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);