efi_block_device.c 5.4 KB

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  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. #include <efi_driver.h>
  31. #include <dm/device-internal.h>
  32. #include <dm/root.h>
  33. /*
  34. * EFI attributes of the udevice handled by this driver.
  35. *
  36. * handle handle of the controller on which this driver is installed
  37. * io block io protocol proxied by this driver
  38. */
  39. struct efi_blk_platdata {
  40. efi_handle_t handle;
  41. struct efi_block_io *io;
  42. };
  43. /**
  44. * Read from block device
  45. *
  46. * @dev: device
  47. * @blknr: first block to be read
  48. * @blkcnt: number of blocks to read
  49. * @buffer: output buffer
  50. * Return: number of blocks transferred
  51. */
  52. static ulong efi_bl_read(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
  53. void *buffer)
  54. {
  55. struct efi_blk_platdata *platdata = dev_get_platdata(dev);
  56. struct efi_block_io *io = platdata->io;
  57. efi_status_t ret;
  58. EFI_PRINT("%s: read '%s', from block " LBAFU ", " LBAFU " blocks\n",
  59. __func__, dev->name, blknr, blkcnt);
  60. ret = EFI_CALL(io->read_blocks(
  61. io, io->media->media_id, (u64)blknr,
  62. (efi_uintn_t)blkcnt *
  63. (efi_uintn_t)io->media->block_size, buffer));
  64. EFI_PRINT("%s: r = %u\n", __func__,
  65. (unsigned int)(ret & ~EFI_ERROR_MASK));
  66. if (ret != EFI_SUCCESS)
  67. return 0;
  68. return blkcnt;
  69. }
  70. /**
  71. * Write to block device
  72. *
  73. * @dev: device
  74. * @blknr: first block to be write
  75. * @blkcnt: number of blocks to write
  76. * @buffer: input buffer
  77. * Return: number of blocks transferred
  78. */
  79. static ulong efi_bl_write(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
  80. const void *buffer)
  81. {
  82. struct efi_blk_platdata *platdata = dev_get_platdata(dev);
  83. struct efi_block_io *io = platdata->io;
  84. efi_status_t ret;
  85. EFI_PRINT("%s: write '%s', from block " LBAFU ", " LBAFU " blocks\n",
  86. __func__, dev->name, blknr, blkcnt);
  87. ret = EFI_CALL(io->write_blocks(
  88. io, io->media->media_id, (u64)blknr,
  89. (efi_uintn_t)blkcnt *
  90. (efi_uintn_t)io->media->block_size,
  91. (void *)buffer));
  92. EFI_PRINT("%s: r = %u\n", __func__,
  93. (unsigned int)(ret & ~EFI_ERROR_MASK));
  94. if (ret != EFI_SUCCESS)
  95. return 0;
  96. return blkcnt;
  97. }
  98. /**
  99. * Create partions for the block device.
  100. *
  101. * @handle: EFI handle of the block device
  102. * @dev: udevice of the block device
  103. * Return: number of partitions created
  104. */
  105. static int efi_bl_bind_partitions(efi_handle_t handle, struct udevice *dev)
  106. {
  107. struct blk_desc *desc;
  108. const char *if_typename;
  109. desc = dev_get_uclass_platdata(dev);
  110. if_typename = blk_get_if_type_name(desc->if_type);
  111. return efi_disk_create_partitions(handle, desc, if_typename,
  112. desc->devnum, dev->name);
  113. }
  114. /**
  115. * Create a block device for a handle
  116. *
  117. * @handle: handle
  118. * @interface: block io protocol
  119. * Return: 0 = success
  120. */
  121. static int efi_bl_bind(efi_handle_t handle, void *interface)
  122. {
  123. struct udevice *bdev, *parent = dm_root();
  124. int ret, devnum;
  125. char *name;
  126. struct efi_object *obj = efi_search_obj(handle);
  127. struct efi_block_io *io = interface;
  128. int disks;
  129. struct efi_blk_platdata *platdata;
  130. EFI_PRINT("%s: handle %p, interface %p\n", __func__, handle, io);
  131. if (!obj)
  132. return -ENOENT;
  133. devnum = blk_find_max_devnum(IF_TYPE_EFI);
  134. if (devnum == -ENODEV)
  135. devnum = 0;
  136. else if (devnum < 0)
  137. return devnum;
  138. name = calloc(1, 18); /* strlen("efiblk#2147483648") + 1 */
  139. if (!name)
  140. return -ENOMEM;
  141. sprintf(name, "efiblk#%d", devnum);
  142. /* Create driver model udevice for the EFI block io device */
  143. ret = blk_create_device(parent, "efi_blk", name, IF_TYPE_EFI, devnum,
  144. io->media->block_size,
  145. (lbaint_t)io->media->last_block, &bdev);
  146. if (ret)
  147. return ret;
  148. if (!bdev)
  149. return -ENOENT;
  150. /* Set the DM_FLAG_NAME_ALLOCED flag to avoid a memory leak */
  151. device_set_name_alloced(bdev);
  152. platdata = dev_get_platdata(bdev);
  153. platdata->handle = handle;
  154. platdata->io = interface;
  155. ret = device_probe(bdev);
  156. if (ret)
  157. return ret;
  158. EFI_PRINT("%s: block device '%s' created\n", __func__, bdev->name);
  159. /* Create handles for the partions of the block device */
  160. disks = efi_bl_bind_partitions(handle, bdev);
  161. EFI_PRINT("Found %d partitions\n", disks);
  162. return 0;
  163. }
  164. /* Block device driver operators */
  165. static const struct blk_ops efi_blk_ops = {
  166. .read = efi_bl_read,
  167. .write = efi_bl_write,
  168. };
  169. /* Identify as block device driver */
  170. U_BOOT_DRIVER(efi_blk) = {
  171. .name = "efi_blk",
  172. .id = UCLASS_BLK,
  173. .ops = &efi_blk_ops,
  174. .platdata_auto_alloc_size = sizeof(struct efi_blk_platdata),
  175. };
  176. /* EFI driver operators */
  177. static const struct efi_driver_ops driver_ops = {
  178. .protocol = &efi_block_io_guid,
  179. .child_protocol = &efi_block_io_guid,
  180. .bind = efi_bl_bind,
  181. };
  182. /* Identify as EFI driver */
  183. U_BOOT_DRIVER(efi_block) = {
  184. .name = "EFI block driver",
  185. .id = UCLASS_EFI,
  186. .ops = &driver_ops,
  187. };