This patch adds a new "extension" command, which aims at detecting extension boards connected to the hardware platform, and apply the Device Tree overlays that describe the hardware present on those extension boards.
In order to enable this mechanism, board-specific code must implement the extension_board_scan() function that fills in a linked list of "struct extension", each describing one extension board. In addition, the board-specific code must select the SUPPORT_EXTENSION_SCAN Kconfig boolean.
Based on this:
- "extension scan" makes the generic code call the board-specific extension_board_scan() function to retrieve the list of detected extension boards.
- "extension list" allows to list the detected extension boards.
- "extension apply <number>|all" allows to apply the Device Tree overlay(s) corresponding to one, or all, extension boards
The latter requires two environment variables to exist:
- extension_overlay_addr: the RAM address where to load the Device Tree overlays
- extension_overlay_cmd: the U-Boot command to load one overlay. Indeed, the location and mechanism to load DT overlays is very setup specific.
When calling the command described in the extension_overlay_cmd variable, the variable extension_overlay_name will be defined. So a typical extension_overlay_cmd will look like this:
extension_overlay_cmd=load mmc 0:1 $extension_overlay_addr /boot/$extension_overlay_name
Here is an example on how to use it: => run loadfdt => fdt addr $fdtaddr => setenv extension_overlay_addr 0x1000 => setenv extension_overlay_cmd 'load mmc 0:1 ${extension_overlay_addr} /boot/${extension_overlay_name}' => extension scan Found 1 extension board(s). => extension apply 0 519 bytes read in 3 ms (168.9 KiB/s)
Signed-off-by: Kory Maincent kory.maincent@bootlin.com --- cmd/Kconfig | 12 +++ cmd/Makefile | 1 + cmd/extension_board.c | 167 ++++++++++++++++++++++++++++++++++++++ doc/README.extension | 80 ++++++++++++++++++ include/extension_board.h | 31 +++++++ 5 files changed, 291 insertions(+) create mode 100644 cmd/extension_board.c create mode 100644 doc/README.extension create mode 100644 include/extension_board.h
diff --git a/cmd/Kconfig b/cmd/Kconfig index 1595de999b..90be5c260a 100644 --- a/cmd/Kconfig +++ b/cmd/Kconfig @@ -314,6 +314,18 @@ config CMD_FDT help Do FDT related setup before booting into the Operating System.
+config SUPPORT_EXTENSION_SCAN + bool + +config CMD_EXTENSION + bool "Extension board management command" + select CMD_FDT + depends on SUPPORT_EXTENSION_SCAN + help + Enables the "extension" command, which allows to detect + extension boards connected to the system, and apply + corresponding Device Tree overlays. + config CMD_GO bool "go" default y diff --git a/cmd/Makefile b/cmd/Makefile index dd86675bf2..87da67d27d 100644 --- a/cmd/Makefile +++ b/cmd/Makefile @@ -53,6 +53,7 @@ obj-$(CONFIG_CMD_DIAG) += diag.o endif obj-$(CONFIG_CMD_ADTIMG) += adtimg.o obj-$(CONFIG_CMD_ABOOTIMG) += abootimg.o +obj-$(CONFIG_CMD_EXTENSION) += extension_board.o obj-$(CONFIG_CMD_ECHO) += echo.o obj-$(CONFIG_ENV_IS_IN_EEPROM) += eeprom.o obj-$(CONFIG_CMD_EEPROM) += eeprom.o diff --git a/cmd/extension_board.c b/cmd/extension_board.c new file mode 100644 index 0000000000..4fed84da2d --- /dev/null +++ b/cmd/extension_board.c @@ -0,0 +1,167 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * (C) Copyright 2021 + * Köry Maincent, Bootlin, kory.maincent@bootlin.com + */ + +#include <common.h> +#include <command.h> +#include <malloc.h> +#include <extension_board.h> +#include <mapmem.h> +#include <linux/libfdt.h> +#include <fdt_support.h> + +static LIST_HEAD(extension_list); + +static int extension_apply(struct extension *extension) +{ + char *overlay_cmd; + ulong extrasize, overlay_addr; + struct fdt_header *blob; + + if (!working_fdt) { + puts( + "No FDT memory address configured. Please configure\n" + "the FDT address via "fdt addr <address>" command.\n"); + return CMD_RET_FAILURE; + } + + overlay_cmd = env_get("extension_overlay_cmd"); + if (!overlay_cmd) { + printf("Environment extension_overlay_cmd is missing\n"); + return CMD_RET_FAILURE; + } + + overlay_addr = env_get_hex("extension_overlay_addr", 0); + if (!overlay_addr) { + printf("Environment extension_overlay_addr is missing\n"); + return CMD_RET_FAILURE; + } + + env_set("extension_overlay_name", extension->overlay); + if (run_command(overlay_cmd, 0) != 0) + return CMD_RET_FAILURE; + + extrasize = env_get_hex("filesize", 0); + if (!extrasize) + return CMD_RET_FAILURE; + + fdt_shrink_to_minimum(working_fdt, extrasize); + + blob = map_sysmem(overlay_addr, 0); + if (!fdt_valid(&blob)) + return CMD_RET_FAILURE; + + /* apply method prints messages on error */ + if (fdt_overlay_apply_verbose(working_fdt, blob)) + return CMD_RET_FAILURE; + + return CMD_RET_SUCCESS; +} + +static int do_extension_list(struct cmd_tbl *cmdtp, int flag, + int argc, char *const argv[]) +{ + int i; + struct extension *extension; + + if (list_empty(&extension_list)) { + printf("No extension registered - Please run "extension scan"\n"); + return CMD_RET_SUCCESS; + } + + list_for_each_entry(extension, &extension_list, list) { + printf("Extension %d: %s\n", i++, extension->name); + printf("\tManufacturer: \t\t%s\n", extension->owner); + printf("\tVersion: \t\t%s\n", extension->version); + printf("\tDevicetree overlay: \t%s\n", extension->overlay); + printf("\tOther information: \t%s\n", extension->other); + } + return CMD_RET_SUCCESS; +} + +static int do_extension_scan(struct cmd_tbl *cmdtp, int flag, + int argc, char *const argv[]) +{ + struct extension *extension, *next; + int extension_num; + + list_for_each_entry_safe(extension, next, &extension_list, list) { + list_del(&extension->list); + free(extension); + } + extension_num = extension_board_scan(&extension_list); + + if (extension_num < 0) + return CMD_RET_FAILURE; + + printf("Found %d extension board(s).\n", extension_num); + + return CMD_RET_SUCCESS; +} + +static int do_extension_apply(struct cmd_tbl *cmdtp, int flag, + int argc, char *const argv[]) +{ + struct extension *extension = NULL; + struct list_head *entry; + int i = 0, extension_id, ret; + + if (argc < 2) + return CMD_RET_USAGE; + + if (strcmp(argv[1], "all") == 0) { + list_for_each_entry(extension, &extension_list, list) + ret = extension_apply(extension); + if (ret != CMD_RET_SUCCESS) + break; + } else { + extension_id = simple_strtol(argv[1], NULL, 10); + list_for_each(entry, &extension_list) { + if (i == extension_id) { + extension = list_entry(entry, struct extension, list); + break; + } + i++; + } + + if (!extension) { + printf("Wrong extension number\n"); + return CMD_RET_FAILURE; + } + + ret = extension_apply(extension); + } + + return ret; +} + +static struct cmd_tbl cmd_extension[] = { + U_BOOT_CMD_MKENT(scan, 1, 1, do_extension_scan, "", ""), + U_BOOT_CMD_MKENT(list, 1, 0, do_extension_list, "", ""), + U_BOOT_CMD_MKENT(apply, 2, 0, do_extension_apply, "", ""), +}; + +static int do_extensionops(struct cmd_tbl *cmdtp, int flag, int argc, + char *const argv[]) +{ + struct cmd_tbl *cp; + + /* Drop the extension command */ + argc--; + argv++; + + cp = find_cmd_tbl(argv[0], cmd_extension, ARRAY_SIZE(cmd_extension)); + if (cp) + return cp->cmd(cmdtp, flag, argc, argv); + + return CMD_RET_USAGE; +} + +U_BOOT_CMD(extension, 3, 1, do_extensionops, + "Extension board management sub system", + "scan - scan plugged extension(s) board(s)\n" + "extension list - lists available extension(s) board(s)\n" + "extension apply <extension number|all> - applies DT overlays corresponding to extension boards\n" +); diff --git a/doc/README.extension b/doc/README.extension new file mode 100644 index 0000000000..6face05084 --- /dev/null +++ b/doc/README.extension @@ -0,0 +1,80 @@ +U-Boot extension board usage (CONFIG_EXTENSION) +=============================================== + +The "extension" command proposes a generic U-Boot mechanism to detect +extension boards connected to the HW platform, and apply the appropriate +Device Tree overlays depending on the detected extension boards. + +The "extension" command comes with three sub-commands: + + - "extension scan" makes the generic code call the board-specific + extension_board_scan() function to retrieve the list of detected + extension boards. + + - "extension list" allows to list the detected extension boards. + + - "extension apply <number>|all" allows to apply the Device Tree + overlay(s) corresponding to one, or all, extension boards + +The latter requires two environment variables to exist: + + - extension_overlay_addr: the RAM address where to load the Device + Tree overlays + + - extension_overlay_cmd: the U-Boot command to load one overlay. + Indeed, the location and mechanism to load DT overlays is very setup + specific. + +In order to enable this mechanism, board-specific code must implement +the extension_board_scan() function that fills in a linked list of +"struct extension", each describing one extension board. In addition, +the board-specific code must select the SUPPORT_EXTENSION_SCAN Kconfig +boolean. + +Usage example +------------- + +1. Make sure your devicetree is loaded and set as the working fdt tree. + +=> run loadfdt +=> fdt addr $fdtaddr + +2. Prepare the environment variables + +=> setenv extension_overlay_addr 0x88080000 +=> setenv extension_overlay_cmd 'load mmc 0:1 ${extension_overlay_addr} /boot/${extension_overlay_name}' + +3. Detect the plugged extension board + +=> extension scan + +4. List the plugged extension board information and the devicetree + overlay name + +=> extension list + +5. Apply the appropriate devicetree overlay + +For apply the selected overlay: +=> extension apply 0 + +For apply all the overlays: +=> extension apply all + +Simple extension_board_scan function example +-------------------------------------------- + +int extension_board_scan(struct list_head *extension_list) +{ + struct extension *extension; + + extension = calloc(1, sizeof(struct extension)); + snprintf(extension->overlay, sizeof(extension->overlay), "overlay.dtbo"); + snprintf(extension->name, sizeof(extension->name), "extension board"); + snprintf(extension->owner, sizeof(extension->owner), "sandbox"); + snprintf(extension->version, sizeof(extension->version), "1.1"); + snprintf(extension->other, sizeof(extension->other), "Extension board information"); + list_add_tail(&extension->list, extension_list); + + return 1; +} diff --git a/include/extension_board.h b/include/extension_board.h new file mode 100644 index 0000000000..c530a0ad8a --- /dev/null +++ b/include/extension_board.h @@ -0,0 +1,31 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * (C) Copyright 2021 + * Köry Maincent, Bootlin, kory.maincent@bootlin.com + */ + +#ifndef __EXTENSION_SUPPORT_H +#define __EXTENSION_SUPPORT_H + +struct extension { + struct list_head list; + char name[32]; + char owner[32]; + char version[32]; + char overlay[32]; + char other[32]; +}; + +/** + * extension_board_scan - Add system-specific function to scan extension board. + * @param extension_list List of extension board information to update. + * @return the number of extension. + * + * This function is called if CONFIG_CMD_EXTENSION is defined. + * Needs to fill the list extension_list with elements. + * Each element need to be allocated to an extension structure. + * + */ +int extension_board_scan(struct list_head *extension_list); + +#endif /* __EXTENSION_SUPPORT_H */