[PATCH v7 01/24] efi: Locate all block devices in the app

Heinrich Schuchardt xypron.glpk at gmx.de
Mon Dec 20 11:51:19 CET 2021



On 12/18/21 19:28, Simon Glass wrote:
> 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.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
> (no changes since v6)
>
> Changes in v6:
> - Add comment for dm_scan_other()
> - Add comment for free_memory()
> - Drop setup_disks() as U-Boot does not support it
> - Fix 'have have' typo
> - Update comment format for devpath_is_partition()
>
> Changes in v2:
> - Don't export efi_bind_block()
> - Only bind devices for media devices, not for partitions
> - Show devices that are processed
> - Store device path in struct efi_media_plat
> - Update documentation
>
>   doc/develop/uefi/u-boot_on_efi.rst |   4 +-
>   include/efi.h                      |   6 +-
>   include/efi_api.h                  |  15 ++
>   lib/efi/efi_app.c                  | 216 +++++++++++++++++++++++++++++
>   4 files changed, 236 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 80109f012bc..ec9fa89a935 100644
> --- a/include/efi_api.h
> +++ b/include/efi_api.h
> @@ -2035,4 +2035,19 @@ 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..6a71cef7acb 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);

This will lead to awkward results.

We don't need this function. Please, use printf("%ls", str) instead.

> +	}
> +}
> +
> +/**
> + * 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;
> @@ -91,6 +152,14 @@ static efi_status_t setup_memory(struct efi_priv *priv)
>   	return 0;
>   }
>
> +/**
> + * free_memory() - Free memory used by the U-Boot app
> + *
> + * This frees memory allocated in setup_memory(), in preparation for returning
> + * to UEFI. It also zeroes the global_data pointer.
> + *
> + * @priv: Private EFI data
> + */
>   static void free_memory(struct efi_priv *priv)
>   {
>   	struct efi_boot_services *boot = priv->boot;
> @@ -105,6 +174,153 @@ static void free_memory(struct efi_priv *priv)
>   	global_data_ptr = NULL;
>   }
>
> +/**
> + * 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 a way to print unicode on the U-Boot

This comment is wrong.

> +		 * console at present, so use our own function.
> +		 */
> +		printf("%2d: %-12s ", i, dev ? dev->name : "<partition>");
> +		efi_print_str(name);
> +		printf("\n");

printf("%2d: %-12s %ls\n", i, dev ? dev->name : "<partition>", name);

Best regards

Heinrich

> +	}
> +	boot->free_pool(handle);
> +
> +	return 0;
> +}
> +
> +/**
> + * dm_scan_other() - Scan for UEFI devices that should be available to U-Boot
> + *
> + * This sets up block devices within U-Boot for those found in UEFI. With this,
> + * U-Boot can access those devices
> + *
> + * @pre_reloc_only: true to only bind pre-relocation devices (ignored)
> + * Returns: 0 on success, -ve on error
> + */
> +int dm_scan_other(bool pre_reloc_only)
> +{
> +	if (gd->flags & GD_FLG_RELOC) {
> +		int ret;
> +
> +		ret = setup_block();
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
>   /**
>    * efi_main() - Start an EFI image
>    *


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