[PATCH v10 04/26] cxl: move register/capability check to driver

[<alucerop@amd.com>]

From: Alejandro Lucero <alucerop@amd.com>

Type3 has some mandatory capabilities which are optional for Type2.

In order to support same register/capability discovery code for both
types, avoid any assumption about what capabilities should be there, and
export the capabilities found for the caller doing the capabilities
check based on the expected ones.

Signed-off-by: Alejandro Lucero <alucerop@amd.com>
---
 drivers/cxl/core/pci.c  |  5 +++--
 drivers/cxl/core/port.c |  8 ++++----
 drivers/cxl/core/regs.c | 36 ++++++++++++++++++++----------------
 drivers/cxl/cxl.h       |  6 +++---
 drivers/cxl/cxlpci.h    |  2 +-
 drivers/cxl/pci.c       | 30 +++++++++++++++++++++++++++---
 include/cxl/cxl.h       | 21 ++++++++++++++++++++-
 7 files changed, 78 insertions(+), 30 deletions(-)

diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index f153ccd87dab..973348aed6c0 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -1060,7 +1060,8 @@ static int cxl_rcrb_get_comp_regs(struct pci_dev *pdev,
 }
 
 int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
-			      struct cxl_register_map *map)
+			      struct cxl_register_map *map,
+			      unsigned long *caps)
 {
 	int rc;
 
@@ -1090,7 +1091,7 @@ int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
 		return rc;
 	}
 
-	return cxl_setup_regs(map);
+	return cxl_setup_regs(map, caps);
 }
 EXPORT_SYMBOL_NS_GPL(cxl_pci_setup_regs, "CXL");
 
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index f9501a16b390..b33faaa1b947 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -759,7 +759,7 @@ static struct cxl_port *cxl_port_alloc(struct device *uport_dev,
 }
 
 static int cxl_setup_comp_regs(struct device *host, struct cxl_register_map *map,
-			       resource_size_t component_reg_phys)
+			       resource_size_t component_reg_phys, unsigned long *caps)
 {
 	*map = (struct cxl_register_map) {
 		.host = host,
@@ -773,7 +773,7 @@ static int cxl_setup_comp_regs(struct device *host, struct cxl_register_map *map
 	map->reg_type = CXL_REGLOC_RBI_COMPONENT;
 	map->max_size = CXL_COMPONENT_REG_BLOCK_SIZE;
 
-	return cxl_setup_regs(map);
+	return cxl_setup_regs(map, caps);
 }
 
 static int cxl_port_setup_regs(struct cxl_port *port,
@@ -782,7 +782,7 @@ static int cxl_port_setup_regs(struct cxl_port *port,
 	if (dev_is_platform(port->uport_dev))
 		return 0;
 	return cxl_setup_comp_regs(&port->dev, &port->reg_map,
-				   component_reg_phys);
+				   component_reg_phys, NULL);
 }
 
 static int cxl_dport_setup_regs(struct device *host, struct cxl_dport *dport,
@@ -799,7 +799,7 @@ static int cxl_dport_setup_regs(struct device *host, struct cxl_dport *dport,
 	 * NULL.
 	 */
 	rc = cxl_setup_comp_regs(dport->dport_dev, &dport->reg_map,
-				 component_reg_phys);
+				 component_reg_phys, NULL);
 	dport->reg_map.host = host;
 	return rc;
 }
diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
index 7d025d38da07..80855635353a 100644
--- a/drivers/cxl/core/regs.c
+++ b/drivers/cxl/core/regs.c
@@ -4,6 +4,7 @@
 #include <linux/device.h>
 #include <linux/slab.h>
 #include <linux/pci.h>
+#include <cxl/cxl.h>
 #include <cxlmem.h>
 #include <cxlpci.h>
 #include <pmu.h>
@@ -29,6 +30,7 @@
  * @dev: Host device of the @base mapping
  * @base: Mapping containing the HDM Decoder Capability Header
  * @map: Map object describing the register block information found
+ * @caps: capabilities to be set when discovered
  *
  * See CXL 2.0 8.2.4 Component Register Layout and Definition
  * See CXL 2.0 8.2.5.5 CXL Device Register Interface
@@ -36,7 +38,8 @@
  * Probe for component register information and return it in map object.
  */
 void cxl_probe_component_regs(struct device *dev, void __iomem *base,
-			      struct cxl_component_reg_map *map)
+			      struct cxl_component_reg_map *map,
+			      unsigned long *caps)
 {
 	int cap, cap_count;
 	u32 cap_array;
@@ -84,6 +87,8 @@ void cxl_probe_component_regs(struct device *dev, void __iomem *base,
 			decoder_cnt = cxl_hdm_decoder_count(hdr);
 			length = 0x20 * decoder_cnt + 0x10;
 			rmap = &map->hdm_decoder;
+			if (caps)
+				set_bit(CXL_DEV_CAP_HDM, caps);
 			break;
 		}
 		case CXL_CM_CAP_CAP_ID_RAS:
@@ -91,6 +96,8 @@ void cxl_probe_component_regs(struct device *dev, void __iomem *base,
 				offset);
 			length = CXL_RAS_CAPABILITY_LENGTH;
 			rmap = &map->ras;
+			if (caps)
+				set_bit(CXL_DEV_CAP_RAS, caps);
 			break;
 		default:
 			dev_dbg(dev, "Unknown CM cap ID: %d (0x%x)\n", cap_id,
@@ -117,7 +124,7 @@ EXPORT_SYMBOL_NS_GPL(cxl_probe_component_regs, "CXL");
  * Probe for device register information and return it in map object.
  */
 void cxl_probe_device_regs(struct device *dev, void __iomem *base,
-			   struct cxl_device_reg_map *map)
+			   struct cxl_device_reg_map *map, unsigned long *caps)
 {
 	int cap, cap_count;
 	u64 cap_array;
@@ -146,10 +153,14 @@ void cxl_probe_device_regs(struct device *dev, void __iomem *base,
 		case CXLDEV_CAP_CAP_ID_DEVICE_STATUS:
 			dev_dbg(dev, "found Status capability (0x%x)\n", offset);
 			rmap = &map->status;
+			if (caps)
+				set_bit(CXL_DEV_CAP_DEV_STATUS, caps);
 			break;
 		case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX:
 			dev_dbg(dev, "found Mailbox capability (0x%x)\n", offset);
 			rmap = &map->mbox;
+			if (caps)
+				set_bit(CXL_DEV_CAP_MAILBOX_PRIMARY, caps);
 			break;
 		case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX:
 			dev_dbg(dev, "found Secondary Mailbox capability (0x%x)\n", offset);
@@ -157,6 +168,8 @@ void cxl_probe_device_regs(struct device *dev, void __iomem *base,
 		case CXLDEV_CAP_CAP_ID_MEMDEV:
 			dev_dbg(dev, "found Memory Device capability (0x%x)\n", offset);
 			rmap = &map->memdev;
+			if (caps)
+				set_bit(CXL_DEV_CAP_MEMDEV, caps);
 			break;
 		default:
 			if (cap_id >= 0x8000)
@@ -433,7 +446,7 @@ static void cxl_unmap_regblock(struct cxl_register_map *map)
 	map->base = NULL;
 }
 
-static int cxl_probe_regs(struct cxl_register_map *map)
+static int cxl_probe_regs(struct cxl_register_map *map, unsigned long *caps)
 {
 	struct cxl_component_reg_map *comp_map;
 	struct cxl_device_reg_map *dev_map;
@@ -443,21 +456,12 @@ static int cxl_probe_regs(struct cxl_register_map *map)
 	switch (map->reg_type) {
 	case CXL_REGLOC_RBI_COMPONENT:
 		comp_map = &map->component_map;
-		cxl_probe_component_regs(host, base, comp_map);
+		cxl_probe_component_regs(host, base, comp_map, caps);
 		dev_dbg(host, "Set up component registers\n");
 		break;
 	case CXL_REGLOC_RBI_MEMDEV:
 		dev_map = &map->device_map;
-		cxl_probe_device_regs(host, base, dev_map);
-		if (!dev_map->status.valid || !dev_map->mbox.valid ||
-		    !dev_map->memdev.valid) {
-			dev_err(host, "registers not found: %s%s%s\n",
-				!dev_map->status.valid ? "status " : "",
-				!dev_map->mbox.valid ? "mbox " : "",
-				!dev_map->memdev.valid ? "memdev " : "");
-			return -ENXIO;
-		}
-
+		cxl_probe_device_regs(host, base, dev_map, caps);
 		dev_dbg(host, "Probing device registers...\n");
 		break;
 	default:
@@ -467,7 +471,7 @@ static int cxl_probe_regs(struct cxl_register_map *map)
 	return 0;
 }
 
-int cxl_setup_regs(struct cxl_register_map *map)
+int cxl_setup_regs(struct cxl_register_map *map, unsigned long *caps)
 {
 	int rc;
 
@@ -475,7 +479,7 @@ int cxl_setup_regs(struct cxl_register_map *map)
 	if (rc)
 		return rc;
 
-	rc = cxl_probe_regs(map);
+	rc = cxl_probe_regs(map, caps);
 	cxl_unmap_regblock(map);
 
 	return rc;
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 74bccf55c8dc..27d1dc48611c 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -292,9 +292,9 @@ struct cxl_register_map {
 };
 
 void cxl_probe_component_regs(struct device *dev, void __iomem *base,
-			      struct cxl_component_reg_map *map);
+			      struct cxl_component_reg_map *map, unsigned long *caps);
 void cxl_probe_device_regs(struct device *dev, void __iomem *base,
-			   struct cxl_device_reg_map *map);
+			   struct cxl_device_reg_map *map, unsigned long *caps);
 int cxl_map_component_regs(const struct cxl_register_map *map,
 			   struct cxl_component_regs *regs,
 			   unsigned long map_mask);
@@ -309,7 +309,7 @@ int cxl_find_regblock_instance(struct pci_dev *pdev, enum cxl_regloc_type type,
 			       struct cxl_register_map *map, unsigned int index);
 int cxl_find_regblock(struct pci_dev *pdev, enum cxl_regloc_type type,
 		      struct cxl_register_map *map);
-int cxl_setup_regs(struct cxl_register_map *map);
+int cxl_setup_regs(struct cxl_register_map *map, unsigned long *caps);
 struct cxl_dport;
 int cxl_dport_map_rcd_linkcap(struct pci_dev *pdev, struct cxl_dport *dport);
 
diff --git a/drivers/cxl/cxlpci.h b/drivers/cxl/cxlpci.h
index 735668f8cca6..7beeb8ecc616 100644
--- a/drivers/cxl/cxlpci.h
+++ b/drivers/cxl/cxlpci.h
@@ -121,5 +121,5 @@ void cxl_cor_error_detected(struct pci_dev *pdev);
 pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
 				    pci_channel_state_t state);
 int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
-		       struct cxl_register_map *map);
+		       struct cxl_register_map *map, unsigned long *caps);
 #endif /* __CXL_PCI_H__ */
diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 39df0ff3af50..cf0991c423d1 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -834,6 +834,8 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	struct pci_host_bridge *host_bridge = pci_find_host_bridge(pdev->bus);
 	struct cxl_dpa_info range_info = { 0 };
+	DECLARE_BITMAP(expected, CXL_MAX_CAPS);
+	DECLARE_BITMAP(found, CXL_MAX_CAPS);
 	struct cxl_memdev_state *mds;
 	struct cxl_dev_state *cxlds;
 	struct cxl_register_map map;
@@ -870,7 +872,18 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	cxlds->rcd = is_cxl_restricted(pdev);
 
-	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map);
+	bitmap_zero(expected, CXL_MAX_CAPS);
+
+	/*
+	 * These are the mandatory capabilities for a Type3 device.
+	 * Only checking capabilities used by current Linux drivers.
+	 */
+	set_bit(CXL_DEV_CAP_HDM, expected);
+	set_bit(CXL_DEV_CAP_DEV_STATUS, expected);
+	set_bit(CXL_DEV_CAP_MAILBOX_PRIMARY, expected);
+	set_bit(CXL_DEV_CAP_MEMDEV, expected);
+
+	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map, found);
 	if (rc)
 		return rc;
 
@@ -882,8 +895,8 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	 * If the component registers can't be found, the cxl_pci driver may
 	 * still be useful for management functions so don't return an error.
 	 */
-	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_COMPONENT,
-				&cxlds->reg_map);
+	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_COMPONENT, &cxlds->reg_map,
+				found);
 	if (rc)
 		dev_warn(&pdev->dev, "No component registers (%d)\n", rc);
 	else if (!cxlds->reg_map.component_map.ras.valid)
@@ -894,6 +907,17 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (rc)
 		dev_dbg(&pdev->dev, "Failed to map RAS capability.\n");
 
+	/*
+	 * Checking mandatory caps are there as, at least, a subset of those
+	 * found.
+	 */
+	if (!bitmap_subset(expected, found, CXL_MAX_CAPS)) {
+		dev_err(&pdev->dev,
+			"Expected mandatory capabilities not found: (%pb - %pb)\n",
+			expected, found);
+		return -ENXIO;
+	}
+
 	rc = cxl_pci_type3_init_mailbox(cxlds);
 	if (rc)
 		return rc;
diff --git a/include/cxl/cxl.h b/include/cxl/cxl.h
index 722782b868ac..790d0520eaf4 100644
--- a/include/cxl/cxl.h
+++ b/include/cxl/cxl.h
@@ -5,6 +5,26 @@
 #define __CXL_H
 
 #include <linux/types.h>
+
+/* Capabilities as defined for:
+ *
+ *	Component Registers (Table 8-22 CXL 3.1 specification)
+ *	Device Registers (8.2.8.2.1 CXL 3.1 specification)
+ *
+ * and currently being used for kernel CXL support.
+ */
+
+enum cxl_dev_cap {
+	/* capabilities from Component Registers */
+	CXL_DEV_CAP_RAS,
+	CXL_DEV_CAP_HDM,
+	/* capabilities from Device Registers */
+	CXL_DEV_CAP_DEV_STATUS,
+	CXL_DEV_CAP_MAILBOX_PRIMARY,
+	CXL_DEV_CAP_MEMDEV,
+	CXL_MAX_CAPS,
+};
+
 /*
  * enum cxl_devtype - delineate type-2 from a generic type-3 device
  * @CXL_DEVTYPE_DEVMEM - Vendor specific CXL Type-2 device implementing HDM-D or
@@ -22,5 +42,4 @@ enum cxl_devtype {
 struct device;
 struct cxl_memdev_state *cxl_memdev_state_create(struct device *dev, u64 serial,
 					   u16 dvsec, enum cxl_devtype type);
-
 #endif
-- 
2.17.1