mach-snapdragon: implement capsule update support

Qualcomm boards flash U-Boot a variety of partitions, implement support
for determining which slot U-Boot is running from, finding the correct
partition for that slot and configuring the appropriate DFU string.

Initially, we only support the RB3 Gen 2 where U-Boot is flashed to the
UEFI partition, and ignore handling of slots. In the future we will
additionally support booting U-Boot from other partitions (e.g. boot)
and correct handling for A/B.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>

arch/arm/mach-snapdragon/Kconfig

@@ -23,6 +23,9 @@ config SPL_SYS_MALLOC_F
 config SPL_SYS_MALLOC_F_LEN
 	default 0x2000
 
+config SYS_MALLOC_LEN
+	default 0x800000
+
 config LNX_KRNL_IMG_TEXT_OFFSET_BASE
 	default 0x80000000
 

arch/arm/mach-snapdragon/Makefile

@@ -3,4 +3,5 @@
 # (C) Copyright 2015 Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
 
 obj-y += board.o
+obj-$(CONFIG_EFI_HAVE_CAPSULE_SUPPORT) += capsule_update.o
 obj-$(CONFIG_OF_LIVE) += of_fixup.o

arch/arm/mach-snapdragon/board.c

@@ -451,6 +451,9 @@ int board_late_init(void)
 	configure_env();
 	qcom_late_init();
 
+	/* Configure the dfu_string for capsule updates */
+	qcom_configure_capsule_updates();
+
 	return 0;
 }
 

arch/arm/mach-snapdragon/capsule_update.c

@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Capsule update support for Qualcomm boards.
+ *
+ * Copyright (c) 2024 Linaro Ltd.
+ * Author: Caleb Connolly <caleb.connolly@linaro.org>
+ */
+
+#define pr_fmt(fmt) "QCOM-FMP: " fmt
+
+#include <dm/device.h>
+#include <dm/uclass.h>
+#include <efi.h>
+#include <efi_loader.h>
+#include <malloc.h>
+#include <scsi.h>
+#include <part.h>
+#include <linux/err.h>
+
+#include "qcom-priv.h"
+
+/*
+ * NOTE: for now this implementation only supports the rb3gen2. Supporting other
+ * boards that boot in different ways (e.g. chainloaded from ABL) will require
+ * additional complexity to properly create the dfu string and fw_images array.
+ */
+
+/*
+ * To handle different variants like chainloaded U-Boot here we'll need to
+ * build the fw_images array dynamically at runtime. It looks like
+ * mach-rockchip is a good example for how to do this.
+ * Detecting which image types a board uses is TBD, hence for now we only
+ * support the one new board that runs U-Boot as its primary bootloader.
+ */
+struct efi_fw_image fw_images[] = {
+	{
+		/* U-Boot flashed to the uefi_X partition (e.g. rb3gen2) */
+		.fw_name = u"UBOOT_UEFI_PARTITION",
+		.image_index = 1,
+	},
+};
+
+struct efi_capsule_update_info update_info = {
+	/* Filled in by configure_dfu_string() */
+	.dfu_string = NULL,
+	.num_images = ARRAY_SIZE(fw_images),
+	.images = fw_images,
+};
+
+/* LSB first */
+struct part_slot_status {
+	u16: 2;
+	u16 active : 1;
+	u16: 3;
+	u16 successful : 1;
+	u16 unbootable : 1;
+	u16 tries_remaining : 4;
+};
+
+static int find_boot_partition(const char *partname, struct blk_desc *blk_dev, char *name)
+{
+	int ret;
+	int partnum;
+	struct disk_partition info;
+	struct part_slot_status *slot_status;
+
+	for (partnum = 1;; partnum++) {
+		ret = part_get_info(blk_dev, partnum, &info);
+		if (ret)
+			return ret;
+
+		slot_status = (struct part_slot_status *)&info.type_flags;
+		log_io("%16s: Active: %1d, Successful: %1d, Unbootable: %1d, Tries left: %1d\n",
+		       info.name, slot_status->active,
+		       slot_status->successful, slot_status->unbootable,
+		       slot_status->tries_remaining);
+		/*
+		 * FIXME: eventually we'll want to find the active/inactive variant of the partition
+		 * but on the rb3gen2 these values might all be 0
+		 */
+		if (!strncmp(info.name, partname, strlen(partname))) {
+			log_debug("Found active %s partition: '%s'!\n", partname, info.name);
+			strlcpy(name, info.name, sizeof(info.name));
+			return partnum;
+		}
+	}
+
+	return -1;
+}
+
+/**
+ * qcom_configure_capsule_updates() - Configure the DFU string for capsule updates
+ *
+ * U-Boot is flashed to the boot partition on Qualcomm boards. In most cases there
+ * are two boot partitions, boot_a and boot_b. As we don't currently support doing
+ * full A/B updates, we only support updating the currently active boot partition.
+ *
+ * So we need to find the current slot suffix and the associated boot partition.
+ * We do this by looking for the boot partition that has the 'active' flag set
+ * in the GPT partition vendor attribute bits.
+ */
+void qcom_configure_capsule_updates(void)
+{
+	struct blk_desc *desc;
+	int ret = 0, partnum = -1, devnum;
+	static char dfu_string[32] = { 0 };
+	char name[32]; /* GPT partition name */
+	char *partname = "uefi_a";
+	struct udevice *dev = NULL;
+
+	if (IS_ENABLED(CONFIG_SCSI)) {
+		/* Scan for SCSI devices */
+		ret = scsi_scan(false);
+		if (ret) {
+			debug("Failed to scan SCSI devices: %d\n", ret);
+			return;
+		}
+	}
+
+	uclass_foreach_dev_probe(UCLASS_BLK, dev) {
+		if (device_get_uclass_id(dev) != UCLASS_BLK)
+			continue;
+
+		desc = dev_get_uclass_plat(dev);
+		if (!desc || desc->part_type == PART_TYPE_UNKNOWN)
+			continue;
+		devnum = desc->devnum;
+		partnum = find_boot_partition(partname, desc,
+					      name);
+		if (partnum >= 0)
+			break;
+	}
+
+	if (partnum < 0) {
+		log_err("Failed to find boot partition\n");
+		return;
+	}
+
+	switch (desc->uclass_id) {
+	case UCLASS_SCSI:
+		snprintf(dfu_string, 32, "scsi %d=u-boot.bin part %d", devnum, partnum);
+		break;
+	case UCLASS_MMC:
+		snprintf(dfu_string, 32, "mmc 0=u-boot.bin part %d %d", devnum, partnum);
+		break;
+	default:
+		debug("Unsupported storage uclass: %d\n", desc->uclass_id);
+		return;
+	}
+	log_debug("boot partition is %s, DFU string: '%s'\n", name, dfu_string);
+
+	update_info.dfu_string = dfu_string;
+}

arch/arm/mach-snapdragon/qcom-priv.h

@@ -3,6 +3,12 @@
 #ifndef __QCOM_PRIV_H__
 #define __QCOM_PRIV_H__
 
+#if IS_ENABLED(CONFIG_EFI_HAVE_CAPSULE_SUPPORT)
+void qcom_configure_capsule_updates(void);
+#else
+void qcom_configure_capsule_updates(void) {}
+#endif /* EFI_HAVE_CAPSULE_SUPPORT */
+
 #if CONFIG_IS_ENABLED(OF_LIVE)
 /**
  * qcom_of_fixup_nodes() - Fixup Qualcomm DT nodes

include/configs/qcom.h

@@ -11,4 +11,9 @@
 
 #define CFG_SYS_BAUDRATE_TABLE	{ 115200, 230400, 460800, 921600 }
 
+// 2a5aa852-b856-4d97-baa9-5c5f4421551f
+#define QUALCOMM_UBOOT_BOOT_IMAGE_GUID \
+	EFI_GUID(0x2a5aa852, 0xb856, 0x4d97, 0xba, 0xa9, \
+		0x5c, 0x5f, 0x44, 0x21, 0x55, 0x1f)
+
 #endif