[PATCH v4 11/34] efi: Locate all block devices in the app

Simon Glass
2021-11-04T03:12:04Z

When starting the app, locate all block devices and make them available
to U-Boot. This allows listing partitions and accessing files in
filesystems.

EFI also has the concept of 'disks', meaning boot media. For now, this
is not obviously useful in U-Boot, but add code to at least locate these.
This can be expanded later as needed.

Series-changes; 2
- Store device path in struct efi_media_plat
- Don't export efi_bind_block()
- Only bind devices for media devices, not for partitions
- Show devices that are processed
- Update documentation

Signed-off-by: Simon Glass <sjg@chromium.org>
---

(no changes since v1)

doc/develop/uefi/u-boot_on_efi.rst | 4 +-
include/efi.h | 6 +-
include/efi_api.h | 15 ++
lib/efi/efi_app.c | 223 +++++++++++++++++++++++++++++
4 files changed, 243 insertions(+), 5 deletions(-)

diff --git a/doc/develop/uefi/u-boot_on_efi.rst b/doc/develop/uefi/u-boot_on_efi.rst
index 5f2f850f071..8f81b799072 100644
--- a/doc/develop/uefi/u-boot_on_efi.rst
+++ b/doc/develop/uefi/u-boot_on_efi.rst
@@ -265,9 +265,7 @@ This work could be extended in a number of ways:

- Figure out how to solve the interrupt problem

-- Add more drivers to the application side (e.g. block devices, USB,
- environment access). This would mostly be an academic exercise as a strong
- use case is not readily apparent, but it might be fun.
+- Add more drivers to the application side (e.g.USB, environment access).

- Avoid turning off boot services in the stub. Instead allow U-Boot to make
use of boot services in case it wants to. It is unclear what it might want
diff --git a/include/efi.h b/include/efi.h
index 0ec5913ddd1..908c5dc6ebd 100644
--- a/include/efi.h
+++ b/include/efi.h
@@ -419,10 +419,12 @@ struct efi_priv {
*
* @handle: handle of the controller on which this driver is installed
* @blkio: block io protocol proxied by this driver
+ * @device_path: EFI path to the device
*/
struct efi_media_plat {
- efi_handle_t handle;
- struct efi_block_io *blkio;
+ efi_handle_t handle;
+ struct efi_block_io *blkio;
+ struct efi_device_path *device_path;
};

/* Base address of the EFI image */
diff --git a/include/efi_api.h b/include/efi_api.h
index 0accad08c8e..1f70e9e106c 100644
--- a/include/efi_api.h
+++ b/include/efi_api.h
@@ -1994,4 +1994,19 @@ struct efi_firmware_management_protocol {
const u16 *package_version_name);
};

+#define EFI_DISK_IO_PROTOCOL_GUID \
+ EFI_GUID(0xce345171, 0xba0b, 0x11d2, 0x8e, 0x4f, \
+ 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b)
+
+struct efi_disk {
+ u64 revision;
+ efi_status_t (EFIAPI *read_disk)(struct efi_disk *this, u32 media_id,
+ u64 offset, efi_uintn_t buffer_size,
+ void *buffer);
+
+ efi_status_t (EFIAPI *write_disk)(struct efi_disk *this, u32 media_id,
+ u64 offset, efi_uintn_t buffer_size,
+ void *buffer);
+};
+
#endif
diff --git a/lib/efi/efi_app.c b/lib/efi/efi_app.c
index f61665686c5..e38d46b15db 100644
--- a/lib/efi/efi_app.c
+++ b/lib/efi/efi_app.c
@@ -21,6 +21,9 @@
#include <efi.h>
#include <efi_api.h>
#include <sysreset.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+#include <dm/root.h>

DECLARE_GLOBAL_DATA_PTR;

@@ -46,6 +49,64 @@ int efi_info_get(enum efi_entry_t type, void **datap, int *sizep)
return -ENOSYS;
}

+/**
+ * efi_print_str() - Print a UFT-16 string to the U-Boot console
+ *
+ * @str: String to print
+ */
+static void efi_print_str(const u16 *str)
+{
+ while (*str) {
+ int ch = *str++;
+
+ if (ch > ' ' && ch < 127)
+ putc(ch);
+ }
+}
+
+/**
+ * efi_bind_block() - bind a new block device to an EFI device
+ *
+ * Binds a new top-level EFI_MEDIA device as well as a child block device so
+ * that the block device can be accessed in U-Boot.
+ *
+ * The device can then be accessed using 'part list efi 0', 'fat ls efi 0:1',
+ * for example, just like any other interface type.
+ *
+ * @handle: handle of the controller on which this driver is installed
+ * @blkio: block io protocol proxied by this driver
+ * @device_path: EFI device path structure for this
+ * @len: Length of @device_path in bytes
+ * @devp: Returns the bound device
+ * @return 0 if OK, -ve on error
+ */
+int efi_bind_block(efi_handle_t handle, struct efi_block_io *blkio,
+ struct efi_device_path *device_path, int len,
+ struct udevice **devp)
+{
+ struct efi_media_plat plat;
+ struct udevice *dev;
+ char name[18];
+ int ret;
+
+ plat.handle = handle;
+ plat.blkio = blkio;
+ plat.device_path = malloc(device_path->length);
+ if (!plat.device_path)
+ return log_msg_ret("path", -ENOMEM);
+ memcpy(plat.device_path, device_path, device_path->length);
+ ret = device_bind(dm_root(), DM_DRIVER_GET(efi_media), "efi_media",
+ &plat, ofnode_null(), &dev);
+ if (ret)
+ return log_msg_ret("bind", ret);
+
+ snprintf(name, sizeof(name), "efi_media_%x", dev_seq(dev));
+ device_set_name(dev, name);
+ *devp = dev;
+
+ return 0;
+}
+
static efi_status_t setup_memory(struct efi_priv *priv)
{
struct efi_boot_services *boot = priv->boot;
@@ -105,6 +166,168 @@ static void free_memory(struct efi_priv *priv)
global_data_ptr = NULL;
}

+static int setup_disks(void)
+{
+ /* This is not fully implemented yet */
+ return 0;
+
+ efi_guid_t efi_disk_guid = EFI_DISK_IO_PROTOCOL_GUID;
+ struct efi_boot_services *boot = efi_get_boot();
+ struct efi_disk *disk;
+ int ret;
+
+ if (!boot)
+ return log_msg_ret("sys", -ENOSYS);
+ ret = boot->locate_protocol(&efi_disk_guid, NULL, (void **)&disk);
+ if (ret)
+ return log_msg_ret("prot", -ENOTSUPP);
+
+ return 0;
+}
+
+/**
+ * devpath_is_partition() - Figure out if a device path is a partition
+ *
+ * Checks if a device path refers to a partition on some media device. This
+ * works by checking for a valid partition number in a hard-driver media device
+ * as the final component of the device path.
+ *
+ * @return true if a partition, false if not (e.g. it might be media which
+ * contains partitions)
+ */
+static bool devpath_is_partition(const struct efi_device_path *path)
+{
+ const struct efi_device_path *p;
+ bool was_part;
+
+ for (p = path; p->type != DEVICE_PATH_TYPE_END;
+ p = (void *)p + p->length) {
+ was_part = false;
+ if (p->type == DEVICE_PATH_TYPE_MEDIA_DEVICE &&
+ p->sub_type == DEVICE_PATH_SUB_TYPE_HARD_DRIVE_PATH) {
+ struct efi_device_path_hard_drive_path *hd =
+ (void *)path;
+
+ if (hd->partition_number)
+ was_part = true;
+ }
+ }
+
+ return was_part;
+}
+
+/**
+ * setup_block() - Find all block devices and setup EFI devices for them
+ *
+ * Partitions are ignored, since U-Boot has partition handling. Errors with
+ * particular devices produce a warning but execution continues to try to
+ * find others.
+ *
+ * @return 0 if found, -ENOSYS if there is no boot-services table, -ENOTSUPP
+ * if a required protocol is not supported
+ */
+static int setup_block(void)
+{
+ efi_guid_t efi_blkio_guid = EFI_BLOCK_IO_PROTOCOL_GUID;
+ efi_guid_t efi_devpath_guid = EFI_DEVICE_PATH_PROTOCOL_GUID;
+ efi_guid_t efi_pathutil_guid = EFI_DEVICE_PATH_UTILITIES_PROTOCOL_GUID;
+ efi_guid_t efi_pathtext_guid = EFI_DEVICE_PATH_TO_TEXT_PROTOCOL_GUID;
+ struct efi_boot_services *boot = efi_get_boot();
+ struct efi_device_path_utilities_protocol *util;
+ struct efi_device_path_to_text_protocol *text;
+ struct efi_device_path *path;
+ struct efi_block_io *blkio;
+ efi_uintn_t num_handles;
+ efi_handle_t *handle;
+ int ret, i;
+
+ if (!boot)
+ return log_msg_ret("sys", -ENOSYS);
+
+ /* Find all devices which support the block I/O protocol */
+ ret = boot->locate_handle_buffer(BY_PROTOCOL, &efi_blkio_guid, NULL,
+ &num_handles, &handle);
+ if (ret)
+ return log_msg_ret("loc", -ENOTSUPP);
+ log_debug("Found %d handles:\n", (int)num_handles);
+
+ /* We need to look up the path size and convert it to text */
+ ret = boot->locate_protocol(&efi_pathutil_guid, NULL, (void **)&util);
+ if (ret)
+ return log_msg_ret("util", -ENOTSUPP);
+ ret = boot->locate_protocol(&efi_pathtext_guid, NULL, (void **)&text);
+ if (ret)
+ return log_msg_ret("text", -ENOTSUPP);
+
+ for (i = 0; i < num_handles; i++) {
+ struct udevice *dev;
+ const u16 *name;
+ bool is_part;
+ int len;
+
+ ret = boot->handle_protocol(handle[i], &efi_devpath_guid,
+ (void **)&path);
+ if (ret) {
+ log_warning("- devpath %d failed (ret=%d)\n", i, ret);
+ continue;
+ }
+
+ ret = boot->handle_protocol(handle[i], &efi_blkio_guid,
+ (void **)&blkio);
+ if (ret) {
+ log_warning("- blkio %d failed (ret=%d)\n", i, ret);
+ continue;
+ }
+
+ name = text->convert_device_path_to_text(path, true, false);
+ is_part = devpath_is_partition(path);
+
+ if (!is_part) {
+ len = util->get_device_path_size(path);
+ ret = efi_bind_block(handle[i], blkio, path, len, &dev);
+ if (ret) {
+ log_warning("- blkio bind %d failed (ret=%d)\n",
+ i, ret);
+ continue;
+ }
+ } else {
+ dev = NULL;
+ }
+
+ /*
+ * Show the device name if we created one. Otherwise indicate
+ * that it is a partition.
+ *
+ * We don't seem to have have a way to print unicode on the
+ * U-Boot console at present, so use our own function.
+ */
+ printf("%2d: %-12s ", i, dev ? dev->name : "<partition>");
+ efi_print_str(name);
+ printf("\n");
+ }
+ boot->free_pool(handle);
+
+ return 0;
+}
+
+int dm_scan_other(bool pre_reloc_only)
+{
+ if (gd->flags & GD_FLG_RELOC) {
+ int ret;
+
+ ret = setup_block();
+ if (ret)
+ return ret;
+
+ /* Not needed at present, but could be useful one day? */
+ ret = setup_disks();
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
/**
* efi_main() - Start an EFI image
*
--
2.34.0.rc0.344.g81b53c2807-goog