linux-kernel - Re: [PATCH V4 09/17] platform/x86/intel/pmc: Allow pmc_core_ssram

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Date:   Mon, 23 Oct 2023 18:17:36 +0300 (EEST)
From:   Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To:     "David E. Box" <david.e.box@...ux.intel.com>
cc:     LKML <linux-kernel@...r.kernel.org>,
        platform-driver-x86@...r.kernel.org, rajvi.jingar@...ux.intel.com
Subject: Re: [PATCH V4 09/17] platform/x86/intel/pmc: Allow pmc_core_ssram_init
 to fail

On Wed, 18 Oct 2023, David E. Box wrote:

> Currently, if the PMC SSRAM initialization fails, no error is returned and
> the only indication is that a PMC device has not been created.  Instead,
> allow an error to be returned and handled directly by the caller. Don't use
> the return value yet. This is in preparation for a future rework of
> pmc_core_sram_init().
> 
> Signed-off-by: David E. Box <david.e.box@...ux.intel.com>

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>

-- 
 i.


> ---
> V4 - Remove return value check in mtl.c. Proper use of the value would
>      require returning an error status from pmc_core_add_pmc(). But
>      the function that calls it will be removed in the next patch so wait
>      to use it then.
> 
> V3 - New patch split from V2 PATCH 9
>    - Add dev_warn on pmc_core_ssram_init fail
> 
>  drivers/platform/x86/intel/pmc/core.h       |  2 +-
>  drivers/platform/x86/intel/pmc/core_ssram.c | 21 +++++++++++++--------
>  2 files changed, 14 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel/pmc/core.h b/drivers/platform/x86/intel/pmc/core.h
> index ccf24e0f5e50..edaa70067e41 100644
> --- a/drivers/platform/x86/intel/pmc/core.h
> +++ b/drivers/platform/x86/intel/pmc/core.h
> @@ -492,7 +492,7 @@ int pmc_core_resume_common(struct pmc_dev *pmcdev);
>  int get_primary_reg_base(struct pmc *pmc);
>  extern void pmc_core_get_low_power_modes(struct pmc_dev *pmcdev);
>  
> -extern void pmc_core_ssram_init(struct pmc_dev *pmcdev);
> +extern int pmc_core_ssram_init(struct pmc_dev *pmcdev);
>  
>  int spt_core_init(struct pmc_dev *pmcdev);
>  int cnp_core_init(struct pmc_dev *pmcdev);
> diff --git a/drivers/platform/x86/intel/pmc/core_ssram.c b/drivers/platform/x86/intel/pmc/core_ssram.c
> index 13fa16f0d52e..815950713e25 100644
> --- a/drivers/platform/x86/intel/pmc/core_ssram.c
> +++ b/drivers/platform/x86/intel/pmc/core_ssram.c
> @@ -35,20 +35,20 @@ static inline u64 get_base(void __iomem *addr, u32 offset)
>  	return lo_hi_readq(addr + offset) & GENMASK_ULL(63, 3);
>  }
>  
> -static void
> +static int
>  pmc_core_pmc_add(struct pmc_dev *pmcdev, u64 pwrm_base,
>  		 const struct pmc_reg_map *reg_map, int pmc_index)
>  {
>  	struct pmc *pmc = pmcdev->pmcs[pmc_index];
>  
>  	if (!pwrm_base)
> -		return;
> +		return -ENODEV;
>  
>  	/* Memory for primary PMC has been allocated in core.c */
>  	if (!pmc) {
>  		pmc = devm_kzalloc(&pmcdev->pdev->dev, sizeof(*pmc), GFP_KERNEL);
>  		if (!pmc)
> -			return;
> +			return -ENOMEM;
>  	}
>  
>  	pmc->map = reg_map;
> @@ -57,10 +57,12 @@ pmc_core_pmc_add(struct pmc_dev *pmcdev, u64 pwrm_base,
>  
>  	if (!pmc->regbase) {
>  		devm_kfree(&pmcdev->pdev->dev, pmc);
> -		return;
> +		return -ENOMEM;
>  	}
>  
>  	pmcdev->pmcs[pmc_index] = pmc;
> +
> +	return 0;
>  }
>  
>  static void
> @@ -96,7 +98,7 @@ pmc_core_ssram_get_pmc(struct pmc_dev *pmcdev, void __iomem *ssram, u32 offset,
>  		iounmap(ssram);
>  }
>  
> -void pmc_core_ssram_init(struct pmc_dev *pmcdev)
> +int pmc_core_ssram_init(struct pmc_dev *pmcdev)
>  {
>  	void __iomem *ssram;
>  	struct pci_dev *pcidev;
> @@ -105,7 +107,7 @@ void pmc_core_ssram_init(struct pmc_dev *pmcdev)
>  
>  	pcidev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(20, 2));
>  	if (!pcidev)
> -		goto out;
> +		return -ENODEV;
>  
>  	ret = pcim_enable_device(pcidev);
>  	if (ret)
> @@ -123,11 +125,14 @@ void pmc_core_ssram_init(struct pmc_dev *pmcdev)
>  	pmc_core_ssram_get_pmc(pmcdev, ssram, SSRAM_PCH_OFFSET, PMC_IDX_PCH);
>  
>  	iounmap(ssram);
> -out:
> -	return;
> +
> +	return 0;
>  
>  disable_dev:
> +	pmcdev->ssram_pcidev = NULL;
>  	pci_disable_device(pcidev);
>  release_dev:
>  	pci_dev_put(pcidev);
> +
> +	return ret;
>  }
>