diff mbox series

[v8,03/27] cxl: add capabilities field to cxl_dev_state and cxl_port

Message ID 20241216161042.42108-4-alejandro.lucero-palau@amd.com (mailing list archive)
State Changes Requested
Headers show
Series cxl: add type2 device basic support | expand

Checks

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netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/build_tools success Errors and warnings before: 0 (+23) this patch: 0 (+23)
netdev/cc_maintainers warning 7 maintainers not CCed: peterz@infradead.org jonathan.cameron@huawei.com ira.weiny@intel.com vishal.l.verma@intel.com dave@stgolabs.net kobayashi.da-06@fujitsu.com alison.schofield@intel.com
netdev/build_clang success Errors and warnings before: 105 this patch: 105
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netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
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netdev/checkpatch warning WARNING: line length of 86 exceeds 80 columns WARNING: line length of 87 exceeds 80 columns
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Commit Message

Lucero Palau, Alejandro Dec. 16, 2024, 4:10 p.m. UTC 
From: Alejandro Lucero <alucerop@amd.com>

Type2 devices have some Type3 functionalities as optional like an mbox
or an hdm decoder, and CXL core needs a way to know what an CXL accelerator
implements.

Add a new field to cxl_dev_state for keeping device capabilities as
discovered during initialization. Add same field to cxl_port as registers
discovery is also used during port initialization.

Signed-off-by: Alejandro Lucero <alucerop@amd.com>
Reviewed-by: Ben Cheatham <benjamin.cheatham@amd.com>
Reviewed-by: Fan Ni <fan.ni@samsung.com>
---
 drivers/cxl/core/port.c | 11 +++++++----
 drivers/cxl/core/regs.c | 23 ++++++++++++++++-------
 drivers/cxl/cxl.h       |  9 ++++++---
 drivers/cxl/cxlmem.h    |  2 ++
 drivers/cxl/pci.c       | 10 ++++++----
 include/cxl/cxl.h       | 19 +++++++++++++++++++
 6 files changed, 56 insertions(+), 18 deletions(-)

Comments

Jonathan Cameron Dec. 24, 2024, 5:08 p.m. UTC | #1 
On Mon, 16 Dec 2024 16:10:18 +0000
<alejandro.lucero-palau@amd.com> wrote:

> From: Alejandro Lucero <alucerop@amd.com>
> 
> Type2 devices have some Type3 functionalities as optional like an mbox
> or an hdm decoder, and CXL core needs a way to know what an CXL accelerator
> implements.
> 
> Add a new field to cxl_dev_state for keeping device capabilities as
> discovered during initialization. Add same field to cxl_port as registers
> discovery is also used during port initialization.
> 
> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
> Reviewed-by: Ben Cheatham <benjamin.cheatham@amd.com>
> Reviewed-by: Fan Ni <fan.ni@samsung.com>

Use set_bit() not dereference and |= to set the bits in the bitmap
At that point you can void need to force the length of the bitmap.

Jonathan

> diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
> index 59cb35b40c7e..ac3a27c6e442 100644
> --- a/drivers/cxl/core/regs.c
> +++ b/drivers/cxl/core/regs.c

> @@ -113,11 +118,12 @@ EXPORT_SYMBOL_NS_GPL(cxl_probe_component_regs, "CXL");
>   * @dev: Host device of the @base mapping
>   * @base: Mapping of CXL 2.0 8.2.8 CXL Device Register Interface
>   * @map: Map object describing the register block information found
> + * @caps: capabilities to be set when discovered
>   *
>   * Probe for device register information and return it in map object.
>   */
>  void cxl_probe_device_regs(struct device *dev, void __iomem *base,
> -			   struct cxl_device_reg_map *map)
> +			   struct cxl_device_reg_map *map, unsigned long *caps)
>  {
>  	int cap, cap_count;
>  	u64 cap_array;
> @@ -146,10 +152,12 @@ void cxl_probe_device_regs(struct device *dev, void __iomem *base,
>  		case CXLDEV_CAP_CAP_ID_DEVICE_STATUS:
>  			dev_dbg(dev, "found Status capability (0x%x)\n", offset);
>  			rmap = &map->status;
> +			*caps |= BIT(CXL_DEV_CAP_DEV_STATUS);
>  			break;
>  		case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX:
>  			dev_dbg(dev, "found Mailbox capability (0x%x)\n", offset);
>  			rmap = &map->mbox;
> +			*caps |= BIT(CXL_DEV_CAP_MAILBOX_PRIMARY);
>  			break;
>  		case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX:
>  			dev_dbg(dev, "found Secondary Mailbox capability (0x%x)\n", offset);
> @@ -157,6 +165,7 @@ void cxl_probe_device_regs(struct device *dev, void __iomem *base,
>  		case CXLDEV_CAP_CAP_ID_MEMDEV:
>  			dev_dbg(dev, "found Memory Device capability (0x%x)\n", offset);
>  			rmap = &map->memdev;
> +			*caps |= BIT(CXL_DEV_CAP_MEMDEV);

Ah. That would will be why the 64 below. use set_bit() for these, not a dereference.


>  			break;
>  		default:
>  			if (cap_id >= 0x8000)
> @@ -421,7 +430,7 @@ static void cxl_unmap_regblock(struct cxl_register_map *map)
>  	map->base = NULL;
>  }
>  
> -static int cxl_probe_regs(struct cxl_register_map *map)
> +static int cxl_probe_regs(struct cxl_register_map *map, unsigned long *caps)
>  {
>  	struct cxl_component_reg_map *comp_map;
>  	struct cxl_device_reg_map *dev_map;
> @@ -431,12 +440,12 @@ static int cxl_probe_regs(struct cxl_register_map *map)
>  	switch (map->reg_type) {
>  	case CXL_REGLOC_RBI_COMPONENT:
>  		comp_map = &map->component_map;
> -		cxl_probe_component_regs(host, base, comp_map);
> +		cxl_probe_component_regs(host, base, comp_map, caps);
>  		dev_dbg(host, "Set up component registers\n");
>  		break;
>  	case CXL_REGLOC_RBI_MEMDEV:
>  		dev_map = &map->device_map;
> -		cxl_probe_device_regs(host, base, dev_map);
> +		cxl_probe_device_regs(host, base, dev_map, caps);
>  		if (!dev_map->status.valid || !dev_map->mbox.valid ||
>  		    !dev_map->memdev.valid) {
>  			dev_err(host, "registers not found: %s%s%s\n",
> @@ -455,7 +464,7 @@ static int cxl_probe_regs(struct cxl_register_map *map)
>  	return 0;
>  }

> diff --git a/include/cxl/cxl.h b/include/cxl/cxl.h
> index 19e5d883557a..f656fcd4945f 100644
> --- a/include/cxl/cxl.h
> +++ b/include/cxl/cxl.h
> @@ -12,6 +12,25 @@ enum cxl_resource {
>  	CXL_RES_PMEM,
>  };
>  
> +/* Capabilities as defined for:
> + *
> + *	Component Registers (Table 8-22 CXL 3.1 specification)
> + *	Device Registers (8.2.8.2.1 CXL 3.1 specification)
> + *
> + * and currently being used for kernel CXL support.
> + */
> +
> +enum cxl_dev_cap {
> +	/* capabilities from Component Registers */
> +	CXL_DEV_CAP_RAS,
> +	CXL_DEV_CAP_HDM,
> +	/* capabilities from Device Registers */
> +	CXL_DEV_CAP_DEV_STATUS,
> +	CXL_DEV_CAP_MAILBOX_PRIMARY,
> +	CXL_DEV_CAP_MEMDEV,
> +	CXL_MAX_CAPS = 64

Why set it to 64?  All the bitmaps etc will autosize so
you just need to ensure you use correct set_bit() and test_bit()
that are happy dealing with bitmaps of multiple longs.


> +};
> +
>  struct cxl_dev_state *cxl_accel_state_create(struct device *dev);
>  
>  void cxl_set_dvsec(struct cxl_dev_state *cxlds, u16 dvsec);
Alejandro Lucero Palau Dec. 27, 2024, 7:07 a.m. UTC | #2 
On 12/24/24 17:08, Jonathan Cameron wrote:
> On Mon, 16 Dec 2024 16:10:18 +0000
> <alejandro.lucero-palau@amd.com> wrote:
>
>> From: Alejandro Lucero <alucerop@amd.com>
>>
>> Type2 devices have some Type3 functionalities as optional like an mbox
>> or an hdm decoder, and CXL core needs a way to know what an CXL accelerator
>> implements.
>>
>> Add a new field to cxl_dev_state for keeping device capabilities as
>> discovered during initialization. Add same field to cxl_port as registers
>> discovery is also used during port initialization.
>>
>> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
>> Reviewed-by: Ben Cheatham <benjamin.cheatham@amd.com>
>> Reviewed-by: Fan Ni <fan.ni@samsung.com>
> Use set_bit() not dereference and |= to set the bits in the bitmap
> At that point you can void need to force the length of the bitmap.
>
> Jonathan
>
>> diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
>> index 59cb35b40c7e..ac3a27c6e442 100644
>> --- a/drivers/cxl/core/regs.c
>> +++ b/drivers/cxl/core/regs.c
>> @@ -113,11 +118,12 @@ EXPORT_SYMBOL_NS_GPL(cxl_probe_component_regs, "CXL");
>>    * @dev: Host device of the @base mapping
>>    * @base: Mapping of CXL 2.0 8.2.8 CXL Device Register Interface
>>    * @map: Map object describing the register block information found
>> + * @caps: capabilities to be set when discovered
>>    *
>>    * Probe for device register information and return it in map object.
>>    */
>>   void cxl_probe_device_regs(struct device *dev, void __iomem *base,
>> -			   struct cxl_device_reg_map *map)
>> +			   struct cxl_device_reg_map *map, unsigned long *caps)
>>   {
>>   	int cap, cap_count;
>>   	u64 cap_array;
>> @@ -146,10 +152,12 @@ void cxl_probe_device_regs(struct device *dev, void __iomem *base,
>>   		case CXLDEV_CAP_CAP_ID_DEVICE_STATUS:
>>   			dev_dbg(dev, "found Status capability (0x%x)\n", offset);
>>   			rmap = &map->status;
>> +			*caps |= BIT(CXL_DEV_CAP_DEV_STATUS);
>>   			break;
>>   		case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX:
>>   			dev_dbg(dev, "found Mailbox capability (0x%x)\n", offset);
>>   			rmap = &map->mbox;
>> +			*caps |= BIT(CXL_DEV_CAP_MAILBOX_PRIMARY);
>>   			break;
>>   		case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX:
>>   			dev_dbg(dev, "found Secondary Mailbox capability (0x%x)\n", offset);
>> @@ -157,6 +165,7 @@ void cxl_probe_device_regs(struct device *dev, void __iomem *base,
>>   		case CXLDEV_CAP_CAP_ID_MEMDEV:
>>   			dev_dbg(dev, "found Memory Device capability (0x%x)\n", offset);
>>   			rmap = &map->memdev;
>> +			*caps |= BIT(CXL_DEV_CAP_MEMDEV);
> Ah. That would will be why the 64 below. use set_bit() for these, not a dereference.
>

Makes sense.

I'll do it.


>>   			break;
>>   		default:
>>   			if (cap_id >= 0x8000)
>> @@ -421,7 +430,7 @@ static void cxl_unmap_regblock(struct cxl_register_map *map)
>>   	map->base = NULL;
>>   }
>>   
>> -static int cxl_probe_regs(struct cxl_register_map *map)
>> +static int cxl_probe_regs(struct cxl_register_map *map, unsigned long *caps)
>>   {
>>   	struct cxl_component_reg_map *comp_map;
>>   	struct cxl_device_reg_map *dev_map;
>> @@ -431,12 +440,12 @@ static int cxl_probe_regs(struct cxl_register_map *map)
>>   	switch (map->reg_type) {
>>   	case CXL_REGLOC_RBI_COMPONENT:
>>   		comp_map = &map->component_map;
>> -		cxl_probe_component_regs(host, base, comp_map);
>> +		cxl_probe_component_regs(host, base, comp_map, caps);
>>   		dev_dbg(host, "Set up component registers\n");
>>   		break;
>>   	case CXL_REGLOC_RBI_MEMDEV:
>>   		dev_map = &map->device_map;
>> -		cxl_probe_device_regs(host, base, dev_map);
>> +		cxl_probe_device_regs(host, base, dev_map, caps);
>>   		if (!dev_map->status.valid || !dev_map->mbox.valid ||
>>   		    !dev_map->memdev.valid) {
>>   			dev_err(host, "registers not found: %s%s%s\n",
>> @@ -455,7 +464,7 @@ static int cxl_probe_regs(struct cxl_register_map *map)
>>   	return 0;
>>   }
>> diff --git a/include/cxl/cxl.h b/include/cxl/cxl.h
>> index 19e5d883557a..f656fcd4945f 100644
>> --- a/include/cxl/cxl.h
>> +++ b/include/cxl/cxl.h
>> @@ -12,6 +12,25 @@ enum cxl_resource {
>>   	CXL_RES_PMEM,
>>   };
>>   
>> +/* Capabilities as defined for:
>> + *
>> + *	Component Registers (Table 8-22 CXL 3.1 specification)
>> + *	Device Registers (8.2.8.2.1 CXL 3.1 specification)
>> + *
>> + * and currently being used for kernel CXL support.
>> + */
>> +
>> +enum cxl_dev_cap {
>> +	/* capabilities from Component Registers */
>> +	CXL_DEV_CAP_RAS,
>> +	CXL_DEV_CAP_HDM,
>> +	/* capabilities from Device Registers */
>> +	CXL_DEV_CAP_DEV_STATUS,
>> +	CXL_DEV_CAP_MAILBOX_PRIMARY,
>> +	CXL_DEV_CAP_MEMDEV,
>> +	CXL_MAX_CAPS = 64
> Why set it to 64?  All the bitmaps etc will autosize so
> you just need to ensure you use correct set_bit() and test_bit()
> that are happy dealing with bitmaps of multiple longs.
>

Initially it was set to 32, but DECLARE_BITMAP uses unsigned long, so 
for initializing/zeroing the locally allocated bitmap in some functions, 
bitmap_clear had to use sizeof for the size, and I was suggested to 
define CXL_MAX_CAPS to 64 and use it instead, what seems cleaner.



>> +};
>> +
>>   struct cxl_dev_state *cxl_accel_state_create(struct device *dev);
>>   
>>   void cxl_set_dvsec(struct cxl_dev_state *cxlds, u16 dvsec);
diff mbox series

Patch

diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 78a5c2c25982..831bc35c2083 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -749,7 +749,7 @@  static struct cxl_port *cxl_port_alloc(struct device *uport_dev,
 }
 
 static int cxl_setup_comp_regs(struct device *host, struct cxl_register_map *map,
-			       resource_size_t component_reg_phys)
+			       resource_size_t component_reg_phys, unsigned long *caps)
 {
 	*map = (struct cxl_register_map) {
 		.host = host,
@@ -763,7 +763,7 @@  static int cxl_setup_comp_regs(struct device *host, struct cxl_register_map *map
 	map->reg_type = CXL_REGLOC_RBI_COMPONENT;
 	map->max_size = CXL_COMPONENT_REG_BLOCK_SIZE;
 
-	return cxl_setup_regs(map);
+	return cxl_setup_regs(map, caps);
 }
 
 static int cxl_port_setup_regs(struct cxl_port *port,
@@ -772,7 +772,7 @@  static int cxl_port_setup_regs(struct cxl_port *port,
 	if (dev_is_platform(port->uport_dev))
 		return 0;
 	return cxl_setup_comp_regs(&port->dev, &port->reg_map,
-				   component_reg_phys);
+				   component_reg_phys, port->capabilities);
 }
 
 static int cxl_dport_setup_regs(struct device *host, struct cxl_dport *dport,
@@ -789,7 +789,8 @@  static int cxl_dport_setup_regs(struct device *host, struct cxl_dport *dport,
 	 * NULL.
 	 */
 	rc = cxl_setup_comp_regs(dport->dport_dev, &dport->reg_map,
-				 component_reg_phys);
+				 component_reg_phys,
+				 dport->port->capabilities);
 	dport->reg_map.host = host;
 	return rc;
 }
@@ -851,6 +852,8 @@  static int cxl_port_add(struct cxl_port *port,
 		port->reg_map = cxlds->reg_map;
 		port->reg_map.host = &port->dev;
 		cxlmd->endpoint = port;
+		bitmap_copy(port->capabilities, cxlds->capabilities,
+			    CXL_MAX_CAPS);
 	} else if (parent_dport) {
 		rc = dev_set_name(dev, "port%d", port->id);
 		if (rc)
diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
index 59cb35b40c7e..ac3a27c6e442 100644
--- a/drivers/cxl/core/regs.c
+++ b/drivers/cxl/core/regs.c
@@ -4,6 +4,7 @@ 
 #include <linux/device.h>
 #include <linux/slab.h>
 #include <linux/pci.h>
+#include <cxl/cxl.h>
 #include <cxlmem.h>
 #include <cxlpci.h>
 #include <pmu.h>
@@ -29,6 +30,7 @@ 
  * @dev: Host device of the @base mapping
  * @base: Mapping containing the HDM Decoder Capability Header
  * @map: Map object describing the register block information found
+ * @caps: capabilities to be set when discovered
  *
  * See CXL 2.0 8.2.4 Component Register Layout and Definition
  * See CXL 2.0 8.2.5.5 CXL Device Register Interface
@@ -36,7 +38,8 @@ 
  * Probe for component register information and return it in map object.
  */
 void cxl_probe_component_regs(struct device *dev, void __iomem *base,
-			      struct cxl_component_reg_map *map)
+			      struct cxl_component_reg_map *map,
+			      unsigned long *caps)
 {
 	int cap, cap_count;
 	u32 cap_array;
@@ -84,6 +87,7 @@  void cxl_probe_component_regs(struct device *dev, void __iomem *base,
 			decoder_cnt = cxl_hdm_decoder_count(hdr);
 			length = 0x20 * decoder_cnt + 0x10;
 			rmap = &map->hdm_decoder;
+			*caps |= BIT(CXL_DEV_CAP_HDM);
 			break;
 		}
 		case CXL_CM_CAP_CAP_ID_RAS:
@@ -91,6 +95,7 @@  void cxl_probe_component_regs(struct device *dev, void __iomem *base,
 				offset);
 			length = CXL_RAS_CAPABILITY_LENGTH;
 			rmap = &map->ras;
+			*caps |= BIT(CXL_DEV_CAP_RAS);
 			break;
 		default:
 			dev_dbg(dev, "Unknown CM cap ID: %d (0x%x)\n", cap_id,
@@ -113,11 +118,12 @@  EXPORT_SYMBOL_NS_GPL(cxl_probe_component_regs, "CXL");
  * @dev: Host device of the @base mapping
  * @base: Mapping of CXL 2.0 8.2.8 CXL Device Register Interface
  * @map: Map object describing the register block information found
+ * @caps: capabilities to be set when discovered
  *
  * Probe for device register information and return it in map object.
  */
 void cxl_probe_device_regs(struct device *dev, void __iomem *base,
-			   struct cxl_device_reg_map *map)
+			   struct cxl_device_reg_map *map, unsigned long *caps)
 {
 	int cap, cap_count;
 	u64 cap_array;
@@ -146,10 +152,12 @@  void cxl_probe_device_regs(struct device *dev, void __iomem *base,
 		case CXLDEV_CAP_CAP_ID_DEVICE_STATUS:
 			dev_dbg(dev, "found Status capability (0x%x)\n", offset);
 			rmap = &map->status;
+			*caps |= BIT(CXL_DEV_CAP_DEV_STATUS);
 			break;
 		case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX:
 			dev_dbg(dev, "found Mailbox capability (0x%x)\n", offset);
 			rmap = &map->mbox;
+			*caps |= BIT(CXL_DEV_CAP_MAILBOX_PRIMARY);
 			break;
 		case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX:
 			dev_dbg(dev, "found Secondary Mailbox capability (0x%x)\n", offset);
@@ -157,6 +165,7 @@  void cxl_probe_device_regs(struct device *dev, void __iomem *base,
 		case CXLDEV_CAP_CAP_ID_MEMDEV:
 			dev_dbg(dev, "found Memory Device capability (0x%x)\n", offset);
 			rmap = &map->memdev;
+			*caps |= BIT(CXL_DEV_CAP_MEMDEV);
 			break;
 		default:
 			if (cap_id >= 0x8000)
@@ -421,7 +430,7 @@  static void cxl_unmap_regblock(struct cxl_register_map *map)
 	map->base = NULL;
 }
 
-static int cxl_probe_regs(struct cxl_register_map *map)
+static int cxl_probe_regs(struct cxl_register_map *map, unsigned long *caps)
 {
 	struct cxl_component_reg_map *comp_map;
 	struct cxl_device_reg_map *dev_map;
@@ -431,12 +440,12 @@  static int cxl_probe_regs(struct cxl_register_map *map)
 	switch (map->reg_type) {
 	case CXL_REGLOC_RBI_COMPONENT:
 		comp_map = &map->component_map;
-		cxl_probe_component_regs(host, base, comp_map);
+		cxl_probe_component_regs(host, base, comp_map, caps);
 		dev_dbg(host, "Set up component registers\n");
 		break;
 	case CXL_REGLOC_RBI_MEMDEV:
 		dev_map = &map->device_map;
-		cxl_probe_device_regs(host, base, dev_map);
+		cxl_probe_device_regs(host, base, dev_map, caps);
 		if (!dev_map->status.valid || !dev_map->mbox.valid ||
 		    !dev_map->memdev.valid) {
 			dev_err(host, "registers not found: %s%s%s\n",
@@ -455,7 +464,7 @@  static int cxl_probe_regs(struct cxl_register_map *map)
 	return 0;
 }
 
-int cxl_setup_regs(struct cxl_register_map *map)
+int cxl_setup_regs(struct cxl_register_map *map, unsigned long *caps)
 {
 	int rc;
 
@@ -463,7 +472,7 @@  int cxl_setup_regs(struct cxl_register_map *map)
 	if (rc)
 		return rc;
 
-	rc = cxl_probe_regs(map);
+	rc = cxl_probe_regs(map, caps);
 	cxl_unmap_regblock(map);
 
 	return rc;
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index f6015f24ad38..22e787748d79 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -4,6 +4,7 @@ 
 #ifndef __CXL_H__
 #define __CXL_H__
 
+#include <cxl/cxl.h>
 #include <linux/libnvdimm.h>
 #include <linux/bitfield.h>
 #include <linux/notifier.h>
@@ -292,9 +293,9 @@  struct cxl_register_map {
 };
 
 void cxl_probe_component_regs(struct device *dev, void __iomem *base,
-			      struct cxl_component_reg_map *map);
+			      struct cxl_component_reg_map *map, unsigned long *caps);
 void cxl_probe_device_regs(struct device *dev, void __iomem *base,
-			   struct cxl_device_reg_map *map);
+			   struct cxl_device_reg_map *map, unsigned long *caps);
 int cxl_map_component_regs(const struct cxl_register_map *map,
 			   struct cxl_component_regs *regs,
 			   unsigned long map_mask);
@@ -308,7 +309,7 @@  int cxl_find_regblock_instance(struct pci_dev *pdev, enum cxl_regloc_type type,
 			       struct cxl_register_map *map, int index);
 int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type,
 		      struct cxl_register_map *map);
-int cxl_setup_regs(struct cxl_register_map *map);
+int cxl_setup_regs(struct cxl_register_map *map, unsigned long *caps);
 struct cxl_dport;
 resource_size_t cxl_rcd_component_reg_phys(struct device *dev,
 					   struct cxl_dport *dport);
@@ -609,6 +610,7 @@  struct cxl_dax_region {
  * @cdat: Cached CDAT data
  * @cdat_available: Should a CDAT attribute be available in sysfs
  * @pci_latency: Upstream latency in picoseconds
+ * @capabilities: those capabilities as defined in device mapped registers
  */
 struct cxl_port {
 	struct device dev;
@@ -632,6 +634,7 @@  struct cxl_port {
 	} cdat;
 	bool cdat_available;
 	long pci_latency;
+	DECLARE_BITMAP(capabilities, CXL_MAX_CAPS);
 };
 
 /**
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 2a25d1957ddb..4c1c53c29544 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -428,6 +428,7 @@  struct cxl_dpa_perf {
  * @serial: PCIe Device Serial Number
  * @type: Generic Memory Class device or Vendor Specific Memory device
  * @cxl_mbox: CXL mailbox context
+ * @capabilities: those capabilities as defined in device mapped registers
  */
 struct cxl_dev_state {
 	struct device *dev;
@@ -443,6 +444,7 @@  struct cxl_dev_state {
 	u64 serial;
 	enum cxl_devtype type;
 	struct cxl_mailbox cxl_mbox;
+	DECLARE_BITMAP(capabilities, CXL_MAX_CAPS);
 };
 
 static inline struct cxl_dev_state *mbox_to_cxlds(struct cxl_mailbox *cxl_mbox)
diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 36098e2b4235..dbc1cd9bec09 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -504,7 +504,8 @@  static int cxl_rcrb_get_comp_regs(struct pci_dev *pdev,
 }
 
 static int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
-			      struct cxl_register_map *map)
+			      struct cxl_register_map *map,
+			      unsigned long *caps)
 {
 	int rc;
 
@@ -534,7 +535,7 @@  static int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
 		return rc;
 	}
 
-	return cxl_setup_regs(map);
+	return cxl_setup_regs(map, caps);
 }
 
 static int cxl_pci_ras_unmask(struct pci_dev *pdev)
@@ -938,7 +939,8 @@  static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	cxl_set_dvsec(cxlds, dvsec);
 
-	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map);
+	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map,
+				cxlds->capabilities);
 	if (rc)
 		return rc;
 
@@ -951,7 +953,7 @@  static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	 * still be useful for management functions so don't return an error.
 	 */
 	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_COMPONENT,
-				&cxlds->reg_map);
+				&cxlds->reg_map, cxlds->capabilities);
 	if (rc)
 		dev_warn(&pdev->dev, "No component registers (%d)\n", rc);
 	else if (!cxlds->reg_map.component_map.ras.valid)
diff --git a/include/cxl/cxl.h b/include/cxl/cxl.h
index 19e5d883557a..f656fcd4945f 100644
--- a/include/cxl/cxl.h
+++ b/include/cxl/cxl.h
@@ -12,6 +12,25 @@  enum cxl_resource {
 	CXL_RES_PMEM,
 };
 
+/* Capabilities as defined for:
+ *
+ *	Component Registers (Table 8-22 CXL 3.1 specification)
+ *	Device Registers (8.2.8.2.1 CXL 3.1 specification)
+ *
+ * and currently being used for kernel CXL support.
+ */
+
+enum cxl_dev_cap {
+	/* capabilities from Component Registers */
+	CXL_DEV_CAP_RAS,
+	CXL_DEV_CAP_HDM,
+	/* capabilities from Device Registers */
+	CXL_DEV_CAP_DEV_STATUS,
+	CXL_DEV_CAP_MAILBOX_PRIMARY,
+	CXL_DEV_CAP_MEMDEV,
+	CXL_MAX_CAPS = 64
+};
+
 struct cxl_dev_state *cxl_accel_state_create(struct device *dev);
 
 void cxl_set_dvsec(struct cxl_dev_state *cxlds, u16 dvsec);