cxl/pci: Prepare for mapping RAS Capability Structure

The RAS Capabilitiy Structure is a CXL Component register capability
block. Unlike the HDM Decoder Capability, it will be referenced by the
cxl_pci driver in response to PCIe AER events. Due to this it is no
longer the case that cxl_map_component_regs() can assume that it should
map all component registers. Plumb a bitmask of capability ids to map
through cxl_map_component_regs().

For symmetry cxl_probe_device_regs() is updated to populate @id in
'struct cxl_reg_map' even though cxl_map_device_regs() does not have a
need to map a subset of the device registers per caller.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/166974412214.1608150.11487843455070795378.stgit@djiang5-desk3.ch.intel.comSigned-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/cxl/core/hdm.c

@@ -97,7 +97,8 @@ static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb,
 		return -ENXIO;
 	}
 
-	return cxl_map_component_regs(&port->dev, regs, &map);
+	return cxl_map_component_regs(&port->dev, regs, &map,
+				      BIT(CXL_CM_CAP_CAP_ID_HDM));
 }
 
 /**

drivers/cxl/core/regs.c

@@ -92,6 +92,7 @@ void cxl_probe_component_regs(struct device *dev, void __iomem *base,
 		if (!rmap)
 			continue;
 		rmap->valid = true;
+		rmap->id = cap_id;
 		rmap->offset = CXL_CM_OFFSET + offset;
 		rmap->size = length;
 	}
@@ -159,6 +160,7 @@ void cxl_probe_device_regs(struct device *dev, void __iomem *base,
 		if (!rmap)
 			continue;
 		rmap->valid = true;
+		rmap->id = cap_id;
 		rmap->offset = offset;
 		rmap->size = length;
 	}
@@ -187,17 +189,31 @@ void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr,
 }
 
 int cxl_map_component_regs(struct device *dev, struct cxl_component_regs *regs,
-			   struct cxl_register_map *map)
+			   struct cxl_register_map *map, unsigned long map_mask)
 {
-	resource_size_t phys_addr;
-	resource_size_t length;
-
-	phys_addr = map->resource;
-	phys_addr += map->component_map.hdm_decoder.offset;
-	length = map->component_map.hdm_decoder.size;
-	regs->hdm_decoder = devm_cxl_iomap_block(dev, phys_addr, length);
-	if (!regs->hdm_decoder)
-		return -ENOMEM;
+	struct mapinfo {
+		struct cxl_reg_map *rmap;
+		void __iomem **addr;
+	} mapinfo[] = {
+		{ &map->component_map.hdm_decoder, &regs->hdm_decoder },
+	};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(mapinfo); i++) {
+		struct mapinfo *mi = &mapinfo[i];
+		resource_size_t phys_addr;
+		resource_size_t length;
+
+		if (!mi->rmap->valid)
+			continue;
+		if (!test_bit(mi->rmap->id, &map_mask))
+			continue;
+		phys_addr = map->resource + mi->rmap->offset;
+		length = mi->rmap->size;
+		*(mi->addr) = devm_cxl_iomap_block(dev, phys_addr, length);
+		if (!*(mi->addr))
+			return -ENOMEM;
+	}
 
 	return 0;
 }

drivers/cxl/cxl.h

@@ -170,6 +170,7 @@ struct cxl_regs {
 
 struct cxl_reg_map {
 	bool valid;
+	int id;
 	unsigned long offset;
 	unsigned long size;
 };
@@ -209,7 +210,8 @@ void cxl_probe_component_regs(struct device *dev, void __iomem *base,
 void cxl_probe_device_regs(struct device *dev, void __iomem *base,
 			   struct cxl_device_reg_map *map);
 int cxl_map_component_regs(struct device *dev, struct cxl_component_regs *regs,
-			   struct cxl_register_map *map);
+			   struct cxl_register_map *map,
+			   unsigned long map_mask);
 int cxl_map_device_regs(struct device *dev, struct cxl_device_regs *regs,
 			struct cxl_register_map *map);