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/*
* Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
/*
* Contains generic routines to fix up the device tree blob passed on to
* payloads like BL32 and BL33 (and further down the boot chain).
* This allows to easily add PSCI nodes, when the original DT does not have
* it or advertises another method.
* Also it supports to add reserved memory nodes to describe memory that
* is used by the secure world, so that non-secure software avoids using
* that.
*/
#include <string.h>
#include <libfdt.h>
#include <common/debug.h>
#include <drivers/console.h>
#include <lib/psci/psci.h>
#include <common/fdt_fixup.h>
static int append_psci_compatible(void *fdt, int offs, const char *str)
{
return fdt_appendprop(fdt, offs, "compatible", str, strlen(str) + 1);
}
/*
* Those defines are for PSCI v0.1 legacy clients, which we expect to use
* the same execution state (AArch32/AArch64) as TF-A.
* Kernels running in AArch32 on an AArch64 TF-A should use PSCI v0.2.
*/
#ifdef __aarch64__
#define PSCI_CPU_SUSPEND_FNID PSCI_CPU_SUSPEND_AARCH64
#define PSCI_CPU_ON_FNID PSCI_CPU_ON_AARCH64
#else
#define PSCI_CPU_SUSPEND_FNID PSCI_CPU_SUSPEND_AARCH32
#define PSCI_CPU_ON_FNID PSCI_CPU_ON_AARCH32
#endif
/*******************************************************************************
* dt_add_psci_node() - Add a PSCI node into an existing device tree
* @fdt: pointer to the device tree blob in memory
*
* Add a device tree node describing PSCI into the root level of an existing
* device tree blob in memory.
* This will add v0.1, v0.2 and v1.0 compatible strings and the standard
* function IDs for v0.1 compatibility.
* An existing PSCI node will not be touched, the function will return success
* in this case. This function will not touch the /cpus enable methods, use
* dt_add_psci_cpu_enable_methods() for that.
*
* Return: 0 on success, -1 otherwise.
******************************************************************************/
int dt_add_psci_node(void *fdt)
{
int offs;
if (fdt_path_offset(fdt, "/psci") >= 0) {
WARN("PSCI Device Tree node already exists!\n");
return 0;
}
offs = fdt_path_offset(fdt, "/");
if (offs < 0)
return -1;
offs = fdt_add_subnode(fdt, offs, "psci");
if (offs < 0)
return -1;
if (append_psci_compatible(fdt, offs, "arm,psci-1.0"))
return -1;
if (append_psci_compatible(fdt, offs, "arm,psci-0.2"))
return -1;
if (append_psci_compatible(fdt, offs, "arm,psci"))
return -1;
if (fdt_setprop_string(fdt, offs, "method", "smc"))
return -1;
if (fdt_setprop_u32(fdt, offs, "cpu_suspend", PSCI_CPU_SUSPEND_FNID))
return -1;
if (fdt_setprop_u32(fdt, offs, "cpu_off", PSCI_CPU_OFF))
return -1;
if (fdt_setprop_u32(fdt, offs, "cpu_on", PSCI_CPU_ON_FNID))
return -1;
return 0;
}
/*
* Find the first subnode that has a "device_type" property with the value
* "cpu" and which's enable-method is not "psci" (yet).
* Returns 0 if no such subnode is found, so all have already been patched
* or none have to be patched in the first place.
* Returns 1 if *one* such subnode has been found and successfully changed
* to "psci".
* Returns -1 on error.
*
* Call in a loop until it returns 0. Recalculate the node offset after
* it has returned 1.
*/
static int dt_update_one_cpu_node(void *fdt, int offset)
{
int offs;
/* Iterate over all subnodes to find those with device_type = "cpu". */
for (offs = fdt_first_subnode(fdt, offset); offs >= 0;
offs = fdt_next_subnode(fdt, offs)) {
const char *prop;
int len;
prop = fdt_getprop(fdt, offs, "device_type", &len);
if (!prop)
continue;
if (memcmp(prop, "cpu", 4) != 0 || len != 4)
continue;
/* Ignore any nodes which already use "psci". */
prop = fdt_getprop(fdt, offs, "enable-method", &len);
if (prop && memcmp(prop, "psci", 5) == 0 && len == 5)
continue;
if (fdt_setprop_string(fdt, offs, "enable-method", "psci"))
return -1;
/*
* Subnode found and patched.
* Restart to accommodate potentially changed offsets.
*/
return 1;
}
if (offs == -FDT_ERR_NOTFOUND)
return 0;
return offs;
}
/*******************************************************************************
* dt_add_psci_cpu_enable_methods() - switch CPU nodes in DT to use PSCI
* @fdt: pointer to the device tree blob in memory
*
* Iterate over all CPU device tree nodes (/cpus/cpu@x) in memory to change
* the enable-method to PSCI. This will add the enable-method properties, if
* required, or will change existing properties to read "psci".
*
* Return: 0 on success, or a negative error value otherwise.
******************************************************************************/
int dt_add_psci_cpu_enable_methods(void *fdt)
{
int offs, ret;
do {
offs = fdt_path_offset(fdt, "/cpus");
if (offs < 0)
return offs;
ret = dt_update_one_cpu_node(fdt, offs);
} while (ret > 0);
return ret;
}
#define HIGH_BITS(x) ((sizeof(x) > 4) ? ((x) >> 32) : (typeof(x))0)
/*******************************************************************************
* fdt_add_reserved_memory() - reserve (secure) memory regions in DT
* @dtb: pointer to the device tree blob in memory
* @node_name: name of the subnode to be used
* @base: physical base address of the reserved region
* @size: size of the reserved region
*
* Add a region of memory to the /reserved-memory node in a device tree in
* memory, creating that node if required. Each region goes into a subnode
* of that node and has a @node_name, a @base address and a @size.
* This will prevent any device tree consumer from using that memory. It
* can be used to announce secure memory regions, as it adds the "no-map"
* property to prevent mapping and speculative operations on that region.
*
* See reserved-memory/reserved-memory.txt in the (Linux kernel) DT binding
* documentation for details.
*
* Return: 0 on success, a negative error value otherwise.
******************************************************************************/
int fdt_add_reserved_memory(void *dtb, const char *node_name,
uintptr_t base, size_t size)
{
int offs = fdt_path_offset(dtb, "/reserved-memory");
uint32_t addresses[3];
if (offs < 0) { /* create if not existing yet */
offs = fdt_add_subnode(dtb, 0, "reserved-memory");
if (offs < 0)
return offs;
fdt_setprop_u32(dtb, offs, "#address-cells", 2);
fdt_setprop_u32(dtb, offs, "#size-cells", 1);
fdt_setprop(dtb, offs, "ranges", NULL, 0);
}
addresses[0] = cpu_to_fdt32(HIGH_BITS(base));
addresses[1] = cpu_to_fdt32(base & 0xffffffff);
addresses[2] = cpu_to_fdt32(size & 0xffffffff);
offs = fdt_add_subnode(dtb, offs, node_name);
fdt_setprop(dtb, offs, "no-map", NULL, 0);
fdt_setprop(dtb, offs, "reg", addresses, 12);
return 0;
}
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