efi_block_device.c 5.5 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 <malloc.h>
  32. #include <dm/device-internal.h>
  33. #include <dm/root.h>
  34. /*
  35. * EFI attributes of the udevice handled by this driver.
  36. *
  37. * handle handle of the controller on which this driver is installed
  38. * io block io protocol proxied by this driver
  39. */
  40. struct efi_blk_platdata {
  41. efi_handle_t handle;
  42. struct efi_block_io *io;
  43. };
  44. /**
  45. * Read from block device
  46. *
  47. * @dev: device
  48. * @blknr: first block to be read
  49. * @blkcnt: number of blocks to read
  50. * @buffer: output buffer
  51. * Return: number of blocks transferred
  52. */
  53. static ulong efi_bl_read(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
  54. void *buffer)
  55. {
  56. struct efi_blk_platdata *platdata = dev_get_platdata(dev);
  57. struct efi_block_io *io = platdata->io;
  58. efi_status_t ret;
  59. EFI_PRINT("%s: read '%s', from block " LBAFU ", " LBAFU " blocks\n",
  60. __func__, dev->name, blknr, blkcnt);
  61. ret = EFI_CALL(io->read_blocks(
  62. io, io->media->media_id, (u64)blknr,
  63. (efi_uintn_t)blkcnt *
  64. (efi_uintn_t)io->media->block_size, buffer));
  65. EFI_PRINT("%s: r = %u\n", __func__,
  66. (unsigned int)(ret & ~EFI_ERROR_MASK));
  67. if (ret != EFI_SUCCESS)
  68. return 0;
  69. return blkcnt;
  70. }
  71. /**
  72. * Write to block device
  73. *
  74. * @dev: device
  75. * @blknr: first block to be write
  76. * @blkcnt: number of blocks to write
  77. * @buffer: input buffer
  78. * Return: number of blocks transferred
  79. */
  80. static ulong efi_bl_write(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
  81. const void *buffer)
  82. {
  83. struct efi_blk_platdata *platdata = dev_get_platdata(dev);
  84. struct efi_block_io *io = platdata->io;
  85. efi_status_t ret;
  86. EFI_PRINT("%s: write '%s', from block " LBAFU ", " LBAFU " blocks\n",
  87. __func__, dev->name, blknr, blkcnt);
  88. ret = EFI_CALL(io->write_blocks(
  89. io, io->media->media_id, (u64)blknr,
  90. (efi_uintn_t)blkcnt *
  91. (efi_uintn_t)io->media->block_size,
  92. (void *)buffer));
  93. EFI_PRINT("%s: r = %u\n", __func__,
  94. (unsigned int)(ret & ~EFI_ERROR_MASK));
  95. if (ret != EFI_SUCCESS)
  96. return 0;
  97. return blkcnt;
  98. }
  99. /**
  100. * Create partions for the block device.
  101. *
  102. * @handle: EFI handle of the block device
  103. * @dev: udevice of the block device
  104. * Return: number of partitions created
  105. */
  106. static int efi_bl_bind_partitions(efi_handle_t handle, struct udevice *dev)
  107. {
  108. struct blk_desc *desc;
  109. const char *if_typename;
  110. desc = dev_get_uclass_platdata(dev);
  111. if_typename = blk_get_if_type_name(desc->if_type);
  112. return efi_disk_create_partitions(handle, desc, if_typename,
  113. desc->devnum, dev->name);
  114. }
  115. /**
  116. * Create a block device for a handle
  117. *
  118. * @handle: handle
  119. * @interface: block io protocol
  120. * Return: 0 = success
  121. */
  122. static int efi_bl_bind(efi_handle_t handle, void *interface)
  123. {
  124. struct udevice *bdev, *parent = dm_root();
  125. int ret, devnum;
  126. char *name;
  127. struct efi_object *obj = efi_search_obj(handle);
  128. struct efi_block_io *io = interface;
  129. int disks;
  130. struct efi_blk_platdata *platdata;
  131. EFI_PRINT("%s: handle %p, interface %p\n", __func__, handle, io);
  132. if (!obj)
  133. return -ENOENT;
  134. devnum = blk_find_max_devnum(IF_TYPE_EFI);
  135. if (devnum == -ENODEV)
  136. devnum = 0;
  137. else if (devnum < 0)
  138. return devnum;
  139. name = calloc(1, 18); /* strlen("efiblk#2147483648") + 1 */
  140. if (!name)
  141. return -ENOMEM;
  142. sprintf(name, "efiblk#%d", devnum);
  143. /* Create driver model udevice for the EFI block io device */
  144. ret = blk_create_device(parent, "efi_blk", name, IF_TYPE_EFI, devnum,
  145. io->media->block_size,
  146. (lbaint_t)io->media->last_block, &bdev);
  147. if (ret)
  148. return ret;
  149. if (!bdev)
  150. return -ENOENT;
  151. /* Set the DM_FLAG_NAME_ALLOCED flag to avoid a memory leak */
  152. device_set_name_alloced(bdev);
  153. platdata = dev_get_platdata(bdev);
  154. platdata->handle = handle;
  155. platdata->io = interface;
  156. ret = device_probe(bdev);
  157. if (ret)
  158. return ret;
  159. EFI_PRINT("%s: block device '%s' created\n", __func__, bdev->name);
  160. /* Create handles for the partions of the block device */
  161. disks = efi_bl_bind_partitions(handle, bdev);
  162. EFI_PRINT("Found %d partitions\n", disks);
  163. return 0;
  164. }
  165. /* Block device driver operators */
  166. static const struct blk_ops efi_blk_ops = {
  167. .read = efi_bl_read,
  168. .write = efi_bl_write,
  169. };
  170. /* Identify as block device driver */
  171. U_BOOT_DRIVER(efi_blk) = {
  172. .name = "efi_blk",
  173. .id = UCLASS_BLK,
  174. .ops = &efi_blk_ops,
  175. .platdata_auto_alloc_size = sizeof(struct efi_blk_platdata),
  176. };
  177. /* EFI driver operators */
  178. static const struct efi_driver_ops driver_ops = {
  179. .protocol = &efi_block_io_guid,
  180. .child_protocol = &efi_block_io_guid,
  181. .bind = efi_bl_bind,
  182. };
  183. /* Identify as EFI driver */
  184. U_BOOT_DRIVER(efi_block) = {
  185. .name = "EFI block driver",
  186. .id = UCLASS_EFI,
  187. .ops = &driver_ops,
  188. };