[PATCH v3 19/20] cxl: add function for obtaining params from a region

alejandro.lucero-palau
2024-09-07T08:19:59Z

From: Alejandro Lucero <alucerop@amd.com>

A CXL region struct contains the physical address to work with.

Add a function for given a opaque cxl region struct returns the params
to be used for mapping such memory range.

Signed-off-by: Alejandro Lucero <alucerop@amd.com>
---
drivers/cxl/core/region.c | 16 ++++++++++++++++
drivers/cxl/cxl.h | 2 ++
include/linux/cxl/cxl.h | 2 ++
3 files changed, 20 insertions(+)

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 45b4891035a6..e0e2342bb1ed 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -2662,6 +2662,22 @@ static struct cxl_region *devm_cxl_add_region(struct cxl_root_decoder *cxlrd,
return ERR_PTR(rc);
}

+int cxl_get_region_params(struct cxl_region *region, resource_size_t *start,
+ resource_size_t *end)
+{
+ if (!region)
+ return -ENODEV;
+
+ if (!region->params.res)
+ return -ENOSPC;
+
+ *start = region->params.res->start;
+ *end = region->params.res->end;
+
+ return 0;
+}
+EXPORT_SYMBOL_NS_GPL(cxl_get_region_params, CXL);
+
static ssize_t __create_region_show(struct cxl_root_decoder *cxlrd, char *buf)
{
return sysfs_emit(buf, "region%u\n", atomic_read(&cxlrd->region_id));
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 120e961f2e31..b26833ff52c0 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -904,6 +904,8 @@ void cxl_coordinates_combine(struct access_coordinate *out,
bool cxl_endpoint_decoder_reset_detected(struct cxl_port *port);

int cxl_region_detach(struct cxl_endpoint_decoder *cxled);
+int cxl_get_region_params(struct cxl_region *region, resource_size_t *start,
+ resource_size_t *end);
/*
* Unit test builds overrides this to __weak, find the 'strong' version
* of these symbols in tools/testing/cxl/.
diff --git a/include/linux/cxl/cxl.h b/include/linux/cxl/cxl.h
index 169683d75030..ef3bd8329bd8 100644
--- a/include/linux/cxl/cxl.h
+++ b/include/linux/cxl/cxl.h
@@ -76,4 +76,6 @@ struct cxl_region *cxl_create_region(struct cxl_root_decoder *cxlrd,
struct cxl_endpoint_decoder *cxled);

int cxl_region_detach(struct cxl_endpoint_decoder *cxled);
+int cxl_get_region_params(struct cxl_region *region, resource_size_t *start,
+ resource_size_t *end);
#endif
--
2.17.1