1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Ultravisor high level interfaces
4  *
5  * Copyright 2019, IBM Corporation.
6  *
7  */
8 #include <linux/init.h>
9 #include <linux/printk.h>
10 #include <linux/of_fdt.h>
11 #include <linux/of.h>
12 
13 #include <asm/ultravisor.h>
14 #include <asm/firmware.h>
15 #include <asm/machdep.h>
16 
17 #include "powernv.h"
18 
19 static struct kobject *ultravisor_kobj;
20 
21 int __init early_init_dt_scan_ultravisor(unsigned long node, const char *uname,
22 					 int depth, void *data)
23 {
24 	if (!of_flat_dt_is_compatible(node, "ibm,ultravisor"))
25 		return 0;
26 
27 	powerpc_firmware_features |= FW_FEATURE_ULTRAVISOR;
28 	pr_debug("Ultravisor detected!\n");
29 	return 1;
30 }
31 
32 static struct memcons *uv_memcons;
33 
34 static ssize_t uv_msglog_read(struct file *file, struct kobject *kobj,
35 			      struct bin_attribute *bin_attr, char *to,
36 			      loff_t pos, size_t count)
37 {
38 	return memcons_copy(uv_memcons, to, pos, count);
39 }
40 
41 static struct bin_attribute uv_msglog_attr = {
42 	.attr = {.name = "msglog", .mode = 0400},
43 	.read = uv_msglog_read
44 };
45 
46 static int __init uv_init(void)
47 {
48 	struct device_node *node;
49 
50 	if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))
51 		return 0;
52 
53 	node = of_find_compatible_node(NULL, NULL, "ibm,uv-firmware");
54 	if (!node)
55 		return -ENODEV;
56 
57 	uv_memcons = memcons_init(node, "memcons");
58 	of_node_put(node);
59 	if (!uv_memcons)
60 		return -ENOENT;
61 
62 	uv_msglog_attr.size = memcons_get_size(uv_memcons);
63 
64 	ultravisor_kobj = kobject_create_and_add("ultravisor", firmware_kobj);
65 	if (!ultravisor_kobj)
66 		return -ENOMEM;
67 
68 	return sysfs_create_bin_file(ultravisor_kobj, &uv_msglog_attr);
69 }
70 machine_subsys_initcall(powernv, uv_init);
71