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

[Dave Jiang <dave.jiang@intel.com>]

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