[v2,1/5] ARM: memory: da8xx-ddrctl: new driver

Commit Message

Sekhar Nori Nov. 21, 2016, 4:33 p.m. UTC

On Monday 31 October 2016 08:15 PM, Bartosz Golaszewski wrote:
> +static int da8xx_ddrctl_probe(struct platform_device *pdev)
> +{
> +	const struct da8xx_ddrctl_config_knob *knob;
> +	const struct da8xx_ddrctl_setting *setting;
> +	struct device_node *node;
> +	struct resource *res;
> +	void __iomem *ddrctl;
> +	struct device *dev;
> +	u32 reg;
> +
> +	dev = &pdev->dev;
> +	node = dev->of_node;
> +
> +	setting = da8xx_ddrctl_get_board_settings();
> +	if (!setting) {
> +		dev_err(dev, "no settings for board '%s'\n",
> +			of_flat_dt_get_machine_name());
> +		return -EINVAL;
> +	}

This causes a section mismatch because of_flat_dt_get_machine_name() 
has an __init annotation. I did not notice that before, sorry.

It can be fixed with a patch like below:

---8<---
A similar fix is required for the other driver in this series (patch 
2/5). I need some advise on whether I should introduce a common 
function to get the machine name post kernel boot-up (I cannot see an 
existing one). If yes, any advise on which file it should go into?

Thanks,
Sekhar

Comments

Bartosz Golaszewski Nov. 21, 2016, 4:48 p.m. UTC | #1

2016-11-21 17:33 GMT+01:00 Sekhar Nori <[e-mail]>:
> On Monday 31 October 2016 08:15 PM, Bartosz Golaszewski wrote:
>> +static int da8xx_ddrctl_probe(struct platform_device *pdev)
>> +{
>> +     const struct da8xx_ddrctl_config_knob *knob;
>> +     const struct da8xx_ddrctl_setting *setting;
>> +     struct device_node *node;
>> +     struct resource *res;
>> +     void __iomem *ddrctl;
>> +     struct device *dev;
>> +     u32 reg;
>> +
>> +     dev = &pdev->dev;
>> +     node = dev->of_node;
>> +
>> +     setting = da8xx_ddrctl_get_board_settings();
>> +     if (!setting) {
>> +             dev_err(dev, "no settings for board '%s'\n",
>> +                     of_flat_dt_get_machine_name());
>> +             return -EINVAL;
>> +     }
>
> This causes a section mismatch because of_flat_dt_get_machine_name()
> has an __init annotation. I did not notice that before, sorry.
>
> It can be fixed with a patch like below:
>
> ---8<---
> diff --git a/drivers/memory/da8xx-ddrctl.c b/drivers/memory/da8xx-ddrctl.c
> index a20e7bbbcbe0..9ca5aab3ac54 100644
> --- a/drivers/memory/da8xx-ddrctl.c
> +++ b/drivers/memory/da8xx-ddrctl.c
> @@ -102,6 +102,18 @@ static const struct da8xx_ddrctl_setting *da8xx_ddrctl_get_board_settings(void)
>         return NULL;
>  }
>
> +static const char* da8xx_ddrctl_get_machine_name(void)
> +{
> +       const char *str;
> +       int ret;
> +
> +       ret = of_property_read_string(of_root, "model", &str);
> +       if (ret)
> +               ret = of_property_read_string(of_root, "compatible", &str);
> +
> +       return str;
> +}
> +
>  static int da8xx_ddrctl_probe(struct platform_device *pdev)
>  {
>         const struct da8xx_ddrctl_config_knob *knob;
> @@ -118,7 +130,7 @@ static int da8xx_ddrctl_probe(struct platform_device *pdev)
>         setting = da8xx_ddrctl_get_board_settings();
>         if (!setting) {
>                 dev_err(dev, "no settings for board '%s'\n",
> -                       of_flat_dt_get_machine_name());
> +                       da8xx_ddrctl_get_machine_name());
>                 return -EINVAL;
>         }
> ---8<---
>
> A similar fix is required for the other driver in this series (patch
> 2/5). I need some advise on whether I should introduce a common
> function to get the machine name post kernel boot-up (I cannot see an
> existing one). If yes, any advise on which file it should go into?
>

Hi Sekhar,

thanks for spotting that.

I think we should introduce this function right away, rather than
having two static functions doing the same thing. If you don't mind,
I'll try to find a good spot for it and send a follow-up series fixing
the issue.

Best regards,
Bartosz Golaszewski

Robin Murphy Nov. 21, 2016, 5:47 p.m. UTC | #2

Hi Bartosz, Sekhar,

On 21/11/16 16:48, Bartosz Golaszewski wrote:
> 2016-11-21 17:33 GMT+01:00 Sekhar Nori <[e-mail]>:
>> On Monday 31 October 2016 08:15 PM, Bartosz Golaszewski wrote:
>>> +static int da8xx_ddrctl_probe(struct platform_device *pdev)
>>> +{
>>> +     const struct da8xx_ddrctl_config_knob *knob;
>>> +     const struct da8xx_ddrctl_setting *setting;
>>> +     struct device_node *node;
>>> +     struct resource *res;
>>> +     void __iomem *ddrctl;
>>> +     struct device *dev;
>>> +     u32 reg;
>>> +
>>> +     dev = &pdev->dev;
>>> +     node = dev->of_node;
>>> +
>>> +     setting = da8xx_ddrctl_get_board_settings();
>>> +     if (!setting) {
>>> +             dev_err(dev, "no settings for board '%s'\n",
>>> +                     of_flat_dt_get_machine_name());
>>> +             return -EINVAL;
>>> +     }
>>
>> This causes a section mismatch because of_flat_dt_get_machine_name()
>> has an __init annotation. I did not notice that before, sorry.
>>
>> It can be fixed with a patch like below:
>>
>> ---8<---
>> diff --git a/drivers/memory/da8xx-ddrctl.c b/drivers/memory/da8xx-ddrctl.c
>> index a20e7bbbcbe0..9ca5aab3ac54 100644
>> --- a/drivers/memory/da8xx-ddrctl.c
>> +++ b/drivers/memory/da8xx-ddrctl.c
>> @@ -102,6 +102,18 @@ static const struct da8xx_ddrctl_setting *da8xx_ddrctl_get_board_settings(void)
>>         return NULL;
>>  }
>>
>> +static const char* da8xx_ddrctl_get_machine_name(void)
>> +{
>> +       const char *str;
>> +       int ret;
>> +
>> +       ret = of_property_read_string(of_root, "model", &str);
>> +       if (ret)
>> +               ret = of_property_read_string(of_root, "compatible", &str);
>> +
>> +       return str;
>> +}
>> +
>>  static int da8xx_ddrctl_probe(struct platform_device *pdev)
>>  {
>>         const struct da8xx_ddrctl_config_knob *knob;
>> @@ -118,7 +130,7 @@ static int da8xx_ddrctl_probe(struct platform_device *pdev)
>>         setting = da8xx_ddrctl_get_board_settings();
>>         if (!setting) {
>>                 dev_err(dev, "no settings for board '%s'\n",
>> -                       of_flat_dt_get_machine_name());
>> +                       da8xx_ddrctl_get_machine_name());
>>                 return -EINVAL;
>>         }
>> ---8<---
>>
>> A similar fix is required for the other driver in this series (patch
>> 2/5). I need some advise on whether I should introduce a common
>> function to get the machine name post kernel boot-up (I cannot see an
>> existing one). If yes, any advise on which file it should go into?
>>
> 
> Hi Sekhar,
> 
> thanks for spotting that.
> 
> I think we should introduce this function right away, rather than
> having two static functions doing the same thing. If you don't mind,
> I'll try to find a good spot for it and send a follow-up series fixing
> the issue.

As it happens, that was already proposed last week, for much the same
reason:

http://www.mail-archive.com/[e-mail]/msg111395.html

Robin.

> 
> Best regards,
> Bartosz Golaszewski
> 
> _______________________________________________
> linux-arm-kernel mailing list
> [e-mail]
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>

Sudeep Holla Nov. 21, 2016, 5:56 p.m. UTC | #3

Hi Robin,

On 21/11/16 17:47, Robin Murphy wrote:
> Hi Bartosz, Sekhar,
>
> On 21/11/16 16:48, Bartosz Golaszewski wrote:

[...]

>> Hi Sekhar,
>>
>> thanks for spotting that.
>>
>> I think we should introduce this function right away, rather than
>> having two static functions doing the same thing. If you don't mind,
>> I'll try to find a good spot for it and send a follow-up series fixing
>> the issue.
>
> As it happens, that was already proposed last week, for much the same
> reason:
>
> http://www.mail-archive.com/[e-mail]/msg111395.html
>

Thanks for pointing this out, yet another platform to move to the new
API after v4.10.

Hi Shekar, Bartosz,

For v4.10, please continue with the open coding as proposed in this
thread in order to avoid cross tree dependencies. I will rework on the
above patch once v4.10 merge window closes to include all these
occurrence and replace them.

Frank Rowand Nov. 22, 2016, 1:43 a.m. UTC | #4

Hi Sekhar,

(And adding Sudeep since he becomes involved in this further
down thread and at that point says he will re-work this
proposed work around in a manner that is incorrect in a
manner that is similar to this proposed work around.)

On 11/21/16 08:33, Sekhar Nori wrote:
> On Monday 31 October 2016 08:15 PM, Bartosz Golaszewski wrote:
>> +static int da8xx_ddrctl_probe(struct platform_device *pdev)
>> +{
>> +	const struct da8xx_ddrctl_config_knob *knob;
>> +	const struct da8xx_ddrctl_setting *setting;
>> +	struct device_node *node;
>> +	struct resource *res;
>> +	void __iomem *ddrctl;
>> +	struct device *dev;
>> +	u32 reg;
>> +
>> +	dev = &pdev->dev;
>> +	node = dev->of_node;
>> +
>> +	setting = da8xx_ddrctl_get_board_settings();
>> +	if (!setting) {
>> +		dev_err(dev, "no settings for board '%s'\n",
>> +			of_flat_dt_get_machine_name());
>> +		return -EINVAL;
>> +	}
> 
> This causes a section mismatch because of_flat_dt_get_machine_name() 
> has an __init annotation. I did not notice that before, sorry.
> 
> It can be fixed with a patch like below:
> 
> ---8<---
> diff --git a/drivers/memory/da8xx-ddrctl.c b/drivers/memory/da8xx-ddrctl.c
> index a20e7bbbcbe0..9ca5aab3ac54 100644
> --- a/drivers/memory/da8xx-ddrctl.c
> +++ b/drivers/memory/da8xx-ddrctl.c
> @@ -102,6 +102,18 @@ static const struct da8xx_ddrctl_setting *da8xx_ddrctl_get_board_settings(void)
>  	return NULL;
>  }
>  
> +static const char* da8xx_ddrctl_get_machine_name(void)
> +{
> +	const char *str;
> +	int ret;
> +
> +	ret = of_property_read_string(of_root, "model", &str);
> +	if (ret)
> +		ret = of_property_read_string(of_root, "compatible", &str);
> +
> +	return str;
> +}
> +
>  static int da8xx_ddrctl_probe(struct platform_device *pdev)
>  {
>  	const struct da8xx_ddrctl_config_knob *knob;
> @@ -118,7 +130,7 @@ static int da8xx_ddrctl_probe(struct platform_device *pdev)
>  	setting = da8xx_ddrctl_get_board_settings();
>  	if (!setting) {
>  		dev_err(dev, "no settings for board '%s'\n",
> -			of_flat_dt_get_machine_name());

da8xx_ddrctl_get_board_settings() tries to match based on the "compatible"
property in the root node.  The "model" property in the root node has
nothing to do with the failure to match. So creating and then using
da8xx_ddrctl_get_machine_name() to potentially report model is not useful.

It should be sufficient to simply report that no compatible matched.


> +			da8xx_ddrctl_get_machine_name());
>  		return -EINVAL;
>  	}
> ---8<--- 
> 
> A similar fix is required for the other driver in this series (patch 
> 2/5). I need some advise on whether I should introduce a common 
> function to get the machine name post kernel boot-up (I cannot see an 
> existing one). If yes, any advise on which file it should go into?
> 
> Thanks,
> Sekhar
> 
>

Sekhar Nori Nov. 22, 2016, 6:25 a.m. UTC | #5

Hi Frank,

On Tuesday 22 November 2016 07:13 AM, Frank Rowand wrote:
> On 11/21/16 08:33, Sekhar Nori wrote:
>> On Monday 31 October 2016 08:15 PM, Bartosz Golaszewski wrote:
>>> +static int da8xx_ddrctl_probe(struct platform_device *pdev)
>>> +{
>>> +	const struct da8xx_ddrctl_config_knob *knob;
>>> +	const struct da8xx_ddrctl_setting *setting;
>>> +	struct device_node *node;
>>> +	struct resource *res;
>>> +	void __iomem *ddrctl;
>>> +	struct device *dev;
>>> +	u32 reg;
>>> +
>>> +	dev = &pdev->dev;
>>> +	node = dev->of_node;
>>> +
>>> +	setting = da8xx_ddrctl_get_board_settings();
>>> +	if (!setting) {
>>> +		dev_err(dev, "no settings for board '%s'\n",
>>> +			of_flat_dt_get_machine_name());
>>> +		return -EINVAL;
>>> +	}
>>
>> This causes a section mismatch because of_flat_dt_get_machine_name() 
>> has an __init annotation. I did not notice that before, sorry.
>>
>> It can be fixed with a patch like below:
>>
>> ---8<---
>> diff --git a/drivers/memory/da8xx-ddrctl.c b/drivers/memory/da8xx-ddrctl.c
>> index a20e7bbbcbe0..9ca5aab3ac54 100644
>> --- a/drivers/memory/da8xx-ddrctl.c
>> +++ b/drivers/memory/da8xx-ddrctl.c
>> @@ -102,6 +102,18 @@ static const struct da8xx_ddrctl_setting *da8xx_ddrctl_get_board_settings(void)
>>  	return NULL;
>>  }
>>  
>> +static const char* da8xx_ddrctl_get_machine_name(void)
>> +{
>> +	const char *str;
>> +	int ret;
>> +
>> +	ret = of_property_read_string(of_root, "model", &str);
>> +	if (ret)
>> +		ret = of_property_read_string(of_root, "compatible", &str);
>> +
>> +	return str;
>> +}
>> +
>>  static int da8xx_ddrctl_probe(struct platform_device *pdev)
>>  {
>>  	const struct da8xx_ddrctl_config_knob *knob;
>> @@ -118,7 +130,7 @@ static int da8xx_ddrctl_probe(struct platform_device *pdev)
>>  	setting = da8xx_ddrctl_get_board_settings();
>>  	if (!setting) {
>>  		dev_err(dev, "no settings for board '%s'\n",
>> -			of_flat_dt_get_machine_name());
> 
> da8xx_ddrctl_get_board_settings() tries to match based on the "compatible"
> property in the root node.  The "model" property in the root node has
> nothing to do with the failure to match. So creating and then using
> da8xx_ddrctl_get_machine_name() to potentially report model is not useful.
> 
> It should be sufficient to simply report that no compatible matched.

I agree with you on this. Even if model name is printed, you will have
to go back and check the compatible anyway. But I think it will be
useful to print the compatible instead of just reporting that nothing
matched.

Bartosz, if you agree too, could you send a fix patch just printing the
compatible?

Thanks,
Sekhar

Frank Rowand Nov. 22, 2016, 6:21 p.m. UTC | #6

On 11/21/16 22:25, Sekhar Nori wrote:
> Hi Frank,
> 
> On Tuesday 22 November 2016 07:13 AM, Frank Rowand wrote:
>> On 11/21/16 08:33, Sekhar Nori wrote:
>>> On Monday 31 October 2016 08:15 PM, Bartosz Golaszewski wrote:
>>>> +static int da8xx_ddrctl_probe(struct platform_device *pdev)
>>>> +{
>>>> +	const struct da8xx_ddrctl_config_knob *knob;
>>>> +	const struct da8xx_ddrctl_setting *setting;
>>>> +	struct device_node *node;
>>>> +	struct resource *res;
>>>> +	void __iomem *ddrctl;
>>>> +	struct device *dev;
>>>> +	u32 reg;
>>>> +
>>>> +	dev = &pdev->dev;
>>>> +	node = dev->of_node;
>>>> +
>>>> +	setting = da8xx_ddrctl_get_board_settings();
>>>> +	if (!setting) {
>>>> +		dev_err(dev, "no settings for board '%s'\n",
>>>> +			of_flat_dt_get_machine_name());
>>>> +		return -EINVAL;
>>>> +	}
>>>
>>> This causes a section mismatch because of_flat_dt_get_machine_name() 
>>> has an __init annotation. I did not notice that before, sorry.
>>>
>>> It can be fixed with a patch like below:
>>>
>>> ---8<---
>>> diff --git a/drivers/memory/da8xx-ddrctl.c b/drivers/memory/da8xx-ddrctl.c
>>> index a20e7bbbcbe0..9ca5aab3ac54 100644
>>> --- a/drivers/memory/da8xx-ddrctl.c
>>> +++ b/drivers/memory/da8xx-ddrctl.c
>>> @@ -102,6 +102,18 @@ static const struct da8xx_ddrctl_setting *da8xx_ddrctl_get_board_settings(void)
>>>  	return NULL;
>>>  }
>>>  
>>> +static const char* da8xx_ddrctl_get_machine_name(void)
>>> +{
>>> +	const char *str;
>>> +	int ret;
>>> +
>>> +	ret = of_property_read_string(of_root, "model", &str);
>>> +	if (ret)
>>> +		ret = of_property_read_string(of_root, "compatible", &str);
>>> +
>>> +	return str;
>>> +}
>>> +
>>>  static int da8xx_ddrctl_probe(struct platform_device *pdev)
>>>  {
>>>  	const struct da8xx_ddrctl_config_knob *knob;
>>> @@ -118,7 +130,7 @@ static int da8xx_ddrctl_probe(struct platform_device *pdev)
>>>  	setting = da8xx_ddrctl_get_board_settings();
>>>  	if (!setting) {
>>>  		dev_err(dev, "no settings for board '%s'\n",
>>> -			of_flat_dt_get_machine_name());
>>
>> da8xx_ddrctl_get_board_settings() tries to match based on the "compatible"
>> property in the root node.  The "model" property in the root node has
>> nothing to do with the failure to match. So creating and then using
>> da8xx_ddrctl_get_machine_name() to potentially report model is not useful.
>>
>> It should be sufficient to simply report that no compatible matched.
> 
> I agree with you on this. Even if model name is printed, you will have
> to go back and check the compatible anyway. But I think it will be
> useful to print the compatible instead of just reporting that nothing
> matched.
> 
> Bartosz, if you agree too, could you send a fix patch just printing the
> compatible?

Please note that the compatible property might contain several strings, not just
a single string.

> 
> Thanks,
> Sekhar
>

Sekhar Nori Nov. 23, 2016, 5:55 a.m. UTC | #7

On Tuesday 22 November 2016 11:51 PM, Frank Rowand wrote:
> Please note that the compatible property might contain several strings, not just
> a single string.

So I guess the best thing to do is to use
of_property_read_string_index() and print the sting at index 0.

Thanks,
Sekhar

Sudeep Holla Nov. 23, 2016, 10:16 a.m. UTC | #8

On 22/11/16 01:43, Frank Rowand wrote:
> Hi Sekhar,
>
> (And adding Sudeep since he becomes involved in this further
> down thread and at that point says he will re-work this
> proposed work around in a manner that is incorrect in a
> manner that is similar to this proposed work around.)
>
> On 11/21/16 08:33, Sekhar Nori wrote:


[...]

>>  static int da8xx_ddrctl_probe(struct platform_device *pdev)
>>  {
>>  	const struct da8xx_ddrctl_config_knob *knob;
>> @@ -118,7 +130,7 @@ static int da8xx_ddrctl_probe(struct platform_device *pdev)
>>  	setting = da8xx_ddrctl_get_board_settings();
>>  	if (!setting) {
>>  		dev_err(dev, "no settings for board '%s'\n",
>> -			of_flat_dt_get_machine_name());
>
> da8xx_ddrctl_get_board_settings() tries to match based on the "compatible"
> property in the root node.  The "model" property in the root node has
> nothing to do with the failure to match. So creating and then using
> da8xx_ddrctl_get_machine_name() to potentially report model is not useful.
>
> It should be sufficient to simply report that no compatible matched.
>

Agreed.

Frank Rowand Nov. 23, 2016, 6:13 p.m. UTC | #9

On 11/22/16 21:55, Sekhar Nori wrote:
> On Tuesday 22 November 2016 11:51 PM, Frank Rowand wrote:
>> Please note that the compatible property might contain several strings, not just
>> a single string.
> 
> So I guess the best thing to do is to use
> of_property_read_string_index() and print the sting at index 0.
> 
> Thanks,
> Sekhar

If you want to print just one compatible value, you could use that method.

To give all of the information needed to understand the problem, the error
message would need to include all of the strings contained in the compatible
property and all of the .board values in the da8xx_ddrctl_board_confs[] array
(currently only one entry, but coded to allow additional entries in the
future).

It is hard to justify an error message that complex.

I would just print an error that no match was found.

-Frank

Frank Rowand Nov. 23, 2016, 6:23 p.m. UTC | #10

On 11/23/16 10:13, Frank Rowand wrote:
> On 11/22/16 21:55, Sekhar Nori wrote:
>> On Tuesday 22 November 2016 11:51 PM, Frank Rowand wrote:
>>> Please note that the compatible property might contain several strings, not just
>>> a single string.
>>
>> So I guess the best thing to do is to use
>> of_property_read_string_index() and print the sting at index 0.
>>
>> Thanks,
>> Sekhar
> 
> If you want to print just one compatible value, you could use that method.
> 
> To give all of the information needed to understand the problem, the error
> message would need to include all of the strings contained in the compatible
> property and all of the .board values in the da8xx_ddrctl_board_confs[] array
> (currently only one entry, but coded to allow additional entries in the
> future).
> 
> It is hard to justify an error message that complex.
> 
> I would just print an error that no match was found.
> 
> -Frank

I just needed to read some more emails.  I see this approach was taken
in the "[PATCH v4 0/2] da8xx: fix section mismatch in new drivers"
series.

-Frank

Patch

diff --git a/drivers/memory/da8xx-ddrctl.c b/drivers/memory/da8xx-ddrctl.c
index a20e7bbbcbe0..9ca5aab3ac54 100644
--- a/drivers/memory/da8xx-ddrctl.c
+++ b/drivers/memory/da8xx-ddrctl.c
@@ -102,6 +102,18 @@  static const struct da8xx_ddrctl_setting *da8xx_ddrctl_get_board_settings(void)
 	return NULL;
 }
 
+static const char* da8xx_ddrctl_get_machine_name(void)
+{
+	const char *str;
+	int ret;
+
+	ret = of_property_read_string(of_root, "model", &str);
+	if (ret)
+		ret = of_property_read_string(of_root, "compatible", &str);
+
+	return str;
+}
+
 static int da8xx_ddrctl_probe(struct platform_device *pdev)
 {
 	const struct da8xx_ddrctl_config_knob *knob;
@@ -118,7 +130,7 @@  static int da8xx_ddrctl_probe(struct platform_device *pdev)
 	setting = da8xx_ddrctl_get_board_settings();
 	if (!setting) {
 		dev_err(dev, "no settings for board '%s'\n",
-			of_flat_dt_get_machine_name());
+			da8xx_ddrctl_get_machine_name());
 		return -EINVAL;
 	}
---8<---