From cd1aed6cefe8f4f2043349e1a614876f67743439 Mon Sep 17 00:00:00 2001

From: Vishal Verma <vishal.l.verma@intel.com>

Date: Thu, 7 Oct 2021 02:21:33 -0600

Subject: [PATCH 040/217] libcxl: add representation for an nvdimm bridge

 object

Add an nvdimm bridge object representation internal to libcxl. A bridge

object is tied to its parent memdev object, and this patch adds its

first interface, which checks whether a bridge is 'active' - i.e.

implying the label space on the memdev is owned by the kernel.

Cc: Dan Williams <dan.j.williams@intel.com>

Reviewed-by: Dan Williams <dan.j.williams@intel.com>

Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>

---

 cxl/lib/libcxl.c   | 73 ++++++++++++++++++++++++++++++++++++++++++++++

 cxl/lib/libcxl.sym |  1 +

 cxl/lib/private.h  |  8 +++++

 cxl/libcxl.h       |  1 +

 4 files changed, 83 insertions(+)

diff --git a/cxl/lib/libcxl.c b/cxl/lib/libcxl.c

index def3a97..60ed646 100644

--- a/cxl/lib/libcxl.c

+++ b/cxl/lib/libcxl.c

@@ -45,11 +45,19 @@ struct cxl_ctx {

 	void *private_data;

 };

+static void free_bridge(struct cxl_nvdimm_bridge *bridge)

+{

+	free(bridge->dev_buf);

+	free(bridge->dev_path);

+	free(bridge);

+}

+

 static void free_memdev(struct cxl_memdev *memdev, struct list_head *head)

 {

 	if (head)

 		list_del_from(head, &memdev->list);

 	kmod_module_unref(memdev->module);

+	free_bridge(memdev->bridge);

 	free(memdev->firmware_version);

 	free(memdev->dev_buf);

 	free(memdev->dev_path);

@@ -205,6 +213,40 @@ CXL_EXPORT void cxl_set_log_priority(struct cxl_ctx *ctx, int priority)

 	ctx->ctx.log_priority = priority;

 }

+static void *add_cxl_bridge(void *parent, int id, const char *br_base)

+{

+	const char *devname = devpath_to_devname(br_base);

+	struct cxl_memdev *memdev = parent;

+	struct cxl_ctx *ctx = memdev->ctx;

+	struct cxl_nvdimm_bridge *bridge;

+

+	dbg(ctx, "%s: bridge_base: \'%s\'\n", devname, br_base);

+

+	bridge = calloc(1, sizeof(*bridge));

+	if (!bridge)

+		goto err_dev;

+	bridge->id = id;

+

+	bridge->dev_path = strdup(br_base);

+	if (!bridge->dev_path)

+		goto err_read;

+

+	bridge->dev_buf = calloc(1, strlen(br_base) + 50);

+	if (!bridge->dev_buf)

+		goto err_read;

+	bridge->buf_len = strlen(br_base) + 50;

+

+	memdev->bridge = bridge;

+	return bridge;

+

+ err_read:

+	free(bridge->dev_buf);

+	free(bridge->dev_path);

+	free(bridge);

+ err_dev:

+	return NULL;

+}

+

 static void *add_cxl_memdev(void *parent, int id, const char *cxlmem_base)

 {

 	const char *devname = devpath_to_devname(cxlmem_base);

@@ -271,6 +313,8 @@ static void *add_cxl_memdev(void *parent, int id, const char *cxlmem_base)

 		goto err_read;

 	memdev->buf_len = strlen(cxlmem_base) + 50;

+	sysfs_device_parse(ctx, cxlmem_base, "pmem", memdev, add_cxl_bridge);

+

 	cxl_memdev_foreach(ctx, memdev_dup)

 		if (memdev_dup->id == memdev->id) {

 			free_memdev(memdev, NULL);

@@ -362,6 +406,35 @@ CXL_EXPORT size_t cxl_memdev_get_label_size(struct cxl_memdev *memdev)

 	return memdev->lsa_size;

 }

+static int is_enabled(const char *drvpath)

+{

+	struct stat st;

+

+	if (lstat(drvpath, &st) < 0 || !S_ISLNK(st.st_mode))

+		return 0;

+	else

+		return 1;

+}

+

+CXL_EXPORT int cxl_memdev_nvdimm_bridge_active(struct cxl_memdev *memdev)

+{

+	struct cxl_ctx *ctx = cxl_memdev_get_ctx(memdev);

+	struct cxl_nvdimm_bridge *bridge = memdev->bridge;

+	char *path = bridge->dev_buf;

+	int len = bridge->buf_len;

+

+	if (!bridge)

+		return 0;

+

+	if (snprintf(path, len, "%s/driver", bridge->dev_path) >= len) {

+		err(ctx, "%s: nvdimm bridge buffer too small!\n",

+				cxl_memdev_get_devname(memdev));

+		return 0;

+	}

+

+	return is_enabled(path);

+}

+

 CXL_EXPORT void cxl_cmd_unref(struct cxl_cmd *cmd)

 {

 	if (!cmd)

diff --git a/cxl/lib/libcxl.sym b/cxl/lib/libcxl.sym

index 858e953..f3b0c63 100644

--- a/cxl/lib/libcxl.sym

+++ b/cxl/lib/libcxl.sym

@@ -65,6 +65,7 @@ global:

 	cxl_cmd_new_read_label;

 	cxl_cmd_read_label_get_payload;

 	cxl_memdev_get_label_size;

+	cxl_memdev_nvdimm_bridge_active;

 local:

         *;

 };

diff --git a/cxl/lib/private.h b/cxl/lib/private.h

index c4ed741..525c41e 100644

--- a/cxl/lib/private.h

+++ b/cxl/lib/private.h

@@ -10,6 +10,13 @@

 #define CXL_EXPORT __attribute__ ((visibility("default")))

+struct cxl_nvdimm_bridge {

+	int id;

+	void *dev_buf;

+	size_t buf_len;

+	char *dev_path;

+};

+

 struct cxl_memdev {

 	int id, major, minor;

 	void *dev_buf;

@@ -23,6 +30,7 @@ struct cxl_memdev {

 	int payload_max;

 	size_t lsa_size;

 	struct kmod_module *module;

+	struct cxl_nvdimm_bridge *bridge;

 };

 enum cxl_cmd_query_status {

diff --git a/cxl/libcxl.h b/cxl/libcxl.h

index d3b97a1..535e349 100644

--- a/cxl/libcxl.h

+++ b/cxl/libcxl.h

@@ -43,6 +43,7 @@ unsigned long long cxl_memdev_get_pmem_size(struct cxl_memdev *memdev);

 unsigned long long cxl_memdev_get_ram_size(struct cxl_memdev *memdev);

 const char *cxl_memdev_get_firmware_verison(struct cxl_memdev *memdev);

 size_t cxl_memdev_get_label_size(struct cxl_memdev *memdev);

+int cxl_memdev_nvdimm_bridge_active(struct cxl_memdev *memdev);

 #define cxl_memdev_foreach(ctx, memdev) \

         for (memdev = cxl_memdev_get_first(ctx); \

-- 

2.27.0