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path: root/drivers/firmware/efi/apple-properties.c
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Diffstat (limited to 'drivers/firmware/efi/apple-properties.c')
-rw-r--r--drivers/firmware/efi/apple-properties.c237
1 files changed, 237 insertions, 0 deletions
diff --git a/drivers/firmware/efi/apple-properties.c b/drivers/firmware/efi/apple-properties.c
new file mode 100644
index 000000000..ea8410803
--- /dev/null
+++ b/drivers/firmware/efi/apple-properties.c
@@ -0,0 +1,237 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * apple-properties.c - EFI device properties on Macs
+ * Copyright (C) 2016 Lukas Wunner <lukas@wunner.de>
+ *
+ * Properties are stored either as:
+ * u8 arrays which can be retrieved with device_property_read_u8_array() or
+ * booleans which can be queried with device_property_present().
+ */
+
+#define pr_fmt(fmt) "apple-properties: " fmt
+
+#include <linux/memblock.h>
+#include <linux/efi.h>
+#include <linux/io.h>
+#include <linux/platform_data/x86/apple.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/ucs2_string.h>
+#include <asm/setup.h>
+
+static bool dump_properties __initdata;
+
+static int __init dump_properties_enable(char *arg)
+{
+ dump_properties = true;
+ return 1;
+}
+
+__setup("dump_apple_properties", dump_properties_enable);
+
+struct dev_header {
+ u32 len;
+ u32 prop_count;
+ struct efi_dev_path path[];
+ /*
+ * followed by key/value pairs, each key and value preceded by u32 len,
+ * len includes itself, value may be empty (in which case its len is 4)
+ */
+};
+
+struct properties_header {
+ u32 len;
+ u32 version;
+ u32 dev_count;
+ struct dev_header dev_header[];
+};
+
+static void __init unmarshal_key_value_pairs(struct dev_header *dev_header,
+ struct device *dev, const void *ptr,
+ struct property_entry entry[])
+{
+ int i;
+
+ for (i = 0; i < dev_header->prop_count; i++) {
+ int remaining = dev_header->len - (ptr - (void *)dev_header);
+ u32 key_len, val_len, entry_len;
+ const u8 *entry_data;
+ char *key;
+
+ if (sizeof(key_len) > remaining)
+ break;
+
+ key_len = *(typeof(key_len) *)ptr;
+ if (key_len + sizeof(val_len) > remaining ||
+ key_len < sizeof(key_len) + sizeof(efi_char16_t) ||
+ *(efi_char16_t *)(ptr + sizeof(key_len)) == 0) {
+ dev_err(dev, "invalid property name len at %#zx\n",
+ ptr - (void *)dev_header);
+ break;
+ }
+
+ val_len = *(typeof(val_len) *)(ptr + key_len);
+ if (key_len + val_len > remaining ||
+ val_len < sizeof(val_len)) {
+ dev_err(dev, "invalid property val len at %#zx\n",
+ ptr - (void *)dev_header + key_len);
+ break;
+ }
+
+ /* 4 bytes to accommodate UTF-8 code points + null byte */
+ key = kzalloc((key_len - sizeof(key_len)) * 4 + 1, GFP_KERNEL);
+ if (!key) {
+ dev_err(dev, "cannot allocate property name\n");
+ break;
+ }
+ ucs2_as_utf8(key, ptr + sizeof(key_len),
+ key_len - sizeof(key_len));
+
+ entry_data = ptr + key_len + sizeof(val_len);
+ entry_len = val_len - sizeof(val_len);
+ if (entry_len)
+ entry[i] = PROPERTY_ENTRY_U8_ARRAY_LEN(key, entry_data,
+ entry_len);
+ else
+ entry[i] = PROPERTY_ENTRY_BOOL(key);
+
+ if (dump_properties) {
+ dev_info(dev, "property: %s\n", key);
+ print_hex_dump(KERN_INFO, pr_fmt(), DUMP_PREFIX_OFFSET,
+ 16, 1, entry_data, entry_len, true);
+ }
+
+ ptr += key_len + val_len;
+ }
+
+ if (i != dev_header->prop_count) {
+ dev_err(dev, "got %d device properties, expected %u\n", i,
+ dev_header->prop_count);
+ print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
+ 16, 1, dev_header, dev_header->len, true);
+ return;
+ }
+
+ dev_info(dev, "assigning %d device properties\n", i);
+}
+
+static int __init unmarshal_devices(struct properties_header *properties)
+{
+ size_t offset = offsetof(struct properties_header, dev_header[0]);
+
+ while (offset + sizeof(struct dev_header) < properties->len) {
+ struct dev_header *dev_header = (void *)properties + offset;
+ struct property_entry *entry = NULL;
+ const struct efi_dev_path *ptr;
+ struct device *dev;
+ size_t len;
+ int ret, i;
+
+ if (offset + dev_header->len > properties->len ||
+ dev_header->len <= sizeof(*dev_header)) {
+ pr_err("invalid len in dev_header at %#zx\n", offset);
+ return -EINVAL;
+ }
+
+ ptr = dev_header->path;
+ len = dev_header->len - sizeof(*dev_header);
+
+ dev = efi_get_device_by_path(&ptr, &len);
+ if (IS_ERR(dev)) {
+ pr_err("device path parse error %ld at %#zx:\n",
+ PTR_ERR(dev), (void *)ptr - (void *)dev_header);
+ print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
+ 16, 1, dev_header, dev_header->len, true);
+ dev = NULL;
+ goto skip_device;
+ }
+
+ entry = kcalloc(dev_header->prop_count + 1, sizeof(*entry),
+ GFP_KERNEL);
+ if (!entry) {
+ dev_err(dev, "cannot allocate properties\n");
+ goto skip_device;
+ }
+
+ unmarshal_key_value_pairs(dev_header, dev, ptr, entry);
+ if (!entry[0].name)
+ goto skip_device;
+
+ ret = device_create_managed_software_node(dev, entry, NULL);
+ if (ret)
+ dev_err(dev, "error %d assigning properties\n", ret);
+
+ for (i = 0; entry[i].name; i++)
+ kfree(entry[i].name);
+
+skip_device:
+ kfree(entry);
+ put_device(dev);
+ offset += dev_header->len;
+ }
+
+ return 0;
+}
+
+static int __init map_properties(void)
+{
+ struct properties_header *properties;
+ struct setup_data *data;
+ u32 data_len;
+ u64 pa_data;
+ int ret;
+
+ if (!x86_apple_machine)
+ return 0;
+
+ pa_data = boot_params.hdr.setup_data;
+ while (pa_data) {
+ data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
+ if (!data) {
+ pr_err("cannot map setup_data header\n");
+ return -ENOMEM;
+ }
+
+ if (data->type != SETUP_APPLE_PROPERTIES) {
+ pa_data = data->next;
+ memunmap(data);
+ continue;
+ }
+
+ data_len = data->len;
+ memunmap(data);
+
+ data = memremap(pa_data, sizeof(*data) + data_len, MEMREMAP_WB);
+ if (!data) {
+ pr_err("cannot map setup_data payload\n");
+ return -ENOMEM;
+ }
+
+ properties = (struct properties_header *)data->data;
+ if (properties->version != 1) {
+ pr_err("unsupported version:\n");
+ print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
+ 16, 1, properties, data_len, true);
+ ret = -ENOTSUPP;
+ } else if (properties->len != data_len) {
+ pr_err("length mismatch, expected %u\n", data_len);
+ print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
+ 16, 1, properties, data_len, true);
+ ret = -EINVAL;
+ } else
+ ret = unmarshal_devices(properties);
+
+ /*
+ * Can only free the setup_data payload but not its header
+ * to avoid breaking the chain of ->next pointers.
+ */
+ data->len = 0;
+ memunmap(data);
+ memblock_free_late(pa_data + sizeof(*data), data_len);
+
+ return ret;
+ }
+ return 0;
+}
+
+fs_initcall(map_properties);