diff mbox series

[4/5] cxl/port: Scan single-target ports for decoders

Message ID 168149845130.792294.3210421233937427962.stgit@dwillia2-xfh.jf.intel.com
State Accepted
Commit 7bba261e0aa6e8e5f28a3a3def8338b6512534ee
Headers show
Series cxl/hdm: Decoder enumeration fixes | expand

Commit Message

Dan Williams April 14, 2023, 6:54 p.m. UTC
Do not assume that a single-target port falls back to a passthrough
decoder configuration. Scan for decoders and only fallback after probing
that the HDM decoder capability is not present.

One user visible affect of this bug is the inability to enumerate
present CXL regions as the decoder settings for the present decoders are
skipped.

Fixes: d17d0540a0db ("cxl/core/hdm: Add CXL standard decoder enumeration to the core")
Reported-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: http://lore.kernel.org/r/20230227153128.8164-1-Jonathan.Cameron@huawei.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/cxl/core/hdm.c |    5 +++--
 drivers/cxl/port.c     |   18 +++++++++++++-----
 2 files changed, 16 insertions(+), 7 deletions(-)

Comments

Alison Schofield April 14, 2023, 8:55 p.m. UTC | #1
On Fri, Apr 14, 2023 at 11:54:11AM -0700, Dan Williams wrote:
> Do not assume that a single-target port falls back to a passthrough
> decoder configuration. Scan for decoders and only fallback after probing
> that the HDM decoder capability is not present.
> 
> One user visible affect of this bug is the inability to enumerate
> present CXL regions as the decoder settings for the present decoders are
> skipped.
> 
> Fixes: d17d0540a0db ("cxl/core/hdm: Add CXL standard decoder enumeration to the core")
> Reported-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Link: http://lore.kernel.org/r/20230227153128.8164-1-Jonathan.Cameron@huawei.com
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Reviewed-by: Alison Schofield <alison.schofield@intel.com>

> ---
>  drivers/cxl/core/hdm.c |    5 +++--
>  drivers/cxl/port.c     |   18 +++++++++++++-----
>  2 files changed, 16 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> index 6fdf7981ddc7..abe3877cfa63 100644
> --- a/drivers/cxl/core/hdm.c
> +++ b/drivers/cxl/core/hdm.c
> @@ -92,8 +92,9 @@ static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb,
>  
>  	cxl_probe_component_regs(&port->dev, crb, &map.component_map);
>  	if (!map.component_map.hdm_decoder.valid) {
> -		dev_err(&port->dev, "HDM decoder registers invalid\n");
> -		return -ENXIO;
> +		dev_dbg(&port->dev, "HDM decoder registers not implemented\n");
> +		/* unique error code to indicate no HDM decoder capability */
> +		return -ENODEV;
>  	}
>  
>  	return cxl_map_component_regs(&port->dev, regs, &map,
> diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
> index 22a7ab2bae7c..eb57324c4ad4 100644
> --- a/drivers/cxl/port.c
> +++ b/drivers/cxl/port.c
> @@ -66,14 +66,22 @@ static int cxl_switch_port_probe(struct cxl_port *port)
>  	if (rc < 0)
>  		return rc;
>  
> -	if (rc == 1)
> -		return devm_cxl_add_passthrough_decoder(port);
> -
>  	cxlhdm = devm_cxl_setup_hdm(port, NULL);
> -	if (IS_ERR(cxlhdm))
> +	if (!IS_ERR(cxlhdm))
> +		return devm_cxl_enumerate_decoders(cxlhdm, NULL);
> +
> +	if (PTR_ERR(cxlhdm) != -ENODEV) {
> +		dev_err(&port->dev, "Failed to map HDM decoder capability\n");
>  		return PTR_ERR(cxlhdm);
> +	}
> +
> +	if (rc == 1) {
> +		dev_dbg(&port->dev, "Fallback to passthrough decoder\n");
> +		return devm_cxl_add_passthrough_decoder(port);
> +	}
>  
> -	return devm_cxl_enumerate_decoders(cxlhdm, NULL);
> +	dev_err(&port->dev, "HDM decoder capability not found\n");
> +	return -ENXIO;
>  }
>  
>  static int cxl_endpoint_port_probe(struct cxl_port *port)
>
Dave Jiang April 14, 2023, 9:24 p.m. UTC | #2
On 4/14/23 11:54 AM, Dan Williams wrote:
> Do not assume that a single-target port falls back to a passthrough
> decoder configuration. Scan for decoders and only fallback after probing
> that the HDM decoder capability is not present.
> 
> One user visible affect of this bug is the inability to enumerate
> present CXL regions as the decoder settings for the present decoders are
> skipped.
> 
> Fixes: d17d0540a0db ("cxl/core/hdm: Add CXL standard decoder enumeration to the core")
> Reported-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Link: http://lore.kernel.org/r/20230227153128.8164-1-Jonathan.Cameron@huawei.com
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>

> ---
>   drivers/cxl/core/hdm.c |    5 +++--
>   drivers/cxl/port.c     |   18 +++++++++++++-----
>   2 files changed, 16 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> index 6fdf7981ddc7..abe3877cfa63 100644
> --- a/drivers/cxl/core/hdm.c
> +++ b/drivers/cxl/core/hdm.c
> @@ -92,8 +92,9 @@ static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb,
>   
>   	cxl_probe_component_regs(&port->dev, crb, &map.component_map);
>   	if (!map.component_map.hdm_decoder.valid) {
> -		dev_err(&port->dev, "HDM decoder registers invalid\n");
> -		return -ENXIO;
> +		dev_dbg(&port->dev, "HDM decoder registers not implemented\n");
> +		/* unique error code to indicate no HDM decoder capability */
> +		return -ENODEV;
>   	}
>   
>   	return cxl_map_component_regs(&port->dev, regs, &map,
> diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
> index 22a7ab2bae7c..eb57324c4ad4 100644
> --- a/drivers/cxl/port.c
> +++ b/drivers/cxl/port.c
> @@ -66,14 +66,22 @@ static int cxl_switch_port_probe(struct cxl_port *port)
>   	if (rc < 0)
>   		return rc;
>   
> -	if (rc == 1)
> -		return devm_cxl_add_passthrough_decoder(port);
> -
>   	cxlhdm = devm_cxl_setup_hdm(port, NULL);
> -	if (IS_ERR(cxlhdm))
> +	if (!IS_ERR(cxlhdm))
> +		return devm_cxl_enumerate_decoders(cxlhdm, NULL);
> +
> +	if (PTR_ERR(cxlhdm) != -ENODEV) {
> +		dev_err(&port->dev, "Failed to map HDM decoder capability\n");
>   		return PTR_ERR(cxlhdm);
> +	}
> +
> +	if (rc == 1) {
> +		dev_dbg(&port->dev, "Fallback to passthrough decoder\n");
> +		return devm_cxl_add_passthrough_decoder(port);
> +	}
>   
> -	return devm_cxl_enumerate_decoders(cxlhdm, NULL);
> +	dev_err(&port->dev, "HDM decoder capability not found\n");
> +	return -ENXIO;
>   }
>   
>   static int cxl_endpoint_port_probe(struct cxl_port *port)
>
Jonathan Cameron April 17, 2023, 4:48 p.m. UTC | #3
On Fri, 14 Apr 2023 11:54:11 -0700
Dan Williams <dan.j.williams@intel.com> wrote:

> Do not assume that a single-target port falls back to a passthrough
> decoder configuration. Scan for decoders and only fallback after probing
> that the HDM decoder capability is not present.
> 
> One user visible affect of this bug is the inability to enumerate
> present CXL regions as the decoder settings for the present decoders are
> skipped.
> 
> Fixes: d17d0540a0db ("cxl/core/hdm: Add CXL standard decoder enumeration to the core")
> Reported-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Link: http://lore.kernel.org/r/20230227153128.8164-1-Jonathan.Cameron@huawei.com
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

*Happy face*

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>


> ---
>  drivers/cxl/core/hdm.c |    5 +++--
>  drivers/cxl/port.c     |   18 +++++++++++++-----
>  2 files changed, 16 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> index 6fdf7981ddc7..abe3877cfa63 100644
> --- a/drivers/cxl/core/hdm.c
> +++ b/drivers/cxl/core/hdm.c
> @@ -92,8 +92,9 @@ static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb,
>  
>  	cxl_probe_component_regs(&port->dev, crb, &map.component_map);
>  	if (!map.component_map.hdm_decoder.valid) {
> -		dev_err(&port->dev, "HDM decoder registers invalid\n");
> -		return -ENXIO;
> +		dev_dbg(&port->dev, "HDM decoder registers not implemented\n");
> +		/* unique error code to indicate no HDM decoder capability */
> +		return -ENODEV;
>  	}
>  
>  	return cxl_map_component_regs(&port->dev, regs, &map,
> diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
> index 22a7ab2bae7c..eb57324c4ad4 100644
> --- a/drivers/cxl/port.c
> +++ b/drivers/cxl/port.c
> @@ -66,14 +66,22 @@ static int cxl_switch_port_probe(struct cxl_port *port)
>  	if (rc < 0)
>  		return rc;
>  
> -	if (rc == 1)
> -		return devm_cxl_add_passthrough_decoder(port);
> -
>  	cxlhdm = devm_cxl_setup_hdm(port, NULL);
> -	if (IS_ERR(cxlhdm))
> +	if (!IS_ERR(cxlhdm))
> +		return devm_cxl_enumerate_decoders(cxlhdm, NULL);
> +
> +	if (PTR_ERR(cxlhdm) != -ENODEV) {
> +		dev_err(&port->dev, "Failed to map HDM decoder capability\n");
>  		return PTR_ERR(cxlhdm);
> +	}
> +
> +	if (rc == 1) {
> +		dev_dbg(&port->dev, "Fallback to passthrough decoder\n");
> +		return devm_cxl_add_passthrough_decoder(port);
> +	}
>  
> -	return devm_cxl_enumerate_decoders(cxlhdm, NULL);
> +	dev_err(&port->dev, "HDM decoder capability not found\n");
> +	return -ENXIO;
>  }
>  
>  static int cxl_endpoint_port_probe(struct cxl_port *port)
> 
>
diff mbox series

Patch

diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index 6fdf7981ddc7..abe3877cfa63 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -92,8 +92,9 @@  static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb,
 
 	cxl_probe_component_regs(&port->dev, crb, &map.component_map);
 	if (!map.component_map.hdm_decoder.valid) {
-		dev_err(&port->dev, "HDM decoder registers invalid\n");
-		return -ENXIO;
+		dev_dbg(&port->dev, "HDM decoder registers not implemented\n");
+		/* unique error code to indicate no HDM decoder capability */
+		return -ENODEV;
 	}
 
 	return cxl_map_component_regs(&port->dev, regs, &map,
diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
index 22a7ab2bae7c..eb57324c4ad4 100644
--- a/drivers/cxl/port.c
+++ b/drivers/cxl/port.c
@@ -66,14 +66,22 @@  static int cxl_switch_port_probe(struct cxl_port *port)
 	if (rc < 0)
 		return rc;
 
-	if (rc == 1)
-		return devm_cxl_add_passthrough_decoder(port);
-
 	cxlhdm = devm_cxl_setup_hdm(port, NULL);
-	if (IS_ERR(cxlhdm))
+	if (!IS_ERR(cxlhdm))
+		return devm_cxl_enumerate_decoders(cxlhdm, NULL);
+
+	if (PTR_ERR(cxlhdm) != -ENODEV) {
+		dev_err(&port->dev, "Failed to map HDM decoder capability\n");
 		return PTR_ERR(cxlhdm);
+	}
+
+	if (rc == 1) {
+		dev_dbg(&port->dev, "Fallback to passthrough decoder\n");
+		return devm_cxl_add_passthrough_decoder(port);
+	}
 
-	return devm_cxl_enumerate_decoders(cxlhdm, NULL);
+	dev_err(&port->dev, "HDM decoder capability not found\n");
+	return -ENXIO;
 }
 
 static int cxl_endpoint_port_probe(struct cxl_port *port)