diff options
Diffstat (limited to 'common/fdt_fixup.c')
| -rw-r--r-- | common/fdt_fixup.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/common/fdt_fixup.c b/common/fdt_fixup.c new file mode 100644 index 000000000..d518eb2a4 --- /dev/null +++ b/common/fdt_fixup.c @@ -0,0 +1,212 @@ +/* + * 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 negative values 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; + int ret; + + prop = fdt_getprop(fdt, offs, "device_type", &len); + if (prop == NULL) + continue; + if ((strcmp(prop, "cpu") != 0) || (len != 4)) + continue; + + /* Ignore any nodes which already use "psci". */ + prop = fdt_getprop(fdt, offs, "enable-method", &len); + if ((prop != NULL) && + (strcmp(prop, "psci") == 0) && (len == 5)) + continue; + + ret = fdt_setprop_string(fdt, offs, "enable-method", "psci"); + if (ret < 0) + return ret; + /* + * 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; +} |