[PATCH] reset: mchp: sparx5: Fix for lan966x

[PATCH] reset: mchp: sparx5: Fix for lan966x

[Horatiu Vultur]

With the blamed commit it seems that lan966x doesn't seem to boot
anymore when the internal CPU is used.
The reason seems to be the usage of the devm_of_iomap, if we replace
this with of_iomap, this seems to fix the issue as we use the same
region also for other devices.

Fixes: 0426a920d6269c ("reset: mchp: sparx5: Map cpu-syscon locally in case of LAN966x")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
---
 drivers/reset/reset-microchip-sparx5.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/reset/reset-microchip-sparx5.c b/drivers/reset/reset-microchip-sparx5.c
index aa5464be7053b..5a75f9833a91a 100644
--- a/drivers/reset/reset-microchip-sparx5.c
+++ b/drivers/reset/reset-microchip-sparx5.c
@@ -8,6 +8,7 @@
  */
 #include <linux/mfd/syscon.h>
 #include <linux/of.h>
+#include <linux/of_address.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
@@ -72,14 +73,17 @@ static struct regmap *mchp_lan966x_syscon_to_regmap(struct device *dev,
 						    struct device_node *syscon_np)
 {
 	struct regmap_config regmap_config = mchp_lan966x_syscon_regmap_config;
-	resource_size_t size;
+	struct resource res;
 	void __iomem *base;
 
-	base = devm_of_iomap(dev, syscon_np, 0, &size);
-	if (IS_ERR(base))
-		return ERR_CAST(base);
+	if (of_address_to_resource(syscon_np, 0, &res))
+		return ERR_PTR(-ENOMEM);
 
-	regmap_config.max_register = size - 4;
+	base = of_iomap(syscon_np, 0);
+	if (!base)
+		return ERR_PTR(-ENOMEM);
+
+	regmap_config.max_register =  resource_size(&res) - 4;
 
 	return devm_regmap_init_mmio(dev, base, &regmap_config);
 }
-- 
2.34.1

Re: [PATCH] reset: mchp: sparx5: Fix for lan966x

[Herve Codina]

Hi Horatiu,

On Mon, 24 Feb 2025 10:29:23 +0100
Horatiu Vultur <horatiu.vultur@microchip.com> wrote:

> With the blamed commit it seems that lan966x doesn't seem to boot
> anymore when the internal CPU is used.
> The reason seems to be the usage of the devm_of_iomap, if we replace
> this with of_iomap, this seems to fix the issue as we use the same
> region also for other devices.
> 
> Fixes: 0426a920d6269c ("reset: mchp: sparx5: Map cpu-syscon locally in case of LAN966x")
> Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
> ---
>  drivers/reset/reset-microchip-sparx5.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/reset/reset-microchip-sparx5.c b/drivers/reset/reset-microchip-sparx5.c
> index aa5464be7053b..5a75f9833a91a 100644
> --- a/drivers/reset/reset-microchip-sparx5.c
> +++ b/drivers/reset/reset-microchip-sparx5.c
> @@ -8,6 +8,7 @@
>   */
>  #include <linux/mfd/syscon.h>
>  #include <linux/of.h>
> +#include <linux/of_address.h>
>  #include <linux/module.h>
>  #include <linux/platform_device.h>
>  #include <linux/property.h>
> @@ -72,14 +73,17 @@ static struct regmap *mchp_lan966x_syscon_to_regmap(struct device *dev,
>  						    struct device_node *syscon_np)
>  {
>  	struct regmap_config regmap_config = mchp_lan966x_syscon_regmap_config;
> -	resource_size_t size;
> +	struct resource res;
>  	void __iomem *base;
>  
> -	base = devm_of_iomap(dev, syscon_np, 0, &size);
> -	if (IS_ERR(base))
> -		return ERR_CAST(base);
> +	if (of_address_to_resource(syscon_np, 0, &res))
> +		return ERR_PTR(-ENOMEM);
>  
> -	regmap_config.max_register = size - 4;
> +	base = of_iomap(syscon_np, 0);
> +	if (!base)
> +		return ERR_PTR(-ENOMEM);
> +
> +	regmap_config.max_register =  resource_size(&res) - 4;
>  
>  	return devm_regmap_init_mmio(dev, base, &regmap_config);
>  }

In the Lan966x PCI device use case, the reset driver can be loaded, unloaded
and re-loaded.

When the driver is unloaded, resources have to be released and so with a
call to of_iomap(), a call to iounmap() is needed.

Maybe .remove() function in this driver should handle the needed iounmap()
call.

Best regards,
Hervé

Re: [PATCH] reset: mchp: sparx5: Fix for lan966x

[Horatiu Vultur]

The 02/24/2025 14:04, Herve Codina wrote:
> 
> Hi Horatiu,

Hi Herve,

> 
> On Mon, 24 Feb 2025 10:29:23 +0100
> Horatiu Vultur <horatiu.vultur@microchip.com> wrote:
> 
> > With the blamed commit it seems that lan966x doesn't seem to boot
> > anymore when the internal CPU is used.
> > The reason seems to be the usage of the devm_of_iomap, if we replace
> > this with of_iomap, this seems to fix the issue as we use the same
> > region also for other devices.
> >
> > Fixes: 0426a920d6269c ("reset: mchp: sparx5: Map cpu-syscon locally in case of LAN966x")
> > Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
> > ---
> >  drivers/reset/reset-microchip-sparx5.c | 14 +++++++++-----
> >  1 file changed, 9 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/reset/reset-microchip-sparx5.c b/drivers/reset/reset-microchip-sparx5.c
> > index aa5464be7053b..5a75f9833a91a 100644
> > --- a/drivers/reset/reset-microchip-sparx5.c
> > +++ b/drivers/reset/reset-microchip-sparx5.c
> > @@ -8,6 +8,7 @@
> >   */
> >  #include <linux/mfd/syscon.h>
> >  #include <linux/of.h>
> > +#include <linux/of_address.h>
> >  #include <linux/module.h>
> >  #include <linux/platform_device.h>
> >  #include <linux/property.h>
> > @@ -72,14 +73,17 @@ static struct regmap *mchp_lan966x_syscon_to_regmap(struct device *dev,
> >                                                   struct device_node *syscon_np)
> >  {
> >       struct regmap_config regmap_config = mchp_lan966x_syscon_regmap_config;
> > -     resource_size_t size;
> > +     struct resource res;
> >       void __iomem *base;
> >
> > -     base = devm_of_iomap(dev, syscon_np, 0, &size);
> > -     if (IS_ERR(base))
> > -             return ERR_CAST(base);
> > +     if (of_address_to_resource(syscon_np, 0, &res))
> > +             return ERR_PTR(-ENOMEM);
> >
> > -     regmap_config.max_register = size - 4;
> > +     base = of_iomap(syscon_np, 0);
> > +     if (!base)
> > +             return ERR_PTR(-ENOMEM);
> > +
> > +     regmap_config.max_register =  resource_size(&res) - 4;
> >
> >       return devm_regmap_init_mmio(dev, base, &regmap_config);
> >  }
> 
> In the Lan966x PCI device use case, the reset driver can be loaded, unloaded
> and re-loaded.
> 
> When the driver is unloaded, resources have to be released and so with a
> call to of_iomap(), a call to iounmap() is needed.
> 
> Maybe .remove() function in this driver should handle the needed iounmap()
> call.

Thanks for the comments.
I think you are right. I will update this in the next version.

> 
> Best regards,
> Hervé

-- 
/Horatiu