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126 lines
3.1 KiB
126 lines
3.1 KiB
/*
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* Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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/*
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* Contains generic routines to fix up the device tree blob passed on to
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* payloads like BL32 and BL33 (and further down the boot chain).
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* This allows to easily add PSCI nodes, when the original DT does not have
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* it or advertises another method.
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*/
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#include <string.h>
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#include <libfdt.h>
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#include <common/debug.h>
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#include <drivers/console.h>
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#include <lib/psci/psci.h>
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#include <common/fdt_fixup.h>
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static int append_psci_compatible(void *fdt, int offs, const char *str)
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{
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return fdt_appendprop(fdt, offs, "compatible", str, strlen(str) + 1);
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}
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int dt_add_psci_node(void *fdt)
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{
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int offs;
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if (fdt_path_offset(fdt, "/psci") >= 0) {
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WARN("PSCI Device Tree node already exists!\n");
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return 0;
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}
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offs = fdt_path_offset(fdt, "/");
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if (offs < 0)
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return -1;
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offs = fdt_add_subnode(fdt, offs, "psci");
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if (offs < 0)
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return -1;
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if (append_psci_compatible(fdt, offs, "arm,psci-1.0"))
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return -1;
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if (append_psci_compatible(fdt, offs, "arm,psci-0.2"))
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return -1;
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if (append_psci_compatible(fdt, offs, "arm,psci"))
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return -1;
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if (fdt_setprop_string(fdt, offs, "method", "smc"))
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return -1;
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if (fdt_setprop_u32(fdt, offs, "cpu_suspend", PSCI_CPU_SUSPEND_AARCH64))
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return -1;
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if (fdt_setprop_u32(fdt, offs, "cpu_off", PSCI_CPU_OFF))
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return -1;
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if (fdt_setprop_u32(fdt, offs, "cpu_on", PSCI_CPU_ON_AARCH64))
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return -1;
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if (fdt_setprop_u32(fdt, offs, "sys_poweroff", PSCI_SYSTEM_OFF))
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return -1;
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if (fdt_setprop_u32(fdt, offs, "sys_reset", PSCI_SYSTEM_RESET))
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return -1;
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return 0;
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}
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/*
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* Find the first subnode that has a "device_type" property with the value
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* "cpu" and which's enable-method is not "psci" (yet).
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* Returns 0 if no such subnode is found, so all have already been patched
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* or none have to be patched in the first place.
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* Returns 1 if *one* such subnode has been found and successfully changed
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* to "psci".
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* Returns -1 on error.
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*
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* Call in a loop until it returns 0. Recalculate the node offset after
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* it has returned 1.
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*/
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static int dt_update_one_cpu_node(void *fdt, int offset)
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{
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int offs;
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/* Iterate over all subnodes to find those with device_type = "cpu". */
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for (offs = fdt_first_subnode(fdt, offset); offs >= 0;
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offs = fdt_next_subnode(fdt, offs)) {
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const char *prop;
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int len;
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prop = fdt_getprop(fdt, offs, "device_type", &len);
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if (!prop)
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continue;
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if (memcmp(prop, "cpu", 4) != 0 || len != 4)
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continue;
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/* Ignore any nodes which already use "psci". */
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prop = fdt_getprop(fdt, offs, "enable-method", &len);
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if (prop && memcmp(prop, "psci", 5) == 0 && len == 5)
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continue;
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if (fdt_setprop_string(fdt, offs, "enable-method", "psci"))
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return -1;
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/*
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* Subnode found and patched.
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* Restart to accommodate potentially changed offsets.
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*/
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return 1;
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}
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if (offs == -FDT_ERR_NOTFOUND)
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return 0;
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return offs;
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}
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int dt_add_psci_cpu_enable_methods(void *fdt)
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{
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int offs, ret;
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do {
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offs = fdt_path_offset(fdt, "/cpus");
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if (offs < 0)
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return offs;
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ret = dt_update_one_cpu_node(fdt, offs);
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} while (ret > 0);
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return ret;
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}
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