1 /* 2 * Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 7 /* 8 * Contains generic routines to fix up the device tree blob passed on to 9 * payloads like BL32 and BL33 (and further down the boot chain). 10 * This allows to easily add PSCI nodes, when the original DT does not have 11 * it or advertises another method. 12 * Also it supports to add reserved memory nodes to describe memory that 13 * is used by the secure world, so that non-secure software avoids using 14 * that. 15 */ 16 17 #include <string.h> 18 19 #include <libfdt.h> 20 21 #include <common/debug.h> 22 #include <drivers/console.h> 23 #include <lib/psci/psci.h> 24 25 #include <common/fdt_fixup.h> 26 27 static int append_psci_compatible(void *fdt, int offs, const char *str) 28 { 29 return fdt_appendprop(fdt, offs, "compatible", str, strlen(str) + 1); 30 } 31 32 /* 33 * Those defines are for PSCI v0.1 legacy clients, which we expect to use 34 * the same execution state (AArch32/AArch64) as TF-A. 35 * Kernels running in AArch32 on an AArch64 TF-A should use PSCI v0.2. 36 */ 37 #ifdef __aarch64__ 38 #define PSCI_CPU_SUSPEND_FNID PSCI_CPU_SUSPEND_AARCH64 39 #define PSCI_CPU_ON_FNID PSCI_CPU_ON_AARCH64 40 #else 41 #define PSCI_CPU_SUSPEND_FNID PSCI_CPU_SUSPEND_AARCH32 42 #define PSCI_CPU_ON_FNID PSCI_CPU_ON_AARCH32 43 #endif 44 45 /******************************************************************************* 46 * dt_add_psci_node() - Add a PSCI node into an existing device tree 47 * @fdt: pointer to the device tree blob in memory 48 * 49 * Add a device tree node describing PSCI into the root level of an existing 50 * device tree blob in memory. 51 * This will add v0.1, v0.2 and v1.0 compatible strings and the standard 52 * function IDs for v0.1 compatibility. 53 * An existing PSCI node will not be touched, the function will return success 54 * in this case. This function will not touch the /cpus enable methods, use 55 * dt_add_psci_cpu_enable_methods() for that. 56 * 57 * Return: 0 on success, -1 otherwise. 58 ******************************************************************************/ 59 int dt_add_psci_node(void *fdt) 60 { 61 int offs; 62 63 if (fdt_path_offset(fdt, "/psci") >= 0) { 64 WARN("PSCI Device Tree node already exists!\n"); 65 return 0; 66 } 67 68 offs = fdt_path_offset(fdt, "/"); 69 if (offs < 0) 70 return -1; 71 offs = fdt_add_subnode(fdt, offs, "psci"); 72 if (offs < 0) 73 return -1; 74 if (append_psci_compatible(fdt, offs, "arm,psci-1.0")) 75 return -1; 76 if (append_psci_compatible(fdt, offs, "arm,psci-0.2")) 77 return -1; 78 if (append_psci_compatible(fdt, offs, "arm,psci")) 79 return -1; 80 if (fdt_setprop_string(fdt, offs, "method", "smc")) 81 return -1; 82 if (fdt_setprop_u32(fdt, offs, "cpu_suspend", PSCI_CPU_SUSPEND_FNID)) 83 return -1; 84 if (fdt_setprop_u32(fdt, offs, "cpu_off", PSCI_CPU_OFF)) 85 return -1; 86 if (fdt_setprop_u32(fdt, offs, "cpu_on", PSCI_CPU_ON_FNID)) 87 return -1; 88 return 0; 89 } 90 91 /* 92 * Find the first subnode that has a "device_type" property with the value 93 * "cpu" and which's enable-method is not "psci" (yet). 94 * Returns 0 if no such subnode is found, so all have already been patched 95 * or none have to be patched in the first place. 96 * Returns 1 if *one* such subnode has been found and successfully changed 97 * to "psci". 98 * Returns -1 on error. 99 * 100 * Call in a loop until it returns 0. Recalculate the node offset after 101 * it has returned 1. 102 */ 103 static int dt_update_one_cpu_node(void *fdt, int offset) 104 { 105 int offs; 106 107 /* Iterate over all subnodes to find those with device_type = "cpu". */ 108 for (offs = fdt_first_subnode(fdt, offset); offs >= 0; 109 offs = fdt_next_subnode(fdt, offs)) { 110 const char *prop; 111 int len; 112 113 prop = fdt_getprop(fdt, offs, "device_type", &len); 114 if (!prop) 115 continue; 116 if (memcmp(prop, "cpu", 4) != 0 || len != 4) 117 continue; 118 119 /* Ignore any nodes which already use "psci". */ 120 prop = fdt_getprop(fdt, offs, "enable-method", &len); 121 if (prop && memcmp(prop, "psci", 5) == 0 && len == 5) 122 continue; 123 124 if (fdt_setprop_string(fdt, offs, "enable-method", "psci")) 125 return -1; 126 /* 127 * Subnode found and patched. 128 * Restart to accommodate potentially changed offsets. 129 */ 130 return 1; 131 } 132 133 if (offs == -FDT_ERR_NOTFOUND) 134 return 0; 135 136 return offs; 137 } 138 139 /******************************************************************************* 140 * dt_add_psci_cpu_enable_methods() - switch CPU nodes in DT to use PSCI 141 * @fdt: pointer to the device tree blob in memory 142 * 143 * Iterate over all CPU device tree nodes (/cpus/cpu@x) in memory to change 144 * the enable-method to PSCI. This will add the enable-method properties, if 145 * required, or will change existing properties to read "psci". 146 * 147 * Return: 0 on success, or a negative error value otherwise. 148 ******************************************************************************/ 149 150 int dt_add_psci_cpu_enable_methods(void *fdt) 151 { 152 int offs, ret; 153 154 do { 155 offs = fdt_path_offset(fdt, "/cpus"); 156 if (offs < 0) 157 return offs; 158 159 ret = dt_update_one_cpu_node(fdt, offs); 160 } while (ret > 0); 161 162 return ret; 163 } 164 165 #define HIGH_BITS(x) ((sizeof(x) > 4) ? ((x) >> 32) : (typeof(x))0) 166 167 /******************************************************************************* 168 * fdt_add_reserved_memory() - reserve (secure) memory regions in DT 169 * @dtb: pointer to the device tree blob in memory 170 * @node_name: name of the subnode to be used 171 * @base: physical base address of the reserved region 172 * @size: size of the reserved region 173 * 174 * Add a region of memory to the /reserved-memory node in a device tree in 175 * memory, creating that node if required. Each region goes into a subnode 176 * of that node and has a @node_name, a @base address and a @size. 177 * This will prevent any device tree consumer from using that memory. It 178 * can be used to announce secure memory regions, as it adds the "no-map" 179 * property to prevent mapping and speculative operations on that region. 180 * 181 * See reserved-memory/reserved-memory.txt in the (Linux kernel) DT binding 182 * documentation for details. 183 * 184 * Return: 0 on success, a negative error value otherwise. 185 ******************************************************************************/ 186 int fdt_add_reserved_memory(void *dtb, const char *node_name, 187 uintptr_t base, size_t size) 188 { 189 int offs = fdt_path_offset(dtb, "/reserved-memory"); 190 uint32_t addresses[3]; 191 192 if (offs < 0) { /* create if not existing yet */ 193 offs = fdt_add_subnode(dtb, 0, "reserved-memory"); 194 if (offs < 0) 195 return offs; 196 fdt_setprop_u32(dtb, offs, "#address-cells", 2); 197 fdt_setprop_u32(dtb, offs, "#size-cells", 1); 198 fdt_setprop(dtb, offs, "ranges", NULL, 0); 199 } 200 201 addresses[0] = cpu_to_fdt32(HIGH_BITS(base)); 202 addresses[1] = cpu_to_fdt32(base & 0xffffffff); 203 addresses[2] = cpu_to_fdt32(size & 0xffffffff); 204 offs = fdt_add_subnode(dtb, offs, node_name); 205 fdt_setprop(dtb, offs, "no-map", NULL, 0); 206 fdt_setprop(dtb, offs, "reg", addresses, 12); 207 208 return 0; 209 } 210