From a055fb525ddf2c646038603d6325f337ab9dceee Mon Sep 17 00:00:00 2001
From: NAKAMURA Gou <go.nakamura.yw@hitachi-solutions.com>
Date: Thu, 26 Nov 2015 21:18:24 +0900
Subject: [PATCH] sysfs sample

---
 kernel/ap.c           | 137 ++++++++++++++++++++++++++++++++++++++++++
 kernel/include/init.h |   1 +
 kernel/init.c         |   6 ++
 3 files changed, 144 insertions(+)

diff --git a/kernel/ap.c b/kernel/ap.c
index 4ec8d78e..39acf866 100644
--- a/kernel/ap.c
+++ b/kernel/ap.c
@@ -89,3 +89,140 @@ void ap_init(void)
 	kprintf("AP Booting: Done\n");
 }
 
+#include <sysfs.h>
+#include <kmalloc.h>
+#include <string.h>
+#include <vsprintf.h>
+
+static ssize_t
+show_int(struct sysfs_ops *ops, void *instance, void *buf, size_t size)
+{
+	int *p = instance;
+
+	return snprintf(buf, size, "%d\n", *p);
+}/* show_int() */
+
+struct sysfs_ops show_int_ops = {
+	.show = &show_int,
+};
+
+struct fake_cpu_info {
+	int online;
+};
+
+static struct fake_cpu_info *fake_cpu_infos = NULL;
+
+enum fake_cpu_info_member {
+	ONLINE,
+};
+
+struct fake_cpu_info_ops {
+	enum fake_cpu_info_member member;
+	struct sysfs_ops ops;
+};
+
+static ssize_t
+show_fake_cpu_info(struct sysfs_ops *ops0, void *instance, void *buf,
+		size_t size)
+{
+	struct fake_cpu_info_ops *ops
+		= container_of(ops0, struct fake_cpu_info_ops, ops);
+	struct fake_cpu_info *info = instance;
+	ssize_t n;
+
+	switch (ops->member) {
+	case ONLINE:
+		n = snprintf(buf, size, "%d\n", info->online);
+		break;
+	default:
+		n = -EINVAL;
+		break;
+	}
+
+	if (n >= size) {
+		n = -ENOSPC;
+	}
+
+	return n;
+} /* show_fake_cpu_info() */
+
+static ssize_t
+store_fake_cpu_info(struct sysfs_ops *ops0, void *instance, void *buf,
+		size_t size)
+{
+	struct fake_cpu_info_ops *ops
+		= container_of(ops0, struct fake_cpu_info_ops, ops);
+	struct fake_cpu_info *info = instance;
+	ssize_t n;
+
+	switch (ops->member) {
+	case ONLINE:
+		kprintf("NYI:store_fake_cpu_info(%p,%p,%p,%ld): "
+				"online %d --> \"%.*s\"\n",
+				ops0, instance, buf, size, info->online,
+				(int)size, buf);
+		n = size;
+		break;
+	default:
+		n = -EIO;
+		break;
+	}
+
+	return n;
+} /* store_fake_cpu_info() */
+
+static struct fake_cpu_info_ops show_fci_online = {
+	.member = ONLINE,
+	.ops.show = &show_fake_cpu_info,
+	.ops.store = &store_fake_cpu_info,
+};
+
+void
+cpu_sysfs_setup(void)
+{
+	int error;
+	int cpu;
+	sysfs_handle_t targeth;
+	struct fake_cpu_info *info;
+
+	/* sample of simple variable **********************************/
+	error = sysfs_createf(&show_int_ops, &num_processors, 0444,
+			"/sys/devices/system/cpu/num_processors");
+	if (error) {
+		panic("cpu_sysfs_setup:sysfs_createf(num_processors) failed\n");
+	}
+
+	/* sample of more complex variable ****************************/
+	/* setup table */
+	info = kmalloc(sizeof(*info) * num_processors, IHK_MC_AP_CRITICAL);
+	for (cpu = 0; cpu < num_processors; ++cpu) {
+		info[cpu].online = 10+cpu;
+	}
+	fake_cpu_infos = info;
+
+	/* setup sysfs tree */
+	for (cpu = 0; cpu < num_processors; ++cpu) {
+		/* online */
+		error = sysfs_createf(&show_fci_online.ops,
+				&fake_cpu_infos[cpu], 0644,
+				"/sys/devices/system/cpu/cpu%d/online", cpu);
+		if (error) {
+			panic("cpu_sysfs_setup:sysfs_createf failed\n");
+		}
+
+		/* link to cpu%d */
+		error = sysfs_lookupf(&targeth,
+				"/sys/devices/system/cpu/cpu%d", cpu);
+		if (error) {
+			panic("cpu_sysfs_setup:sysfs_lookupf failed\n");
+		}
+
+		error = sysfs_symlinkf(targeth, "/sys/bus/cpu/devices/cpu%d",
+				cpu);
+		if (error) {
+			panic("cpu_sysfs_setup:sysfs_symlinkf failed\n");
+		}
+	}
+
+	return;
+} /* cpu_sysfs_setup() */
diff --git a/kernel/include/init.h b/kernel/include/init.h
index 858a96c4..31717f16 100644
--- a/kernel/include/init.h
+++ b/kernel/include/init.h
@@ -28,6 +28,7 @@ extern void init_host_syscall_channel(void);
 extern void init_host_syscall_channel2(void);
 extern void sched_init(void);
 extern void pc_ap_init(void);
+extern void cpu_sysfs_setup(void);
 
 extern char *find_command_line(char *name);
 
diff --git a/kernel/init.c b/kernel/init.c
index 82cd6a61..1e651c0b 100644
--- a/kernel/init.c
+++ b/kernel/init.c
@@ -251,6 +251,11 @@ static void rest_init(void)
 	sched_init();
 }
 
+static void populate_sysfs(void)
+{
+	cpu_sysfs_setup();
+} /* populate_sysfs() */
+
 int host_ikc_inited = 0;
 extern int num_processors;
 extern void zero_tsc(void);
@@ -280,6 +285,7 @@ static void post_init(void)
 
 	create_os_procfs_files();
 	sysfs_init();
+	populate_sysfs();
 }
 #ifdef DCFA_RUN
 extern void user_main();