1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * (C) Copyright 2017 Theobroma Systems Design und Consulting GmbH
4  */
5 
6 #include <common.h>
7 #include <dm.h>
8 #include <mmc.h>
9 #include <spl.h>
10 
11 #if CONFIG_IS_ENABLED(OF_CONTROL)
12 /**
13  * spl_node_to_boot_device() - maps from a DT-node to a SPL boot device
14  * @node:	of_offset of the node
15  *
16  * The SPL framework uses BOOT_DEVICE_... constants to identify its boot
17  * sources.  These may take on a device-specific meaning, depending on
18  * what nodes are enabled in a DTS (e.g. BOOT_DEVICE_MMC1 may refer to
19  * different controllers/block-devices, depending on which SD/MMC controllers
20  * are enabled in any given DTS).  This function maps from a DT-node back
21  * onto a BOOT_DEVICE_... constant, considering the currently active devices.
22  *
23  * Returns
24  *   -ENOENT, if no device matching the node could be found
25  *   -ENOSYS, if the device matching the node can not be mapped onto a
26  *            SPL boot device (e.g. the third MMC device)
27  *   -1, for unspecified failures
28  *   a positive integer (from the BOOT_DEVICE_... family) on succes.
29  */
30 
31 static int spl_node_to_boot_device(int node)
32 {
33 	struct udevice *parent;
34 
35 	/*
36 	 * This should eventually move into the SPL code, once SPL becomes
37 	 * aware of the block-device layer.  Until then (and to avoid unneeded
38 	 * delays in getting this feature out, it lives at the board-level).
39 	 */
40 	if (!uclass_get_device_by_of_offset(UCLASS_MMC, node, &parent)) {
41 		struct udevice *dev;
42 		struct blk_desc *desc = NULL;
43 
44 		for (device_find_first_child(parent, &dev);
45 		     dev;
46 		     device_find_next_child(&dev)) {
47 			if (device_get_uclass_id(dev) == UCLASS_BLK) {
48 				desc = dev_get_uclass_platdata(dev);
49 				break;
50 			}
51 		}
52 
53 		if (!desc)
54 			return -ENOENT;
55 
56 		switch (desc->devnum) {
57 		case 0:
58 			return BOOT_DEVICE_MMC1;
59 		case 1:
60 			return BOOT_DEVICE_MMC2;
61 		default:
62 			return -ENOSYS;
63 		}
64 	}
65 
66 	/*
67 	 * SPL doesn't differentiate SPI flashes, so we keep the detection
68 	 * brief and inaccurate... hopefully, the common SPL layer can be
69 	 * extended with awareness of the BLK layer (and matching OF_CONTROL)
70 	 * soon.
71 	 */
72 	if (!uclass_get_device_by_of_offset(UCLASS_SPI_FLASH, node, &parent))
73 		return BOOT_DEVICE_SPI;
74 
75 	return -1;
76 }
77 
78 /**
79  * board_spl_was_booted_from() - retrieves the of-path the SPL was loaded from
80  *
81  * To support a 'same-as-spl' specification in the search-order for the next
82  * stage, we need a SoC- or board-specific way to handshake with what 'came
83  * before us' (either a BROM or TPL stage) and map the info retrieved onto
84  * a OF path.
85  *
86  * Returns
87  *   NULL, on failure or if the device could not be identified
88  *   a of_path (a string), on success
89  */
90 __weak const char *board_spl_was_booted_from(void)
91 {
92 	debug("%s: no support for 'same-as-spl' for this board\n", __func__);
93 	return NULL;
94 }
95 
96 void board_boot_order(u32 *spl_boot_list)
97 {
98 	const void *blob = gd->fdt_blob;
99 	int chosen_node = fdt_path_offset(blob, "/chosen");
100 	int idx = 0;
101 	int elem;
102 	int boot_device;
103 	int node;
104 	const char *conf;
105 
106 	if (chosen_node < 0) {
107 		debug("%s: /chosen not found, using spl_boot_device()\n",
108 		      __func__);
109 		spl_boot_list[0] = spl_boot_device();
110 		return;
111 	}
112 
113 	for (elem = 0;
114 	     (conf = fdt_stringlist_get(blob, chosen_node,
115 					"u-boot,spl-boot-order", elem, NULL));
116 	     elem++) {
117 		const char *alias;
118 
119 		/* Handle the case of 'same device the SPL was loaded from' */
120 		if (strncmp(conf, "same-as-spl", 11) == 0) {
121 			conf = board_spl_was_booted_from();
122 			if (!conf)
123 				continue;
124 		}
125 
126 		/* First check if the list element is an alias */
127 		alias = fdt_get_alias(blob, conf);
128 		if (alias)
129 			conf = alias;
130 
131 		/* Try to resolve the config item (or alias) as a path */
132 		node = fdt_path_offset(blob, conf);
133 		if (node < 0) {
134 			debug("%s: could not find %s in FDT", __func__, conf);
135 			continue;
136 		}
137 
138 		/* Try to map this back onto SPL boot devices */
139 		boot_device = spl_node_to_boot_device(node);
140 		if (boot_device < 0) {
141 			debug("%s: could not map node @%x to a boot-device\n",
142 			      __func__, node);
143 			continue;
144 		}
145 
146 		spl_boot_list[idx++] = boot_device;
147 	}
148 
149 	/* If we had no matches, fall back to spl_boot_device */
150 	if (idx == 0)
151 		spl_boot_list[0] = spl_boot_device();
152 }
153 #endif
154