@@ -102,6 +102,17 @@ config CXL_MEM
If unsure say 'm'.
+config CXL_FEATURES
+ bool "CXL: Features"
+ depends on CXL_PCI
+ help
+ Enable support for CXL Features. A CXL device that includes a mailbox
+ supports commands that allows listing, getting, and setting of
+ optionally defined features such as memory sparing or post package
+ sparing. Vendors may define custom features for the device.
+
+ If unsure say 'n'
+
config CXL_PORT
default CXL_BUS
tristate
@@ -16,3 +16,4 @@ cxl_core-y += pmu.o
cxl_core-y += cdat.o
cxl_core-$(CONFIG_TRACING) += trace.o
cxl_core-$(CONFIG_CXL_REGION) += region.o
+cxl_core-$(CONFIG_CXL_FEATURES) += features.o
new file mode 100644
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2024-2025 Intel Corporation. All rights reserved. */
+#include <linux/device.h>
+#include <cxl/mailbox.h>
+#include <cxl/features.h>
+#include "cxl.h"
+#include "cxlmem.h"
+
+inline struct cxl_features_state *to_cxlfs(struct cxl_dev_state *cxlds)
+{
+ return cxlds->cxlfs;
+}
+EXPORT_SYMBOL_NS_GPL(to_cxlfs, "CXL");
+
+static int cxl_get_supported_features_count(struct cxl_mailbox *cxl_mbox)
+{
+ struct cxl_mbox_get_sup_feats_out mbox_out;
+ struct cxl_mbox_get_sup_feats_in mbox_in;
+ struct cxl_mbox_cmd mbox_cmd;
+ int rc;
+
+ memset(&mbox_in, 0, sizeof(mbox_in));
+ mbox_in.count = cpu_to_le32(sizeof(mbox_out));
+ memset(&mbox_out, 0, sizeof(mbox_out));
+ mbox_cmd = (struct cxl_mbox_cmd) {
+ .opcode = CXL_MBOX_OP_GET_SUPPORTED_FEATURES,
+ .size_in = sizeof(mbox_in),
+ .payload_in = &mbox_in,
+ .size_out = sizeof(mbox_out),
+ .payload_out = &mbox_out,
+ .min_out = sizeof(mbox_out),
+ };
+ rc = cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
+ if (rc < 0)
+ return rc;
+
+ return le16_to_cpu(mbox_out.supported_feats);
+}
+
+static struct cxl_feat_entries *
+get_supported_features(struct cxl_features_state *cxlfs)
+{
+ int remain_feats, max_size, max_feats, start, rc, hdr_size;
+ struct cxl_mailbox *cxl_mbox = &cxlfs->cxlds->cxl_mbox;
+ int feat_size = sizeof(struct cxl_feat_entry);
+ struct cxl_mbox_get_sup_feats_in mbox_in;
+ struct cxl_feat_entry *entry;
+ struct cxl_mbox_cmd mbox_cmd;
+ int count;
+
+ count = cxl_get_supported_features_count(cxl_mbox);
+ if (count <= 0)
+ return NULL;
+
+ struct cxl_feat_entries *entries __free(kvfree) =
+ kvmalloc(struct_size(entries, ent, count), GFP_KERNEL);
+ if (!entries)
+ return NULL;
+
+ struct cxl_mbox_get_sup_feats_out *mbox_out __free(kvfree) =
+ kvmalloc(cxl_mbox->payload_size, GFP_KERNEL);
+ if (!mbox_out)
+ return NULL;
+
+ hdr_size = struct_size(mbox_out, ents, 0);
+ max_size = cxl_mbox->payload_size - hdr_size;
+ /* max feat entries that can fit in mailbox max payload size */
+ max_feats = max_size / feat_size;
+ entry = entries->ent;
+
+ start = 0;
+ remain_feats = count;
+ do {
+ int retrieved, alloc_size, copy_feats;
+ int num_entries;
+
+ if (remain_feats > max_feats) {
+ alloc_size = struct_size(mbox_out, ents, max_feats);
+ remain_feats = remain_feats - max_feats;
+ copy_feats = max_feats;
+ } else {
+ alloc_size = struct_size(mbox_out, ents, remain_feats);
+ copy_feats = remain_feats;
+ remain_feats = 0;
+ }
+
+ memset(&mbox_in, 0, sizeof(mbox_in));
+ mbox_in.count = cpu_to_le32(alloc_size);
+ mbox_in.start_idx = cpu_to_le16(start);
+ memset(mbox_out, 0, alloc_size);
+ mbox_cmd = (struct cxl_mbox_cmd) {
+ .opcode = CXL_MBOX_OP_GET_SUPPORTED_FEATURES,
+ .size_in = sizeof(mbox_in),
+ .payload_in = &mbox_in,
+ .size_out = alloc_size,
+ .payload_out = mbox_out,
+ .min_out = hdr_size,
+ };
+ rc = cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
+ if (rc < 0)
+ return NULL;
+
+ if (mbox_cmd.size_out <= hdr_size)
+ return NULL;
+
+ /*
+ * Make sure retrieved out buffer is multiple of feature
+ * entries.
+ */
+ retrieved = mbox_cmd.size_out - hdr_size;
+ if (retrieved % feat_size)
+ return NULL;
+
+ num_entries = le16_to_cpu(mbox_out->num_entries);
+ /*
+ * If the reported output entries * defined entry size !=
+ * retrieved output bytes, then the output package is incorrect.
+ */
+ if (num_entries * feat_size != retrieved)
+ return NULL;
+
+ memcpy(entry, mbox_out->ents, retrieved);
+ entry += num_entries;
+ /*
+ * If the number of output entries is less than expected, add the
+ * remaining entries to the next batch.
+ */
+ remain_feats += copy_feats - num_entries;
+ start += num_entries;
+ } while (remain_feats);
+
+ entries->num_features = count;
+
+ return no_free_ptr(entries);
+}
+
+static void free_cxlfs(void *_cxlfs)
+{
+ struct cxl_features_state *cxlfs = _cxlfs;
+ struct cxl_dev_state *cxlds = cxlfs->cxlds;
+
+ cxlds->cxlfs = NULL;
+ kvfree(cxlfs->entries);
+ kfree(cxlfs);
+}
+
+/**
+ * devm_cxl_setup_features() - Allocate and initialize features context
+ * @cxlds: CXL device context
+ *
+ * Return 0 on success or -errno on failure.
+ */
+int devm_cxl_setup_features(struct cxl_dev_state *cxlds)
+{
+ struct cxl_mailbox *cxl_mbox = &cxlds->cxl_mbox;
+
+ if (cxl_mbox->feat_cap < CXL_FEATURES_RO)
+ return -ENODEV;
+
+ struct cxl_features_state *cxlfs __free(kfree) =
+ kzalloc(sizeof(*cxlfs), GFP_KERNEL);
+ if (!cxlfs)
+ return -ENOMEM;
+
+ cxlfs->cxlds = cxlds;
+
+ cxlfs->entries = get_supported_features(cxlfs);
+ if (!cxlfs->entries)
+ return -ENOMEM;
+
+ cxlds->cxlfs = cxlfs;
+
+ return devm_add_action_or_reset(cxlds->dev, free_cxlfs, no_free_ptr(cxlfs));
+}
+EXPORT_SYMBOL_NS_GPL(devm_cxl_setup_features, "CXL");
@@ -392,6 +392,7 @@ struct cxl_dpa_perf {
* @serial: PCIe Device Serial Number
* @type: Generic Memory Class device or Vendor Specific Memory device
* @cxl_mbox: CXL mailbox context
+ * @cxl_features: CXL features context
*/
struct cxl_dev_state {
struct device *dev;
@@ -407,6 +408,9 @@ struct cxl_dev_state {
u64 serial;
enum cxl_devtype type;
struct cxl_mailbox cxl_mbox;
+#ifdef CONFIG_CXL_FEATURES
+ struct cxl_features_state *cxlfs;
+#endif
};
static inline struct cxl_dev_state *mbox_to_cxlds(struct cxl_mailbox *cxl_mbox)
@@ -997,6 +997,10 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
if (rc)
return rc;
+ rc = devm_cxl_setup_features(cxlds);
+ if (rc)
+ dev_dbg(&pdev->dev, "No CXL Features discovered\n");
+
cxlmd = devm_cxl_add_memdev(&pdev->dev, cxlds);
if (IS_ERR(cxlmd))
return PTR_ERR(cxlmd);
@@ -3,6 +3,8 @@
#ifndef __CXL_FEATURES_H__
#define __CXL_FEATURES_H__
+#include <linux/uuid.h>
+
/* Feature commands capability supported by a device */
enum cxl_features_capability {
CXL_FEATURES_NONE = 0,
@@ -10,4 +12,89 @@ enum cxl_features_capability {
CXL_FEATURES_RW,
};
+/* Get Supported Features (0x500h) CXL r3.2 8.2.9.6.1 */
+struct cxl_mbox_get_sup_feats_in {
+ __le32 count;
+ __le16 start_idx;
+ u8 reserved[2];
+} __packed;
+
+/* CXL spec r3.2 Table 8-87 command effects */
+#define CXL_CMD_CONFIG_CHANGE_COLD_RESET BIT(0)
+#define CXL_CMD_CONFIG_CHANGE_IMMEDIATE BIT(1)
+#define CXL_CMD_DATA_CHANGE_IMMEDIATE BIT(2)
+#define CXL_CMD_POLICY_CHANGE_IMMEDIATE BIT(3)
+#define CXL_CMD_LOG_CHANGE_IMMEDIATE BIT(4)
+#define CXL_CMD_SECURITY_STATE_CHANGE BIT(5)
+#define CXL_CMD_BACKGROUND BIT(6)
+#define CXL_CMD_BGCMD_ABORT_SUPPORTED BIT(7)
+#define CXL_CMD_EFFECTS_VALID BIT(9)
+#define CXL_CMD_CONFIG_CHANGE_CONV_RESET BIT(10)
+#define CXL_CMD_CONFIG_CHANGE_CXL_RESET BIT(11)
+
+/*
+ * CXL spec r3.2 Table 8-109
+ * Get Supported Features Supported Feature Entry
+ */
+struct cxl_feat_entry {
+ uuid_t uuid;
+ __le16 id;
+ __le16 get_feat_size;
+ __le16 set_feat_size;
+ __le32 flags;
+ u8 get_feat_ver;
+ u8 set_feat_ver;
+ __le16 effects;
+ u8 reserved[18];
+} __packed;
+
+/* @flags field for 'struct cxl_feat_entry' */
+#define CXL_FEATURE_F_CHANGEABLE BIT(0)
+#define CXL_FEATURE_F_PERSIST_FW_UPDATE BIT(4)
+#define CXL_FEATURE_F_DEFAULT_SEL BIT(5)
+#define CXL_FEATURE_F_SAVED_SEL BIT(6)
+
+/*
+ * CXL spec r3.2 Table 8-108
+ * Get supported Features Output Payload
+ */
+struct cxl_mbox_get_sup_feats_out {
+ __struct_group(cxl_mbox_get_sup_feats_out_hdr, hdr, /* no attrs */,
+ __le16 num_entries;
+ __le16 supported_feats;
+ __u8 reserved[4];
+ );
+ struct cxl_feat_entry ents[] __counted_by_le(num_entries);
+} __packed;
+
+/**
+ * struct cxl_features_state - The Features state for the device
+ * @cxlds: Pointer to CXL device state
+ * @entries: CXl feature entry context
+ * @num_features: total Features supported by the device
+ * @ent: Flex array of Feature detail entries from the device
+ */
+struct cxl_features_state {
+ struct cxl_dev_state *cxlds;
+ struct cxl_feat_entries {
+ int num_features;
+ struct cxl_feat_entry ent[] __counted_by(num_features);
+ } *entries;
+};
+
+#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);
+#else
+static inline struct cxl_features_state *to_cxlfs(struct cxl_dev_state *cxlds)
+{
+ return NULL;
+}
+
+static inline int devm_cxl_setup_features(struct cxl_dev_state *cxlds)
+{
+ return -EOPNOTSUPP;
+}
+#endif
+
#endif
@@ -63,6 +63,7 @@ cxl_core-y += $(CXL_CORE_SRC)/pmu.o
cxl_core-y += $(CXL_CORE_SRC)/cdat.o
cxl_core-$(CONFIG_TRACING) += $(CXL_CORE_SRC)/trace.o
cxl_core-$(CONFIG_CXL_REGION) += $(CXL_CORE_SRC)/region.o
+cxl_core-$(CONFIG_CXL_FEATURES) += $(CXL_CORE_SRC)/features.o
cxl_core-y += config_check.o
cxl_core-y += cxl_core_test.o
cxl_core-y += cxl_core_exports.o
@@ -1558,6 +1558,10 @@ static int cxl_mock_mem_probe(struct platform_device *pdev)
if (rc)
return rc;
+ rc = devm_cxl_setup_features(cxlds);
+ if (rc)
+ dev_dbg(dev, "No CXL Features discovered\n");
+
cxl_mock_add_event_logs(&mdata->mes);
cxlmd = devm_cxl_add_memdev(&pdev->dev, cxlds);