1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *  EFI block driver
4  *
5  *  Copyright (c) 2017 Heinrich Schuchardt
6  *
7  * The EFI uclass creates a handle for this driver and installs the
8  * driver binding protocol on it.
9  *
10  * The EFI block driver binds to controllers implementing the block io
11  * protocol.
12  *
13  * When the bind function of the EFI block driver is called it creates a
14  * new U-Boot block device. It installs child handles for all partitions and
15  * installs the simple file protocol on these.
16  *
17  * The read and write functions of the EFI block driver delegate calls to the
18  * controller that it is bound to.
19  *
20  * A usage example is as following:
21  *
22  * U-Boot loads the iPXE snp.efi executable. iPXE connects an iSCSI drive and
23  * exposes a handle with the block IO protocol. It calls ConnectController.
24  *
25  * Now the EFI block driver installs the partitions with the simple file
26  * protocol.
27  *
28  * iPXE uses the simple file protocol to load Grub or the Linux Kernel.
29  */
30 
31 #include <efi_driver.h>
32 #include <dm/device-internal.h>
33 #include <dm/root.h>
34 
35 /*
36  * EFI attributes of the udevice handled by this driver.
37  *
38  * handle	handle of the controller on which this driver is installed
39  * io		block io protocol proxied by this driver
40  */
41 struct efi_blk_platdata {
42 	efi_handle_t		handle;
43 	struct efi_block_io	*io;
44 };
45 
46 /*
47  * Read from block device
48  *
49  * @dev		device
50  * @blknr	first block to be read
51  * @blkcnt	number of blocks to read
52  * @buffer	output buffer
53  * @return	number of blocks transferred
54  */
55 static ulong efi_bl_read(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
56 			 void *buffer)
57 {
58 	struct efi_blk_platdata *platdata = dev_get_platdata(dev);
59 	struct efi_block_io *io = platdata->io;
60 	efi_status_t ret;
61 
62 	EFI_PRINT("%s: read '%s', from block " LBAFU ", " LBAFU " blocks\n",
63 		  __func__, dev->name, blknr, blkcnt);
64 	ret = EFI_CALL(io->read_blocks(
65 				io, io->media->media_id, (u64)blknr,
66 				(efi_uintn_t)blkcnt *
67 				(efi_uintn_t)io->media->block_size, buffer));
68 	EFI_PRINT("%s: r = %u\n", __func__,
69 		  (unsigned int)(ret & ~EFI_ERROR_MASK));
70 	if (ret != EFI_SUCCESS)
71 		return 0;
72 	return blkcnt;
73 }
74 
75 /*
76  * Write to block device
77  *
78  * @dev		device
79  * @blknr	first block to be write
80  * @blkcnt	number of blocks to write
81  * @buffer	input buffer
82  * @return	number of blocks transferred
83  */
84 static ulong efi_bl_write(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
85 			  const void *buffer)
86 {
87 	struct efi_blk_platdata *platdata = dev_get_platdata(dev);
88 	struct efi_block_io *io = platdata->io;
89 	efi_status_t ret;
90 
91 	EFI_PRINT("%s: write '%s', from block " LBAFU ", " LBAFU " blocks\n",
92 		  __func__, dev->name, blknr, blkcnt);
93 	ret = EFI_CALL(io->write_blocks(
94 				io, io->media->media_id, (u64)blknr,
95 				(efi_uintn_t)blkcnt *
96 				(efi_uintn_t)io->media->block_size,
97 				(void *)buffer));
98 	EFI_PRINT("%s: r = %u\n", __func__,
99 		  (unsigned int)(ret & ~EFI_ERROR_MASK));
100 	if (ret != EFI_SUCCESS)
101 		return 0;
102 	return blkcnt;
103 }
104 
105 /*
106  * Create partions for the block device.
107  *
108  * @handle	EFI handle of the block device
109  * @dev		udevice of the block device
110  */
111 static int efi_bl_bind_partitions(efi_handle_t handle, struct udevice *dev)
112 {
113 	struct blk_desc *desc;
114 	const char *if_typename;
115 
116 	desc = dev_get_uclass_platdata(dev);
117 	if_typename = blk_get_if_type_name(desc->if_type);
118 
119 	return efi_disk_create_partitions(handle, desc, if_typename,
120 					  desc->devnum, dev->name);
121 }
122 
123 /*
124  * Create a block device for a handle
125  *
126  * @handle	handle
127  * @interface	block io protocol
128  * @return	0 = success
129  */
130 static int efi_bl_bind(efi_handle_t handle, void *interface)
131 {
132 	struct udevice *bdev, *parent = dm_root();
133 	int ret, devnum;
134 	char *name;
135 	struct efi_object *obj = efi_search_obj(handle);
136 	struct efi_block_io *io = interface;
137 	int disks;
138 	struct efi_blk_platdata *platdata;
139 
140 	EFI_PRINT("%s: handle %p, interface %p\n", __func__, handle, io);
141 
142 	if (!obj)
143 		return -ENOENT;
144 
145 	devnum = blk_find_max_devnum(IF_TYPE_EFI);
146 	if (devnum == -ENODEV)
147 		devnum = 0;
148 	else if (devnum < 0)
149 		return devnum;
150 
151 	name = calloc(1, 18); /* strlen("efiblk#2147483648") + 1 */
152 	if (!name)
153 		return -ENOMEM;
154 	sprintf(name, "efiblk#%d", devnum);
155 
156 	/* Create driver model udevice for the EFI block io device */
157 	ret = blk_create_device(parent, "efi_blk", name, IF_TYPE_EFI, devnum,
158 				io->media->block_size,
159 				(lbaint_t)io->media->last_block, &bdev);
160 	if (ret)
161 		return ret;
162 	if (!bdev)
163 		return -ENOENT;
164 	/* Set the DM_FLAG_NAME_ALLOCED flag to avoid a memory leak */
165 	device_set_name_alloced(bdev);
166 
167 	platdata = dev_get_platdata(bdev);
168 	platdata->handle = handle;
169 	platdata->io = interface;
170 
171 	ret = device_probe(bdev);
172 	if (ret)
173 		return ret;
174 	EFI_PRINT("%s: block device '%s' created\n", __func__, bdev->name);
175 
176 	/* Create handles for the partions of the block device */
177 	disks = efi_bl_bind_partitions(handle, bdev);
178 	EFI_PRINT("Found %d partitions\n", disks);
179 
180 	return 0;
181 }
182 
183 /* Block device driver operators */
184 static const struct blk_ops efi_blk_ops = {
185 	.read	= efi_bl_read,
186 	.write	= efi_bl_write,
187 };
188 
189 /* Identify as block device driver */
190 U_BOOT_DRIVER(efi_blk) = {
191 	.name			= "efi_blk",
192 	.id			= UCLASS_BLK,
193 	.ops			= &efi_blk_ops,
194 	.platdata_auto_alloc_size = sizeof(struct efi_blk_platdata),
195 };
196 
197 /* EFI driver operators */
198 static const struct efi_driver_ops driver_ops = {
199 	.protocol	= &efi_block_io_guid,
200 	.child_protocol = &efi_block_io_guid,
201 	.bind		= efi_bl_bind,
202 };
203 
204 /* Identify as EFI driver */
205 U_BOOT_DRIVER(efi_block) = {
206 	.name		= "EFI block driver",
207 	.id		= UCLASS_EFI,
208 	.ops		= &driver_ops,
209 };
210