[PATCH v4] mfd: syscon: Add hardware spinlock support

[PATCH v4] mfd: syscon: Add hardware spinlock support

[Baolin Wang]

Some system control registers need hardware spinlock to synchronize
between the multiple subsystems, so we should add hardware spinlock
support for syscon.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
---
Changes since v3:
 - Add error handling for of_hwspin_lock_get_id()

Changes since v2:
 - Add acked tag from Rob.

Changes since v1:
 - Remove timeout configuration.
 - Modify the binding file to add hwlocks.
---
 Documentation/devicetree/bindings/mfd/syscon.txt |    1 +
 drivers/mfd/syscon.c                             |   21 +++++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt
index 8b92d45..f464cc8 100644
--- a/Documentation/devicetree/bindings/mfd/syscon.txt
+++ b/Documentation/devicetree/bindings/mfd/syscon.txt
@@ -16,6 +16,7 @@ Required properties:
 Optional property:
 - reg-io-width: the size (in bytes) of the IO accesses that should be
   performed on the device.
+- hwlocks: reference to a phandle of a hardware spinlock provider node.
 
 Examples:
 gpr: iomuxc-gpr@20e0000 {
diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
index b93fe4c..caf6a25 100644
--- a/drivers/mfd/syscon.c
+++ b/drivers/mfd/syscon.c
@@ -13,6 +13,7 @@
  */
 
 #include <linux/err.h>
+#include <linux/hwspinlock.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/list.h>
@@ -87,6 +88,26 @@ static struct syscon *of_syscon_register(struct device_node *np)
 	if (ret)
 		reg_io_width = 4;
 
+	ret = of_hwspin_lock_get_id(np, 0);
+	if (ret > 0) {
+		syscon_config.hwlock_id = ret;
+		syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
+	} else {
+		switch (ret) {
+		case -ENOENT:
+			/* ignore missing hwlock, it's optional */
+			break;
+		case 0:
+			ret = -EINVAL;
+			/* fall-through */
+		default:
+			pr_err("Failed to retrieve valid hwlock: %d\n", ret);
+			/* fall-through */
+		case -EPROBE_DEFER:
+			goto err_regmap;
+		}
+	}
+
 	syscon_config.reg_stride = reg_io_width;
 	syscon_config.val_bits = reg_io_width * 8;
 	syscon_config.max_register = resource_size(&res) - reg_io_width;
-- 
1.7.9.5

Re: [PATCH v4] mfd: syscon: Add hardware spinlock support

[Lee Jones]

On Thu, 30 Nov 2017, Baolin Wang wrote:

> Some system control registers need hardware spinlock to synchronize
> between the multiple subsystems, so we should add hardware spinlock
> support for syscon.
> 
> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
> Acked-by: Rob Herring <robh@kernel.org>
> ---
> Changes since v3:
>  - Add error handling for of_hwspin_lock_get_id()
> 
> Changes since v2:
>  - Add acked tag from Rob.
> 
> Changes since v1:
>  - Remove timeout configuration.
>  - Modify the binding file to add hwlocks.
> ---
>  Documentation/devicetree/bindings/mfd/syscon.txt |    1 +
>  drivers/mfd/syscon.c                             |   21 +++++++++++++++++++++
>  2 files changed, 22 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt
> index 8b92d45..f464cc8 100644
> --- a/Documentation/devicetree/bindings/mfd/syscon.txt
> +++ b/Documentation/devicetree/bindings/mfd/syscon.txt
> @@ -16,6 +16,7 @@ Required properties:
>  Optional property:
>  - reg-io-width: the size (in bytes) of the IO accesses that should be
>    performed on the device.
> +- hwlocks: reference to a phandle of a hardware spinlock provider node.

Example?

Perhaps even include the hwlock node (I'm not sure what that would
look like).

>  Examples:
>  gpr: iomuxc-gpr@20e0000 {
> diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
> index b93fe4c..caf6a25 100644
> --- a/drivers/mfd/syscon.c
> +++ b/drivers/mfd/syscon.c
> @@ -13,6 +13,7 @@
>   */
>  
>  #include <linux/err.h>
> +#include <linux/hwspinlock.h>
>  #include <linux/io.h>
>  #include <linux/module.h>
>  #include <linux/list.h>
> @@ -87,6 +88,26 @@ static struct syscon *of_syscon_register(struct device_node *np)
>  	if (ret)
>  		reg_io_width = 4;
>  
> +	ret = of_hwspin_lock_get_id(np, 0);
> +	if (ret > 0) {
> +		syscon_config.hwlock_id = ret;
> +		syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
> +	} else {
> +		switch (ret) {
> +		case -ENOENT:
> +			/* ignore missing hwlock, it's optional */

Is your shift key broken? ;)

Please use proper grammar.  Sentences start with capital letters.

> +			break;
> +		case 0:
> +			ret = -EINVAL;
> +			/* fall-through */
> +		default:
> +			pr_err("Failed to retrieve valid hwlock: %d\n", ret);
> +			/* fall-through */
> +		case -EPROBE_DEFER:
> +			goto err_regmap;
> +		}
> +	}
> +
>  	syscon_config.reg_stride = reg_io_width;
>  	syscon_config.val_bits = reg_io_width * 8;
>  	syscon_config.max_register = resource_size(&res) - reg_io_width;

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v4] mfd: syscon: Add hardware spinlock support

[Baolin Wang]

On 30 November 2017 at 16:35, Lee Jones <lee.jones@linaro.org> wrote:
> On Thu, 30 Nov 2017, Baolin Wang wrote:
>
>> Some system control registers need hardware spinlock to synchronize
>> between the multiple subsystems, so we should add hardware spinlock
>> support for syscon.
>>
>> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
>> Acked-by: Rob Herring <robh@kernel.org>
>> ---
>> Changes since v3:
>>  - Add error handling for of_hwspin_lock_get_id()
>>
>> Changes since v2:
>>  - Add acked tag from Rob.
>>
>> Changes since v1:
>>  - Remove timeout configuration.
>>  - Modify the binding file to add hwlocks.
>> ---
>>  Documentation/devicetree/bindings/mfd/syscon.txt |    1 +
>>  drivers/mfd/syscon.c                             |   21 +++++++++++++++++++++
>>  2 files changed, 22 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt
>> index 8b92d45..f464cc8 100644
>> --- a/Documentation/devicetree/bindings/mfd/syscon.txt
>> +++ b/Documentation/devicetree/bindings/mfd/syscon.txt
>> @@ -16,6 +16,7 @@ Required properties:
>>  Optional property:
>>  - reg-io-width: the size (in bytes) of the IO accesses that should be
>>    performed on the device.
>> +- hwlocks: reference to a phandle of a hardware spinlock provider node.
>
> Example?
>
> Perhaps even include the hwlock node (I'm not sure what that would
> look like).

Sure, I will add one example node here.

>
>>  Examples:
>>  gpr: iomuxc-gpr@20e0000 {
>> diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
>> index b93fe4c..caf6a25 100644
>> --- a/drivers/mfd/syscon.c
>> +++ b/drivers/mfd/syscon.c
>> @@ -13,6 +13,7 @@
>>   */
>>
>>  #include <linux/err.h>
>> +#include <linux/hwspinlock.h>
>>  #include <linux/io.h>
>>  #include <linux/module.h>
>>  #include <linux/list.h>
>> @@ -87,6 +88,26 @@ static struct syscon *of_syscon_register(struct device_node *np)
>>       if (ret)
>>               reg_io_width = 4;
>>
>> +     ret = of_hwspin_lock_get_id(np, 0);
>> +     if (ret > 0) {
>> +             syscon_config.hwlock_id = ret;
>> +             syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
>> +     } else {
>> +             switch (ret) {
>> +             case -ENOENT:
>> +                     /* ignore missing hwlock, it's optional */
>
> Is your shift key broken? ;)
>
> Please use proper grammar.  Sentences start with capital letters.

OK. Thanks for your comments.

-- 
Baolin.wang
Best Regards