cxl: Add FWCTL support to CXL

Add fwctl support code to allow sending of CXL feature commands from
userspace through as ioctls via FWCTL. Provide initial setup bits. The
CXL PCI probe function will call devm_cxl_setup_fwctl() after the
cxl_memdev has been enumerated in order to setup FWCTL char device under
the cxl_memdev like the existing memdev char device for issuing CXL raw
mailbox commands from userspace via ioctls.

Link: https://patch.msgid.link/r/20250307205648.1021626-2-dave.jiang@intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Li Ming <ming.li@zohomail.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
index ad2e796e4ac63fd4529f8daf3caf9474addb416f..8ac1e9d70eeb1f71d84e280c2838446050d4cdd1 100644 (file)
--- a/drivers/cxl/Kconfig
+++ b/drivers/cxl/Kconfig
@@ -7,6 +7,7 @@ menuconfig CXL_BUS
        select PCI_DOE
        select FIRMWARE_TABLE
        select NUMA_KEEP_MEMINFO if NUMA_MEMBLKS
+       select FWCTL if CXL_FEATURES
        help
          CXL is a bus that is electrically compatible with PCI Express, but
          layers three protocols on that signalling (CXL.io, CXL.cache, and

diff --git a/drivers/cxl/core/features.c b/drivers/cxl/core/features.c
index 048ba4fc3538e7dc5c08e59f5d71384dd931caa0..7dac74fd76edefb6ae71d7b3ec180f3fe53872b6 100644 (file)
--- a/drivers/cxl/core/features.c
+++ b/drivers/cxl/core/features.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /* Copyright(c) 2024-2025 Intel Corporation. All rights reserved. */
+#include <linux/fwctl.h>
 #include <linux/device.h>
 #include <cxl/mailbox.h>
 #include <cxl/features.h>
@@ -331,3 +332,74 @@ int cxl_set_feature(struct cxl_mailbox *cxl_mbox,
                }
        } while (true);
 }
+
+/* FWCTL support */
+
+static inline struct cxl_memdev *fwctl_to_memdev(struct fwctl_device *fwctl_dev)
+{
+       return to_cxl_memdev(fwctl_dev->dev.parent);
+}
+
+static int cxlctl_open_uctx(struct fwctl_uctx *uctx)
+{
+       return 0;
+}
+
+static void cxlctl_close_uctx(struct fwctl_uctx *uctx)
+{
+}
+
+static void *cxlctl_fw_rpc(struct fwctl_uctx *uctx, enum fwctl_rpc_scope scope,
+                          void *in, size_t in_len, size_t *out_len)
+{
+       /* Place holder */
+       return ERR_PTR(-EOPNOTSUPP);
+}
+
+static const struct fwctl_ops cxlctl_ops = {
+       .device_type = FWCTL_DEVICE_TYPE_CXL,
+       .uctx_size = sizeof(struct fwctl_uctx),
+       .open_uctx = cxlctl_open_uctx,
+       .close_uctx = cxlctl_close_uctx,
+       .fw_rpc = cxlctl_fw_rpc,
+};
+
+DEFINE_FREE(free_fwctl_dev, struct fwctl_device *, if (_T) fwctl_put(_T))
+
+static void free_memdev_fwctl(void *_fwctl_dev)
+{
+       struct fwctl_device *fwctl_dev = _fwctl_dev;
+
+       fwctl_unregister(fwctl_dev);
+       fwctl_put(fwctl_dev);
+}
+
+int devm_cxl_setup_fwctl(struct cxl_memdev *cxlmd)
+{
+       struct cxl_dev_state *cxlds = cxlmd->cxlds;
+       struct cxl_features_state *cxlfs;
+       int rc;
+
+       cxlfs = to_cxlfs(cxlds);
+       if (!cxlfs)
+               return -ENODEV;
+
+       /* No need to setup FWCTL if there are no user allowed features found */
+       if (!cxlfs->entries->num_user_features)
+               return -ENODEV;
+
+       struct fwctl_device *fwctl_dev __free(free_fwctl_dev) =
+               _fwctl_alloc_device(&cxlmd->dev, &cxlctl_ops, sizeof(*fwctl_dev));
+       if (!fwctl_dev)
+               return -ENOMEM;
+
+       rc = fwctl_register(fwctl_dev);
+       if (rc)
+               return rc;
+
+       return devm_add_action_or_reset(&cxlmd->dev, free_memdev_fwctl,
+                                       no_free_ptr(fwctl_dev));
+}
+EXPORT_SYMBOL_NS_GPL(devm_cxl_setup_fwctl, "CXL");
+
+MODULE_IMPORT_NS("FWCTL");

diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 3e666ec515808756e709018bcd9f80bb6357e3f6..993fa60fe453a2fb5918a6536398911058884631 100644 (file)
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -1013,6 +1013,10 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
        if (rc)
                return rc;
 
+       rc = devm_cxl_setup_fwctl(cxlmd);
+       if (rc)
+               dev_dbg(&pdev->dev, "No CXL FWCTL setup\n");
+
        pmu_count = cxl_count_regblock(pdev, CXL_REGLOC_RBI_PMU);
        if (pmu_count < 0)
                return pmu_count;

diff --git a/include/cxl/features.h b/include/cxl/features.h
index d2cde46b0fec8aebd2f1d88aeb3670b8abd845fc..596c85ee269959eff4196f18bbb21d4779c4858d 100644 (file)
--- a/include/cxl/features.h
+++ b/include/cxl/features.h
@@ -4,6 +4,7 @@
 #define __CXL_FEATURES_H__
 
 #include <linux/uuid.h>
+#include <linux/fwctl.h>
 
 /* Feature UUIDs used by the kernel */
 #define CXL_FEAT_PATROL_SCRUB_UUID                                             \
@@ -173,9 +174,11 @@ struct cxl_features_state {
 };
 
 struct cxl_mailbox;
+struct cxl_memdev;
 #ifdef CONFIG_CXL_FEATURES
 inline struct cxl_features_state *to_cxlfs(struct cxl_dev_state *cxlds);
 int devm_cxl_setup_features(struct cxl_dev_state *cxlds);
+int devm_cxl_setup_fwctl(struct cxl_memdev *cxlmd);
 #else
 static inline struct cxl_features_state *to_cxlfs(struct cxl_dev_state *cxlds)
 {
@@ -186,6 +189,11 @@ static inline int devm_cxl_setup_features(struct cxl_dev_state *cxlds)
 {
        return -EOPNOTSUPP;
 }
+
+static inline int devm_cxl_setup_fwctl(struct cxl_memdev *cxlmd)
+{
+       return -EOPNOTSUPP;
+}
 #endif
 
 #endif

diff --git a/include/uapi/fwctl/fwctl.h b/include/uapi/fwctl/fwctl.h
index 584a5ea8ecee1171f066c3ccb50a1c7def9d72a4..c2d5abc5a7261b9822fe827fdc325dabdce59437 100644 (file)
--- a/include/uapi/fwctl/fwctl.h
+++ b/include/uapi/fwctl/fwctl.h
@@ -43,6 +43,7 @@ enum {
 enum fwctl_device_type {
        FWCTL_DEVICE_TYPE_ERROR = 0,
        FWCTL_DEVICE_TYPE_MLX5 = 1,
+       FWCTL_DEVICE_TYPE_CXL = 2,
 };
 
 /**

diff --git a/tools/testing/cxl/test/mem.c b/tools/testing/cxl/test/mem.c
index 4809a90ff9b66987b955e0bd252e49564542a6af..848db399102c10223eecee8ac8cf901df2e5dd3b 100644 (file)
--- a/tools/testing/cxl/test/mem.c
+++ b/tools/testing/cxl/test/mem.c
@@ -1646,6 +1646,10 @@ static int cxl_mock_mem_probe(struct platform_device *pdev)
        if (rc)
                return rc;
 
+       rc = devm_cxl_setup_fwctl(cxlmd);
+       if (rc)
+               dev_dbg(dev, "No CXL FWCTL setup\n");
+
        cxl_mem_get_event_records(mds, CXLDEV_EVENT_STATUS_ALL);
 
        return 0;