[U-Boot] [PATCH 07/16] efi_loader: Add disk interfaces

[Alexander Graf]

A EFI applications usually want to access storage devices to load data from.

This patch adds support for EFI disk interfaces. It loops through all block
storage interfaces known to U-Boot and creates an EFI object for each existing
one. EFI applications can then through these objects call U-Boot's read and
write functions.

Signed-off-by: Alexander Graf <agraf at suse.de>
Reviewed-by: Simon Glass <sjg at chromium.org>

---

v1 -> v2:

  - Move to block_drvr array
  - Move to GPLv2+
  - Fix header order
  - Document efi block object struct
  - Use calloc rather than malloc & memset

v2 -> v3:

  - Adapt to newer u-boot block API
  - Add EFIAPI to function prototypes
  - Document header
  - Check for DEV_TYPE_UNKNOWN
  - Document 16byte limit for dp string
---
 include/efi_loader.h      |   2 +
 lib/efi_loader/efi_disk.c | 218 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 220 insertions(+)
 create mode 100644 lib/efi_loader/efi_disk.c

diff --git a/include/efi_loader.h b/include/efi_loader.h
index 640e703..91ab6cb 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -86,6 +86,8 @@ struct efi_object {
 /* This list contains all UEFI objects we know of */
 extern struct list_head efi_obj_list;
 
+/* Called by bootefi to make all disk storage accessible as EFI objects */
+int efi_disk_register(void);
 /*
  * Stub implementation for a protocol opener that just returns the handle as
  * interface
diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
new file mode 100644
index 0000000..f93fcb2
--- /dev/null
+++ b/lib/efi_loader/efi_disk.c
@@ -0,0 +1,218 @@
+/*
+ *  EFI application disk support
+ *
+ *  Copyright (c) 2016 Alexander Graf
+ *
+ *  SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#include <common.h>
+#include <efi_loader.h>
+#include <inttypes.h>
+#include <part.h>
+#include <malloc.h>
+
+static const efi_guid_t efi_block_io_guid = BLOCK_IO_GUID;
+
+struct efi_disk_obj {
+	/* Generic EFI object parent class data */
+	struct efi_object parent;
+	/* EFI Interface callback struct for block I/O */
+	struct efi_block_io ops;
+	/* U-Boot ifname for block device */
+	const char *ifname;
+	/* U-Boot dev_index for block device */
+	int dev_index;
+	/* EFI Interface Media descriptor struct, referenced by ops */
+	struct efi_block_io_media media;
+	/* EFI device path to this block device */
+	struct efi_device_path_file_path *dp;
+};
+
+static void ascii2unicode(u16 *unicode, char *ascii)
+{
+	while (*ascii)
+		*(unicode++) = *(ascii++);
+}
+
+static efi_status_t efi_disk_open_block(void *handle, efi_guid_t *protocol,
+			void **protocol_interface, void *agent_handle,
+			void *controller_handle, uint32_t attributes)
+{
+	struct efi_disk_obj *diskobj = handle;
+
+	*protocol_interface = &diskobj->ops;
+
+	return EFI_SUCCESS;
+}
+
+static efi_status_t efi_disk_open_dp(void *handle, efi_guid_t *protocol,
+			void **protocol_interface, void *agent_handle,
+			void *controller_handle, uint32_t attributes)
+{
+	struct efi_disk_obj *diskobj = handle;
+
+	*protocol_interface = diskobj->dp;
+
+	return EFI_SUCCESS;
+}
+
+static efi_status_t EFIAPI efi_disk_reset(struct efi_block_io *this,
+			char extended_verification)
+{
+	EFI_ENTRY("%p, %x", this, extended_verification);
+	return EFI_EXIT(EFI_DEVICE_ERROR);
+}
+
+enum efi_disk_direction {
+	EFI_DISK_READ,
+	EFI_DISK_WRITE,
+};
+
+static efi_status_t EFIAPI efi_disk_rw_blocks(struct efi_block_io *this,
+			u32 media_id, u64 lba, unsigned long buffer_size,
+			void *buffer, enum efi_disk_direction direction)
+{
+	struct efi_disk_obj *diskobj;
+	struct block_dev_desc *desc;
+	int blksz;
+	int blocks;
+	unsigned long n;
+
+	EFI_ENTRY("%p, %x, %"PRIx64", %lx, %p", this, media_id, lba,
+		  buffer_size, buffer);
+
+	diskobj = container_of(this, struct efi_disk_obj, ops);
+	if (!(desc = get_dev(diskobj->ifname, diskobj->dev_index)))
+		return EFI_EXIT(EFI_DEVICE_ERROR);
+	blksz = desc->blksz;
+	blocks = buffer_size / blksz;
+
+#ifdef DEBUG_EFI
+	printf("EFI: %s:%d blocks=%x lba=%"PRIx64" blksz=%x dir=%d\n", __func__,
+	       __LINE__, blocks, lba, blksz, direction);
+#endif
+
+	/* We only support full block access */
+	if (buffer_size & (blksz - 1))
+		return EFI_EXIT(EFI_DEVICE_ERROR);
+
+	if (direction == EFI_DISK_READ)
+		n = desc->block_read(desc, lba, blocks, buffer);
+	else
+		n = desc->block_write(desc, lba, blocks, buffer);
+
+	/* We don't do interrupts, so check for timers cooperatively */
+	efi_timer_check();
+
+#ifdef DEBUG_EFI
+	printf("EFI: %s:%d n=%lx blocks=%x\n", __func__, __LINE__, n, blocks);
+#endif
+	if (n != blocks)
+		return EFI_EXIT(EFI_DEVICE_ERROR);
+
+	return EFI_EXIT(EFI_SUCCESS);
+}
+
+static efi_status_t efi_disk_read_blocks(struct efi_block_io *this,
+			u32 media_id, u64 lba, unsigned long buffer_size,
+			void *buffer)
+{
+	return efi_disk_rw_blocks(this, media_id, lba, buffer_size, buffer,
+				  EFI_DISK_READ);
+}
+
+static efi_status_t efi_disk_write_blocks(struct efi_block_io *this,
+			u32 media_id, u64 lba, unsigned long buffer_size,
+			void *buffer)
+{
+	return efi_disk_rw_blocks(this, media_id, lba, buffer_size, buffer,
+				  EFI_DISK_WRITE);
+}
+
+static efi_status_t EFIAPI efi_disk_flush_blocks(struct efi_block_io *this)
+{
+	/* We always write synchronously */
+	EFI_ENTRY("%p", this);
+	return EFI_EXIT(EFI_SUCCESS);
+}
+
+static const struct efi_block_io block_io_disk_template = {
+	.reset = &efi_disk_reset,
+	.read_blocks = &efi_disk_read_blocks,
+	.write_blocks = &efi_disk_write_blocks,
+	.flush_blocks = &efi_disk_flush_blocks,
+};
+
+/*
+ * U-Boot doesn't have a list of all online disk devices. So when running our
+ * EFI payload, we scan through all of the potentially available ones and
+ * store them in our object pool.
+ *
+ * This gets called from do_bootefi_exec().
+ */
+int efi_disk_register(void)
+{
+	const struct block_drvr *cur_drvr;
+	int i;
+	int disks = 0;
+
+	/* Search for all available disk devices */
+	for (cur_drvr = block_drvr; cur_drvr->name; cur_drvr++) {
+		printf("Scanning disks on %s...\n", cur_drvr->name);
+		for (i = 0; i < 4; i++) {
+			block_dev_desc_t *desc;
+			struct efi_disk_obj *diskobj;
+			struct efi_device_path_file_path *dp;
+			int objlen = sizeof(*diskobj) + (sizeof(*dp) * 2);
+			char devname[16] = { 0 }; /* dp->str is u16[16] long */
+
+			desc = get_dev(cur_drvr->name, i);
+			if (!desc)
+				continue;
+			if (desc->type == DEV_TYPE_UNKNOWN)
+				continue;
+
+			diskobj = calloc(1, objlen);
+
+			/* Fill in object data */
+			diskobj->parent.protocols[0].guid = &efi_block_io_guid;
+			diskobj->parent.protocols[0].open = efi_disk_open_block;
+			diskobj->parent.protocols[1].guid = &efi_guid_device_path;
+			diskobj->parent.protocols[1].open = efi_disk_open_dp;
+			diskobj->parent.handle = diskobj;
+			diskobj->ops = block_io_disk_template;
+			diskobj->ifname = cur_drvr->name;
+			diskobj->dev_index = i;
+
+			/* Fill in EFI IO Media info (for read/write callbacks) */
+			diskobj->media.removable_media = desc->removable;
+			diskobj->media.media_present = 1;
+			diskobj->media.block_size = desc->blksz;
+			diskobj->media.io_align = desc->blksz;
+			diskobj->media.last_block = desc->lba;
+			diskobj->ops.media = &diskobj->media;
+
+			/* Fill in device path */
+			dp = (void*)&diskobj[1];
+			diskobj->dp = dp;
+			dp[0].dp.type = DEVICE_PATH_TYPE_MEDIA_DEVICE;
+			dp[0].dp.sub_type = DEVICE_PATH_SUB_TYPE_FILE_PATH;
+			dp[0].dp.length = sizeof(*dp);
+			snprintf(devname, sizeof(devname), "%s%d",
+				 cur_drvr->name, i);
+			ascii2unicode(dp[0].str, devname);
+
+			dp[1].dp.type = DEVICE_PATH_TYPE_END;
+			dp[1].dp.sub_type = DEVICE_PATH_SUB_TYPE_END;
+			dp[1].dp.length = sizeof(*dp);
+
+			/* Hook up to the device list */
+			list_add_tail(&diskobj->parent.link, &efi_obj_list);
+			disks++;
+		}
+	}
+	printf("Found %d disks\n", disks);
+
+	return 0;
+}
-- 
2.6.2