[PATCH 03/10] Add a command to find a load address

[Simon Glass]

On Sat, 23 Nov 2024 at 12:57, Matthew Garrett <mjg59 at srcf.ucam.org> wrote:
>
> From: Matthew Garrett <mgarrett at aurora.tech>
>
> For systems with more complicated firmware, the firmware memory map may
> vary significantly based on a number of factors. This makes it difficult to
> pick a hardcoded load address. Add a command for finding an available
> address with sufficient room to load the provided path.
>
> Signed-off-by: Matthew Garrett <mgarrett at aurora.tech>
> ---
>
>  cmd/Kconfig     |  7 ++++
>  cmd/Makefile    |  1 +
>  cmd/addr_find.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 95 insertions(+)
>  create mode 100644 cmd/addr_find.c

Reviewed-by: Simon Glass <sjg at chromium.org>

(again, this needs doc/ and test/cmd/...)

>
> diff --git a/cmd/Kconfig b/cmd/Kconfig
> index ee85928ca21..5ed6a50121c 100644
> --- a/cmd/Kconfig
> +++ b/cmd/Kconfig
> @@ -128,6 +128,13 @@ config CMD_ACPI
>           between the firmware and OS, and is particularly useful when you
>           want to make hardware changes without the OS needing to be adjusted.
>
> +config CMD_ADDR_FIND
> +        bool "addr_find"
> +       help
> +         This command searches for an unused region of address space
> +         sufficiently large to hold a file. If successful, it sets the
> +         loadaddr variable to this address.
> +
>  config CMD_ADDRMAP
>         bool "addrmap"
>         depends on ADDR_MAP
> diff --git a/cmd/Makefile b/cmd/Makefile
> index 16fd8dcd723..38cb7a4aea5 100644
> --- a/cmd/Makefile
> +++ b/cmd/Makefile
> @@ -15,6 +15,7 @@ obj-y += version.o
>  obj-$(CONFIG_CMD_ARMFFA) += armffa.o
>  obj-$(CONFIG_CMD_2048) += 2048.o
>  obj-$(CONFIG_CMD_ACPI) += acpi.o
> +obj-$(CONFIG_CMD_ADDR_FIND) += addr_find.o
>  obj-$(CONFIG_CMD_ADDRMAP) += addrmap.o
>  obj-$(CONFIG_CMD_AES) += aes.o
>  obj-$(CONFIG_CMD_ADC) += adc.o
> diff --git a/cmd/addr_find.c b/cmd/addr_find.c
> new file mode 100644
> index 00000000000..b187337d885
> --- /dev/null
> +++ b/cmd/addr_find.c
> @@ -0,0 +1,87 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Aurora Innovation, Inc. Copyright 2022.
> + *
> + */
> +
> +#include <blk.h>
> +#include <config.h>
> +#include <command.h>
> +#include <env.h>
> +#include <fs.h>
> +#include <lmb.h>
> +#include <asm/global_data.h>
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +int do_addr_find(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
> +{
> +       struct lmb_region *mem, *reserved;
> +       const char *filename;
> +       struct lmb lmb;
> +       loff_t size;
> +       int ret;
> +       int i, j;
> +
> +       if (!gd->fdt_blob) {
> +               log_err("No FDT setup\n");
> +               return CMD_RET_FAILURE;
> +       }
> +
> +       if (fs_set_blk_dev(argv[1], argc >= 3 ? argv[2] : NULL, FS_TYPE_FAT)) {
> +               log_err("Can't set block device\n");
> +               return CMD_RET_FAILURE;
> +       }
> +
> +       if (argc >= 4) {
> +               filename = argv[3];
> +       } else {
> +               filename = env_get("bootfile");
> +               if (!filename) {
> +                       log_err("No boot file defined\n");
> +                       return CMD_RET_FAILURE;
> +               }
> +       }
> +
> +       ret = fs_size(filename, &size);
> +       if (ret != 0) {
> +               log_err("Failed to get file size\n");
> +               return CMD_RET_FAILURE;
> +       }
> +
> +       lmb_init_and_reserve(&lmb, gd->bd, (void *)gd->fdt_blob);

As Tom says, lmb has changed to be global for now. However, since we
are not using EFI_LOADER's memory allocation here, it seems fine to
me.

> +       mem = &lmb.memory;
> +       reserved = &lmb.reserved;
> +
> +       for (i = 0; i < mem->cnt; i++) {
> +               unsigned long long start, end;
> +
> +               start = mem->region[i].base;
> +               end = mem->region[i].base + mem->region[i].size - 1;
> +               if ((start + size) > end)
> +                       continue;
> +               for (j = 0; j < reserved->cnt; j++) {
> +                       if ((reserved->region[j].base + reserved->region[j].size) < start)
> +                               continue;
> +                       if ((start + size) > reserved->region[j].base)
> +                               start = reserved->region[j].base + reserved->region[j].size;
> +               }
> +               if ((start + size) <= end) {
> +                       env_set_hex("loadaddr", start);
> +                       debug("Set loadaddr to 0x%llx\n", start);
> +                       return CMD_RET_SUCCESS;
> +               }
> +       }
> +
> +       log_err("Failed to find enough RAM for 0x%llx bytes\n", size);
> +       return CMD_RET_FAILURE;
> +}
> +
> +U_BOOT_CMD(
> +       addr_find, 7, 1, do_addr_find,
> +       "find a load address suitable for a file",
> +       "<interface> [<dev[:part]>] <filename>\n"
> +       "- find a consecutive region of memory sufficiently large to hold\n"
> +       "  the file called 'filename' from 'dev' on 'interface'. If\n"
> +       "  successful, 'loadaddr' will be set to the located address."
> +);
> --
> 2.47.0
>

Regards,
Simon