powerpc/ps3: Add firmware version to sysfs

Add a new sysfs entry /sys/firmware/ps3/fw-version that exports
the PS3's firmware version.

The firmware version is available through an LV1 hypercall, and we've
been printing it to the boot log, but haven't provided an easy way for
user utilities to get it.
Signed-off-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/41509b2da647cd34b1331cc4756c8774b1e284eb.1622822173.git.geoff@infradead.org

arch/powerpc/platforms/ps3/setup.c

@@ -36,6 +36,7 @@ DEFINE_MUTEX(ps3_gpu_mutex);
 EXPORT_SYMBOL_GPL(ps3_gpu_mutex);
 
 static union ps3_firmware_version ps3_firmware_version;
+static char ps3_firmware_version_str[16];
 
 void ps3_get_firmware_version(union ps3_firmware_version *v)
 {
@@ -182,6 +183,40 @@ static int ps3_set_dabr(unsigned long dabr, unsigned long dabrx)
 	return lv1_set_dabr(dabr, dabrx) ? -1 : 0;
 }
 
+static ssize_t ps3_fw_version_show(struct kobject *kobj,
+	struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%s", ps3_firmware_version_str);
+}
+
+static int __init ps3_setup_sysfs(void)
+{
+	static struct kobj_attribute attr = __ATTR(fw-version, S_IRUGO,
+		ps3_fw_version_show, NULL);
+	static struct kobject *kobj;
+	int result;
+
+	kobj = kobject_create_and_add("ps3", firmware_kobj);
+
+	if (!kobj) {
+		pr_warn("%s:%d: kobject_create_and_add failed.\n", __func__,
+			__LINE__);
+		return -ENOMEM;
+	}
+
+	result = sysfs_create_file(kobj, &attr.attr);
+
+	if (result) {
+		pr_warn("%s:%d: sysfs_create_file failed.\n", __func__,
+			__LINE__);
+		kobject_put(kobj);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+core_initcall(ps3_setup_sysfs);
+
 static void __init ps3_setup_arch(void)
 {
 	u64 tmp;
@@ -190,9 +225,11 @@ static void __init ps3_setup_arch(void)
 
 	lv1_get_version_info(&ps3_firmware_version.raw, &tmp);
 
-	printk(KERN_INFO "PS3 firmware version %u.%u.%u\n",
-	       ps3_firmware_version.major, ps3_firmware_version.minor,
-	       ps3_firmware_version.rev);
+	snprintf(ps3_firmware_version_str, sizeof(ps3_firmware_version_str),
+		"%u.%u.%u", ps3_firmware_version.major,
+		ps3_firmware_version.minor, ps3_firmware_version.rev);
+
+	printk(KERN_INFO "PS3 firmware version %s\n", ps3_firmware_version_str);
 
 	ps3_spu_set_platform();