powerpc/powernv: Add ultravisor message log interface

bool cpu_core_split_required(void);

struct memcons;

ssize_t memcons_copy(struct memcons *mc, char *to, loff_t pos, size_t count);

u32 memcons_get_size(struct memcons *mc);

struct memcons *memcons_init(struct device_node *node, const char *mc_prop_name);

#endif /* _POWERNV_H */

#include <linux/init.h>

#include <linux/printk.h>

#include <linux/of_fdt.h>

#include <linux/of.h>

#include <asm/ultravisor.h>

#include <asm/firmware.h>

#include <asm/machdep.h>

#include "powernv.h"

static struct kobject *ultravisor_kobj;

int __init early_init_dt_scan_ultravisor(unsigned long node, const char *uname,

					 int depth, void *data)

	pr_debug("Ultravisor detected!\n");

	return 1;

}

static struct memcons *uv_memcons;

static ssize_t uv_msglog_read(struct file *file, struct kobject *kobj,

			      struct bin_attribute *bin_attr, char *to,

			      loff_t pos, size_t count)

{

	return memcons_copy(uv_memcons, to, pos, count);

}

static struct bin_attribute uv_msglog_attr = {

	.attr = {.name = "msglog", .mode = 0400},

	.read = uv_msglog_read

};

static int __init uv_init(void)

{

	struct device_node *node;

	if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))

		return 0;

	node = of_find_compatible_node(NULL, NULL, "ibm,uv-firmware");

	if (!node)

		return -ENODEV;

	uv_memcons = memcons_init(node, "memcons");

	if (!uv_memcons)

		return -ENOENT;

	uv_msglog_attr.size = memcons_get_size(uv_memcons);

	ultravisor_kobj = kobject_create_and_add("ultravisor", firmware_kobj);

	if (!ultravisor_kobj)

		return -ENOMEM;

	return sysfs_create_bin_file(ultravisor_kobj, &uv_msglog_attr);

}

machine_subsys_initcall(powernv, uv_init);