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1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  * Copyright (C) 2014 Google, Inc
4  * Copyright (C) 2015 Bin Meng <bmeng.cn@gmail.com>
5  */
6 
7 #ifndef _ASM_MRCCACHE_H
8 #define _ASM_MRCCACHE_H
9 
10 #define MRC_DATA_ALIGN		0x1000
11 #define MRC_DATA_SIGNATURE	(('M' << 0) | ('R' << 8) | \
12 				 ('C' << 16) | ('D'<<24))
13 
14 #define MRC_DATA_HEADER_SIZE	32
15 
16 struct __packed mrc_data_container {
17 	u32	signature;	/* "MRCD" */
18 	u32	data_size;	/* Size of the 'data' field */
19 	u32	checksum;	/* IP style checksum */
20 	u32	reserved;	/* For header alignment */
21 	u8	data[0];	/* Variable size, platform/run time dependent */
22 };
23 
24 struct mrc_region {
25 	u32	base;
26 	u32	offset;
27 	u32	length;
28 };
29 
30 struct udevice;
31 
32 /**
33  * mrccache_find_current() - find the latest MRC cache record
34  *
35  * This searches the MRC cache region looking for the latest record to use
36  * for setting up SDRAM
37  *
38  * @entry:	Position and size of MRC cache in SPI flash
39  * @return pointer to latest record, or NULL if none
40  */
41 struct mrc_data_container *mrccache_find_current(struct mrc_region *entry);
42 
43 /**
44  * mrccache_update() - update the MRC cache with a new record
45  *
46  * This writes a new record to the end of the MRC cache region. If the new
47  * record is the same as the latest record then the write is skipped
48  *
49  * @sf:		SPI flash to write to
50  * @entry:	Position and size of MRC cache in SPI flash
51  * @cur:	Record to write
52  * @return 0 if updated, -EEXIST if the record is the same as the latest
53  * record, -EINVAL if the record is not valid, other error if SPI write failed
54  */
55 int mrccache_update(struct udevice *sf, struct mrc_region *entry,
56 		    struct mrc_data_container *cur);
57 
58 /**
59  * mrccache_reserve() - reserve MRC data on the stack
60  *
61  * This copies MRC data pointed by gd->arch.mrc_output to a new place on the
62  * stack with length gd->arch.mrc_output_len, and updates gd->arch.mrc_output
63  * to point to the new place once the migration is done.
64  *
65  * This routine should be called by reserve_arch() before U-Boot is relocated
66  * when MRC cache is enabled.
67  *
68  * @return 0 always
69  */
70 int mrccache_reserve(void);
71 
72 /**
73  * mrccache_get_region() - get MRC region on the SPI flash
74  *
75  * This gets MRC region whose offset and size are described in the device tree
76  * as a subnode to the SPI flash. If a non-NULL device pointer is supplied,
77  * this also probes the SPI flash device and returns its device pointer for
78  * the caller to use later.
79  *
80  * Be careful when calling this routine with a non-NULL device pointer:
81  * - driver model initialization must be complete
82  * - calling in the pre-relocation phase may bring some side effects during
83  *   the SPI flash device probe (eg: for SPI controllers on a PCI bus, it
84  *   triggers PCI bus enumeration during which insufficient memory issue
85  *   might be exposed and it causes subsequent SPI flash probe fails).
86  *
87  * @devp:	Returns pointer to the SPI flash device
88  * @entry:	Position and size of MRC cache in SPI flash
89  * @return 0 if success, -ENOENT if SPI flash node does not exist in the
90  * device tree, -EPERM if MRC region subnode does not exist in the device
91  * tree, -EINVAL if MRC region properties format is incorrect, other error
92  * if SPI flash probe failed.
93  */
94 int mrccache_get_region(struct udevice **devp, struct mrc_region *entry);
95 
96 /**
97  * mrccache_save() - save MRC data to the SPI flash
98  *
99  * This saves MRC data stored previously by gd->arch.mrc_output to a proper
100  * place within the MRC region on the SPI flash.
101  *
102  * @return 0 if saved to SPI flash successfully, other error if failed
103  */
104 int mrccache_save(void);
105 
106 #endif /* _ASM_MRCCACHE_H */
107