arch/powerpc/platforms/powernv/ultravisor.c

   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);