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 */
efi_bl_read(struct udevice * dev,lbaint_t blknr,lbaint_t blkcnt,void * buffer)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 */
efi_bl_write(struct udevice * dev,lbaint_t blknr,lbaint_t blkcnt,const void * buffer)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 */
efi_bl_bind_partitions(efi_handle_t handle,struct udevice * dev)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 */
efi_bl_bind(efi_handle_t handle,void * interface)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