[RFC PATCH 2/5] cxl/core: introduce cxl_memdev_dpa_to_hpa()

[Shiyang Ruan via]

When a memdev is assigned to a region, its Device Physical Address will be
mapped to Host Physical Address.  Introduce this helper function to
translate HPA from a given memdev and its DPA.

Signed-off-by: Shiyang Ruan <ruansy.f...@fujitsu.com>
---
 drivers/cxl/core/memdev.c | 12 ++++++++++++
 drivers/cxl/cxlmem.h      |  1 +
 2 files changed, 13 insertions(+)

diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index dae8802ecdb0..c304e709ef0e 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -319,6 +319,18 @@ static int cxl_validate_poison_dpa(struct cxl_memdev 
*cxlmd, u64 dpa)
        return 0;
 }
 
+phys_addr_t cxl_memdev_dpa_to_hpa(struct cxl_memdev *cxlmd, u64 dpa)
+{
+       struct cxl_region *cxlr = cxl_dpa_to_region(cxlmd, dpa);
+
+       if (cxlr)
+               return cxlr->params.res->start + dpa;
+       else {
+               dev_dbg(&cxlmd->dev, "device belongs to no region.\n");
+               return 0;
+       }
+}
+
 int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
 {
        struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 5303d6942b88..97ddab421e63 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -833,6 +833,7 @@ int cxl_poison_state_init(struct cxl_memdev_state *mds);
 int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
                       struct cxl_region *cxlr);
 int cxl_trigger_poison_list(struct cxl_memdev *cxlmd);
+phys_addr_t cxl_memdev_dpa_to_hpa(struct cxl_memdev *cxlmd, u64 dpa);
 int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa);
 int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa);
 
-- 
2.34.1