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// SPDX-License-Identifier: GPL-2.0+
/*
* FDT Address translation based on u-boot fdt_support.c which in turn was
* based on the kernel unflattened DT address translation code.
*
* (C) Copyright 2007
* Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com
*
* Copyright 2010-2011 Freescale Semiconductor, Inc.
*/
#define pr_fmt(fmt) "OF: fdt: " fmt
#include <linux/kernel.h>
#include <linux/libfdt.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/sizes.h>
/* Max address size we deal with */
#define OF_MAX_ADDR_CELLS 4
#define OF_CHECK_COUNTS(na, ns) ((na) > 0 && (na) <= OF_MAX_ADDR_CELLS && \
(ns) > 0)
/* Debug utility */
#ifdef DEBUG
static void __init of_dump_addr(const char *s, const __be32 *addr, int na)
{
pr_debug("%s", s);
while(na--)
pr_cont(" %08x", *(addr++));
pr_cont("\n");
}
#else
static void __init of_dump_addr(const char *s, const __be32 *addr, int na) { }
#endif
/* Callbacks for bus specific translators */
struct of_bus {
void (*count_cells)(const void *blob, int parentoffset,
int *addrc, int *sizec);
u64 (*map)(__be32 *addr, const __be32 *range,
int na, int ns, int pna);
int (*translate)(__be32 *addr, u64 offset, int na);
};
/* Default translator (generic bus) */
static void __init fdt_bus_default_count_cells(const void *blob, int parentoffset,
int *addrc, int *sizec)
{
const __be32 *prop;
if (addrc) {
prop = fdt_getprop(blob, parentoffset, "#address-cells", NULL);
if (prop)
*addrc = be32_to_cpup(prop);
else
*addrc = dt_root_addr_cells;
}
if (sizec) {
prop = fdt_getprop(blob, parentoffset, "#size-cells", NULL);
if (prop)
*sizec = be32_to_cpup(prop);
else
*sizec = dt_root_size_cells;
}
}
static u64 __init fdt_bus_default_map(__be32 *addr, const __be32 *range,
int na, int ns, int pna)
{
u64 cp, s, da;
cp = of_read_number(range, na);
s = of_read_number(range + na + pna, ns);
da = of_read_number(addr, na);
pr_debug("default map, cp=%llx, s=%llx, da=%llx\n",
cp, s, da);
if (da < cp || da >= (cp + s))
return OF_BAD_ADDR;
return da - cp;
}
static int __init fdt_bus_default_translate(__be32 *addr, u64 offset, int na)
{
u64 a = of_read_number(addr, na);
memset(addr, 0, na * 4);
a += offset;
if (na > 1)
addr[na - 2] = cpu_to_fdt32(a >> 32);
addr[na - 1] = cpu_to_fdt32(a & 0xffffffffu);
return 0;
}
/* Array of bus specific translators */
static const struct of_bus of_busses[] __initconst = {
/* Default */
{
.count_cells = fdt_bus_default_count_cells,
.map = fdt_bus_default_map,
.translate = fdt_bus_default_translate,
},
};
static int __init fdt_translate_one(const void *blob, int parent,
const struct of_bus *bus,
const struct of_bus *pbus, __be32 *addr,
int na, int ns, int pna, const char *rprop)
{
const __be32 *ranges;
int rlen;
int rone;
u64 offset = OF_BAD_ADDR;
ranges = fdt_getprop(blob, parent, rprop, &rlen);
if (!ranges)
return 1;
if (rlen == 0) {
offset = of_read_number(addr, na);
memset(addr, 0, pna * 4);
pr_debug("empty ranges, 1:1 translation\n");
goto finish;
}
pr_debug("walking ranges...\n");
/* Now walk through the ranges */
rlen /= 4;
rone = na + pna + ns;
for (; rlen >= rone; rlen -= rone, ranges += rone) {
offset = bus->map(addr, ranges, na, ns, pna);
if (offset != OF_BAD_ADDR)
break;
}
if (offset == OF_BAD_ADDR) {
pr_debug("not found !\n");
return 1;
}
memcpy(addr, ranges + na, 4 * pna);
finish:
of_dump_addr("parent translation for:", addr, pna);
pr_debug("with offset: %llx\n", offset);
/* Translate it into parent bus space */
return pbus->translate(addr, offset, pna);
}
/*
* Translate an address from the device-tree into a CPU physical address,
* this walks up the tree and applies the various bus mappings on the
* way.
*
* Note: We consider that crossing any level with #size-cells == 0 to mean
* that translation is impossible (that is we are not dealing with a value
* that can be mapped to a cpu physical address). This is not really specified
* that way, but this is traditionally the way IBM at least do things
*/
static u64 __init fdt_translate_address(const void *blob, int node_offset)
{
int parent, len;
const struct of_bus *bus, *pbus;
const __be32 *reg;
__be32 addr[OF_MAX_ADDR_CELLS];
int na, ns, pna, pns;
u64 result = OF_BAD_ADDR;
pr_debug("** translation for device %s **\n",
fdt_get_name(blob, node_offset, NULL));
reg = fdt_getprop(blob, node_offset, "reg", &len);
if (!reg) {
pr_err("warning: device tree node '%s' has no address.\n",
fdt_get_name(blob, node_offset, NULL));
goto bail;
}
/* Get parent & match bus type */
parent = fdt_parent_offset(blob, node_offset);
if (parent < 0)
goto bail;
bus = &of_busses[0];
/* Cound address cells & copy address locally */
bus->count_cells(blob, parent, &na, &ns);
if (!OF_CHECK_COUNTS(na, ns)) {
pr_err("Bad cell count for %s\n",
fdt_get_name(blob, node_offset, NULL));
goto bail;
}
memcpy(addr, reg, na * 4);
pr_debug("bus (na=%d, ns=%d) on %s\n",
na, ns, fdt_get_name(blob, parent, NULL));
of_dump_addr("translating address:", addr, na);
/* Translate */
for (;;) {
/* Switch to parent bus */
node_offset = parent;
parent = fdt_parent_offset(blob, node_offset);
/* If root, we have finished */
if (parent < 0) {
pr_debug("reached root node\n");
result = of_read_number(addr, na);
break;
}
/* Get new parent bus and counts */
pbus = &of_busses[0];
pbus->count_cells(blob, parent, &pna, &pns);
if (!OF_CHECK_COUNTS(pna, pns)) {
pr_err("Bad cell count for %s\n",
fdt_get_name(blob, node_offset, NULL));
break;
}
pr_debug("parent bus (na=%d, ns=%d) on %s\n",
pna, pns, fdt_get_name(blob, parent, NULL));
/* Apply bus translation */
if (fdt_translate_one(blob, node_offset, bus, pbus,
addr, na, ns, pna, "ranges"))
break;
/* Complete the move up one level */
na = pna;
ns = pns;
bus = pbus;
of_dump_addr("one level translation:", addr, na);
}
bail:
return result;
}
/**
* of_flat_dt_translate_address - translate DT addr into CPU phys addr
* @node: node in the flat blob
*/
u64 __init of_flat_dt_translate_address(unsigned long node)
{
return fdt_translate_address(initial_boot_params, node);
}
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