[RFC PATCH for Juno 0/2] Drivers for Juno to boot from ACPI

[RFC PATCH for Juno 0/2] Drivers for Juno to boot from ACPI

[Hanjun Guo]

This patch set is example of the sort of driver changes needed to boot
Juno using ACPI tables, which using the ACPI tables devloped for MS
Windows and published by ARM [1].

For the smsc911x driver, it is based on the following ASL fragment
which is part of DSDT for Juno:

    // LAN9118 Ethernet
    //
    Device(ETH0) {
      Name(_HID, "ARMH9118")
      Name(_UID, Zero)
      Name(_CRS, ResourceTemplate() {
              Memory32Fixed(ReadWrite, 0x1A000000, 0x1000)
              Interrupt(ResourceConsumer, Level, ActiveHigh, Exclusive) { 192 }
      })
    }

UART driver is just for review purpose, ARM is working on a more
functional UART driver that does not poll to transmit. But it shows
how to initialise SBSA compatible UART without clock definitions in
DSDT.

You also can refer to the boot log from [2].

[1]: https://github.com/ARM-software/edk2/tree/juno-acpi/ArmPlatformPkg/ArmJunoPkg/AcpiTables
[2]: http://www.xora.org.uk/2014/08/29/juno-booting-from-acpi-tables/


Graeme Gregory (2):
  net: smsc911x add support for probing from ACPI
  tty: SBSA compatible UART

 drivers/net/ethernet/smsc/smsc911x.c |   38 ++++
 drivers/tty/Kconfig                  |    6 +
 drivers/tty/Makefile                 |    1 +
 drivers/tty/sbsauart.c               |  328 ++++++++++++++++++++++++++++++++++
 4 files changed, 373 insertions(+)
 create mode 100644 drivers/tty/sbsauart.c

-- 
1.7.9.5

[RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Hanjun Guo]

From: Graeme Gregory <graeme.gregory@linaro.org>

This is a standard platform device to resources are converted in the
ACPI core in the same fasion as DT resources. For the other DT
provided information there is _DSD for ACPI.

Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
---
 drivers/net/ethernet/smsc/smsc911x.c |   38 ++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/drivers/net/ethernet/smsc/smsc911x.c b/drivers/net/ethernet/smsc/smsc911x.c
index 5e13fa5..69d725a 100644
--- a/drivers/net/ethernet/smsc/smsc911x.c
+++ b/drivers/net/ethernet/smsc/smsc911x.c
@@ -59,6 +59,7 @@
 #include <linux/of_device.h>
 #include <linux/of_gpio.h>
 #include <linux/of_net.h>
+#include <linux/acpi.h>
 #include "smsc911x.h"
 
 #define SMSC_CHIPNAME		"smsc911x"
@@ -2369,9 +2370,36 @@ static inline int smsc911x_probe_config_dt(
 }
 #endif /* CONFIG_OF */
 
+#ifdef CONFIG_ACPI
+/* Configure some sensible defaults for ACPI mode */
+static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
+				    acpi_handle *ahandle)
+{
+	if (!ahandle)
+		return -ENOSYS;
+
+	config->phy_interface = PHY_INTERFACE_MODE_MII;
+
+	config->flags |= SMSC911X_USE_32BIT;
+
+	config->irq_polarity = SMSC911X_IRQ_POLARITY_ACTIVE_HIGH;
+
+	config->irq_type = SMSC911X_IRQ_TYPE_PUSH_PULL;
+
+	return 0;
+}
+#else
+static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
+				      acpi_handle *ahandle)
+{
+	return -ENOSYS;
+}
+#endif /* CONFIG_ACPI */
+
 static int smsc911x_drv_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
+	acpi_handle *ahandle = ACPI_HANDLE(&pdev->dev);
 	struct net_device *dev;
 	struct smsc911x_data *pdata;
 	struct smsc911x_platform_config *config = dev_get_platdata(&pdev->dev);
@@ -2436,6 +2464,9 @@ static int smsc911x_drv_probe(struct platform_device *pdev)
 	}
 
 	retval = smsc911x_probe_config_dt(&pdata->config, np);
+	if (retval)
+		retval = smsc911x_probe_config_acpi(&pdata->config, ahandle);
+
 	if (retval && config) {
 		/* copy config parameters across to pdata */
 		memcpy(&pdata->config, config, sizeof(pdata->config));
@@ -2606,6 +2637,12 @@ static const struct of_device_id smsc911x_dt_ids[] = {
 MODULE_DEVICE_TABLE(of, smsc911x_dt_ids);
 #endif
 
+static const struct acpi_device_id smsc911x_acpi_ids[] = {
+	{ "LNRO001B", },
+	{ "ARMH9118", },
+	{ }
+};
+
 static struct platform_driver smsc911x_driver = {
 	.probe = smsc911x_drv_probe,
 	.remove = smsc911x_drv_remove,
@@ -2614,6 +2651,7 @@ static struct platform_driver smsc911x_driver = {
 		.owner	= THIS_MODULE,
 		.pm	= SMSC911X_PM_OPS,
 		.of_match_table = of_match_ptr(smsc911x_dt_ids),
+		.acpi_match_table = ACPI_PTR(smsc911x_acpi_ids),
 	},
 };
 
-- 
1.7.9.5

Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Arnd Bergmann]

On Monday 01 September 2014 23:06:00 Hanjun Guo wrote:
> +#ifdef CONFIG_ACPI
> +/* Configure some sensible defaults for ACPI mode */
> +static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
> +                                   acpi_handle *ahandle)
> +{
> +       if (!ahandle)
> +               return -ENOSYS;
> +
> +       config->phy_interface = PHY_INTERFACE_MODE_MII;
> 

Please remove the #ifdef and use 

	if (!IS_ENABLED(CONFIG_ACPI) || !ahandle)

to check for ACPI support. This should result in the same object code
in all cases, but give better compile-time coverage when ACPI is
disabled.

Also, -ENOSYS is probably the wrong return value. I think you mean
-ENXIO.

	Arnd

Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Graeme Gregory]

On Mon, Sep 01, 2014 at 05:17:51PM +0200, Arnd Bergmann wrote:
> On Monday 01 September 2014 23:06:00 Hanjun Guo wrote:
> > +#ifdef CONFIG_ACPI
> > +/* Configure some sensible defaults for ACPI mode */
> > +static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
> > +                                   acpi_handle *ahandle)
> > +{
> > +       if (!ahandle)
> > +               return -ENOSYS;
> > +
> > +       config->phy_interface = PHY_INTERFACE_MODE_MII;
> > 
> 
> Please remove the #ifdef and use 
> 
> 	if (!IS_ENABLED(CONFIG_ACPI) || !ahandle)
> 
> to check for ACPI support. This should result in the same object code
> in all cases, but give better compile-time coverage when ACPI is
> disabled.
> 
struct acpi_handle does not exist in the case !CONFIG_ACPI

> Also, -ENOSYS is probably the wrong return value. I think you mean
> -ENXIO.
> 
Yes that would make sense thanks.

Not sure if we are planning to actually upstream this patch, I guess it
depends if ARM start shipping Junos with the ACPI tables loaded on them.

Graeme

Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Arnd Bergmann]

On Monday 01 September 2014 16:28:54 Graeme Gregory wrote:
> On Mon, Sep 01, 2014 at 05:17:51PM +0200, Arnd Bergmann wrote:
> > On Monday 01 September 2014 23:06:00 Hanjun Guo wrote:
> > > +#ifdef CONFIG_ACPI
> > > +/* Configure some sensible defaults for ACPI mode */
> > > +static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
> > > +                                   acpi_handle *ahandle)
> > > +{
> > > +       if (!ahandle)
> > > +               return -ENOSYS;
> > > +
> > > +       config->phy_interface = PHY_INTERFACE_MODE_MII;
> > > 
> > 
> > Please remove the #ifdef and use 
> > 
> >       if (!IS_ENABLED(CONFIG_ACPI) || !ahandle)
> > 
> > to check for ACPI support. This should result in the same object code
> > in all cases, but give better compile-time coverage when ACPI is
> > disabled.
> > 
> struct acpi_handle does not exist in the case !CONFIG_ACPI

That should be easy to fix, and a good idea in general, independent
of this patch.
We generally make function declarations and type definitions visible
(possibly empty) for disabled subsystems so the code using them
silently goes away when that subsystem is disabled.

	Arnd

Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Catalin Marinas]

On Mon, Sep 01, 2014 at 04:28:54PM +0100, Graeme Gregory wrote:
> On Mon, Sep 01, 2014 at 05:17:51PM +0200, Arnd Bergmann wrote:
> > On Monday 01 September 2014 23:06:00 Hanjun Guo wrote:
> > > +#ifdef CONFIG_ACPI
> > > +/* Configure some sensible defaults for ACPI mode */
> > > +static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
> > > +                                   acpi_handle *ahandle)
> > > +{
> > > +       if (!ahandle)
> > > +               return -ENOSYS;
> > > +
> > > +       config->phy_interface = PHY_INTERFACE_MODE_MII;
> > > 
> > 
> > Please remove the #ifdef and use 
> > 
> > 	if (!IS_ENABLED(CONFIG_ACPI) || !ahandle)
> > 
> > to check for ACPI support. This should result in the same object code
> > in all cases, but give better compile-time coverage when ACPI is
> > disabled.
> > 
> struct acpi_handle does not exist in the case !CONFIG_ACPI

Confused. Then how come smsc911x_drv_probe() has this line:

	acpi_handle *ahandle = ACPI_HANDLE(&pdev->dev);

without any #ifdef's.

-- 
Catalin

Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Mark Brown]

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On Mon, Sep 01, 2014 at 05:53:33PM +0100, Catalin Marinas wrote:

> Confused. Then how come smsc911x_drv_probe() has this line:

> 	acpi_handle *ahandle = ACPI_HANDLE(&pdev->dev);

> without any #ifdef's.

There's a stub smsc911x_probe_config_acpi() provided in the non-ACPI
case, Arnd's suggestion is basically to remove the stub.

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Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Sudeep Holla]

Hi Mark,

On 01/09/14 17:58, Mark Brown wrote:
> On Mon, Sep 01, 2014 at 05:53:33PM +0100, Catalin Marinas wrote:
>
>> Confused. Then how come smsc911x_drv_probe() has this line:
>
>> 	acpi_handle *ahandle = ACPI_HANDLE(&pdev->dev);
>
>> without any #ifdef's.
>
> There's a stub smsc911x_probe_config_acpi() provided in the non-ACPI
> case, Arnd's suggestion is basically to remove the stub.
>

I think Catalin is referring to ACPI_HANDLE used without any #ifdefs

Catalin, few macros like ACPI_HANDLE and ACPI_PTR are defined in
include/linux/acpi.h even when CONFIG_ACPI is not set mainly to
avoid #ifdef's around simple assignments like the above one and one
in platform_driver.acpi_match_table

Regards,
Sudeep

Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Catalin Marinas]

On Mon, Sep 01, 2014 at 06:08:49PM +0100, Sudeep Holla wrote:
> On 01/09/14 17:58, Mark Brown wrote:
> > On Mon, Sep 01, 2014 at 05:53:33PM +0100, Catalin Marinas wrote:
> >
> >> Confused. Then how come smsc911x_drv_probe() has this line:
> >
> >> 	acpi_handle *ahandle = ACPI_HANDLE(&pdev->dev);
> >
> >> without any #ifdef's.
> >
> > There's a stub smsc911x_probe_config_acpi() provided in the non-ACPI
> > case, Arnd's suggestion is basically to remove the stub.
> >
> 
> I think Catalin is referring to ACPI_HANDLE used without any #ifdefs
> 
> Catalin, few macros like ACPI_HANDLE and ACPI_PTR are defined in
> include/linux/acpi.h even when CONFIG_ACPI is not set mainly to
> avoid #ifdef's around simple assignments like the above one and one
> in platform_driver.acpi_match_table

My comment was to Graeme who said that #ifdef's were needed because
acpi_handle (lowercase) was not defined in the !CONFIG_ACPI case.
However, further down in the patch it was used without any #ifdef's.

-- 
Catalin

Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Sudeep Holla]

On 01/09/14 18:14, Catalin Marinas wrote:
> On Mon, Sep 01, 2014 at 06:08:49PM +0100, Sudeep Holla wrote:
>> On 01/09/14 17:58, Mark Brown wrote:
>>> On Mon, Sep 01, 2014 at 05:53:33PM +0100, Catalin Marinas wrote:
>>>
>>>> Confused. Then how come smsc911x_drv_probe() has this line:
>>>
>>>> 	acpi_handle *ahandle = ACPI_HANDLE(&pdev->dev);
>>>
>>>> without any #ifdef's.
>>>
>>> There's a stub smsc911x_probe_config_acpi() provided in the non-ACPI
>>> case, Arnd's suggestion is basically to remove the stub.
>>>
>>
>> I think Catalin is referring to ACPI_HANDLE used without any #ifdefs
>>
>> Catalin, few macros like ACPI_HANDLE and ACPI_PTR are defined in
>> include/linux/acpi.h even when CONFIG_ACPI is not set mainly to
>> avoid #ifdef's around simple assignments like the above one and one
>> in platform_driver.acpi_match_table
>
> My comment was to Graeme who said that #ifdef's were needed because
> acpi_handle (lowercase) was not defined in the !CONFIG_ACPI case.
> However, further down in the patch it was used without any #ifdef's.
>

Ah OK, I misunderstood. In that case Graeme statement is wrong.
IIRC acpi_handle is not structure, it's just a ptr used for object
references in ACPI namespace and is available even when !CONFIG_ACPI

Regards,
Sudeep

Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Graeme Gregory]

On Mon, Sep 01, 2014 at 05:53:33PM +0100, Catalin Marinas wrote:
> On Mon, Sep 01, 2014 at 04:28:54PM +0100, Graeme Gregory wrote:
> > On Mon, Sep 01, 2014 at 05:17:51PM +0200, Arnd Bergmann wrote:
> > > On Monday 01 September 2014 23:06:00 Hanjun Guo wrote:
> > > > +#ifdef CONFIG_ACPI
> > > > +/* Configure some sensible defaults for ACPI mode */
> > > > +static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
> > > > +                                   acpi_handle *ahandle)
> > > > +{
> > > > +       if (!ahandle)
> > > > +               return -ENOSYS;
> > > > +
> > > > +       config->phy_interface = PHY_INTERFACE_MODE_MII;
> > > > 
> > > 
> > > Please remove the #ifdef and use 
> > > 
> > > 	if (!IS_ENABLED(CONFIG_ACPI) || !ahandle)
> > > 
> > > to check for ACPI support. This should result in the same object code
> > > in all cases, but give better compile-time coverage when ACPI is
> > > disabled.
> > > 
> > struct acpi_handle does not exist in the case !CONFIG_ACPI
> 
> Confused. Then how come smsc911x_drv_probe() has this line:
> 
> 	acpi_handle *ahandle = ACPI_HANDLE(&pdev->dev);
> 
> without any #ifdef's.
> 
It is possible I confused myself as some types moved around in ACPI
recently. I will re-check!

Graeme

Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Grant Likely]

On Mon, 1 Sep 2014 16:28:54 +0100, Graeme Gregory <graeme.gregory@linaro.org> wrote:
> On Mon, Sep 01, 2014 at 05:17:51PM +0200, Arnd Bergmann wrote:
> > On Monday 01 September 2014 23:06:00 Hanjun Guo wrote:
> > > +#ifdef CONFIG_ACPI
> > > +/* Configure some sensible defaults for ACPI mode */
> > > +static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
> > > +                                   acpi_handle *ahandle)
> > > +{
> > > +       if (!ahandle)
> > > +               return -ENOSYS;
> > > +
> > > +       config->phy_interface = PHY_INTERFACE_MODE_MII;
> > > 
> > 
> > Please remove the #ifdef and use 
> > 
> > 	if (!IS_ENABLED(CONFIG_ACPI) || !ahandle)
> > 
> > to check for ACPI support. This should result in the same object code
> > in all cases, but give better compile-time coverage when ACPI is
> > disabled.
> > 
> struct acpi_handle does not exist in the case !CONFIG_ACPI
> 
> > Also, -ENOSYS is probably the wrong return value. I think you mean
> > -ENXIO.
> > 
> Yes that would make sense thanks.
> 
> Not sure if we are planning to actually upstream this patch, I guess it
> depends if ARM start shipping Junos with the ACPI tables loaded on them.

I think we do want this upstreamed. Juno is intended to be a readily
available reference platform, regardless of the firmware loaded when
shipped. There will be users who use it as a test platform for ACPI
development.

g.

Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Catalin Marinas]

On Mon, Sep 15, 2014 at 05:08:44AM +0100, Grant Likely wrote:
> On Mon, 1 Sep 2014 16:28:54 +0100, Graeme Gregory <graeme.gregory@linaro.org> wrote:
> > On Mon, Sep 01, 2014 at 05:17:51PM +0200, Arnd Bergmann wrote:
> > > On Monday 01 September 2014 23:06:00 Hanjun Guo wrote:
> > > > +#ifdef CONFIG_ACPI
> > > > +/* Configure some sensible defaults for ACPI mode */
> > > > +static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
> > > > +                                   acpi_handle *ahandle)
> > > > +{
> > > > +       if (!ahandle)
> > > > +               return -ENOSYS;
> > > > +
> > > > +       config->phy_interface = PHY_INTERFACE_MODE_MII;
> > > > 
> > > 
> > > Please remove the #ifdef and use 
> > > 
> > > 	if (!IS_ENABLED(CONFIG_ACPI) || !ahandle)
> > > 
> > > to check for ACPI support. This should result in the same object code
> > > in all cases, but give better compile-time coverage when ACPI is
> > > disabled.
> > > 
> > struct acpi_handle does not exist in the case !CONFIG_ACPI
> > 
> > > Also, -ENOSYS is probably the wrong return value. I think you mean
> > > -ENXIO.
> > > 
> > Yes that would make sense thanks.
> > 
> > Not sure if we are planning to actually upstream this patch, I guess it
> > depends if ARM start shipping Junos with the ACPI tables loaded on them.
> 
> I think we do want this upstreamed. Juno is intended to be a readily
> available reference platform, regardless of the firmware loaded when
> shipped. There will be users who use it as a test platform for ACPI
> development.

The patches for Juno are not intrusive. The only problem I have is
giving the wrong example on how to deal with the platform-specific
device information like this patch. I would much prefer to use _DSD
(once we agree on how to do this) than hard-coding information based on
the ACPI device id (you would need one for each SoC). I don't think we
have reached an agreement yet:

https://lkml.kernel.org/g/4816592.tj3on6vUaC@wuerfel

-- 
Catalin

Re: [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Catalin Marinas]

On Mon, Sep 01, 2014 at 04:06:00PM +0100, Hanjun Guo wrote:
> +#ifdef CONFIG_ACPI
> +/* Configure some sensible defaults for ACPI mode */
> +static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
> +				    acpi_handle *ahandle)
> +{
> +	if (!ahandle)
> +		return -ENOSYS;
> +
> +	config->phy_interface = PHY_INTERFACE_MODE_MII;
> +
> +	config->flags |= SMSC911X_USE_32BIT;
> +
> +	config->irq_polarity = SMSC911X_IRQ_POLARITY_ACTIVE_HIGH;
> +
> +	config->irq_type = SMSC911X_IRQ_TYPE_PUSH_PULL;
> +
> +	return 0;
> +}
> +#else

I don't like this and it shows issues we have with ACPI on certain ARM
platforms. You hard-code these values to match the Juno platform. What
if we get another SoC which has different configuration here? For DT, we
have the smsc911x_probe_config_dt() which reads the relevant information
from DT. I think this kind of configuration would be more suitable as
_DSD properties and sharing the similar names with DT (but we go back to
the question about who's in charge of the _DSD properties).

>  static int smsc911x_drv_probe(struct platform_device *pdev)
>  {
>  	struct device_node *np = pdev->dev.of_node;
> +	acpi_handle *ahandle = ACPI_HANDLE(&pdev->dev);
>  	struct net_device *dev;
>  	struct smsc911x_data *pdata;
>  	struct smsc911x_platform_config *config = dev_get_platdata(&pdev->dev);
> @@ -2436,6 +2464,9 @@ static int smsc911x_drv_probe(struct platform_device *pdev)
>  	}
>  
>  	retval = smsc911x_probe_config_dt(&pdata->config, np);
> +	if (retval)
> +		retval = smsc911x_probe_config_acpi(&pdata->config, ahandle);
> +

In most of the ACPI patches so far we check for ACPI first with DT as a
fall-back if ACPI is not enabled. This changes here. I would prefer
something which probes only ACPI if the ACPI is enabled (run-time, not
config) otherwise DT only. E.g.

-- 
Catalin

Re: [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Arnd Bergmann]

On Monday 01 September 2014 18:04:47 Catalin Marinas wrote:
> On Mon, Sep 01, 2014 at 04:06:00PM +0100, Hanjun Guo wrote:
> > +#ifdef CONFIG_ACPI
> > +/* Configure some sensible defaults for ACPI mode */
> > +static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
> > +                                 acpi_handle *ahandle)
> > +{
> > +     if (!ahandle)
> > +             return -ENOSYS;
> > +
> > +     config->phy_interface = PHY_INTERFACE_MODE_MII;
> > +
> > +     config->flags |= SMSC911X_USE_32BIT;
> > +
> > +     config->irq_polarity = SMSC911X_IRQ_POLARITY_ACTIVE_HIGH;
> > +
> > +     config->irq_type = SMSC911X_IRQ_TYPE_PUSH_PULL;
> > +
> > +     return 0;
> > +}
> > +#else
> 
> I don't like this and it shows issues we have with ACPI on certain ARM
> platforms. You hard-code these values to match the Juno platform. What
> if we get another SoC which has different configuration here? For DT, we
> have the smsc911x_probe_config_dt() which reads the relevant information
> from DT. I think this kind of configuration would be more suitable as
> _DSD properties and sharing the similar names with DT (but we go back to
> the question about who's in charge of the _DSD properties).

Good point, I totally missed that.

There is of course the possibility to set those values based on the
acpi_device_id, but that is exactly the part that _DSD is trying to
avoid.

> >  static int smsc911x_drv_probe(struct platform_device *pdev)
> >  {
> >       struct device_node *np = pdev->dev.of_node;
> > +     acpi_handle *ahandle = ACPI_HANDLE(&pdev->dev);
> >       struct net_device *dev;
> >       struct smsc911x_data *pdata;
> >       struct smsc911x_platform_config *config = dev_get_platdata(&pdev->dev);
> > @@ -2436,6 +2464,9 @@ static int smsc911x_drv_probe(struct platform_device *pdev)
> >       }
> >  
> >       retval = smsc911x_probe_config_dt(&pdata->config, np);
> > +     if (retval)
> > +             retval = smsc911x_probe_config_acpi(&pdata->config, ahandle);
> > +
> 
> In most of the ACPI patches so far we check for ACPI first with DT as a
> fall-back if ACPI is not enabled. This changes here.

Does this really make a difference?

> I would prefer
> something which probes only ACPI if the ACPI is enabled (run-time, not
> config) otherwise DT only. E.g.

(example missing?)

I think we should have the equivalent of of_have_populated_dt(), to
check whether acpi is being used to boot, and have that new function
be hardcoded to zero in case of !IS_ENABLED(CONFIG_ACPI).

	Arnd

Re: [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Catalin Marinas]

On Mon, Sep 01, 2014 at 06:11:44PM +0100, Arnd Bergmann wrote:
> On Monday 01 September 2014 18:04:47 Catalin Marinas wrote:
> > On Mon, Sep 01, 2014 at 04:06:00PM +0100, Hanjun Guo wrote:
> > > +#ifdef CONFIG_ACPI
> > > +/* Configure some sensible defaults for ACPI mode */
> > > +static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
> > > +                                 acpi_handle *ahandle)
> > > +{
> > > +     if (!ahandle)
> > > +             return -ENOSYS;
> > > +
> > > +     config->phy_interface = PHY_INTERFACE_MODE_MII;
> > > +
> > > +     config->flags |= SMSC911X_USE_32BIT;
> > > +
> > > +     config->irq_polarity = SMSC911X_IRQ_POLARITY_ACTIVE_HIGH;
> > > +
> > > +     config->irq_type = SMSC911X_IRQ_TYPE_PUSH_PULL;
> > > +
> > > +     return 0;
> > > +}
> > > +#else
> > 
> > I don't like this and it shows issues we have with ACPI on certain ARM
> > platforms. You hard-code these values to match the Juno platform. What
> > if we get another SoC which has different configuration here? For DT, we
> > have the smsc911x_probe_config_dt() which reads the relevant information
> > from DT. I think this kind of configuration would be more suitable as
> > _DSD properties and sharing the similar names with DT (but we go back to
> > the question about who's in charge of the _DSD properties).
> 
> Good point, I totally missed that.
> 
> There is of course the possibility to set those values based on the
> acpi_device_id, but that is exactly the part that _DSD is trying to
> avoid.

I would prefer to avoid acpi_device_id checks. This would defeat the
alleged aim of ACPI to run newer hardware configuration with older
kernels.

> > >  static int smsc911x_drv_probe(struct platform_device *pdev)
> > >  {
> > >       struct device_node *np = pdev->dev.of_node;
> > > +     acpi_handle *ahandle = ACPI_HANDLE(&pdev->dev);
> > >       struct net_device *dev;
> > >       struct smsc911x_data *pdata;
> > >       struct smsc911x_platform_config *config = dev_get_platdata(&pdev->dev);
> > > @@ -2436,6 +2464,9 @@ static int smsc911x_drv_probe(struct platform_device *pdev)
> > >       }
> > >  
> > >       retval = smsc911x_probe_config_dt(&pdata->config, np);
> > > +     if (retval)
> > > +             retval = smsc911x_probe_config_acpi(&pdata->config, ahandle);
> > > +
> > 
> > In most of the ACPI patches so far we check for ACPI first with DT as a
> > fall-back if ACPI is not enabled. This changes here.
> 
> Does this really make a difference?

Not the order (well, someone may think that if they unflatten the DT in
a vendor kernel even though it boot as ACPI, they could get away with a
mix of DT and ACPI ;)).

> > I would prefer
> > something which probes only ACPI if the ACPI is enabled (run-time, not
> > config) otherwise DT only. E.g.
> 
> (example missing?)

I was looking through the code and forgot. Something like:

	if (acpi_disabled)
		retval = smsc911x_probe_config_dt();
	else
		retval = smsc911x_probe_config_acpi();

> I think we should have the equivalent of of_have_populated_dt(), to
> check whether acpi is being used to boot, and have that new function
> be hardcoded to zero in case of !IS_ENABLED(CONFIG_ACPI).

I think you meant hardcoded to 1 when !ACPI. That would work as well.

-- 
Catalin

Re: [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Graeme Gregory]

On Mon, Sep 01, 2014 at 07:11:44PM +0200, Arnd Bergmann wrote:
> On Monday 01 September 2014 18:04:47 Catalin Marinas wrote:
> > On Mon, Sep 01, 2014 at 04:06:00PM +0100, Hanjun Guo wrote:
> > > +#ifdef CONFIG_ACPI
> > > +/* Configure some sensible defaults for ACPI mode */
> > > +static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
> > > +                                 acpi_handle *ahandle)
> > > +{
> > > +     if (!ahandle)
> > > +             return -ENOSYS;
> > > +
> > > +     config->phy_interface = PHY_INTERFACE_MODE_MII;
> > > +
> > > +     config->flags |= SMSC911X_USE_32BIT;
> > > +
> > > +     config->irq_polarity = SMSC911X_IRQ_POLARITY_ACTIVE_HIGH;
> > > +
> > > +     config->irq_type = SMSC911X_IRQ_TYPE_PUSH_PULL;
> > > +
> > > +     return 0;
> > > +}
> > > +#else
> > 
> > I don't like this and it shows issues we have with ACPI on certain ARM
> > platforms. You hard-code these values to match the Juno platform. What
> > if we get another SoC which has different configuration here? For DT, we
> > have the smsc911x_probe_config_dt() which reads the relevant information
> > from DT. I think this kind of configuration would be more suitable as
> > _DSD properties and sharing the similar names with DT (but we go back to
> > the question about who's in charge of the _DSD properties).
> 
> Good point, I totally missed that.
> 
> There is of course the possibility to set those values based on the
> acpi_device_id, but that is exactly the part that _DSD is trying to
> avoid.
> 
This will of course most likely be replaced by _DSD values. I just
hardcoded for now as _DSD is not yet in the kernel and issues around
maintenance of bindings are not solved (unless this happened at KS where
I was not present).

> > >  static int smsc911x_drv_probe(struct platform_device *pdev)
> > >  {
> > >       struct device_node *np = pdev->dev.of_node;
> > > +     acpi_handle *ahandle = ACPI_HANDLE(&pdev->dev);
> > >       struct net_device *dev;
> > >       struct smsc911x_data *pdata;
> > >       struct smsc911x_platform_config *config = dev_get_platdata(&pdev->dev);
> > > @@ -2436,6 +2464,9 @@ static int smsc911x_drv_probe(struct platform_device *pdev)
> > >       }
> > >  
> > >       retval = smsc911x_probe_config_dt(&pdata->config, np);
> > > +     if (retval)
> > > +             retval = smsc911x_probe_config_acpi(&pdata->config, ahandle);
> > > +
> > 
> > In most of the ACPI patches so far we check for ACPI first with DT as a
> > fall-back if ACPI is not enabled. This changes here.
> 
> Does this really make a difference?
> 
> > I would prefer
> > something which probes only ACPI if the ACPI is enabled (run-time, not
> > config) otherwise DT only. E.g.
> 
> (example missing?)
> 
> I think we should have the equivalent of of_have_populated_dt(), to
> check whether acpi is being used to boot, and have that new function
> be hardcoded to zero in case of !IS_ENABLED(CONFIG_ACPI).
> 
if (!acpi_disabled) is the equivalent if I understand you correctly.

But people until this point had expressed a preference for checking
.of_node and ACPI_HANDLE() to this point. This is obviously mutable
though depending on community preference.

Graeme

Re: [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Mark Brown]

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On Mon, Sep 01, 2014 at 06:32:45PM +0100, Graeme Gregory wrote:

> This will of course most likely be replaced by _DSD values. I just
> hardcoded for now as _DSD is not yet in the kernel and issues around
> maintenance of bindings are not solved (unless this happened at KS where
> I was not present).

Not really.  AIUI the official thing is still some combination of
getting a DT binding defined and then use that verbatim (as the x86
embedded people want to though I'm still not clear that the Windows
people are on board with this) and the UEFI processes.  It's possible I
misunderstood though.

Realistically if something is usable on x86 embedded it's going to be
supported on ARMv8 servers too unless we jump through hoops, and even
there real implementations in the wild will probably win out.

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Re: [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Catalin Marinas]

On Mon, Sep 01, 2014 at 06:32:45PM +0100, Graeme Gregory wrote:
> On Mon, Sep 01, 2014 at 07:11:44PM +0200, Arnd Bergmann wrote:
> > On Monday 01 September 2014 18:04:47 Catalin Marinas wrote:
> > > On Mon, Sep 01, 2014 at 04:06:00PM +0100, Hanjun Guo wrote:
> > > > +#ifdef CONFIG_ACPI
> > > > +/* Configure some sensible defaults for ACPI mode */
> > > > +static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
> > > > +                                 acpi_handle *ahandle)
> > > > +{
> > > > +     if (!ahandle)
> > > > +             return -ENOSYS;
> > > > +
> > > > +     config->phy_interface = PHY_INTERFACE_MODE_MII;
> > > > +
> > > > +     config->flags |= SMSC911X_USE_32BIT;
> > > > +
> > > > +     config->irq_polarity = SMSC911X_IRQ_POLARITY_ACTIVE_HIGH;
> > > > +
> > > > +     config->irq_type = SMSC911X_IRQ_TYPE_PUSH_PULL;
> > > > +
> > > > +     return 0;
> > > > +}
> > > > +#else
> > > 
> > > I don't like this and it shows issues we have with ACPI on certain ARM
> > > platforms. You hard-code these values to match the Juno platform. What
> > > if we get another SoC which has different configuration here? For DT, we
> > > have the smsc911x_probe_config_dt() which reads the relevant information
> > > from DT. I think this kind of configuration would be more suitable as
> > > _DSD properties and sharing the similar names with DT (but we go back to
> > > the question about who's in charge of the _DSD properties).
> > 
> > Good point, I totally missed that.
> > 
> > There is of course the possibility to set those values based on the
> > acpi_device_id, but that is exactly the part that _DSD is trying to
> > avoid.
> 
> This will of course most likely be replaced by _DSD values. I just
> hardcoded for now as _DSD is not yet in the kernel and issues around
> maintenance of bindings are not solved (unless this happened at KS where
> I was not present).

Not much at the KS, I think it will need to be followed up on lkml
(https://lkml.org/lkml/2014/8/17/10 is the last I'm aware of, not sure
about any updates in the meantime).

While the above gets sorted, what's the position from an ARM
perspective (and covered by Documentation/arm64/arm-acpi.txt)? I think
the "Device Enumeration" section in this document is fine, it's just the
kernel infrastructure missing.

Alternatively, you can say _DSD is not allowed (yet?) but I don't
particularly like basing the configuration on acpi_device_id like in
this patch. Which would leave us with ignoring any SoC containing
devices that require such specific configuration.

-- 
Catalin

Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Arnd Bergmann]

On Tuesday 02 September 2014 14:26:52 Catalin Marinas wrote:
> 
> Not much at the KS, I think it will need to be followed up on lkml
> (https://lkml.org/lkml/2014/8/17/10 is the last I'm aware of, not sure
> about any updates in the meantime).
> 
> While the above gets sorted, what's the position from an ARM
> perspective (and covered by Documentation/arm64/arm-acpi.txt)? I think
> the "Device Enumeration" section in this document is fine, it's just the
> kernel infrastructure missing.
> 
> Alternatively, you can say _DSD is not allowed (yet?) but I don't
> particularly like basing the configuration on acpi_device_id like in
> this patch. Which would leave us with ignoring any SoC containing
> devices that require such specific configuration.

The way I recall the discussion, most people were on one extreme
side of the discussion or the other:

a) We should use _DSD for ARM64 servers to maximize code reuse with
DT-enabled drivers, work around the slow UEFI standardization process,
remain in control of the actual bindings, and avoid the need for
endless per-ID platform-data definitions in drivers.

b) We should never use _DSD at all, since doing that would have no
advantage over using DT directly, and we should force every device
manufacturer to specify their bindings in an official ACPI document
to prevent random incompatible bindings from being established.
Any device that shows up in servers should not need arbitrary detailed
properties anyway, as the details are supposed to be hidden in AML.

I can understand the reasons for both approaches, and I find it hard
to say either one is invalid. However, the worst possible outcome in
my opinion would be having to support a mix of the two.

	Arnd

Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 1229 bytes --]

On Tue, Sep 02, 2014 at 03:42:53PM +0200, Arnd Bergmann wrote:

> The way I recall the discussion, most people were on one extreme
> side of the discussion or the other:

> a) We should use _DSD for ARM64 servers to maximize code reuse with
> DT-enabled drivers, work around the slow UEFI standardization process,
> remain in control of the actual bindings, and avoid the need for
> endless per-ID platform-data definitions in drivers.

> b) We should never use _DSD at all, since doing that would have no
> advantage over using DT directly, and we should force every device
> manufacturer to specify their bindings in an official ACPI document
> to prevent random incompatible bindings from being established.
> Any device that shows up in servers should not need arbitrary detailed
> properties anyway, as the details are supposed to be hidden in AML.

> I can understand the reasons for both approaches, and I find it hard
> to say either one is invalid. However, the worst possible outcome in
> my opinion would be having to support a mix of the two.

Right, and the x86 embedded folks are going full steam ahead with _DSD
regardless so it seems there will be some systems out there using it
even if they're not ARM servers.

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Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Rafael J. Wysocki]

On Tuesday, September 02, 2014 05:26:06 PM Mark Brown wrote:
> 
> --s3puAW9DMBtS2ARW
> Content-Type: text/plain; charset=us-ascii
> Content-Disposition: inline
> 
> On Tue, Sep 02, 2014 at 03:42:53PM +0200, Arnd Bergmann wrote:
> 
> > The way I recall the discussion, most people were on one extreme
> > side of the discussion or the other:
> 
> > a) We should use _DSD for ARM64 servers to maximize code reuse with
> > DT-enabled drivers, work around the slow UEFI standardization process,
> > remain in control of the actual bindings, and avoid the need for
> > endless per-ID platform-data definitions in drivers.
> 
> > b) We should never use _DSD at all, since doing that would have no
> > advantage over using DT directly, and we should force every device
> > manufacturer to specify their bindings in an official ACPI document
> > to prevent random incompatible bindings from being established.
> > Any device that shows up in servers should not need arbitrary detailed
> > properties anyway, as the details are supposed to be hidden in AML.
> 
> > I can understand the reasons for both approaches, and I find it hard
> > to say either one is invalid. However, the worst possible outcome in
> > my opinion would be having to support a mix of the two.
> 
> Right, and the x86 embedded folks are going full steam ahead with _DSD
> regardless so it seems there will be some systems out there using it
> even if they're not ARM servers.

Our intention is specifically not to use "random incompatible bindings"
in that.  We'd rather have a common venue and process for establishing
new bindings for both DT and _DSD in a compatible way.

Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.

Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Arnd Bergmann]

On Wednesday 03 September 2014 01:00:23 Rafael J. Wysocki wrote:
> On Tuesday, September 02, 2014 05:26:06 PM Mark Brown wrote:
> > 
> > --s3puAW9DMBtS2ARW
> > Content-Type: text/plain; charset=us-ascii
> > Content-Disposition: inline
> > 
> > On Tue, Sep 02, 2014 at 03:42:53PM +0200, Arnd Bergmann wrote:
> > 
> > > The way I recall the discussion, most people were on one extreme
> > > side of the discussion or the other:
> > 
> > > a) We should use _DSD for ARM64 servers to maximize code reuse with
> > > DT-enabled drivers, work around the slow UEFI standardization process,
> > > remain in control of the actual bindings, and avoid the need for
> > > endless per-ID platform-data definitions in drivers.
> > 
> > > b) We should never use _DSD at all, since doing that would have no
> > > advantage over using DT directly, and we should force every device
> > > manufacturer to specify their bindings in an official ACPI document
> > > to prevent random incompatible bindings from being established.
> > > Any device that shows up in servers should not need arbitrary detailed
> > > properties anyway, as the details are supposed to be hidden in AML.
> > 
> > > I can understand the reasons for both approaches, and I find it hard
> > > to say either one is invalid. However, the worst possible outcome in
> > > my opinion would be having to support a mix of the two.
> > 
> > Right, and the x86 embedded folks are going full steam ahead with _DSD
> > regardless so it seems there will be some systems out there using it
> > even if they're not ARM servers.
> 
> Our intention is specifically not to use "random incompatible bindings"
> in that.  We'd rather have a common venue and process for establishing
> new bindings for both DT and _DSD in a compatible way.

Right, I think everyone is on the same page for the embedded x86 case,
my point was that there is no consensus about that yet among the
parties involved in arm64 servers.

	Arnd

Re: [Linaro-acpi] [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Jon Masters]

Hi Arnd,

On 09/03/2014 11:09 AM, Arnd Bergmann wrote:
> On Wednesday 03 September 2014 01:00:23 Rafael J. Wysocki wrote:

>> Our intention is specifically not to use "random incompatible bindings"
>> in that.  We'd rather have a common venue and process for establishing
>> new bindings for both DT and _DSD in a compatible way.
> 
> Right, I think everyone is on the same page for the embedded x86 case,
> my point was that there is no consensus about that yet among the
> parties involved in arm64 servers.

However, in the case of MAC devices where you might need to specify just
a couple of properties using _DSD, a specific set of discussions has
been instigated. As you mentioned, though, this pertains only to certain
devices and isn't necessarily true for every Ethernet device.
Consequently, while a Juno PoC patch might use a kludge today, that
doesn't mean it's a limitation of ACPI, just of certain devices.

Jon.

Re: [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Grant Likely]

On Mon, 01 Sep 2014 19:11:44 +0200, Arnd Bergmann <arnd@arndb.de> wrote:
> On Monday 01 September 2014 18:04:47 Catalin Marinas wrote:
> > On Mon, Sep 01, 2014 at 04:06:00PM +0100, Hanjun Guo wrote:
> > > +#ifdef CONFIG_ACPI
> > > +/* Configure some sensible defaults for ACPI mode */
> > > +static int smsc911x_probe_config_acpi(struct smsc911x_platform_config *config,
> > > +                                 acpi_handle *ahandle)
> > > +{
> > > +     if (!ahandle)
> > > +             return -ENOSYS;
> > > +
> > > +     config->phy_interface = PHY_INTERFACE_MODE_MII;
> > > +
> > > +     config->flags |= SMSC911X_USE_32BIT;
> > > +
> > > +     config->irq_polarity = SMSC911X_IRQ_POLARITY_ACTIVE_HIGH;
> > > +
> > > +     config->irq_type = SMSC911X_IRQ_TYPE_PUSH_PULL;
> > > +
> > > +     return 0;
> > > +}
> > > +#else
> > 
> > I don't like this and it shows issues we have with ACPI on certain ARM
> > platforms. You hard-code these values to match the Juno platform. What
> > if we get another SoC which has different configuration here? For DT, we
> > have the smsc911x_probe_config_dt() which reads the relevant information
> > from DT. I think this kind of configuration would be more suitable as
> > _DSD properties and sharing the similar names with DT (but we go back to
> > the question about who's in charge of the _DSD properties).
> 
> Good point, I totally missed that.
> 
> There is of course the possibility to set those values based on the
> acpi_device_id, but that is exactly the part that _DSD is trying to
> avoid.

These are merely defaults. DSD parsing, when implemented, would be
override these default values.

> 
> > >  static int smsc911x_drv_probe(struct platform_device *pdev)
> > >  {
> > >       struct device_node *np = pdev->dev.of_node;
> > > +     acpi_handle *ahandle = ACPI_HANDLE(&pdev->dev);
> > >       struct net_device *dev;
> > >       struct smsc911x_data *pdata;
> > >       struct smsc911x_platform_config *config = dev_get_platdata(&pdev->dev);
> > > @@ -2436,6 +2464,9 @@ static int smsc911x_drv_probe(struct platform_device *pdev)
> > >       }
> > >  
> > >       retval = smsc911x_probe_config_dt(&pdata->config, np);
> > > +     if (retval)
> > > +             retval = smsc911x_probe_config_acpi(&pdata->config, ahandle);
> > > +
> > 
> > In most of the ACPI patches so far we check for ACPI first with DT as a
> > fall-back if ACPI is not enabled. This changes here.
> 
> Does this really make a difference?

Nope. Only one of DT or ACPI will be matched.

> 
> > I would prefer
> > something which probes only ACPI if the ACPI is enabled (run-time, not
> > config) otherwise DT only. E.g.
> 
> (example missing?)
> 
> I think we should have the equivalent of of_have_populated_dt(), to
> check whether acpi is being used to boot, and have that new function
> be hardcoded to zero in case of !IS_ENABLED(CONFIG_ACPI).

The code already accounts for it. If ACPI isn't enabled, or isn't
populated, then the ACPI_HANDLE macro will return NULL and the
smsc911x_probe_config_acpi() function will fail.

g.

Re: [RFC PATCH for Juno 1/2] net: smsc911x add support for probing from ACPI

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 1708 bytes --]

On Sun, Sep 14, 2014 at 09:14:04PM -0700, Grant Likely wrote:
> On Mon, 01 Sep 2014 19:11:44 +0200, Arnd Bergmann <arnd@arndb.de> wrote:

> > > > +     config->phy_interface = PHY_INTERFACE_MODE_MII;

> > > > +     config->flags |= SMSC911X_USE_32BIT;

> > > > +     config->irq_polarity = SMSC911X_IRQ_POLARITY_ACTIVE_HIGH;

> > > > +     config->irq_type = SMSC911X_IRQ_TYPE_PUSH_PULL;

> > > > +     return 0;
> > > > +}

...

> > There is of course the possibility to set those values based on the
> > acpi_device_id, but that is exactly the part that _DSD is trying to
> > avoid.

> These are merely defaults. DSD parsing, when implemented, would be
> override these default values.

One note of caution here: I do agree that default settings are good but
it's worth having clear rules for how we pick the defaults, and advice
for maintainers on how to pick those rules.  If there's a default people
often want to pick it to match their particular system and it can
sometimes be hard for the maintainer to identify if a given tweak
someone is proposing in the defaults might break some other existing
system.  Having clear guidelines for picking the defaults avoids
arguments and breakage.

The two basic rules I've seen are that we either follow the defaults
the hardware has after reset or we follow the state the hardware is left
in when the kernel starts.  Neither is perfect and sometimes the
bootloader option just doesn't make sense at all but they're at least
clear and simple to understand.

It's not the end of the world to do something else, and sometimes the
way systems are done just doesn't lend itself to providing clear rules,
but if we encourage people to set them they can save grief.

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[RFC PATCH for Juno 2/2] tty: SBSA compatible UART

[Hanjun Guo]

From: Graeme Gregory <graeme.gregory@linaro.org>

This is a subset of pl011 UART which does not supprt DMA or baud rate
changing.

It is specified in the Server Base System Architecture document from
ARM.

Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
---
 drivers/tty/Kconfig    |    6 +
 drivers/tty/Makefile   |    1 +
 drivers/tty/sbsauart.c |  328 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 335 insertions(+)
 create mode 100644 drivers/tty/sbsauart.c

diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index b24aa01..50fe279 100644
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -419,4 +419,10 @@ config DA_CONSOLE
 	help
 	  This enables a console on a Dash channel.
 
+config SBSAUART_TTY
+	tristate "SBSA UART TTY Driver"
+	help
+	  Console and system TTY driver for the SBSA UART which is defined
+	  in the Server Base System Architecure document for ARM64 servers.
+
 endif # TTY
diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile
index 58ad1c0..c3211c0 100644
--- a/drivers/tty/Makefile
+++ b/drivers/tty/Makefile
@@ -29,5 +29,6 @@ obj-$(CONFIG_SYNCLINK)		+= synclink.o
 obj-$(CONFIG_PPC_EPAPR_HV_BYTECHAN) += ehv_bytechan.o
 obj-$(CONFIG_GOLDFISH_TTY)	+= goldfish.o
 obj-$(CONFIG_DA_TTY)		+= metag_da.o
+obj-$(CONFIG_SBSAUART_TTY)	+= sbsauart.o
 
 obj-y += ipwireless/
diff --git a/drivers/tty/sbsauart.c b/drivers/tty/sbsauart.c
new file mode 100644
index 0000000..3a3ff88
--- /dev/null
+++ b/drivers/tty/sbsauart.c
@@ -0,0 +1,328 @@
+/*
+ * SBSA (Server Base System Architecture) Compatible UART driver
+ *
+ * Copyright (C) 2014 Linaro Ltd
+ *
+ * Author: Graeme Gregory <graeme.gregory@linaro.org>
+ *
+ * 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/acpi.h>
+#include <linux/amba/serial.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+
+struct sbsa_tty {
+	struct tty_port port;
+	spinlock_t lock;
+	void __iomem *base;
+	u32 irq;
+	int opencount;
+	struct console console;
+};
+
+static struct tty_driver *sbsa_tty_driver;
+static struct sbsa_tty *sbsa_tty;
+
+#define SBSAUART_CHAR_MASK	0xFF
+
+static void sbsa_tty_do_write(const char *buf, unsigned count)
+{
+	unsigned long irq_flags;
+	struct sbsa_tty *qtty = sbsa_tty;
+	void __iomem *base = qtty->base;
+	unsigned n;
+
+	spin_lock_irqsave(&qtty->lock, irq_flags);
+	for (n = 0; n < count; n++) {
+		while (readw(base + UART01x_FR) & UART01x_FR_TXFF)
+			mdelay(10);
+		writew(buf[n], base + UART01x_DR);
+	}
+	spin_unlock_irqrestore(&qtty->lock, irq_flags);
+}
+
+static void sbsauart_fifo_to_tty(struct sbsa_tty *qtty)
+{
+	void __iomem *base = qtty->base;
+	unsigned int flag, max_count = 32;
+	u16 status, ch;
+
+	while (max_count--) {
+		status = readw(base + UART01x_FR);
+		if (status & UART01x_FR_RXFE)
+			break;
+
+		/* Take chars from the FIFO and update status */
+		ch = readw(base + UART01x_DR);
+		flag = TTY_NORMAL;
+
+		if (ch & UART011_DR_BE)
+			flag = TTY_BREAK;
+		else if (ch & UART011_DR_PE)
+			flag = TTY_PARITY;
+		else if (ch & UART011_DR_FE)
+			flag = TTY_FRAME;
+		else if (ch & UART011_DR_OE)
+			flag = TTY_OVERRUN;
+
+		ch &= SBSAUART_CHAR_MASK;
+
+		tty_insert_flip_char(&qtty->port, ch, flag);
+	}
+
+	tty_schedule_flip(&qtty->port);
+
+	/* Clear the RX IRQ */
+	writew(UART011_RXIC | UART011_RXIC, base + UART011_ICR);
+}
+
+static irqreturn_t sbsa_tty_interrupt(int irq, void *dev_id)
+{
+	struct sbsa_tty *qtty = sbsa_tty;
+	unsigned long irq_flags;
+
+	spin_lock_irqsave(&qtty->lock, irq_flags);
+	sbsauart_fifo_to_tty(qtty);
+	spin_unlock_irqrestore(&qtty->lock, irq_flags);
+
+	return IRQ_HANDLED;
+}
+
+static int sbsa_tty_open(struct tty_struct *tty, struct file *filp)
+{
+	struct sbsa_tty *qtty = sbsa_tty;
+
+	return tty_port_open(&qtty->port, tty, filp);
+}
+
+static void sbsa_tty_close(struct tty_struct *tty, struct file *filp)
+{
+	tty_port_close(tty->port, tty, filp);
+}
+
+static void sbsa_tty_hangup(struct tty_struct *tty)
+{
+	tty_port_hangup(tty->port);
+}
+
+static int sbsa_tty_write(struct tty_struct *tty, const unsigned char *buf,
+								int count)
+{
+	sbsa_tty_do_write(buf, count);
+	return count;
+}
+
+static int sbsa_tty_write_room(struct tty_struct *tty)
+{
+	return 32;
+}
+
+static void sbsa_tty_console_write(struct console *co, const char *b,
+								unsigned count)
+{
+	sbsa_tty_do_write(b, count);
+	
+	if(b[count - 1] == '\n');
+		sbsa_tty_do_write("\r", 1);
+}
+
+static struct tty_driver *sbsa_tty_console_device(struct console *c,
+								int *index)
+{
+	*index = c->index;
+	return sbsa_tty_driver;
+}
+
+static int sbsa_tty_console_setup(struct console *co, char *options)
+{
+	if ((unsigned)co->index > 0)
+		return -ENODEV;
+	if (sbsa_tty->base == NULL)
+		return -ENODEV;
+	return 0;
+}
+
+static struct tty_port_operations sbsa_port_ops = {
+};
+
+static const struct tty_operations sbsa_tty_ops = {
+	.open = sbsa_tty_open,
+	.close = sbsa_tty_close,
+	.hangup = sbsa_tty_hangup,
+	.write = sbsa_tty_write,
+	.write_room = sbsa_tty_write_room,
+};
+
+static int sbsa_tty_create_driver(void)
+{
+	int ret;
+	struct tty_driver *tty;
+
+	sbsa_tty = kzalloc(sizeof(*sbsa_tty), GFP_KERNEL);
+	if (sbsa_tty == NULL) {
+		ret = -ENOMEM;
+		goto err_alloc_sbsa_tty_failed;
+	}
+	tty = alloc_tty_driver(1);
+	if (tty == NULL) {
+		ret = -ENOMEM;
+		goto err_alloc_tty_driver_failed;
+	}
+	tty->driver_name = "sbsauart";
+	tty->name = "ttySBSA";
+	tty->type = TTY_DRIVER_TYPE_SERIAL;
+	tty->subtype = SERIAL_TYPE_NORMAL;
+	tty->init_termios = tty_std_termios;
+	tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
+						TTY_DRIVER_DYNAMIC_DEV;
+	tty_set_operations(tty, &sbsa_tty_ops);
+	ret = tty_register_driver(tty);
+	if (ret)
+		goto err_tty_register_driver_failed;
+
+	sbsa_tty_driver = tty;
+	return 0;
+
+err_tty_register_driver_failed:
+	put_tty_driver(tty);
+err_alloc_tty_driver_failed:
+	kfree(sbsa_tty);
+	sbsa_tty = NULL;
+err_alloc_sbsa_tty_failed:
+	return ret;
+}
+
+static void sbsa_tty_delete_driver(void)
+{
+	tty_unregister_driver(sbsa_tty_driver);
+	put_tty_driver(sbsa_tty_driver);
+	sbsa_tty_driver = NULL;
+	kfree(sbsa_tty);
+	sbsa_tty = NULL;
+}
+
+static int sbsa_tty_probe(struct platform_device *pdev)
+{
+	struct sbsa_tty *qtty;
+	int ret = -EINVAL;
+	int i;
+	struct resource *r;
+	struct device *ttydev;
+	void __iomem *base;
+	u32 irq;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (r == NULL)
+		return -EINVAL;
+
+	base = ioremap(r->start, r->end - r->start);
+	if (base == NULL)
+		pr_err("sbsa_tty: unable to remap base\n");
+
+	r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (r == NULL)
+		goto err_unmap;
+
+	irq = r->start;
+
+	if (pdev->id > 0)
+		goto err_unmap;
+
+	ret = sbsa_tty_create_driver();
+	if (ret)
+		goto err_unmap;
+
+	qtty = sbsa_tty;
+	spin_lock_init(&qtty->lock);
+	tty_port_init(&qtty->port);
+	qtty->port.ops = &sbsa_port_ops;
+	qtty->base = base;
+	qtty->irq = irq;
+
+	/* Clear and Mask all IRQs */
+	writew(0, base + UART011_IMSC);
+	writew(0xFFFF, base + UART011_ICR);
+
+	ret = request_irq(irq, sbsa_tty_interrupt, IRQF_SHARED,
+						"sbsa_tty", pdev);
+	if (ret)
+		goto err_request_irq_failed;
+
+	/* Unmask the RX IRQ */
+	writew(UART011_RXIM | UART011_RTIM, base + UART011_IMSC);
+
+	ttydev = tty_port_register_device(&qtty->port, sbsa_tty_driver,
+							0, &pdev->dev);
+	if (IS_ERR(ttydev)) {
+		ret = PTR_ERR(ttydev);
+		goto err_tty_register_device_failed;
+	}
+
+	strcpy(qtty->console.name, "ttySBSA");
+	qtty->console.write = sbsa_tty_console_write;
+	qtty->console.device = sbsa_tty_console_device;
+	qtty->console.setup = sbsa_tty_console_setup;
+	qtty->console.flags = CON_PRINTBUFFER;
+	qtty->console.index = pdev->id;
+	register_console(&qtty->console);
+
+	return 0;
+
+	tty_unregister_device(sbsa_tty_driver, i);
+err_tty_register_device_failed:
+	free_irq(irq, pdev);
+err_request_irq_failed:
+	sbsa_tty_delete_driver();
+err_unmap:
+	iounmap(base);
+	return ret;
+}
+
+static int sbsa_tty_remove(struct platform_device *pdev)
+{
+	struct sbsa_tty *qtty;
+
+	qtty = sbsa_tty;
+	unregister_console(&qtty->console);
+	tty_unregister_device(sbsa_tty_driver, pdev->id);
+	iounmap(qtty->base);
+	qtty->base = 0;
+	free_irq(qtty->irq, pdev);
+	sbsa_tty_delete_driver();
+	return 0;
+}
+
+static const struct acpi_device_id sbsa_acpi_match[] = {
+	{ "ARMH0011", 0 },
+	{ }
+};
+
+static struct platform_driver sbsa_tty_platform_driver = {
+	.probe = sbsa_tty_probe,
+	.remove = sbsa_tty_remove,
+	.driver = {
+		.name = "sbsa_tty",
+		.acpi_match_table = ACPI_PTR(sbsa_acpi_match),
+	}
+};
+
+module_platform_driver(sbsa_tty_platform_driver);
+
+MODULE_LICENSE("GPL v2");
-- 
1.7.9.5

Re: [RFC PATCH for Juno 2/2] tty: SBSA compatible UART

[Mark Brown]

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On Mon, Sep 01, 2014 at 11:06:01PM +0800, Hanjun Guo wrote:
> From: Graeme Gregory <graeme.gregory@linaro.org>
> 
> This is a subset of pl011 UART which does not supprt DMA or baud rate
> changing.
> 
> It is specified in the Server Base System Architecture document from
> ARM.

Is there any reason not to consider submitting this as a TTY driver now
- are there known problems other than the issues with ACPI in general
(I've not reviewed the code at all)?  The ACPI binding in this case
seems particularly safe since it's a purposely basic and unconfigurable
IP.

I guess we may want to consider handoff to the full pl011 driver at some
point but there's a bunch of stuff with clocks to worry about before
then.

> 
> Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
> ---

Missing signoff here.

> +config SBSAUART_TTY
> +	tristate "SBSA UART TTY Driver"
> +	help
> +	  Console and system TTY driver for the SBSA UART which is defined
> +	  in the Server Base System Architecure document for ARM64 servers.
> +

depends on ARM || ARM64 || COMPILE_TEST?

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Re: [RFC PATCH for Juno 2/2] tty: SBSA compatible UART

[Catalin Marinas]

On Mon, Sep 01, 2014 at 04:06:01PM +0100, Hanjun Guo wrote:
> From: Graeme Gregory <graeme.gregory@linaro.org>
> 
> This is a subset of pl011 UART which does not supprt DMA or baud rate
> changing.
> 
> It is specified in the Server Base System Architecture document from
> ARM.
> 
> Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
> ---
>  drivers/tty/Kconfig    |    6 +
>  drivers/tty/Makefile   |    1 +
>  drivers/tty/sbsauart.c |  328 ++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 335 insertions(+)
>  create mode 100644 drivers/tty/sbsauart.c

Any overlap with this?

http://www.spinics.net/lists/arm-kernel/msg358084.html

-- 
Catalin

Re: [RFC PATCH for Juno 2/2] tty: SBSA compatible UART

[Graeme Gregory]

On Mon, Sep 01, 2014 at 06:12:48PM +0100, Catalin Marinas wrote:
> On Mon, Sep 01, 2014 at 04:06:01PM +0100, Hanjun Guo wrote:
> > From: Graeme Gregory <graeme.gregory@linaro.org>
> > 
> > This is a subset of pl011 UART which does not supprt DMA or baud rate
> > changing.
> > 
> > It is specified in the Server Base System Architecture document from
> > ARM.
> > 
> > Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
> > ---
> >  drivers/tty/Kconfig    |    6 +
> >  drivers/tty/Makefile   |    1 +
> >  drivers/tty/sbsauart.c |  328 ++++++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 335 insertions(+)
> >  create mode 100644 drivers/tty/sbsauart.c
> 
> Any overlap with this?
> 
> http://www.spinics.net/lists/arm-kernel/msg358084.html
> 
I knew that driver was being developed and is why we specifically said
we did not plan to upstream this in preference for ARMs version.

I just missed the release of this 2 days ago.

Graeme

Re: [RFC PATCH for Juno 2/2] tty: SBSA compatible UART

[Catalin Marinas]

On Mon, Sep 01, 2014 at 06:18:56PM +0100, Graeme Gregory wrote:
> On Mon, Sep 01, 2014 at 06:12:48PM +0100, Catalin Marinas wrote:
> > On Mon, Sep 01, 2014 at 04:06:01PM +0100, Hanjun Guo wrote:
> > > From: Graeme Gregory <graeme.gregory@linaro.org>
> > > 
> > > This is a subset of pl011 UART which does not supprt DMA or baud rate
> > > changing.
> > > 
> > > It is specified in the Server Base System Architecture document from
> > > ARM.
> > > 
> > > Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
> > > ---
> > >  drivers/tty/Kconfig    |    6 +
> > >  drivers/tty/Makefile   |    1 +
> > >  drivers/tty/sbsauart.c |  328 ++++++++++++++++++++++++++++++++++++++++++++++++
> > >  3 files changed, 335 insertions(+)
> > >  create mode 100644 drivers/tty/sbsauart.c
> > 
> > Any overlap with this?
> > 
> > http://www.spinics.net/lists/arm-kernel/msg358084.html
> > 
> I knew that driver was being developed and is why we specifically said
> we did not plan to upstream this in preference for ARMs version.
> 
> I just missed the release of this 2 days ago.

Thanks. Please give feedback to Andre when you had the chance to look at
it.

-- 
Catalin

Re: [RFC PATCH for Juno 0/2] Drivers for Juno to boot from ACPI

[Arnd Bergmann]

On Monday 01 September 2014 23:05:59 Hanjun Guo wrote:
> This patch set is example of the sort of driver changes needed to boot
> Juno using ACPI tables, which using the ACPI tables devloped for MS
> Windows and published by ARM [1].

What about platform support?

I see that there is a patch in your git tree at
https://git.linaro.org/leg/acpi/acpi.git/commitdiff/b9a635e3b4cb167d399
that exposes the raw system registers in the same way that the DT support
does, which I guess is not how you plan to do it for ACPI when you are
done.

Is that still work in progress? How do you plan to abstract things
like the hwmon, LEDs, GPIO etc that are handled through the
sysregs in hardware?

	Arnd