dev/fdt/fdt_subr.c

/* $NetBSD: fdt_subr.c,v 1.10 2017/04/29 12:38:26 jmcneill Exp $ */

/*-
 * Copyright (c) 2015 Jared D. McNeill <jmcneill (at) invisible.ca>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: fdt_subr.c,v 1.10 2017/04/29 12:38:26 jmcneill Exp $");

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kmem.h>

#include <libfdt.h>
#include <dev/fdt/fdtvar.h>

static const void *fdt_data;

bool
fdtbus_set_data(const void *data)
{
	KASSERT(fdt_data == NULL);
	if (fdt_check_header(data) != 0) {
		return false;
	}
	fdt_data = data;
	return true;
}

const void *
fdtbus_get_data(void)
{
	return fdt_data;
}

int
fdtbus_offset2phandle(int offset)
{
	if (offset < 0)
		return 0;

	return offset + fdt_off_dt_struct(fdt_data);
}

int
fdtbus_phandle2offset(int phandle)
{
	const int dtoff = fdt_off_dt_struct(fdt_data);

	if (phandle == -1)
		phandle = dtoff;

	if (phandle < dtoff)
		return -1;

	return phandle - dtoff;
}


static int
fdtbus_get_addr_cells(int phandle)
{
	uint32_t addr_cells;

	const int parent = OF_parent(phandle);
	if (parent == -1)
		return -1;

	if (of_getprop_uint32(parent, "#address-cells", &addr_cells))
		addr_cells = 2;

	return addr_cells;
}

static int
fdtbus_get_size_cells(int phandle)
{
	uint32_t size_cells;

	const int parent = OF_parent(phandle);
	if (parent == -1)
		return -1;

	if (of_getprop_uint32(parent, "#size-cells", &size_cells))
		size_cells = 0;

	return size_cells;
}

int
fdtbus_get_phandle(int phandle, const char *prop)
{
	u_int phandle_ref;
	u_int *buf;
	int len;

	len = OF_getproplen(phandle, prop);
	if (len < sizeof(phandle_ref))
		return -1;

	buf = kmem_alloc(len, KM_SLEEP);

	if (OF_getprop(phandle, prop, buf, len) != len) {
		kmem_free(buf, len);
		return -1;
	}

	phandle_ref = fdt32_to_cpu(buf[0]);
	kmem_free(buf, len);

	return fdtbus_get_phandle_from_native(phandle_ref);
}

int
fdtbus_get_phandle_from_native(int phandle)
{
	const int off = fdt_node_offset_by_phandle(fdt_data, phandle);
	if (off < 0) {
		return -1;
	}
	return fdtbus_offset2phandle(off);
}

bool
fdtbus_get_path(int phandle, char *buf, size_t buflen)
{
	const int off = fdtbus_phandle2offset(phandle);
	if (off < 0) {
		return false;
	}
	if (fdt_get_path(fdt_data, off, buf, (int)buflen) != 0) {
		return false;
	}
	return true;
}

int
fdtbus_get_reg(int phandle, u_int index, bus_addr_t *paddr, bus_size_t *psize)
{
	bus_addr_t addr;
	bus_size_t size;
	const uint8_t *buf;
	int len;

	const int addr_cells = fdtbus_get_addr_cells(phandle);
	const int size_cells = fdtbus_get_size_cells(phandle);
	if (addr_cells == -1 || size_cells == -1)
		return -1;

	buf = fdt_getprop(fdtbus_get_data(),
	    fdtbus_phandle2offset(phandle), "reg", &len);
	if (buf == NULL || len <= 0)
		return -1;

	const u_int reglen = size_cells * 4 + addr_cells * 4;
	if (reglen == 0)
		return -1;

	if (index >= len / reglen)
		return -1;

	switch (addr_cells) {
	case 0:
		addr = 0;
		break;
	case 1:
		addr = be32dec(&buf[index * reglen + 0]);
		break;
	case 2:
		addr = be64dec(&buf[index * reglen + 0]);
		break;
	default:
		panic("fdtbus_get_reg: unsupported addr_cells %d", addr_cells);
	}

	switch (size_cells) {
	case 0:
		size = 0;
		break;
	case 1:
		size = be32dec(&buf[index * reglen + addr_cells * 4]);
		break;
	case 2:
		size = be64dec(&buf[index * reglen + addr_cells * 4]);
		break;
	default:
		panic("fdtbus_get_reg: unsupported size_cells %d", size_cells);
	}

	if (paddr)
		*paddr = addr;
	if (psize)
		*psize = size;

	return 0;
}

const char *
fdtbus_get_stdout_path(void)
{
	const char *prop;

	const int off = fdt_path_offset(fdtbus_get_data(), "/chosen");
	if (off < 0)
		return NULL;

	prop = fdt_getprop(fdtbus_get_data(), off, "stdout-path", NULL);
	if (prop != NULL)
		return prop;

	/* If the stdout-path property is not found, assume serial0 */
	return "serial0:115200n8";
}

int
fdtbus_get_stdout_phandle(void)
{
	const char *prop, *p;
	int off, len;

	prop = fdtbus_get_stdout_path();
	if (prop == NULL)
		return -1;

	p = strchr(prop, ':');
	len = p == NULL ? strlen(prop) : (p - prop);
	if (*prop != '/') {
		/* Alias */
		prop = fdt_get_alias_namelen(fdtbus_get_data(), prop, len);
		if (prop == NULL)
			return -1;
		len = strlen(prop);
	}
	off = fdt_path_offset_namelen(fdtbus_get_data(), prop, len);
	if (off < 0)
		return -1;

	return fdtbus_offset2phandle(off);
}

int
fdtbus_get_stdout_speed(void)
{
	const char *prop, *p;

	prop = fdtbus_get_stdout_path();
	if (prop == NULL)
		return -1;

	p = strchr(prop, ':');
	if (p == NULL)
		return -1;

	return (int)strtoul(p + 1, NULL, 10);
}

bool
fdtbus_status_okay(int phandle)
{
	const int off = fdtbus_phandle2offset(phandle);

	const char *prop = fdt_getprop(fdtbus_get_data(), off, "status", NULL);
	if (prop == NULL)
		return true;

	return strncmp(prop, "ok", 2) == 0;
}