platforms/powernv/ultravisor.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Ultravisor high level interfaces
0004  *
0005  * Copyright 2019, IBM Corporation.
0006  *
0007  */
0008 #include <linux/init.h>
0009 #include <linux/printk.h>
0010 #include <linux/of_fdt.h>
0011 #include <linux/of.h>
0012
0013 #include <asm/ultravisor.h>
0014 #include <asm/firmware.h>
0015 #include <asm/machdep.h>
0016
0017 #include "powernv.h"
0018
0019 static struct kobject *ultravisor_kobj;
0020
0021 int __init early_init_dt_scan_ultravisor(unsigned long node, const char *uname,
0022                      int depth, void *data)
0023 {
0024     if (!of_flat_dt_is_compatible(node, "ibm,ultravisor"))
0025         return 0;
0026
0027     powerpc_firmware_features |= FW_FEATURE_ULTRAVISOR;
0028     pr_debug("Ultravisor detected!\n");
0029     return 1;
0030 }
0031
0032 static struct memcons *uv_memcons;
0033
0034 static ssize_t uv_msglog_read(struct file *file, struct kobject *kobj,
0035                   struct bin_attribute *bin_attr, char *to,
0036                   loff_t pos, size_t count)
0037 {
0038     return memcons_copy(uv_memcons, to, pos, count);
0039 }
0040
0041 static struct bin_attribute uv_msglog_attr = {
0042     .attr = {.name = "msglog", .mode = 0400},
0043     .read = uv_msglog_read
0044 };
0045
0046 static int __init uv_init(void)
0047 {
0048     struct device_node *node;
0049
0050     if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))
0051         return 0;
0052
0053     node = of_find_compatible_node(NULL, NULL, "ibm,uv-firmware");
0054     if (!node)
0055         return -ENODEV;
0056
0057     uv_memcons = memcons_init(node, "memcons");
0058     of_node_put(node);
0059     if (!uv_memcons)
0060         return -ENOENT;
0061
0062     uv_msglog_attr.size = memcons_get_size(uv_memcons);
0063
0064     ultravisor_kobj = kobject_create_and_add("ultravisor", firmware_kobj);
0065     if (!ultravisor_kobj)
0066         return -ENOMEM;
0067
0068     return sysfs_create_bin_file(ultravisor_kobj, &uv_msglog_attr);
0069 }
0070 machine_subsys_initcall(powernv, uv_init);