From 6eaf928d66fbded8e190aaa189e1a0810ba79252 Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Thu, 19 Sep 2019 10:45:28 +0100 Subject: [PATCH] FDT helper functions: Add function documentation Since we moved some functions that amend a DT blob in memory to common code, let's add proper function documentation. This covers the three exported functions in common/fdt_fixup.c. Change-Id: I67d7d27344e62172c789d308662f78d54903cf57 Signed-off-by: Andre Przywara --- common/fdt_fixup.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/common/fdt_fixup.c b/common/fdt_fixup.c index 8843404d..48ae9751 100644 --- a/common/fdt_fixup.c +++ b/common/fdt_fixup.c @@ -29,6 +29,20 @@ static int append_psci_compatible(void *fdt, int offs, const char *str) return fdt_appendprop(fdt, offs, "compatible", str, strlen(str) + 1); } +/******************************************************************************* + * 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; @@ -113,6 +127,17 @@ static int dt_update_one_cpu_node(void *fdt, int offset) 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; @@ -130,6 +155,25 @@ int dt_add_psci_cpu_enable_methods(void *fdt) #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) { -- 2.30.2