[PATCH v3] cxl: Remove core/acpi.c and cxl core dependency on ACPI

[PATCH v3] cxl: Remove core/acpi.c and cxl core dependency on ACPI

[Dave Jiang]

It was a mistake to introduce core/acpi.c and putting ACPI dependency on
cxl_core when adding the extended linear cache support. Add a callback
in the cxl_root_decoder to retrieve the extended linear cache size from
ACPI via the cxl_acpi driver.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
v3:
- Remove commit log paragraph on adding extra dev parameter. (Jonathan)
- Add device ref put. (Jonathan)
- Adjust var declaration. (Jonathan)
- Move callback assignment to same group. (Jonathan)
---
 drivers/cxl/acpi.c            | 13 +++++++++++-
 drivers/cxl/core/Makefile     |  1 -
 drivers/cxl/core/acpi.c       | 11 ----------
 drivers/cxl/core/core.h       |  2 --
 drivers/cxl/core/port.c       |  5 ++++-
 drivers/cxl/core/region.c     |  5 ++++-
 drivers/cxl/cxl.h             | 10 ++++++++-
 tools/testing/cxl/Kbuild      |  2 +-
 tools/testing/cxl/test/cxl.c  | 40 +++++++++++++++++++++++++++++++++++
 tools/testing/cxl/test/mock.c | 19 +++++++++++++++++
 tools/testing/cxl/test/mock.h |  3 +++
 11 files changed, 92 insertions(+), 19 deletions(-)
 delete mode 100644 drivers/cxl/core/acpi.c

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index a1a99ec3f12c..48478bc406ee 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -335,6 +335,17 @@ static int add_or_reset_cxl_resource(struct resource *parent, struct resource *r
 	return rc;
 }
 
+static int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
+						   int nid,
+						   resource_size_t *size)
+{
+	return hmat_get_extended_linear_cache_size(backing_res, nid, size);
+}
+
+static const struct cxl_rd_ops acpi_rd_ops = {
+	.get_extended_linear_cache_size = cxl_acpi_get_extended_linear_cache_size,
+};
+
 DEFINE_FREE(put_cxlrd, struct cxl_root_decoder *,
 	    if (!IS_ERR_OR_NULL(_T)) put_device(&_T->cxlsd.cxld.dev))
 DEFINE_FREE(del_cxl_resource, struct resource *, if (_T) del_cxl_resource(_T))
@@ -373,7 +384,7 @@ static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws,
 		return rc;
 
 	struct cxl_root_decoder *cxlrd __free(put_cxlrd) =
-		cxl_root_decoder_alloc(root_port, ways);
+		cxl_root_decoder_alloc(root_port, ways, &acpi_rd_ops);
 
 	if (IS_ERR(cxlrd))
 		return PTR_ERR(cxlrd);
diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
index 79e2ef81fde8..5ad8fef210b5 100644
--- a/drivers/cxl/core/Makefile
+++ b/drivers/cxl/core/Makefile
@@ -15,7 +15,6 @@ cxl_core-y += hdm.o
 cxl_core-y += pmu.o
 cxl_core-y += cdat.o
 cxl_core-y += ras.o
-cxl_core-y += acpi.o
 cxl_core-$(CONFIG_TRACING) += trace.o
 cxl_core-$(CONFIG_CXL_REGION) += region.o
 cxl_core-$(CONFIG_CXL_MCE) += mce.o
diff --git a/drivers/cxl/core/acpi.c b/drivers/cxl/core/acpi.c
deleted file mode 100644
index f13b4dae6ac5..000000000000
--- a/drivers/cxl/core/acpi.c
+++ /dev/null
@@ -1,11 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/* Copyright(c) 2024 Intel Corporation. All rights reserved. */
-#include <linux/acpi.h>
-#include "cxl.h"
-#include "core.h"
-
-int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
-					    int nid, resource_size_t *size)
-{
-	return hmat_get_extended_linear_cache_size(backing_res, nid, size);
-}
diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 29b61828a847..9462aea9ce9d 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -120,8 +120,6 @@ int cxl_port_get_switch_dport_bandwidth(struct cxl_port *port,
 int cxl_ras_init(void);
 void cxl_ras_exit(void);
 int cxl_gpf_port_setup(struct cxl_dport *dport);
-int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
-					    int nid, resource_size_t *size);
 
 #ifdef CONFIG_CXL_FEATURES
 struct cxl_feat_entry *
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index eb46c6764d20..cbb9c5a3c309 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -1793,6 +1793,7 @@ static int cxl_switch_decoder_init(struct cxl_port *port,
  * cxl_root_decoder_alloc - Allocate a root level decoder
  * @port: owning CXL root of this decoder
  * @nr_targets: static number of downstream targets
+ * @ops: root decoder callback operations
  *
  * Return: A new cxl decoder to be registered by cxl_decoder_add(). A
  * 'CXL root' decoder is one that decodes from a top-level / static platform
@@ -1800,7 +1801,8 @@ static int cxl_switch_decoder_init(struct cxl_port *port,
  * topology.
  */
 struct cxl_root_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
-						unsigned int nr_targets)
+						unsigned int nr_targets,
+						const struct cxl_rd_ops *ops)
 {
 	struct cxl_root_decoder *cxlrd;
 	struct cxl_switch_decoder *cxlsd;
@@ -1839,6 +1841,7 @@ struct cxl_root_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
 
 	atomic_set(&cxlrd->region_id, rc);
 	cxlrd->qos_class = CXL_QOS_CLASS_INVALID;
+	cxlrd->ops = ops;
 	return cxlrd;
 }
 EXPORT_SYMBOL_NS_GPL(cxl_root_decoder_alloc, "CXL");
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 6e5e1460068d..0a5effbc0529 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -3287,7 +3287,10 @@ static int cxl_extended_linear_cache_resize(struct cxl_region *cxlr,
 	resource_size_t cache_size, start;
 	int rc;
 
-	rc = cxl_acpi_get_extended_linear_cache_size(res, nid, &cache_size);
+	if (!cxlrd->ops || !cxlrd->ops->get_extended_linear_cache_size)
+		return -EOPNOTSUPP;
+
+	rc = cxlrd->ops->get_extended_linear_cache_size(res, nid, &cache_size);
 	if (rc)
 		return rc;
 
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 3f1695c96abc..9a17e8beca7a 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -420,6 +420,11 @@ struct cxl_switch_decoder {
 struct cxl_root_decoder;
 typedef u64 (*cxl_hpa_to_spa_fn)(struct cxl_root_decoder *cxlrd, u64 hpa);
 
+struct cxl_rd_ops {
+	int (*get_extended_linear_cache_size)(struct resource *backing_res,
+					      int nid, resource_size_t *size);
+};
+
 /**
  * struct cxl_root_decoder - Static platform CXL address decoder
  * @res: host / parent resource for region allocations
@@ -428,6 +433,7 @@ typedef u64 (*cxl_hpa_to_spa_fn)(struct cxl_root_decoder *cxlrd, u64 hpa);
  * @platform_data: platform specific configuration data
  * @range_lock: sync region autodiscovery by address range
  * @qos_class: QoS performance class cookie
+ * @ops: root decoder specific operations
  * @cxlsd: base cxl switch decoder
  */
 struct cxl_root_decoder {
@@ -437,6 +443,7 @@ struct cxl_root_decoder {
 	void *platform_data;
 	struct mutex range_lock;
 	int qos_class;
+	const struct cxl_rd_ops *ops;
 	struct cxl_switch_decoder cxlsd;
 };
 
@@ -775,7 +782,8 @@ bool is_root_decoder(struct device *dev);
 bool is_switch_decoder(struct device *dev);
 bool is_endpoint_decoder(struct device *dev);
 struct cxl_root_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
-						unsigned int nr_targets);
+						unsigned int nr_targets,
+						const struct cxl_rd_ops *ops);
 struct cxl_switch_decoder *cxl_switch_decoder_alloc(struct cxl_port *port,
 						    unsigned int nr_targets);
 int cxl_decoder_add(struct cxl_decoder *cxld, int *target_map);
diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild
index 31a2d73c963f..c4fd68db41ba 100644
--- a/tools/testing/cxl/Kbuild
+++ b/tools/testing/cxl/Kbuild
@@ -15,6 +15,7 @@ ldflags-y += --wrap=devm_cxl_add_rch_dport
 ldflags-y += --wrap=cxl_rcd_component_reg_phys
 ldflags-y += --wrap=cxl_endpoint_parse_cdat
 ldflags-y += --wrap=cxl_dport_init_ras_reporting
+ldflags-y += --wrap=hmat_get_extended_linear_cache_size
 
 DRIVERS := ../../../drivers
 CXL_SRC := $(DRIVERS)/cxl
@@ -62,7 +63,6 @@ cxl_core-y += $(CXL_CORE_SRC)/hdm.o
 cxl_core-y += $(CXL_CORE_SRC)/pmu.o
 cxl_core-y += $(CXL_CORE_SRC)/cdat.o
 cxl_core-y += $(CXL_CORE_SRC)/ras.o
-cxl_core-y += $(CXL_CORE_SRC)/acpi.o
 cxl_core-$(CONFIG_TRACING) += $(CXL_CORE_SRC)/trace.o
 cxl_core-$(CONFIG_CXL_REGION) += $(CXL_CORE_SRC)/region.o
 cxl_core-$(CONFIG_CXL_MCE) += $(CXL_CORE_SRC)/mce.o
diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
index 8a5815ca870d..c0eb95632062 100644
--- a/tools/testing/cxl/test/cxl.c
+++ b/tools/testing/cxl/test/cxl.c
@@ -470,6 +470,44 @@ struct cxl_cedt_context {
 	struct device *dev;
 };
 
+static int match_root_decoder_by_range(struct device *dev, const void *data)
+{
+	struct cxl_root_decoder *cxlrd;
+	const struct range *r2 = data;
+	const struct range *r1;
+
+	if (!is_root_decoder(dev))
+		return 0;
+
+	cxlrd = to_cxl_root_decoder(dev);
+	r1 = &cxlrd->cxlsd.cxld.hpa_range;
+	return range_contains(r1, r2);
+}
+
+static int mock_hmat_get_extended_linear_cache_size(struct resource *backing_res,
+						    int nid, resource_size_t *size)
+{
+	struct range backing_range = {
+		.start = backing_res->start,
+		.end = backing_res->end,
+	};
+	struct cxl_decoder *cxld;
+	struct cxl_port *port;
+
+	struct device *dev __free(put_device) =
+		bus_find_device(&cxl_bus_type, NULL, &backing_range,
+				match_root_decoder_by_range);
+	if (!dev)
+		return -ENODEV;
+
+	cxld = to_cxl_decoder(dev);
+	port = to_cxl_port(cxld->dev.parent);
+	if (is_mock_dev(port->uport_dev))
+		return -EOPNOTSUPP;
+
+	return hmat_get_extended_linear_cache_size(backing_res, nid, size);
+}
+
 static int mock_acpi_table_parse_cedt(enum acpi_cedt_type id,
 				      acpi_tbl_entry_handler_arg handler_arg,
 				      void *arg)
@@ -1039,6 +1077,8 @@ static struct cxl_mock_ops cxl_mock_ops = {
 	.devm_cxl_add_passthrough_decoder = mock_cxl_add_passthrough_decoder,
 	.devm_cxl_enumerate_decoders = mock_cxl_enumerate_decoders,
 	.cxl_endpoint_parse_cdat = mock_cxl_endpoint_parse_cdat,
+	.hmat_get_extended_linear_cache_size =
+		mock_hmat_get_extended_linear_cache_size,
 	.list = LIST_HEAD_INIT(cxl_mock_ops.list),
 };
 
diff --git a/tools/testing/cxl/test/mock.c b/tools/testing/cxl/test/mock.c
index 1989ae020df3..ec8fc4a44073 100644
--- a/tools/testing/cxl/test/mock.c
+++ b/tools/testing/cxl/test/mock.c
@@ -78,6 +78,25 @@ int __wrap_acpi_table_parse_cedt(enum acpi_cedt_type id,
 }
 EXPORT_SYMBOL_NS_GPL(__wrap_acpi_table_parse_cedt, "ACPI");
 
+int __wrap_hmat_get_extended_linear_cache_size(struct resource *res,
+					       int nid,
+					       resource_size_t *size)
+{
+	int index;
+	struct cxl_mock_ops *ops = get_cxl_mock_ops(&index);
+	int rc;
+
+	if (ops)
+		rc = ops->hmat_get_extended_linear_cache_size(res, nid, size);
+	else
+		rc = hmat_get_extended_linear_cache_size(res, nid, size);
+
+	put_cxl_mock_ops(index);
+
+	return rc;
+}
+EXPORT_SYMBOL_NS_GPL(__wrap_hmat_get_extended_linear_cache_size, "CXL");
+
 acpi_status __wrap_acpi_evaluate_integer(acpi_handle handle,
 					 acpi_string pathname,
 					 struct acpi_object_list *arguments,
diff --git a/tools/testing/cxl/test/mock.h b/tools/testing/cxl/test/mock.h
index d1b0271d2822..469a270ee245 100644
--- a/tools/testing/cxl/test/mock.h
+++ b/tools/testing/cxl/test/mock.h
@@ -26,6 +26,9 @@ struct cxl_mock_ops {
 	int (*devm_cxl_enumerate_decoders)(
 		struct cxl_hdm *hdm, struct cxl_endpoint_dvsec_info *info);
 	void (*cxl_endpoint_parse_cdat)(struct cxl_port *port);
+	int (*hmat_get_extended_linear_cache_size)(struct resource *backing_res,
+						   int nid,
+						   resource_size_t *size);
 };
 
 void register_cxl_mock_ops(struct cxl_mock_ops *ops);

base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494
-- 
2.49.0

Re: [PATCH v3] cxl: Remove core/acpi.c and cxl core dependency on ACPI

[Jonathan Cameron]

On Tue, 10 Jun 2025 10:29:38 -0700
Dave Jiang <dave.jiang@intel.com> wrote:

> It was a mistake to introduce core/acpi.c and putting ACPI dependency on
> cxl_core when adding the extended linear cache support. Add a callback
> in the cxl_root_decoder to retrieve the extended linear cache size from
> ACPI via the cxl_acpi driver.
> 
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
LGTM
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>

Re: [PATCH v3] cxl: Remove core/acpi.c and cxl core dependency on ACPI

[Alison Schofield]

On Tue, Jun 10, 2025 at 10:29:38AM -0700, Dave Jiang wrote:
> It was a mistake to introduce core/acpi.c and putting ACPI dependency on
> cxl_core when adding the extended linear cache support. Add a callback
> in the cxl_root_decoder to retrieve the extended linear cache size from
> ACPI via the cxl_acpi driver.

I see the introduction of struct cxl_rd_ops and am wondering why
the other existing root decoder callback is not added to that
new grouping...
* @hpa_to_spa: translate CXL host-physical-address to Platform system-physical-address

Seems it can join that _ops group with some updates at the call site.
BTW - another root decoder callback is in the works for the inverse
spa_to_hpa, so that'll join your ops group too.

If you don't want to do that now, or it's not a fit, you can add:
Reviewed-by: Alison Schofield <alison.schofield@intel.com>

Otherwise, I'll review and tag a v4.

> 
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> ---
> v3:
> - Remove commit log paragraph on adding extra dev parameter. (Jonathan)
> - Add device ref put. (Jonathan)
> - Adjust var declaration. (Jonathan)
> - Move callback assignment to same group. (Jonathan)
> ---
>  drivers/cxl/acpi.c            | 13 +++++++++++-
>  drivers/cxl/core/Makefile     |  1 -
>  drivers/cxl/core/acpi.c       | 11 ----------
>  drivers/cxl/core/core.h       |  2 --
>  drivers/cxl/core/port.c       |  5 ++++-
>  drivers/cxl/core/region.c     |  5 ++++-
>  drivers/cxl/cxl.h             | 10 ++++++++-
>  tools/testing/cxl/Kbuild      |  2 +-
>  tools/testing/cxl/test/cxl.c  | 40 +++++++++++++++++++++++++++++++++++
>  tools/testing/cxl/test/mock.c | 19 +++++++++++++++++
>  tools/testing/cxl/test/mock.h |  3 +++
>  11 files changed, 92 insertions(+), 19 deletions(-)
>  delete mode 100644 drivers/cxl/core/acpi.c
> 
> diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
> index a1a99ec3f12c..48478bc406ee 100644
> --- a/drivers/cxl/acpi.c
> +++ b/drivers/cxl/acpi.c
> @@ -335,6 +335,17 @@ static int add_or_reset_cxl_resource(struct resource *parent, struct resource *r
>  	return rc;
>  }
>  
> +static int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
> +						   int nid,
> +						   resource_size_t *size)
> +{
> +	return hmat_get_extended_linear_cache_size(backing_res, nid, size);
> +}
> +
> +static const struct cxl_rd_ops acpi_rd_ops = {
> +	.get_extended_linear_cache_size = cxl_acpi_get_extended_linear_cache_size,
> +};
> +
>  DEFINE_FREE(put_cxlrd, struct cxl_root_decoder *,
>  	    if (!IS_ERR_OR_NULL(_T)) put_device(&_T->cxlsd.cxld.dev))
>  DEFINE_FREE(del_cxl_resource, struct resource *, if (_T) del_cxl_resource(_T))
> @@ -373,7 +384,7 @@ static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws,
>  		return rc;
>  
>  	struct cxl_root_decoder *cxlrd __free(put_cxlrd) =
> -		cxl_root_decoder_alloc(root_port, ways);
> +		cxl_root_decoder_alloc(root_port, ways, &acpi_rd_ops);
>  
>  	if (IS_ERR(cxlrd))
>  		return PTR_ERR(cxlrd);
> diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
> index 79e2ef81fde8..5ad8fef210b5 100644
> --- a/drivers/cxl/core/Makefile
> +++ b/drivers/cxl/core/Makefile
> @@ -15,7 +15,6 @@ cxl_core-y += hdm.o
>  cxl_core-y += pmu.o
>  cxl_core-y += cdat.o
>  cxl_core-y += ras.o
> -cxl_core-y += acpi.o
>  cxl_core-$(CONFIG_TRACING) += trace.o
>  cxl_core-$(CONFIG_CXL_REGION) += region.o
>  cxl_core-$(CONFIG_CXL_MCE) += mce.o
> diff --git a/drivers/cxl/core/acpi.c b/drivers/cxl/core/acpi.c
> deleted file mode 100644
> index f13b4dae6ac5..000000000000
> --- a/drivers/cxl/core/acpi.c
> +++ /dev/null
> @@ -1,11 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-only
> -/* Copyright(c) 2024 Intel Corporation. All rights reserved. */
> -#include <linux/acpi.h>
> -#include "cxl.h"
> -#include "core.h"
> -
> -int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
> -					    int nid, resource_size_t *size)
> -{
> -	return hmat_get_extended_linear_cache_size(backing_res, nid, size);
> -}
> diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
> index 29b61828a847..9462aea9ce9d 100644
> --- a/drivers/cxl/core/core.h
> +++ b/drivers/cxl/core/core.h
> @@ -120,8 +120,6 @@ int cxl_port_get_switch_dport_bandwidth(struct cxl_port *port,
>  int cxl_ras_init(void);
>  void cxl_ras_exit(void);
>  int cxl_gpf_port_setup(struct cxl_dport *dport);
> -int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
> -					    int nid, resource_size_t *size);
>  
>  #ifdef CONFIG_CXL_FEATURES
>  struct cxl_feat_entry *
> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> index eb46c6764d20..cbb9c5a3c309 100644
> --- a/drivers/cxl/core/port.c
> +++ b/drivers/cxl/core/port.c
> @@ -1793,6 +1793,7 @@ static int cxl_switch_decoder_init(struct cxl_port *port,
>   * cxl_root_decoder_alloc - Allocate a root level decoder
>   * @port: owning CXL root of this decoder
>   * @nr_targets: static number of downstream targets
> + * @ops: root decoder callback operations
>   *
>   * Return: A new cxl decoder to be registered by cxl_decoder_add(). A
>   * 'CXL root' decoder is one that decodes from a top-level / static platform
> @@ -1800,7 +1801,8 @@ static int cxl_switch_decoder_init(struct cxl_port *port,
>   * topology.
>   */
>  struct cxl_root_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
> -						unsigned int nr_targets)
> +						unsigned int nr_targets,
> +						const struct cxl_rd_ops *ops)
>  {
>  	struct cxl_root_decoder *cxlrd;
>  	struct cxl_switch_decoder *cxlsd;
> @@ -1839,6 +1841,7 @@ struct cxl_root_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
>  
>  	atomic_set(&cxlrd->region_id, rc);
>  	cxlrd->qos_class = CXL_QOS_CLASS_INVALID;
> +	cxlrd->ops = ops;
>  	return cxlrd;
>  }
>  EXPORT_SYMBOL_NS_GPL(cxl_root_decoder_alloc, "CXL");
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 6e5e1460068d..0a5effbc0529 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3287,7 +3287,10 @@ static int cxl_extended_linear_cache_resize(struct cxl_region *cxlr,
>  	resource_size_t cache_size, start;
>  	int rc;
>  
> -	rc = cxl_acpi_get_extended_linear_cache_size(res, nid, &cache_size);
> +	if (!cxlrd->ops || !cxlrd->ops->get_extended_linear_cache_size)
> +		return -EOPNOTSUPP;
> +
> +	rc = cxlrd->ops->get_extended_linear_cache_size(res, nid, &cache_size);
>  	if (rc)
>  		return rc;
>  
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 3f1695c96abc..9a17e8beca7a 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -420,6 +420,11 @@ struct cxl_switch_decoder {
>  struct cxl_root_decoder;
>  typedef u64 (*cxl_hpa_to_spa_fn)(struct cxl_root_decoder *cxlrd, u64 hpa);
>  
> +struct cxl_rd_ops {
> +	int (*get_extended_linear_cache_size)(struct resource *backing_res,
> +					      int nid, resource_size_t *size);
> +};
> +
>  /**
>   * struct cxl_root_decoder - Static platform CXL address decoder
>   * @res: host / parent resource for region allocations
> @@ -428,6 +433,7 @@ typedef u64 (*cxl_hpa_to_spa_fn)(struct cxl_root_decoder *cxlrd, u64 hpa);
>   * @platform_data: platform specific configuration data
>   * @range_lock: sync region autodiscovery by address range
>   * @qos_class: QoS performance class cookie
> + * @ops: root decoder specific operations
>   * @cxlsd: base cxl switch decoder
>   */
>  struct cxl_root_decoder {
> @@ -437,6 +443,7 @@ struct cxl_root_decoder {
>  	void *platform_data;
>  	struct mutex range_lock;
>  	int qos_class;
> +	const struct cxl_rd_ops *ops;
>  	struct cxl_switch_decoder cxlsd;
>  };
>  
> @@ -775,7 +782,8 @@ bool is_root_decoder(struct device *dev);
>  bool is_switch_decoder(struct device *dev);
>  bool is_endpoint_decoder(struct device *dev);
>  struct cxl_root_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
> -						unsigned int nr_targets);
> +						unsigned int nr_targets,
> +						const struct cxl_rd_ops *ops);
>  struct cxl_switch_decoder *cxl_switch_decoder_alloc(struct cxl_port *port,
>  						    unsigned int nr_targets);
>  int cxl_decoder_add(struct cxl_decoder *cxld, int *target_map);
> diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild
> index 31a2d73c963f..c4fd68db41ba 100644
> --- a/tools/testing/cxl/Kbuild
> +++ b/tools/testing/cxl/Kbuild
> @@ -15,6 +15,7 @@ ldflags-y += --wrap=devm_cxl_add_rch_dport
>  ldflags-y += --wrap=cxl_rcd_component_reg_phys
>  ldflags-y += --wrap=cxl_endpoint_parse_cdat
>  ldflags-y += --wrap=cxl_dport_init_ras_reporting
> +ldflags-y += --wrap=hmat_get_extended_linear_cache_size
>  
>  DRIVERS := ../../../drivers
>  CXL_SRC := $(DRIVERS)/cxl
> @@ -62,7 +63,6 @@ cxl_core-y += $(CXL_CORE_SRC)/hdm.o
>  cxl_core-y += $(CXL_CORE_SRC)/pmu.o
>  cxl_core-y += $(CXL_CORE_SRC)/cdat.o
>  cxl_core-y += $(CXL_CORE_SRC)/ras.o
> -cxl_core-y += $(CXL_CORE_SRC)/acpi.o
>  cxl_core-$(CONFIG_TRACING) += $(CXL_CORE_SRC)/trace.o
>  cxl_core-$(CONFIG_CXL_REGION) += $(CXL_CORE_SRC)/region.o
>  cxl_core-$(CONFIG_CXL_MCE) += $(CXL_CORE_SRC)/mce.o
> diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
> index 8a5815ca870d..c0eb95632062 100644
> --- a/tools/testing/cxl/test/cxl.c
> +++ b/tools/testing/cxl/test/cxl.c
> @@ -470,6 +470,44 @@ struct cxl_cedt_context {
>  	struct device *dev;
>  };
>  
> +static int match_root_decoder_by_range(struct device *dev, const void *data)
> +{
> +	struct cxl_root_decoder *cxlrd;
> +	const struct range *r2 = data;
> +	const struct range *r1;
> +
> +	if (!is_root_decoder(dev))
> +		return 0;
> +
> +	cxlrd = to_cxl_root_decoder(dev);
> +	r1 = &cxlrd->cxlsd.cxld.hpa_range;
> +	return range_contains(r1, r2);
> +}
> +
> +static int mock_hmat_get_extended_linear_cache_size(struct resource *backing_res,
> +						    int nid, resource_size_t *size)
> +{
> +	struct range backing_range = {
> +		.start = backing_res->start,
> +		.end = backing_res->end,
> +	};
> +	struct cxl_decoder *cxld;
> +	struct cxl_port *port;
> +
> +	struct device *dev __free(put_device) =
> +		bus_find_device(&cxl_bus_type, NULL, &backing_range,
> +				match_root_decoder_by_range);
> +	if (!dev)
> +		return -ENODEV;
> +
> +	cxld = to_cxl_decoder(dev);
> +	port = to_cxl_port(cxld->dev.parent);
> +	if (is_mock_dev(port->uport_dev))
> +		return -EOPNOTSUPP;
> +
> +	return hmat_get_extended_linear_cache_size(backing_res, nid, size);
> +}
> +
>  static int mock_acpi_table_parse_cedt(enum acpi_cedt_type id,
>  				      acpi_tbl_entry_handler_arg handler_arg,
>  				      void *arg)
> @@ -1039,6 +1077,8 @@ static struct cxl_mock_ops cxl_mock_ops = {
>  	.devm_cxl_add_passthrough_decoder = mock_cxl_add_passthrough_decoder,
>  	.devm_cxl_enumerate_decoders = mock_cxl_enumerate_decoders,
>  	.cxl_endpoint_parse_cdat = mock_cxl_endpoint_parse_cdat,
> +	.hmat_get_extended_linear_cache_size =
> +		mock_hmat_get_extended_linear_cache_size,
>  	.list = LIST_HEAD_INIT(cxl_mock_ops.list),
>  };
>  
> diff --git a/tools/testing/cxl/test/mock.c b/tools/testing/cxl/test/mock.c
> index 1989ae020df3..ec8fc4a44073 100644
> --- a/tools/testing/cxl/test/mock.c
> +++ b/tools/testing/cxl/test/mock.c
> @@ -78,6 +78,25 @@ int __wrap_acpi_table_parse_cedt(enum acpi_cedt_type id,
>  }
>  EXPORT_SYMBOL_NS_GPL(__wrap_acpi_table_parse_cedt, "ACPI");
>  
> +int __wrap_hmat_get_extended_linear_cache_size(struct resource *res,
> +					       int nid,
> +					       resource_size_t *size)
> +{
> +	int index;
> +	struct cxl_mock_ops *ops = get_cxl_mock_ops(&index);
> +	int rc;
> +
> +	if (ops)
> +		rc = ops->hmat_get_extended_linear_cache_size(res, nid, size);
> +	else
> +		rc = hmat_get_extended_linear_cache_size(res, nid, size);
> +
> +	put_cxl_mock_ops(index);
> +
> +	return rc;
> +}
> +EXPORT_SYMBOL_NS_GPL(__wrap_hmat_get_extended_linear_cache_size, "CXL");
> +
>  acpi_status __wrap_acpi_evaluate_integer(acpi_handle handle,
>  					 acpi_string pathname,
>  					 struct acpi_object_list *arguments,
> diff --git a/tools/testing/cxl/test/mock.h b/tools/testing/cxl/test/mock.h
> index d1b0271d2822..469a270ee245 100644
> --- a/tools/testing/cxl/test/mock.h
> +++ b/tools/testing/cxl/test/mock.h
> @@ -26,6 +26,9 @@ struct cxl_mock_ops {
>  	int (*devm_cxl_enumerate_decoders)(
>  		struct cxl_hdm *hdm, struct cxl_endpoint_dvsec_info *info);
>  	void (*cxl_endpoint_parse_cdat)(struct cxl_port *port);
> +	int (*hmat_get_extended_linear_cache_size)(struct resource *backing_res,
> +						   int nid,
> +						   resource_size_t *size);
>  };
>  
>  void register_cxl_mock_ops(struct cxl_mock_ops *ops);
> 
> base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494
> -- 
> 2.49.0
> 

Re: [PATCH v3] cxl: Remove core/acpi.c and cxl core dependency on ACPI

[Dave Jiang]

On 7/2/25 1:53 PM, Alison Schofield wrote:
> On Tue, Jun 10, 2025 at 10:29:38AM -0700, Dave Jiang wrote:
>> It was a mistake to introduce core/acpi.c and putting ACPI dependency on
>> cxl_core when adding the extended linear cache support. Add a callback
>> in the cxl_root_decoder to retrieve the extended linear cache size from
>> ACPI via the cxl_acpi driver.
> 
> I see the introduction of struct cxl_rd_ops and am wondering why
> the other existing root decoder callback is not added to that
> new grouping...
> * @hpa_to_spa: translate CXL host-physical-address to Platform system-physical-address
> 
> Seems it can join that _ops group with some updates at the call site.
> BTW - another root decoder callback is in the works for the inverse
> spa_to_hpa, so that'll join your ops group too.

Will create a follow on patch for this.
DJ
> 
> If you don't want to do that now, or it's not a fit, you can add:
> Reviewed-by: Alison Schofield <alison.schofield@intel.com>
> 
> Otherwise, I'll review and tag a v4.
> 
>>
>> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
>> ---
>> v3:
>> - Remove commit log paragraph on adding extra dev parameter. (Jonathan)
>> - Add device ref put. (Jonathan)
>> - Adjust var declaration. (Jonathan)
>> - Move callback assignment to same group. (Jonathan)
>> ---
>>  drivers/cxl/acpi.c            | 13 +++++++++++-
>>  drivers/cxl/core/Makefile     |  1 -
>>  drivers/cxl/core/acpi.c       | 11 ----------
>>  drivers/cxl/core/core.h       |  2 --
>>  drivers/cxl/core/port.c       |  5 ++++-
>>  drivers/cxl/core/region.c     |  5 ++++-
>>  drivers/cxl/cxl.h             | 10 ++++++++-
>>  tools/testing/cxl/Kbuild      |  2 +-
>>  tools/testing/cxl/test/cxl.c  | 40 +++++++++++++++++++++++++++++++++++
>>  tools/testing/cxl/test/mock.c | 19 +++++++++++++++++
>>  tools/testing/cxl/test/mock.h |  3 +++
>>  11 files changed, 92 insertions(+), 19 deletions(-)
>>  delete mode 100644 drivers/cxl/core/acpi.c
>>
>> diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
>> index a1a99ec3f12c..48478bc406ee 100644
>> --- a/drivers/cxl/acpi.c
>> +++ b/drivers/cxl/acpi.c
>> @@ -335,6 +335,17 @@ static int add_or_reset_cxl_resource(struct resource *parent, struct resource *r
>>  	return rc;
>>  }
>>  
>> +static int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
>> +						   int nid,
>> +						   resource_size_t *size)
>> +{
>> +	return hmat_get_extended_linear_cache_size(backing_res, nid, size);
>> +}
>> +
>> +static const struct cxl_rd_ops acpi_rd_ops = {
>> +	.get_extended_linear_cache_size = cxl_acpi_get_extended_linear_cache_size,
>> +};
>> +
>>  DEFINE_FREE(put_cxlrd, struct cxl_root_decoder *,
>>  	    if (!IS_ERR_OR_NULL(_T)) put_device(&_T->cxlsd.cxld.dev))
>>  DEFINE_FREE(del_cxl_resource, struct resource *, if (_T) del_cxl_resource(_T))
>> @@ -373,7 +384,7 @@ static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws,
>>  		return rc;
>>  
>>  	struct cxl_root_decoder *cxlrd __free(put_cxlrd) =
>> -		cxl_root_decoder_alloc(root_port, ways);
>> +		cxl_root_decoder_alloc(root_port, ways, &acpi_rd_ops);
>>  
>>  	if (IS_ERR(cxlrd))
>>  		return PTR_ERR(cxlrd);
>> diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
>> index 79e2ef81fde8..5ad8fef210b5 100644
>> --- a/drivers/cxl/core/Makefile
>> +++ b/drivers/cxl/core/Makefile
>> @@ -15,7 +15,6 @@ cxl_core-y += hdm.o
>>  cxl_core-y += pmu.o
>>  cxl_core-y += cdat.o
>>  cxl_core-y += ras.o
>> -cxl_core-y += acpi.o
>>  cxl_core-$(CONFIG_TRACING) += trace.o
>>  cxl_core-$(CONFIG_CXL_REGION) += region.o
>>  cxl_core-$(CONFIG_CXL_MCE) += mce.o
>> diff --git a/drivers/cxl/core/acpi.c b/drivers/cxl/core/acpi.c
>> deleted file mode 100644
>> index f13b4dae6ac5..000000000000
>> --- a/drivers/cxl/core/acpi.c
>> +++ /dev/null
>> @@ -1,11 +0,0 @@
>> -// SPDX-License-Identifier: GPL-2.0-only
>> -/* Copyright(c) 2024 Intel Corporation. All rights reserved. */
>> -#include <linux/acpi.h>
>> -#include "cxl.h"
>> -#include "core.h"
>> -
>> -int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
>> -					    int nid, resource_size_t *size)
>> -{
>> -	return hmat_get_extended_linear_cache_size(backing_res, nid, size);
>> -}
>> diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
>> index 29b61828a847..9462aea9ce9d 100644
>> --- a/drivers/cxl/core/core.h
>> +++ b/drivers/cxl/core/core.h
>> @@ -120,8 +120,6 @@ int cxl_port_get_switch_dport_bandwidth(struct cxl_port *port,
>>  int cxl_ras_init(void);
>>  void cxl_ras_exit(void);
>>  int cxl_gpf_port_setup(struct cxl_dport *dport);
>> -int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
>> -					    int nid, resource_size_t *size);
>>  
>>  #ifdef CONFIG_CXL_FEATURES
>>  struct cxl_feat_entry *
>> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
>> index eb46c6764d20..cbb9c5a3c309 100644
>> --- a/drivers/cxl/core/port.c
>> +++ b/drivers/cxl/core/port.c
>> @@ -1793,6 +1793,7 @@ static int cxl_switch_decoder_init(struct cxl_port *port,
>>   * cxl_root_decoder_alloc - Allocate a root level decoder
>>   * @port: owning CXL root of this decoder
>>   * @nr_targets: static number of downstream targets
>> + * @ops: root decoder callback operations
>>   *
>>   * Return: A new cxl decoder to be registered by cxl_decoder_add(). A
>>   * 'CXL root' decoder is one that decodes from a top-level / static platform
>> @@ -1800,7 +1801,8 @@ static int cxl_switch_decoder_init(struct cxl_port *port,
>>   * topology.
>>   */
>>  struct cxl_root_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
>> -						unsigned int nr_targets)
>> +						unsigned int nr_targets,
>> +						const struct cxl_rd_ops *ops)
>>  {
>>  	struct cxl_root_decoder *cxlrd;
>>  	struct cxl_switch_decoder *cxlsd;
>> @@ -1839,6 +1841,7 @@ struct cxl_root_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
>>  
>>  	atomic_set(&cxlrd->region_id, rc);
>>  	cxlrd->qos_class = CXL_QOS_CLASS_INVALID;
>> +	cxlrd->ops = ops;
>>  	return cxlrd;
>>  }
>>  EXPORT_SYMBOL_NS_GPL(cxl_root_decoder_alloc, "CXL");
>> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
>> index 6e5e1460068d..0a5effbc0529 100644
>> --- a/drivers/cxl/core/region.c
>> +++ b/drivers/cxl/core/region.c
>> @@ -3287,7 +3287,10 @@ static int cxl_extended_linear_cache_resize(struct cxl_region *cxlr,
>>  	resource_size_t cache_size, start;
>>  	int rc;
>>  
>> -	rc = cxl_acpi_get_extended_linear_cache_size(res, nid, &cache_size);
>> +	if (!cxlrd->ops || !cxlrd->ops->get_extended_linear_cache_size)
>> +		return -EOPNOTSUPP;
>> +
>> +	rc = cxlrd->ops->get_extended_linear_cache_size(res, nid, &cache_size);
>>  	if (rc)
>>  		return rc;
>>  
>> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
>> index 3f1695c96abc..9a17e8beca7a 100644
>> --- a/drivers/cxl/cxl.h
>> +++ b/drivers/cxl/cxl.h
>> @@ -420,6 +420,11 @@ struct cxl_switch_decoder {
>>  struct cxl_root_decoder;
>>  typedef u64 (*cxl_hpa_to_spa_fn)(struct cxl_root_decoder *cxlrd, u64 hpa);
>>  
>> +struct cxl_rd_ops {
>> +	int (*get_extended_linear_cache_size)(struct resource *backing_res,
>> +					      int nid, resource_size_t *size);
>> +};
>> +
>>  /**
>>   * struct cxl_root_decoder - Static platform CXL address decoder
>>   * @res: host / parent resource for region allocations
>> @@ -428,6 +433,7 @@ typedef u64 (*cxl_hpa_to_spa_fn)(struct cxl_root_decoder *cxlrd, u64 hpa);
>>   * @platform_data: platform specific configuration data
>>   * @range_lock: sync region autodiscovery by address range
>>   * @qos_class: QoS performance class cookie
>> + * @ops: root decoder specific operations
>>   * @cxlsd: base cxl switch decoder
>>   */
>>  struct cxl_root_decoder {
>> @@ -437,6 +443,7 @@ struct cxl_root_decoder {
>>  	void *platform_data;
>>  	struct mutex range_lock;
>>  	int qos_class;
>> +	const struct cxl_rd_ops *ops;
>>  	struct cxl_switch_decoder cxlsd;
>>  };
>>  
>> @@ -775,7 +782,8 @@ bool is_root_decoder(struct device *dev);
>>  bool is_switch_decoder(struct device *dev);
>>  bool is_endpoint_decoder(struct device *dev);
>>  struct cxl_root_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
>> -						unsigned int nr_targets);
>> +						unsigned int nr_targets,
>> +						const struct cxl_rd_ops *ops);
>>  struct cxl_switch_decoder *cxl_switch_decoder_alloc(struct cxl_port *port,
>>  						    unsigned int nr_targets);
>>  int cxl_decoder_add(struct cxl_decoder *cxld, int *target_map);
>> diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild
>> index 31a2d73c963f..c4fd68db41ba 100644
>> --- a/tools/testing/cxl/Kbuild
>> +++ b/tools/testing/cxl/Kbuild
>> @@ -15,6 +15,7 @@ ldflags-y += --wrap=devm_cxl_add_rch_dport
>>  ldflags-y += --wrap=cxl_rcd_component_reg_phys
>>  ldflags-y += --wrap=cxl_endpoint_parse_cdat
>>  ldflags-y += --wrap=cxl_dport_init_ras_reporting
>> +ldflags-y += --wrap=hmat_get_extended_linear_cache_size
>>  
>>  DRIVERS := ../../../drivers
>>  CXL_SRC := $(DRIVERS)/cxl
>> @@ -62,7 +63,6 @@ cxl_core-y += $(CXL_CORE_SRC)/hdm.o
>>  cxl_core-y += $(CXL_CORE_SRC)/pmu.o
>>  cxl_core-y += $(CXL_CORE_SRC)/cdat.o
>>  cxl_core-y += $(CXL_CORE_SRC)/ras.o
>> -cxl_core-y += $(CXL_CORE_SRC)/acpi.o
>>  cxl_core-$(CONFIG_TRACING) += $(CXL_CORE_SRC)/trace.o
>>  cxl_core-$(CONFIG_CXL_REGION) += $(CXL_CORE_SRC)/region.o
>>  cxl_core-$(CONFIG_CXL_MCE) += $(CXL_CORE_SRC)/mce.o
>> diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
>> index 8a5815ca870d..c0eb95632062 100644
>> --- a/tools/testing/cxl/test/cxl.c
>> +++ b/tools/testing/cxl/test/cxl.c
>> @@ -470,6 +470,44 @@ struct cxl_cedt_context {
>>  	struct device *dev;
>>  };
>>  
>> +static int match_root_decoder_by_range(struct device *dev, const void *data)
>> +{
>> +	struct cxl_root_decoder *cxlrd;
>> +	const struct range *r2 = data;
>> +	const struct range *r1;
>> +
>> +	if (!is_root_decoder(dev))
>> +		return 0;
>> +
>> +	cxlrd = to_cxl_root_decoder(dev);
>> +	r1 = &cxlrd->cxlsd.cxld.hpa_range;
>> +	return range_contains(r1, r2);
>> +}
>> +
>> +static int mock_hmat_get_extended_linear_cache_size(struct resource *backing_res,
>> +						    int nid, resource_size_t *size)
>> +{
>> +	struct range backing_range = {
>> +		.start = backing_res->start,
>> +		.end = backing_res->end,
>> +	};
>> +	struct cxl_decoder *cxld;
>> +	struct cxl_port *port;
>> +
>> +	struct device *dev __free(put_device) =
>> +		bus_find_device(&cxl_bus_type, NULL, &backing_range,
>> +				match_root_decoder_by_range);
>> +	if (!dev)
>> +		return -ENODEV;
>> +
>> +	cxld = to_cxl_decoder(dev);
>> +	port = to_cxl_port(cxld->dev.parent);
>> +	if (is_mock_dev(port->uport_dev))
>> +		return -EOPNOTSUPP;
>> +
>> +	return hmat_get_extended_linear_cache_size(backing_res, nid, size);
>> +}
>> +
>>  static int mock_acpi_table_parse_cedt(enum acpi_cedt_type id,
>>  				      acpi_tbl_entry_handler_arg handler_arg,
>>  				      void *arg)
>> @@ -1039,6 +1077,8 @@ static struct cxl_mock_ops cxl_mock_ops = {
>>  	.devm_cxl_add_passthrough_decoder = mock_cxl_add_passthrough_decoder,
>>  	.devm_cxl_enumerate_decoders = mock_cxl_enumerate_decoders,
>>  	.cxl_endpoint_parse_cdat = mock_cxl_endpoint_parse_cdat,
>> +	.hmat_get_extended_linear_cache_size =
>> +		mock_hmat_get_extended_linear_cache_size,
>>  	.list = LIST_HEAD_INIT(cxl_mock_ops.list),
>>  };
>>  
>> diff --git a/tools/testing/cxl/test/mock.c b/tools/testing/cxl/test/mock.c
>> index 1989ae020df3..ec8fc4a44073 100644
>> --- a/tools/testing/cxl/test/mock.c
>> +++ b/tools/testing/cxl/test/mock.c
>> @@ -78,6 +78,25 @@ int __wrap_acpi_table_parse_cedt(enum acpi_cedt_type id,
>>  }
>>  EXPORT_SYMBOL_NS_GPL(__wrap_acpi_table_parse_cedt, "ACPI");
>>  
>> +int __wrap_hmat_get_extended_linear_cache_size(struct resource *res,
>> +					       int nid,
>> +					       resource_size_t *size)
>> +{
>> +	int index;
>> +	struct cxl_mock_ops *ops = get_cxl_mock_ops(&index);
>> +	int rc;
>> +
>> +	if (ops)
>> +		rc = ops->hmat_get_extended_linear_cache_size(res, nid, size);
>> +	else
>> +		rc = hmat_get_extended_linear_cache_size(res, nid, size);
>> +
>> +	put_cxl_mock_ops(index);
>> +
>> +	return rc;
>> +}
>> +EXPORT_SYMBOL_NS_GPL(__wrap_hmat_get_extended_linear_cache_size, "CXL");
>> +
>>  acpi_status __wrap_acpi_evaluate_integer(acpi_handle handle,
>>  					 acpi_string pathname,
>>  					 struct acpi_object_list *arguments,
>> diff --git a/tools/testing/cxl/test/mock.h b/tools/testing/cxl/test/mock.h
>> index d1b0271d2822..469a270ee245 100644
>> --- a/tools/testing/cxl/test/mock.h
>> +++ b/tools/testing/cxl/test/mock.h
>> @@ -26,6 +26,9 @@ struct cxl_mock_ops {
>>  	int (*devm_cxl_enumerate_decoders)(
>>  		struct cxl_hdm *hdm, struct cxl_endpoint_dvsec_info *info);
>>  	void (*cxl_endpoint_parse_cdat)(struct cxl_port *port);
>> +	int (*hmat_get_extended_linear_cache_size)(struct resource *backing_res,
>> +						   int nid,
>> +						   resource_size_t *size);
>>  };
>>  
>>  void register_cxl_mock_ops(struct cxl_mock_ops *ops);
>>
>> base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494
>> -- 
>> 2.49.0
>>

Re: [PATCH v3] cxl: Remove core/acpi.c and cxl core dependency on ACPI

[Dave Jiang]

On 6/10/25 10:29 AM, Dave Jiang wrote:
> It was a mistake to introduce core/acpi.c and putting ACPI dependency on
> cxl_core when adding the extended linear cache support. Add a callback
> in the cxl_root_decoder to retrieve the extended linear cache size from
> ACPI via the cxl_acpi driver.
> 
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>

Applied to cxl/next
1a45e1cd694fdf2d2a22e3c70a6917ff39fe77ab

> ---
> v3:
> - Remove commit log paragraph on adding extra dev parameter. (Jonathan)
> - Add device ref put. (Jonathan)
> - Adjust var declaration. (Jonathan)
> - Move callback assignment to same group. (Jonathan)
> ---
>  drivers/cxl/acpi.c            | 13 +++++++++++-
>  drivers/cxl/core/Makefile     |  1 -
>  drivers/cxl/core/acpi.c       | 11 ----------
>  drivers/cxl/core/core.h       |  2 --
>  drivers/cxl/core/port.c       |  5 ++++-
>  drivers/cxl/core/region.c     |  5 ++++-
>  drivers/cxl/cxl.h             | 10 ++++++++-
>  tools/testing/cxl/Kbuild      |  2 +-
>  tools/testing/cxl/test/cxl.c  | 40 +++++++++++++++++++++++++++++++++++
>  tools/testing/cxl/test/mock.c | 19 +++++++++++++++++
>  tools/testing/cxl/test/mock.h |  3 +++
>  11 files changed, 92 insertions(+), 19 deletions(-)
>  delete mode 100644 drivers/cxl/core/acpi.c
> 
> diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
> index a1a99ec3f12c..48478bc406ee 100644
> --- a/drivers/cxl/acpi.c
> +++ b/drivers/cxl/acpi.c
> @@ -335,6 +335,17 @@ static int add_or_reset_cxl_resource(struct resource *parent, struct resource *r
>  	return rc;
>  }
>  
> +static int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
> +						   int nid,
> +						   resource_size_t *size)
> +{
> +	return hmat_get_extended_linear_cache_size(backing_res, nid, size);
> +}
> +
> +static const struct cxl_rd_ops acpi_rd_ops = {
> +	.get_extended_linear_cache_size = cxl_acpi_get_extended_linear_cache_size,
> +};
> +
>  DEFINE_FREE(put_cxlrd, struct cxl_root_decoder *,
>  	    if (!IS_ERR_OR_NULL(_T)) put_device(&_T->cxlsd.cxld.dev))
>  DEFINE_FREE(del_cxl_resource, struct resource *, if (_T) del_cxl_resource(_T))
> @@ -373,7 +384,7 @@ static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws,
>  		return rc;
>  
>  	struct cxl_root_decoder *cxlrd __free(put_cxlrd) =
> -		cxl_root_decoder_alloc(root_port, ways);
> +		cxl_root_decoder_alloc(root_port, ways, &acpi_rd_ops);
>  
>  	if (IS_ERR(cxlrd))
>  		return PTR_ERR(cxlrd);
> diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
> index 79e2ef81fde8..5ad8fef210b5 100644
> --- a/drivers/cxl/core/Makefile
> +++ b/drivers/cxl/core/Makefile
> @@ -15,7 +15,6 @@ cxl_core-y += hdm.o
>  cxl_core-y += pmu.o
>  cxl_core-y += cdat.o
>  cxl_core-y += ras.o
> -cxl_core-y += acpi.o
>  cxl_core-$(CONFIG_TRACING) += trace.o
>  cxl_core-$(CONFIG_CXL_REGION) += region.o
>  cxl_core-$(CONFIG_CXL_MCE) += mce.o
> diff --git a/drivers/cxl/core/acpi.c b/drivers/cxl/core/acpi.c
> deleted file mode 100644
> index f13b4dae6ac5..000000000000
> --- a/drivers/cxl/core/acpi.c
> +++ /dev/null
> @@ -1,11 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-only
> -/* Copyright(c) 2024 Intel Corporation. All rights reserved. */
> -#include <linux/acpi.h>
> -#include "cxl.h"
> -#include "core.h"
> -
> -int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
> -					    int nid, resource_size_t *size)
> -{
> -	return hmat_get_extended_linear_cache_size(backing_res, nid, size);
> -}
> diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
> index 29b61828a847..9462aea9ce9d 100644
> --- a/drivers/cxl/core/core.h
> +++ b/drivers/cxl/core/core.h
> @@ -120,8 +120,6 @@ int cxl_port_get_switch_dport_bandwidth(struct cxl_port *port,
>  int cxl_ras_init(void);
>  void cxl_ras_exit(void);
>  int cxl_gpf_port_setup(struct cxl_dport *dport);
> -int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
> -					    int nid, resource_size_t *size);
>  
>  #ifdef CONFIG_CXL_FEATURES
>  struct cxl_feat_entry *
> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> index eb46c6764d20..cbb9c5a3c309 100644
> --- a/drivers/cxl/core/port.c
> +++ b/drivers/cxl/core/port.c
> @@ -1793,6 +1793,7 @@ static int cxl_switch_decoder_init(struct cxl_port *port,
>   * cxl_root_decoder_alloc - Allocate a root level decoder
>   * @port: owning CXL root of this decoder
>   * @nr_targets: static number of downstream targets
> + * @ops: root decoder callback operations
>   *
>   * Return: A new cxl decoder to be registered by cxl_decoder_add(). A
>   * 'CXL root' decoder is one that decodes from a top-level / static platform
> @@ -1800,7 +1801,8 @@ static int cxl_switch_decoder_init(struct cxl_port *port,
>   * topology.
>   */
>  struct cxl_root_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
> -						unsigned int nr_targets)
> +						unsigned int nr_targets,
> +						const struct cxl_rd_ops *ops)
>  {
>  	struct cxl_root_decoder *cxlrd;
>  	struct cxl_switch_decoder *cxlsd;
> @@ -1839,6 +1841,7 @@ struct cxl_root_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
>  
>  	atomic_set(&cxlrd->region_id, rc);
>  	cxlrd->qos_class = CXL_QOS_CLASS_INVALID;
> +	cxlrd->ops = ops;
>  	return cxlrd;
>  }
>  EXPORT_SYMBOL_NS_GPL(cxl_root_decoder_alloc, "CXL");
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 6e5e1460068d..0a5effbc0529 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3287,7 +3287,10 @@ static int cxl_extended_linear_cache_resize(struct cxl_region *cxlr,
>  	resource_size_t cache_size, start;
>  	int rc;
>  
> -	rc = cxl_acpi_get_extended_linear_cache_size(res, nid, &cache_size);
> +	if (!cxlrd->ops || !cxlrd->ops->get_extended_linear_cache_size)
> +		return -EOPNOTSUPP;
> +
> +	rc = cxlrd->ops->get_extended_linear_cache_size(res, nid, &cache_size);
>  	if (rc)
>  		return rc;
>  
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 3f1695c96abc..9a17e8beca7a 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -420,6 +420,11 @@ struct cxl_switch_decoder {
>  struct cxl_root_decoder;
>  typedef u64 (*cxl_hpa_to_spa_fn)(struct cxl_root_decoder *cxlrd, u64 hpa);
>  
> +struct cxl_rd_ops {
> +	int (*get_extended_linear_cache_size)(struct resource *backing_res,
> +					      int nid, resource_size_t *size);
> +};
> +
>  /**
>   * struct cxl_root_decoder - Static platform CXL address decoder
>   * @res: host / parent resource for region allocations
> @@ -428,6 +433,7 @@ typedef u64 (*cxl_hpa_to_spa_fn)(struct cxl_root_decoder *cxlrd, u64 hpa);
>   * @platform_data: platform specific configuration data
>   * @range_lock: sync region autodiscovery by address range
>   * @qos_class: QoS performance class cookie
> + * @ops: root decoder specific operations
>   * @cxlsd: base cxl switch decoder
>   */
>  struct cxl_root_decoder {
> @@ -437,6 +443,7 @@ struct cxl_root_decoder {
>  	void *platform_data;
>  	struct mutex range_lock;
>  	int qos_class;
> +	const struct cxl_rd_ops *ops;
>  	struct cxl_switch_decoder cxlsd;
>  };
>  
> @@ -775,7 +782,8 @@ bool is_root_decoder(struct device *dev);
>  bool is_switch_decoder(struct device *dev);
>  bool is_endpoint_decoder(struct device *dev);
>  struct cxl_root_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
> -						unsigned int nr_targets);
> +						unsigned int nr_targets,
> +						const struct cxl_rd_ops *ops);
>  struct cxl_switch_decoder *cxl_switch_decoder_alloc(struct cxl_port *port,
>  						    unsigned int nr_targets);
>  int cxl_decoder_add(struct cxl_decoder *cxld, int *target_map);
> diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild
> index 31a2d73c963f..c4fd68db41ba 100644
> --- a/tools/testing/cxl/Kbuild
> +++ b/tools/testing/cxl/Kbuild
> @@ -15,6 +15,7 @@ ldflags-y += --wrap=devm_cxl_add_rch_dport
>  ldflags-y += --wrap=cxl_rcd_component_reg_phys
>  ldflags-y += --wrap=cxl_endpoint_parse_cdat
>  ldflags-y += --wrap=cxl_dport_init_ras_reporting
> +ldflags-y += --wrap=hmat_get_extended_linear_cache_size
>  
>  DRIVERS := ../../../drivers
>  CXL_SRC := $(DRIVERS)/cxl
> @@ -62,7 +63,6 @@ cxl_core-y += $(CXL_CORE_SRC)/hdm.o
>  cxl_core-y += $(CXL_CORE_SRC)/pmu.o
>  cxl_core-y += $(CXL_CORE_SRC)/cdat.o
>  cxl_core-y += $(CXL_CORE_SRC)/ras.o
> -cxl_core-y += $(CXL_CORE_SRC)/acpi.o
>  cxl_core-$(CONFIG_TRACING) += $(CXL_CORE_SRC)/trace.o
>  cxl_core-$(CONFIG_CXL_REGION) += $(CXL_CORE_SRC)/region.o
>  cxl_core-$(CONFIG_CXL_MCE) += $(CXL_CORE_SRC)/mce.o
> diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
> index 8a5815ca870d..c0eb95632062 100644
> --- a/tools/testing/cxl/test/cxl.c
> +++ b/tools/testing/cxl/test/cxl.c
> @@ -470,6 +470,44 @@ struct cxl_cedt_context {
>  	struct device *dev;
>  };
>  
> +static int match_root_decoder_by_range(struct device *dev, const void *data)
> +{
> +	struct cxl_root_decoder *cxlrd;
> +	const struct range *r2 = data;
> +	const struct range *r1;
> +
> +	if (!is_root_decoder(dev))
> +		return 0;
> +
> +	cxlrd = to_cxl_root_decoder(dev);
> +	r1 = &cxlrd->cxlsd.cxld.hpa_range;
> +	return range_contains(r1, r2);
> +}
> +
> +static int mock_hmat_get_extended_linear_cache_size(struct resource *backing_res,
> +						    int nid, resource_size_t *size)
> +{
> +	struct range backing_range = {
> +		.start = backing_res->start,
> +		.end = backing_res->end,
> +	};
> +	struct cxl_decoder *cxld;
> +	struct cxl_port *port;
> +
> +	struct device *dev __free(put_device) =
> +		bus_find_device(&cxl_bus_type, NULL, &backing_range,
> +				match_root_decoder_by_range);
> +	if (!dev)
> +		return -ENODEV;
> +
> +	cxld = to_cxl_decoder(dev);
> +	port = to_cxl_port(cxld->dev.parent);
> +	if (is_mock_dev(port->uport_dev))
> +		return -EOPNOTSUPP;
> +
> +	return hmat_get_extended_linear_cache_size(backing_res, nid, size);
> +}
> +
>  static int mock_acpi_table_parse_cedt(enum acpi_cedt_type id,
>  				      acpi_tbl_entry_handler_arg handler_arg,
>  				      void *arg)
> @@ -1039,6 +1077,8 @@ static struct cxl_mock_ops cxl_mock_ops = {
>  	.devm_cxl_add_passthrough_decoder = mock_cxl_add_passthrough_decoder,
>  	.devm_cxl_enumerate_decoders = mock_cxl_enumerate_decoders,
>  	.cxl_endpoint_parse_cdat = mock_cxl_endpoint_parse_cdat,
> +	.hmat_get_extended_linear_cache_size =
> +		mock_hmat_get_extended_linear_cache_size,
>  	.list = LIST_HEAD_INIT(cxl_mock_ops.list),
>  };
>  
> diff --git a/tools/testing/cxl/test/mock.c b/tools/testing/cxl/test/mock.c
> index 1989ae020df3..ec8fc4a44073 100644
> --- a/tools/testing/cxl/test/mock.c
> +++ b/tools/testing/cxl/test/mock.c
> @@ -78,6 +78,25 @@ int __wrap_acpi_table_parse_cedt(enum acpi_cedt_type id,
>  }
>  EXPORT_SYMBOL_NS_GPL(__wrap_acpi_table_parse_cedt, "ACPI");
>  
> +int __wrap_hmat_get_extended_linear_cache_size(struct resource *res,
> +					       int nid,
> +					       resource_size_t *size)
> +{
> +	int index;
> +	struct cxl_mock_ops *ops = get_cxl_mock_ops(&index);
> +	int rc;
> +
> +	if (ops)
> +		rc = ops->hmat_get_extended_linear_cache_size(res, nid, size);
> +	else
> +		rc = hmat_get_extended_linear_cache_size(res, nid, size);
> +
> +	put_cxl_mock_ops(index);
> +
> +	return rc;
> +}
> +EXPORT_SYMBOL_NS_GPL(__wrap_hmat_get_extended_linear_cache_size, "CXL");
> +
>  acpi_status __wrap_acpi_evaluate_integer(acpi_handle handle,
>  					 acpi_string pathname,
>  					 struct acpi_object_list *arguments,
> diff --git a/tools/testing/cxl/test/mock.h b/tools/testing/cxl/test/mock.h
> index d1b0271d2822..469a270ee245 100644
> --- a/tools/testing/cxl/test/mock.h
> +++ b/tools/testing/cxl/test/mock.h
> @@ -26,6 +26,9 @@ struct cxl_mock_ops {
>  	int (*devm_cxl_enumerate_decoders)(
>  		struct cxl_hdm *hdm, struct cxl_endpoint_dvsec_info *info);
>  	void (*cxl_endpoint_parse_cdat)(struct cxl_port *port);
> +	int (*hmat_get_extended_linear_cache_size)(struct resource *backing_res,
> +						   int nid,
> +						   resource_size_t *size);
>  };
>  
>  void register_cxl_mock_ops(struct cxl_mock_ops *ops);
> 
> base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494

[REWORK][PATCH] cxl: Remove core/acpi.c and cxl core dependency on ACPI

[Robert Richter]

Hi Dave,

On 03.07.25 16:49:11, Dave Jiang wrote:
> 
> 
> On 6/10/25 10:29 AM, Dave Jiang wrote:
> > It was a mistake to introduce core/acpi.c and putting ACPI dependency on
> > cxl_core when adding the extended linear cache support. Add a callback
> > in the cxl_root_decoder to retrieve the extended linear cache size from
> > ACPI via the cxl_acpi driver.
> > 
> > Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> 
> Applied to cxl/next
> 1a45e1cd694fdf2d2a22e3c70a6917ff39fe77ab

I am sorry to come back to this patch that late in the process. While
rebasing my current region rework and address translation patches I
came across your patch and realized that I have a much more simpler
rework of that in my patch queue. I extracted that patch below from my
series I am working on. Could you take a look at it? The changes are
less intrusive and part of my rework required for address translation.
If it looks good to you and during review, I rather prefer to replace
your patch with this one. Note that I have follow on patches that
reduce more code and remove the cxl_extended_linear_cache_resize()
function entirely.

Patch below bases on:

 ac0fe6a57317 cxl: make cxl_bus_type constant

Many thanks,

-Robert




From fd3f1f5b33313bb10a2e51861031015ac48a8cd1 Mon Sep 17 00:00:00 2001
From: Robert Richter <rrichter@amd.com>
Date: Fri, 11 Jul 2025 11:56:56 +0200
Subject: [PATCH] cxl: Remove core/acpi.c and cxl core dependency on ACPI

From Dave [1]:

"""
It was a mistake to introduce core/acpi.c and putting ACPI dependency on
cxl_core when adding the extended linear cache support.
"""

Current implementation calls hmat_get_extended_linear_cache_size() of
the ACPI subsystem. That external reference causes issue running
cxl_test as there is no way to "mock" that function and ignore it when
using cxl test.

Instead of working around that using cxlrd ops and extensively
expanding cxl_test code [1], just move HMAT calls out of the core
module to cxl_acpi. Implement this by adding a @cache_size member to
struct cxl_root_decoder. During initialization the cache size is
determined and added to the root decoder object in cxl_acpi. Later on
in cxl_core the cache_size parameter is used to setup extended linear
caching.

[1] https://patch.msgid.link/20250610172938.139428-1-dave.jiang@intel.com

Cc: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Robert Richter <rrichter@amd.com>
---
 drivers/cxl/acpi.c        | 59 +++++++++++++++++++++++++++++++++++++++
 drivers/cxl/core/Makefile |  1 -
 drivers/cxl/core/acpi.c   | 11 --------
 drivers/cxl/core/core.h   |  2 --
 drivers/cxl/core/region.c |  7 +----
 drivers/cxl/cxl.h         |  1 +
 6 files changed, 61 insertions(+), 20 deletions(-)
 delete mode 100644 drivers/cxl/core/acpi.c

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index a1a99ec3f12c..712624cba2b6 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -335,6 +335,63 @@ static int add_or_reset_cxl_resource(struct resource *parent, struct resource *r
 	return rc;
 }
 
+static int cxl_acpi_set_cache_size(struct cxl_root_decoder *cxlrd)
+{
+	struct cxl_decoder *cxld = &cxlrd->cxlsd.cxld;
+	struct range *hpa = &cxld->hpa_range;
+	resource_size_t size = range_len(hpa);
+	resource_size_t start = hpa->start;
+	resource_size_t cache_size;
+	struct resource res;
+	int nid, rc;
+
+	res = DEFINE_RES(start, size, 0);
+	nid = phys_to_target_node(start);
+
+	rc = hmat_get_extended_linear_cache_size(&res, nid, &cache_size);
+	if (rc)
+		return rc;
+
+	/*
+	 * The cache range is expected to be within the CFMWS.
+	 * Currently there is only support cache_size == cxl_size. CXL
+	 * size is then half of the total CFMWS window size.
+	 */
+	size = size >> 1;
+	if (cache_size && size != cache_size) {
+		dev_warn(&cxld->dev,
+			 "Extended Linear Cache size %pa != CXL size %pa. No Support!",
+			 &cache_size, &size);
+		return -ENXIO;
+	}
+
+	cxlrd->cache_size = cache_size;
+
+	return 0;
+}
+
+static void cxl_setup_extended_linear_cache(struct cxl_root_decoder *cxlrd)
+{
+	int rc;
+
+	rc = cxl_acpi_set_cache_size(cxlrd);
+	if (!rc)
+		return;
+
+	if (rc != -EOPNOTSUPP) {
+		/*
+		 * Failing to support extended linear cache region resize does not
+		 * prevent the region from functioning. Only causes cxl list showing
+		 * incorrect region size.
+		 */
+		dev_warn(cxlrd->cxlsd.cxld.dev.parent,
+			 "Extended linear cache calculation failed rc:%d\n", rc);
+	}
+
+	/* Ignoring return code */
+	cxlrd->cache_size = 0;
+}
+
 DEFINE_FREE(put_cxlrd, struct cxl_root_decoder *,
 	    if (!IS_ERR_OR_NULL(_T)) put_device(&_T->cxlsd.cxld.dev))
 DEFINE_FREE(del_cxl_resource, struct resource *, if (_T) del_cxl_resource(_T))
@@ -394,6 +451,8 @@ static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws,
 		ig = CXL_DECODER_MIN_GRANULARITY;
 	cxld->interleave_granularity = ig;
 
+	cxl_setup_extended_linear_cache(cxlrd);
+
 	if (cfmws->interleave_arithmetic == ACPI_CEDT_CFMWS_ARITHMETIC_XOR) {
 		if (ways != 1 && ways != 3) {
 			cxims_ctx = (struct cxl_cxims_context) {
diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
index 79e2ef81fde8..5ad8fef210b5 100644
--- a/drivers/cxl/core/Makefile
+++ b/drivers/cxl/core/Makefile
@@ -15,7 +15,6 @@ cxl_core-y += hdm.o
 cxl_core-y += pmu.o
 cxl_core-y += cdat.o
 cxl_core-y += ras.o
-cxl_core-y += acpi.o
 cxl_core-$(CONFIG_TRACING) += trace.o
 cxl_core-$(CONFIG_CXL_REGION) += region.o
 cxl_core-$(CONFIG_CXL_MCE) += mce.o
diff --git a/drivers/cxl/core/acpi.c b/drivers/cxl/core/acpi.c
deleted file mode 100644
index f13b4dae6ac5..000000000000
--- a/drivers/cxl/core/acpi.c
+++ /dev/null
@@ -1,11 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/* Copyright(c) 2024 Intel Corporation. All rights reserved. */
-#include <linux/acpi.h>
-#include "cxl.h"
-#include "core.h"
-
-int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
-					    int nid, resource_size_t *size)
-{
-	return hmat_get_extended_linear_cache_size(backing_res, nid, size);
-}
diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 29b61828a847..9462aea9ce9d 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -120,8 +120,6 @@ int cxl_port_get_switch_dport_bandwidth(struct cxl_port *port,
 int cxl_ras_init(void);
 void cxl_ras_exit(void);
 int cxl_gpf_port_setup(struct cxl_dport *dport);
-int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
-					    int nid, resource_size_t *size);
 
 #ifdef CONFIG_CXL_FEATURES
 struct cxl_feat_entry *
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 6e5e1460068d..bc542a7142c0 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -3282,15 +3282,10 @@ static int cxl_extended_linear_cache_resize(struct cxl_region *cxlr,
 {
 	struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(cxlr->dev.parent);
 	struct cxl_region_params *p = &cxlr->params;
-	int nid = phys_to_target_node(res->start);
 	resource_size_t size = resource_size(res);
 	resource_size_t cache_size, start;
-	int rc;
-
-	rc = cxl_acpi_get_extended_linear_cache_size(res, nid, &cache_size);
-	if (rc)
-		return rc;
 
+	cache_size = cxlrd->cache_size;
 	if (!cache_size)
 		return 0;
 
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index e7b66ca1d423..4643a95ca111 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -432,6 +432,7 @@ typedef u64 (*cxl_hpa_to_spa_fn)(struct cxl_root_decoder *cxlrd, u64 hpa);
  */
 struct cxl_root_decoder {
 	struct resource *res;
+	resource_size_t cache_size;
 	atomic_t region_id;
 	cxl_hpa_to_spa_fn hpa_to_spa;
 	void *platform_data;
-- 
2.39.5

Re: [REWORK][PATCH] cxl: Remove core/acpi.c and cxl core dependency on ACPI

[Dave Jiang]

On 7/11/25 4:37 AM, Robert Richter wrote:
> Hi Dave,
> 
> On 03.07.25 16:49:11, Dave Jiang wrote:
>>
>>
>> On 6/10/25 10:29 AM, Dave Jiang wrote:
>>> It was a mistake to introduce core/acpi.c and putting ACPI dependency on
>>> cxl_core when adding the extended linear cache support. Add a callback
>>> in the cxl_root_decoder to retrieve the extended linear cache size from
>>> ACPI via the cxl_acpi driver.
>>>
>>> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
>>
>> Applied to cxl/next
>> 1a45e1cd694fdf2d2a22e3c70a6917ff39fe77ab
> 
> I am sorry to come back to this patch that late in the process. While
> rebasing my current region rework and address translation patches I
> came across your patch and realized that I have a much more simpler
> rework of that in my patch queue. I extracted that patch below from my
> series I am working on. Could you take a look at it? The changes are
> less intrusive and part of my rework required for address translation.
> If it looks good to you and during review, I rather prefer to replace
> your patch with this one. Note that I have follow on patches that
> reduce more code and remove the cxl_extended_linear_cache_resize()
> function entirely.
> 
> Patch below bases on:
> 
>  ac0fe6a57317 cxl: make cxl_bus_type constant

Hi Robert. I do like the simplicity of this. So lets go with that. Can you please post your patch directly to the mailing list as a stand alone? I'll drop my patch from cxl/next. We still should refactor the hpa_to_spa callback function into the cxl_rd_ops struct though. But that is a much smaller change.

DJ

> 
> Many thanks,
> 
> -Robert
> 
> 
> 
> 
> From fd3f1f5b33313bb10a2e51861031015ac48a8cd1 Mon Sep 17 00:00:00 2001
> From: Robert Richter <rrichter@amd.com>
> Date: Fri, 11 Jul 2025 11:56:56 +0200
> Subject: [PATCH] cxl: Remove core/acpi.c and cxl core dependency on ACPI
> 
> From Dave [1]:
> 
> """
> It was a mistake to introduce core/acpi.c and putting ACPI dependency on
> cxl_core when adding the extended linear cache support.
> """
> 
> Current implementation calls hmat_get_extended_linear_cache_size() of
> the ACPI subsystem. That external reference causes issue running
> cxl_test as there is no way to "mock" that function and ignore it when
> using cxl test.
> 
> Instead of working around that using cxlrd ops and extensively
> expanding cxl_test code [1], just move HMAT calls out of the core
> module to cxl_acpi. Implement this by adding a @cache_size member to
> struct cxl_root_decoder. During initialization the cache size is
> determined and added to the root decoder object in cxl_acpi. Later on
> in cxl_core the cache_size parameter is used to setup extended linear
> caching.
> 
> [1] https://patch.msgid.link/20250610172938.139428-1-dave.jiang@intel.com
> 
> Cc: Dave Jiang <dave.jiang@intel.com>
> Signed-off-by: Robert Richter <rrichter@amd.com>
> ---
>  drivers/cxl/acpi.c        | 59 +++++++++++++++++++++++++++++++++++++++
>  drivers/cxl/core/Makefile |  1 -
>  drivers/cxl/core/acpi.c   | 11 --------
>  drivers/cxl/core/core.h   |  2 --
>  drivers/cxl/core/region.c |  7 +----
>  drivers/cxl/cxl.h         |  1 +
>  6 files changed, 61 insertions(+), 20 deletions(-)
>  delete mode 100644 drivers/cxl/core/acpi.c
> 
> diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
> index a1a99ec3f12c..712624cba2b6 100644
> --- a/drivers/cxl/acpi.c
> +++ b/drivers/cxl/acpi.c
> @@ -335,6 +335,63 @@ static int add_or_reset_cxl_resource(struct resource *parent, struct resource *r
>  	return rc;
>  }
>  
> +static int cxl_acpi_set_cache_size(struct cxl_root_decoder *cxlrd)
> +{
> +	struct cxl_decoder *cxld = &cxlrd->cxlsd.cxld;
> +	struct range *hpa = &cxld->hpa_range;
> +	resource_size_t size = range_len(hpa);
> +	resource_size_t start = hpa->start;
> +	resource_size_t cache_size;
> +	struct resource res;
> +	int nid, rc;
> +
> +	res = DEFINE_RES(start, size, 0);
> +	nid = phys_to_target_node(start);
> +
> +	rc = hmat_get_extended_linear_cache_size(&res, nid, &cache_size);
> +	if (rc)
> +		return rc;
> +
> +	/*
> +	 * The cache range is expected to be within the CFMWS.
> +	 * Currently there is only support cache_size == cxl_size. CXL
> +	 * size is then half of the total CFMWS window size.
> +	 */
> +	size = size >> 1;
> +	if (cache_size && size != cache_size) {
> +		dev_warn(&cxld->dev,
> +			 "Extended Linear Cache size %pa != CXL size %pa. No Support!",
> +			 &cache_size, &size);
> +		return -ENXIO;
> +	}
> +
> +	cxlrd->cache_size = cache_size;
> +
> +	return 0;
> +}
> +
> +static void cxl_setup_extended_linear_cache(struct cxl_root_decoder *cxlrd)
> +{
> +	int rc;
> +
> +	rc = cxl_acpi_set_cache_size(cxlrd);
> +	if (!rc)
> +		return;
> +
> +	if (rc != -EOPNOTSUPP) {
> +		/*
> +		 * Failing to support extended linear cache region resize does not
> +		 * prevent the region from functioning. Only causes cxl list showing
> +		 * incorrect region size.
> +		 */
> +		dev_warn(cxlrd->cxlsd.cxld.dev.parent,
> +			 "Extended linear cache calculation failed rc:%d\n", rc);
> +	}
> +
> +	/* Ignoring return code */
> +	cxlrd->cache_size = 0;
> +}
> +
>  DEFINE_FREE(put_cxlrd, struct cxl_root_decoder *,
>  	    if (!IS_ERR_OR_NULL(_T)) put_device(&_T->cxlsd.cxld.dev))
>  DEFINE_FREE(del_cxl_resource, struct resource *, if (_T) del_cxl_resource(_T))
> @@ -394,6 +451,8 @@ static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws,
>  		ig = CXL_DECODER_MIN_GRANULARITY;
>  	cxld->interleave_granularity = ig;
>  
> +	cxl_setup_extended_linear_cache(cxlrd);
> +
>  	if (cfmws->interleave_arithmetic == ACPI_CEDT_CFMWS_ARITHMETIC_XOR) {
>  		if (ways != 1 && ways != 3) {
>  			cxims_ctx = (struct cxl_cxims_context) {
> diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
> index 79e2ef81fde8..5ad8fef210b5 100644
> --- a/drivers/cxl/core/Makefile
> +++ b/drivers/cxl/core/Makefile
> @@ -15,7 +15,6 @@ cxl_core-y += hdm.o
>  cxl_core-y += pmu.o
>  cxl_core-y += cdat.o
>  cxl_core-y += ras.o
> -cxl_core-y += acpi.o
>  cxl_core-$(CONFIG_TRACING) += trace.o
>  cxl_core-$(CONFIG_CXL_REGION) += region.o
>  cxl_core-$(CONFIG_CXL_MCE) += mce.o
> diff --git a/drivers/cxl/core/acpi.c b/drivers/cxl/core/acpi.c
> deleted file mode 100644
> index f13b4dae6ac5..000000000000
> --- a/drivers/cxl/core/acpi.c
> +++ /dev/null
> @@ -1,11 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-only
> -/* Copyright(c) 2024 Intel Corporation. All rights reserved. */
> -#include <linux/acpi.h>
> -#include "cxl.h"
> -#include "core.h"
> -
> -int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
> -					    int nid, resource_size_t *size)
> -{
> -	return hmat_get_extended_linear_cache_size(backing_res, nid, size);
> -}
> diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
> index 29b61828a847..9462aea9ce9d 100644
> --- a/drivers/cxl/core/core.h
> +++ b/drivers/cxl/core/core.h
> @@ -120,8 +120,6 @@ int cxl_port_get_switch_dport_bandwidth(struct cxl_port *port,
>  int cxl_ras_init(void);
>  void cxl_ras_exit(void);
>  int cxl_gpf_port_setup(struct cxl_dport *dport);
> -int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
> -					    int nid, resource_size_t *size);
>  
>  #ifdef CONFIG_CXL_FEATURES
>  struct cxl_feat_entry *
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 6e5e1460068d..bc542a7142c0 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3282,15 +3282,10 @@ static int cxl_extended_linear_cache_resize(struct cxl_region *cxlr,
>  {
>  	struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(cxlr->dev.parent);
>  	struct cxl_region_params *p = &cxlr->params;
> -	int nid = phys_to_target_node(res->start);
>  	resource_size_t size = resource_size(res);
>  	resource_size_t cache_size, start;
> -	int rc;
> -
> -	rc = cxl_acpi_get_extended_linear_cache_size(res, nid, &cache_size);
> -	if (rc)
> -		return rc;
>  
> +	cache_size = cxlrd->cache_size;
>  	if (!cache_size)
>  		return 0;
>  
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index e7b66ca1d423..4643a95ca111 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -432,6 +432,7 @@ typedef u64 (*cxl_hpa_to_spa_fn)(struct cxl_root_decoder *cxlrd, u64 hpa);
>   */
>  struct cxl_root_decoder {
>  	struct resource *res;
> +	resource_size_t cache_size;
>  	atomic_t region_id;
>  	cxl_hpa_to_spa_fn hpa_to_spa;
>  	void *platform_data;

Re: [REWORK][PATCH] cxl: Remove core/acpi.c and cxl core dependency on ACPI

[Robert Richter]

On 11.07.25 07:58:27, Dave Jiang wrote:
> On 7/11/25 4:37 AM, Robert Richter wrote:

> > Patch below bases on:
> > 
> >  ac0fe6a57317 cxl: make cxl_bus_type constant
> 

> Hi Robert. I do like the simplicity of this. So lets go with
> that. Can you please post your patch directly to the mailing list as
> a stand alone? I'll drop my patch from cxl/next. We still should
> refactor the hpa_to_spa callback function into the cxl_rd_ops struct
> though. But that is a much smaller change.

Just sent it, thanks for the quick reply.

-Robert