board: ti: common: Add support for dynamic dfu_alt_info

Add support for setting dfu_alt_info environment variable
dynamically for SPI flash devices, the dfu_alt_info is populated
from existing mtd partitions, there is no modification made
to the environment variable if it already is defined.

Signed-off-by: Vaishnav Achath <vaishnav.a@ti.com>

board/ti/common/Makefile

@@ -3,3 +3,4 @@
 
 obj-${CONFIG_TI_I2C_BOARD_DETECT} += board_detect.o
 obj-${CONFIG_CMD_EXTENSION} += cape_detect.o
+obj-$(CONFIG_SET_DFU_ALT_INFO) += k3_dfu.o

board/ti/common/k3_dfu.c

@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2023, Texas Instruments Incorporated - https://www.ti.com/
+ */
+
+#include <common.h>
+#include <blk.h>
+#include <dm.h>
+#include <dfu.h>
+#include <env.h>
+#include <memalign.h>
+#include <misc.h>
+#include <mtd.h>
+#include <mtd_node.h>
+
+#define DFU_ALT_BUF_LEN 512
+
+static void board_get_alt_info_sf(struct mtd_info *mtd, char *buf)
+{
+	struct mtd_info *part;
+	bool first = true;
+	const char *name;
+	int len;
+
+	name = mtd->name;
+	len = strlen(buf);
+
+	list_for_each_entry(part, &mtd->partitions, node) {
+		if (!first)
+			len += snprintf(buf + len, DFU_ALT_BUF_LEN - len, "; ");
+		first = false;
+		len += snprintf(buf + len, DFU_ALT_BUF_LEN - len,
+				"%s raw %llx %llx", part->name, part->offset, part->size);
+	}
+}
+
+void set_dfu_alt_info(char *interface, char *devstr)
+{
+	struct udevice *dev;
+	struct mtd_info *mtd;
+	char *st, *devstr_bkup;
+	unsigned int bus;
+
+	ALLOC_CACHE_ALIGN_BUFFER(char, buf, DFU_ALT_BUF_LEN);
+
+	if (env_get("dfu_alt_info"))
+		return;
+
+	memset(buf, 0, sizeof(buf));
+
+	if (!strcmp(interface, "sf")) {
+		devstr_bkup = strdup(devstr);
+		st = strsep(&devstr_bkup, ":");
+		if (!st || !*st) {
+			printf("Invalid SPI bus %s\n", st);
+			return;
+		}
+		bus = simple_strtoul(st, NULL, 0);
+
+		if (uclass_get_device(UCLASS_SPI_FLASH, bus, &dev)) {
+			printf("Failed to get device on bus %d\n", bus);
+			return;
+		}
+		if (CONFIG_IS_ENABLED(MTD)) {
+			mtd_probe_devices();
+			mtd_for_each_device(mtd) {
+				if (!mtd_is_partition(mtd) && mtd->dev && dev == mtd->dev)
+					board_get_alt_info_sf(mtd, buf);
+			}
+		}
+	} else {
+		printf("dynamic dfu_alt_info supported only for sf\n");
+		return;
+	}
+
+	env_set("dfu_alt_info", buf);
+}