[PATCH v3 25/27] powerpc/powernv/pmem: Expose the serial number in sysfs

["Alastair D'Silva" <alastair@xxxxxxxxxxx>]

From: Alastair D'Silva <alastair@xxxxxxxxxxx>

This information will be used by ndctl in userspace to help users identify
the device.

Signed-off-by: Alastair D'Silva <alastair@xxxxxxxxxxx>
---
 arch/powerpc/platforms/powernv/pmem/Makefile  |  2 +-
 arch/powerpc/platforms/powernv/pmem/ocxl.c    |  5 +++
 .../platforms/powernv/pmem/ocxl_internal.h    |  6 +++
 .../platforms/powernv/pmem/ocxl_sysfs.c       | 37 +++++++++++++++++++
 4 files changed, 49 insertions(+), 1 deletion(-)
 create mode 100644 arch/powerpc/platforms/powernv/pmem/ocxl_sysfs.c

diff --git a/arch/powerpc/platforms/powernv/pmem/Makefile b/arch/powerpc/platforms/powernv/pmem/Makefile
index 4ceda25907d4..d02870806f30 100644
--- a/arch/powerpc/platforms/powernv/pmem/Makefile
+++ b/arch/powerpc/platforms/powernv/pmem/Makefile
@@ -4,4 +4,4 @@ ccflags-$(CONFIG_PPC_WERROR)	+= -Werror
 
 obj-$(CONFIG_OCXL_PMEM) += ocxlpmem.o
 
-ocxlpmem-y := ocxl.o ocxl_internal.o
+ocxlpmem-y := ocxl.o ocxl_internal.o ocxl_sysfs.o
diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl.c b/arch/powerpc/platforms/powernv/pmem/ocxl.c
index 5cd1b6d78dd6..ec73713d05ad 100644
--- a/arch/powerpc/platforms/powernv/pmem/ocxl.c
+++ b/arch/powerpc/platforms/powernv/pmem/ocxl.c
@@ -1878,6 +1878,11 @@ static int probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto err;
 	}
 
+	if (ocxlpmem_sysfs_add(ocxlpmem)) {
+		dev_err(&pdev->dev, "Could not create sysfs entries\n");
+		goto err;
+	}
+
 	elapsed = 0;
 	timeout = ocxlpmem->readiness_timeout + ocxlpmem->memory_available_timeout;
 	while (!is_usable(ocxlpmem, false)) {
diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
index 0eb7a35d24ae..12304ceace61 100644
--- a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
+++ b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
@@ -246,3 +246,9 @@ int ns_response_handled(const struct ocxlpmem *ocxlpmem);
  */
 void warn_status(const struct ocxlpmem *ocxlpmem, const char *message,
 		 u8 status);
+
+/**
+ * ocxlpmem_sysfs_add() - Create sysfs entries for an OpenCAPI persistent memory device
+ * @ocxlpmem: the device metadata
+ */
+int ocxlpmem_sysfs_add(struct ocxlpmem *ocxlpmem);
diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl_sysfs.c b/arch/powerpc/platforms/powernv/pmem/ocxl_sysfs.c
new file mode 100644
index 000000000000..7829e4bc887d
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/pmem/ocxl_sysfs.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright 2018 IBM Corp.
+
+#include <linux/sysfs.h>
+#include <linux/capability.h>
+#include <linux/limits.h>
+#include <linux/firmware.h>
+#include "ocxl_internal.h"
+
+static ssize_t serial_show(struct device *device, struct device_attribute *attr,
+			   char *buf)
+{
+	struct ocxlpmem *ocxlpmem = container_of(device, struct ocxlpmem, dev);
+	const struct ocxl_fn_config *fn_config = ocxl_function_config(ocxlpmem->ocxl_fn);
+
+	return scnprintf(buf, PAGE_SIZE, "%llu\n", fn_config->serial);
+}
+
+static struct device_attribute attrs[] = {
+	__ATTR_RO(serial),
+};
+
+int ocxlpmem_sysfs_add(struct ocxlpmem *ocxlpmem)
+{
+	int i, rc;
+
+	for (i = 0; i < ARRAY_SIZE(attrs); i++) {
+		rc = device_create_file(&ocxlpmem->dev, &attrs[i]);
+		if (rc) {
+			for (; --i >= 0;)
+				device_remove_file(&ocxlpmem->dev, &attrs[i]);
+
+			return rc;
+		}
+	}
+	return 0;
+}
-- 
2.24.1