[PATCH v2 05/20] cxl/region: Validate region mode vs decoder mode

[Dan Williams <dan.j.williams@intel.com>]

In preparation for a new region mode, do not, for example, allow
'ram' decoders to be assigned to 'pmem' regions and vice versa.

Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Reviewed-by: Gregory Price <gregory.price@memverge.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Tested-by: Fan Ni <fan.ni@samsung.com>
Link: https://lore.kernel.org/r/167564537131.847146.9020072654741860107.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/cxl/core/region.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 0fc80478ff6b..285835145e9b 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -1221,6 +1221,12 @@ static int cxl_region_attach(struct cxl_region *cxlr,
 	struct cxl_dport *dport;
 	int i, rc = -ENXIO;
 
+	if (cxled->mode != cxlr->mode) {
+		dev_dbg(&cxlr->dev, "%s region mode: %d mismatch: %d\n",
+			dev_name(&cxled->cxld.dev), cxlr->mode, cxled->mode);
+		return -EINVAL;
+	}
+
 	if (cxled->mode == CXL_DECODER_DEAD) {
 		dev_dbg(&cxlr->dev, "%s dead\n", dev_name(&cxled->cxld.dev));
 		return -ENODEV;