linux-kernel - Re: [PATCH] reset: mchp: sparx5: Fix for lan966x

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Message-ID: <20250225095930.paeqka2z2tjuxp6g@DEN-DL-M31836.microchip.com>
Date: Tue, 25 Feb 2025 10:59:30 +0100
From: Horatiu Vultur <horatiu.vultur@...rochip.com>
To: Herve Codina <herve.codina@...tlin.com>
CC: <p.zabel@...gutronix.de>, <Steen.Hegelund@...rochip.com>,
	<daniel.machon@...rochip.com>, <UNGLinuxDriver@...rochip.com>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] reset: mchp: sparx5: Fix for lan966x

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@...rochip.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@...rochip.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