;
};
+#if IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE)
+static int __init uniphier_early_console_setup(struct earlycon_device *device,
+ const char *options)
+{
+ if (!device->port.membase)
+ return -ENODEV;
+
+ /* This hardware always expects MMIO32 register interface. */
+ device->port.iotype = UPIO_MEM32;
+ device->port.regshift = 2;
+
+ /*
+ * Do not touch the divisor register in early_serial8250_setup();
+ * we assume it has been initialized by a boot loader.
+ */
+ device->baud = 0;
+
+ return early_serial8250_setup(device, options);
+}
+OF_EARLYCON_DECLARE(uniphier_uart, "socionext,uniphier-uart",
+ uniphier_early_console_setup);
+#endif
+
/*
* The register map is slightly different from that of 8250.
* IO callbacks must be overridden for correct access to FCR, LCR, and MCR.
--
1.9.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] serial: 8250_uniphier: add earlycon support
2015-10-22 8:39 [PATCH] serial: 8250_uniphier: add earlycon support Masahiro Yamada
@ 2015-10-28 15:21 ` Peter Hurley
2015-10-29 1:49 ` Masahiro Yamada
0 siblings, 1 reply; 4+ messages in thread
From: Peter Hurley @ 2015-10-28 15:21 UTC (permalink / raw)
To: Masahiro Yamada, linux-serial
Cc: Jiri Slaby, linux-kernel, Greg Kroah-Hartman, linux-arm-kernel
Hi Masahiro,
On 10/22/2015 04:39 AM, Masahiro Yamada wrote:
> This reuses the code of drivers/tty/serial/8250/8250_early.c except
>
> - Overwrite device->port.iotype and device->port.regshift for
> UPIO_MEM32 because of_setup_earlycon() has set them for UPIO_MEM.
>
> - Set device->baud to zero to prevent early8250_setup() from
> initializing the divisor register because port->uartclk does not
> match the frequency expected by this hardware.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> ---
>
> drivers/tty/serial/8250/8250_uniphier.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/drivers/tty/serial/8250/8250_uniphier.c b/drivers/tty/serial/8250/8250_uniphier.c
> index 245edbb..c1075c5 100644
> --- a/drivers/tty/serial/8250/8250_uniphier.c
> +++ b/drivers/tty/serial/8250/8250_uniphier.c
> @@ -13,6 +13,7 @@
> */
>
> #include <linux/clk.h>
> +#include <linux/console.h>
> #include <linux/io.h>
> #include <linux/module.h>
> #include <linux/of.h>
> @@ -34,6 +35,29 @@ struct uniphier8250_priv {
> spinlock_t atomic_write_lock;
> };
>
> +#if IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE)
#ifdef CONFIG_SERIAL_8250_CONSOLE
Customarily, IS_ENABLED() is only used in-function with control flow
statements; eg.,
if (IS_ENABLED() && .... )
....
> +static int __init uniphier_early_console_setup(struct earlycon_device *device,
> + const char *options)
> +{
> + if (!device->port.membase)
> + return -ENODEV;
> +
> + /* This hardware always expects MMIO32 register interface. */
> + device->port.iotype = UPIO_MEM32;
> + device->port.regshift = 2;
> +
> + /*
> + * Do not touch the divisor register in early_serial8250_setup();
> + * we assume it has been initialized by a boot loader.
> + */
> + device->baud = 0;
> +
> + return early_serial8250_setup(device, options);
> +}
> +OF_EARLYCON_DECLARE(uniphier_uart, "socionext,uniphier-uart",
> + uniphier_early_console_setup);
Please change the earlycon name to just "uniphier" or "uniphier8250"; eg.,
OF_EARLYCON_DECLARE(uniphier, "socionext,uniphier-uart",
uniphier_early_console_setup);
My earlycon series merges OF_EARLYCON_DECLARE() => EARLYCON_DECLARE()
and "uniphier" is simpler on the command line.
Regards,
Peter Hurley
> +#endif
> +
> /*
> * The register map is slightly different from that of 8250.
> * IO callbacks must be overridden for correct access to FCR, LCR, and MCR.
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] serial: 8250_uniphier: add earlycon support
2015-10-28 15:21 ` Peter Hurley
@ 2015-10-29 1:49 ` Masahiro Yamada
2015-11-05 16:48 ` Peter Hurley
0 siblings, 1 reply; 4+ messages in thread
From: Masahiro Yamada @ 2015-10-29 1:49 UTC (permalink / raw)
To: Peter Hurley
Cc: linux-serial, Greg Kroah-Hartman, Linux Kernel Mailing List,
linux-arm-kernel, Jiri Slaby
Hi Peter,
>>
>> +#if IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE)
>
> #ifdef CONFIG_SERIAL_8250_CONSOLE
I am OK with this change because this CONFIG is boolean.
I still believe
#if IS_ENABLED(CONFIG_FOO)
is a nice shorthand for
#if defined(CONFIG_FOO) || defined(CONFIG_FOO_MODULE)
when CONFIG_FOO is tristate.
>> +static int __init uniphier_early_console_setup(struct earlycon_device *device,
>> + const char *options)
>> +{
>> + if (!device->port.membase)
>> + return -ENODEV;
>> +
>> + /* This hardware always expects MMIO32 register interface. */
>> + device->port.iotype = UPIO_MEM32;
>> + device->port.regshift = 2;
>> +
>> + /*
>> + * Do not touch the divisor register in early_serial8250_setup();
>> + * we assume it has been initialized by a boot loader.
>> + */
>> + device->baud = 0;
>> +
>> + return early_serial8250_setup(device, options);
>> +}
>> +OF_EARLYCON_DECLARE(uniphier_uart, "socionext,uniphier-uart",
>> + uniphier_early_console_setup);
>
> Please change the earlycon name to just "uniphier" or "uniphier8250"; eg.,
>
> OF_EARLYCON_DECLARE(uniphier, "socionext,uniphier-uart",
> uniphier_early_console_setup);
>
>
> My earlycon series merges OF_EARLYCON_DECLARE() => EARLYCON_DECLARE()
> and "uniphier" is simpler on the command line.
>
I am also OK with this change, too.
But I still see some *_serial and *_uart are used
in EARLYCON_DECLARE.
yamada@beagle:~/workspace/linux/drivers/tty$ git grep -e
'EARLYCON_DECLARE(.*_uart'
serial/8250/8250_ingenic.c:EARLYCON_DECLARE(jz4740_uart,
ingenic_early_console_setup);
serial/8250/8250_ingenic.c:OF_EARLYCON_DECLARE(jz4740_uart,
"ingenic,jz4740-uart",
serial/8250/8250_ingenic.c:EARLYCON_DECLARE(jz4775_uart,
ingenic_early_console_setup);
serial/8250/8250_ingenic.c:OF_EARLYCON_DECLARE(jz4775_uart,
"ingenic,jz4775-uart",
serial/8250/8250_ingenic.c:EARLYCON_DECLARE(jz4780_uart,
ingenic_early_console_setup);
serial/8250/8250_ingenic.c:OF_EARLYCON_DECLARE(jz4780_uart,
"ingenic,jz4780-uart",
serial/arc_uart.c:EARLYCON_DECLARE(arc_uart, arc_early_console_setup);
serial/arc_uart.c:OF_EARLYCON_DECLARE(arc_uart, "snps,arc-uart",
arc_early_console_setup);
serial/bcm63xx_uart.c:OF_EARLYCON_DECLARE(bcm63xx_uart,
"brcm,bcm6345-uart", bcm_early_console_setup);
yamada@beagle:~/workspace/linux/drivers/tty$ git grep -e
'EARLYCON_DECLARE(.*_serial'
serial/8250/8250_early.c:EARLYCON_DECLARE(uart8250, early_serial8250_setup);
serial/8250/8250_early.c:EARLYCON_DECLARE(uart, early_serial8250_setup);
serial/msm_serial.c:EARLYCON_DECLARE(msm_serial,
msm_serial_early_console_setup);
serial/msm_serial.c:OF_EARLYCON_DECLARE(msm_serial, "qcom,msm-uart",
serial/msm_serial.c:EARLYCON_DECLARE(msm_serial_dm,
msm_serial_early_console_setup_dm);
serial/msm_serial.c:OF_EARLYCON_DECLARE(msm_serial_dm, "qcom,msm-uartdm",
serial/sprd_serial.c:EARLYCON_DECLARE(sprd_serial, sprd_early_console_setup);
serial/sprd_serial.c:OF_EARLYCON_DECLARE(sprd_serial, "sprd,sc9836-uart",
--
Best Regards
Masahiro Yamada
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] serial: 8250_uniphier: add earlycon support
2015-10-29 1:49 ` Masahiro Yamada
@ 2015-11-05 16:48 ` Peter Hurley
0 siblings, 0 replies; 4+ messages in thread
From: Peter Hurley @ 2015-11-05 16:48 UTC (permalink / raw)
To: Masahiro Yamada
Cc: linux-serial, Greg Kroah-Hartman, Linux Kernel Mailing List,
linux-arm-kernel, Jiri Slaby
Hi Masahiro,
Apologies for the delay in reply; I didn't see the lower part of your email.
On 10/28/2015 09:49 PM, Masahiro Yamada wrote:
>>> +#if IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE)
>>
>> #ifdef CONFIG_SERIAL_8250_CONSOLE
>
> I am OK with this change because this CONFIG is boolean.
>
>
> I still believe
>
> #if IS_ENABLED(CONFIG_FOO)
>
> is a nice shorthand for
>
> #if defined(CONFIG_FOO) || defined(CONFIG_FOO_MODULE)
>
> when CONFIG_FOO is tristate.
I agree.
>>> +static int __init uniphier_early_console_setup(struct earlycon_device *device,
>>> + const char *options)
>>> +{
>>> + if (!device->port.membase)
>>> + return -ENODEV;
>>> +
>>> + /* This hardware always expects MMIO32 register interface. */
>>> + device->port.iotype = UPIO_MEM32;
>>> + device->port.regshift = 2;
>>> +
>>> + /*
>>> + * Do not touch the divisor register in early_serial8250_setup();
>>> + * we assume it has been initialized by a boot loader.
>>> + */
>>> + device->baud = 0;
>>> +
>>> + return early_serial8250_setup(device, options);
>>> +}
>>> +OF_EARLYCON_DECLARE(uniphier_uart, "socionext,uniphier-uart",
>>> + uniphier_early_console_setup);
>>
>> Please change the earlycon name to just "uniphier" or "uniphier8250"; eg.,
>>
>> OF_EARLYCON_DECLARE(uniphier, "socionext,uniphier-uart",
>> uniphier_early_console_setup);
>>
>>
>> My earlycon series merges OF_EARLYCON_DECLARE() => EARLYCON_DECLARE()
>> and "uniphier" is simpler on the command line.
>>
>
> I am also OK with this change, too.
>
> But I still see some *_serial and *_uart are used
> in EARLYCON_DECLARE.
>
> yamada@beagle:~/workspace/linux/drivers/tty$ git grep -e
> 'EARLYCON_DECLARE(.*_uart'
> serial/8250/8250_ingenic.c:EARLYCON_DECLARE(jz4740_uart,
> ingenic_early_console_setup);
> serial/8250/8250_ingenic.c:OF_EARLYCON_DECLARE(jz4740_uart,
> "ingenic,jz4740-uart",
> serial/8250/8250_ingenic.c:EARLYCON_DECLARE(jz4775_uart,
> ingenic_early_console_setup);
> serial/8250/8250_ingenic.c:OF_EARLYCON_DECLARE(jz4775_uart,
> "ingenic,jz4775-uart",
> serial/8250/8250_ingenic.c:EARLYCON_DECLARE(jz4780_uart,
> ingenic_early_console_setup);
> serial/8250/8250_ingenic.c:OF_EARLYCON_DECLARE(jz4780_uart,
> "ingenic,jz4780-uart",
> serial/arc_uart.c:EARLYCON_DECLARE(arc_uart, arc_early_console_setup);
> serial/arc_uart.c:OF_EARLYCON_DECLARE(arc_uart, "snps,arc-uart",
> arc_early_console_setup);
> serial/bcm63xx_uart.c:OF_EARLYCON_DECLARE(bcm63xx_uart,
> "brcm,bcm6345-uart", bcm_early_console_setup);
> yamada@beagle:~/workspace/linux/drivers/tty$ git grep -e
> 'EARLYCON_DECLARE(.*_serial'
> serial/8250/8250_early.c:EARLYCON_DECLARE(uart8250, early_serial8250_setup);
> serial/8250/8250_early.c:EARLYCON_DECLARE(uart, early_serial8250_setup);
> serial/msm_serial.c:EARLYCON_DECLARE(msm_serial,
> msm_serial_early_console_setup);
> serial/msm_serial.c:OF_EARLYCON_DECLARE(msm_serial, "qcom,msm-uart",
> serial/msm_serial.c:EARLYCON_DECLARE(msm_serial_dm,
> msm_serial_early_console_setup_dm);
> serial/msm_serial.c:OF_EARLYCON_DECLARE(msm_serial_dm, "qcom,msm-uartdm",
> serial/sprd_serial.c:EARLYCON_DECLARE(sprd_serial, sprd_early_console_setup);
> serial/sprd_serial.c:OF_EARLYCON_DECLARE(sprd_serial, "sprd,sc9836-uart",
This brings up an important point: the names for EARLYCON_DECLARE() should not
be changed after being in at least one kernel release, since this would cause
existing command line setups to fail.
Regards,
Peter Hurley
^ permalink raw reply [flat|nested] 4+ messages in thread
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2015-10-22 8:39 [PATCH] serial: 8250_uniphier: add earlycon support Masahiro Yamada
2015-10-28 15:21 ` Peter Hurley
2015-10-29 1:49 ` Masahiro Yamada
2015-11-05 16:48 ` Peter Hurley
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