netdev - Re: [PATCH v22 14/25] sfc: obtain decoder and region if committed by firmware

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Message-ID: <20251215135715.00001ee7@huawei.com>
Date: Mon, 15 Dec 2025 13:57:15 +0000
From: Jonathan Cameron <jonathan.cameron@...wei.com>
To: <alejandro.lucero-palau@....com>
CC: <linux-cxl@...r.kernel.org>, <netdev@...r.kernel.org>,
	<dan.j.williams@...el.com>, <edward.cree@....com>, <davem@...emloft.net>,
	<kuba@...nel.org>, <pabeni@...hat.com>, <edumazet@...gle.com>,
	<dave.jiang@...el.com>, Alejandro Lucero <alucerop@....com>
Subject: Re: [PATCH v22 14/25] sfc: obtain decoder and region if committed
 by firmware

On Fri, 5 Dec 2025 11:52:37 +0000
<alejandro.lucero-palau@....com> wrote:

> From: Alejandro Lucero <alucerop@....com>
> 
> Check if device HDM is already committed during firmware/BIOS
> initialization.
> 
> A CXL region should exist if so after memdev allocation/initialization.
> Get HPA from region and map it.
I'm confused.  If this only occurs if there is a committed decoder,
why is the exist cleanup unconditional?

Looks like you add logic around this in patch 16. I think that should be
back here for ease of reading even if for some reason this isn't broken.

Jonathan

> 
> Signed-off-by: Alejandro Lucero <alucerop@....com>
> ---
>  drivers/net/ethernet/sfc/efx_cxl.c | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> 
> diff --git a/drivers/net/ethernet/sfc/efx_cxl.c b/drivers/net/ethernet/sfc/efx_cxl.c
> index f6eda93e67e2..ad1f49e76179 100644
> --- a/drivers/net/ethernet/sfc/efx_cxl.c
> +++ b/drivers/net/ethernet/sfc/efx_cxl.c
> @@ -19,6 +19,7 @@ int efx_cxl_init(struct efx_probe_data *probe_data)
>  	struct efx_nic *efx = &probe_data->efx;
>  	struct pci_dev *pci_dev = efx->pci_dev;
>  	struct efx_cxl *cxl;
> +	struct range range;
>  	u16 dvsec;
>  	int rc;
>  
> @@ -90,6 +91,26 @@ int efx_cxl_init(struct efx_probe_data *probe_data)
>  		return PTR_ERR(cxl->cxlmd);
>  	}
>  
> +	cxl->cxled = cxl_get_committed_decoder(cxl->cxlmd, &cxl->efx_region);
> +	if (cxl->cxled) {
> +		if (!cxl->efx_region) {
> +			pci_err(pci_dev, "CXL found committed decoder without a region");
> +			return -ENODEV;
> +		}
> +		rc = cxl_get_region_range(cxl->efx_region, &range);
> +		if (rc) {
> +			pci_err(pci_dev,
> +				"CXL getting regions params from a committed decoder failed");
> +			return rc;
> +		}
> +
> +		cxl->ctpio_cxl = ioremap(range.start, range.end - range.start + 1);
> +		if (!cxl->ctpio_cxl) {
> +			pci_err(pci_dev, "CXL ioremap region (%pra) failed", &range);
> +			return -ENOMEM;
> +		}
> +	}
> +
>  	probe_data->cxl = cxl;
>  
>  	return 0;
> @@ -97,6 +118,12 @@ int efx_cxl_init(struct efx_probe_data *probe_data)
>  
>  void efx_cxl_exit(struct efx_probe_data *probe_data)
>  {
> +	if (!probe_data->cxl)
> +		return;
> +
> +	iounmap(probe_data->cxl->ctpio_cxl);
> +	cxl_decoder_detach(NULL, probe_data->cxl->cxled, 0, DETACH_INVALIDATE);
> +	unregister_region(probe_data->cxl->efx_region);
>  }
>  
>  MODULE_IMPORT_NS("CXL");