driver: misc: imx8ulp: Add fuse driver for imx8ulp

This driver uses FSB to read some fuses, but not support program fuse.
It only works in SPL (secure mode), u-boot needs traps to ATF to
read them.

Some fuses can read from S400 API and others are from FSB.
Also support program some fuses via S400 API
Signed-off-by: NYe Li <ye.li@nxp.com>

drivers/misc/imx8ulp/Makefile

 # SPDX-License-Identifier: GPL-2.0+
 
 obj-y += s400_api.o imx8ulp_mu.o
+obj-$(CONFIG_CMD_FUSE) += fuse.o

drivers/misc/imx8ulp/fuse.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2020 NXP
+ */
+
+#include <common.h>
+#include <console.h>
+#include <errno.h>
+#include <fuse.h>
+#include <asm/arch/sys_proto.h>
+#include <asm/arch/imx-regs.h>
+#include <env.h>
+#include <asm/arch/s400_api.h>
+#include <asm/global_data.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define FUSE_BANKS	64
+#define WORDS_PER_BANKS 8
+
+struct fsb_map_entry {
+	s32 fuse_bank;
+	u32 fuse_words;
+	bool redundancy;
+};
+
+struct s400_map_entry {
+	s32 fuse_bank;
+	u32 fuse_words;
+	u32 fuse_offset;
+	u32 s400_index;
+};
+
+struct fsb_map_entry fsb_mapping_table[] = {
+	{ 3, 8 },
+	{ 4, 8 },
+	{ 5, 8 },
+	{ 6, 8 },
+	{ -1, 48 }, /* Reserve 48 words */
+	{ 8,  4, true },
+	{ 24, 4, true },
+	{ 26, 4, true },
+	{ 27, 4, true },
+	{ 28, 8 },
+	{ 29, 8 },
+	{ 30, 8 },
+	{ 31, 8 },
+	{ 37, 8 },
+	{ 38, 8 },
+	{ 39, 8 },
+	{ 40, 8 },
+	{ 41, 8 },
+	{ 42, 8 },
+	{ 43, 8 },
+	{ 44, 8 },
+	{ 45, 8 },
+	{ 46, 8 },
+};
+
+struct s400_map_entry s400_api_mapping_table[] = {
+	{ 1, 8 },	/* LOCK */
+	{ 2, 8 },	/* ECID */
+	{ 7, 4, 0, 1 },	/* OTP_UNIQ_ID */
+	{ 23, 1, 4, 2 }, /* OTFAD */
+};
+
+static s32 map_fsb_fuse_index(u32 bank, u32 word, bool *redundancy)
+{
+	s32 size = ARRAY_SIZE(fsb_mapping_table);
+	s32 i, word_pos = 0;
+
+	/* map the fuse from ocotp fuse map to FSB*/
+	for (i = 0; i < size; i++) {
+		if (fsb_mapping_table[i].fuse_bank != -1 &&
+		    fsb_mapping_table[i].fuse_bank == bank) {
+			break;
+		}
+
+		word_pos += fsb_mapping_table[i].fuse_words;
+	}
+
+	if (i == size)
+		return -1; /* Failed to find */
+
+	if (fsb_mapping_table[i].redundancy) {
+		*redundancy = true;
+		return (word >> 1) + word_pos;
+	}
+
+	*redundancy = false;
+	return word + word_pos;
+}
+
+static s32 map_s400_fuse_index(u32 bank, u32 word)
+{
+	s32 size = ARRAY_SIZE(s400_api_mapping_table);
+	s32 i;
+
+	/* map the fuse from ocotp fuse map to FSB*/
+	for (i = 0; i < size; i++) {
+		if (s400_api_mapping_table[i].fuse_bank != -1 &&
+		    s400_api_mapping_table[i].fuse_bank == bank) {
+			if (word >= s400_api_mapping_table[i].fuse_offset &&
+			    word < (s400_api_mapping_table[i].fuse_offset +
+			    s400_api_mapping_table[i].fuse_words))
+				break;
+		}
+	}
+
+	if (i == size)
+		return -1; /* Failed to find */
+
+	if (s400_api_mapping_table[i].s400_index != 0)
+		return s400_api_mapping_table[i].s400_index;
+
+	return s400_api_mapping_table[i].fuse_bank * 8 + word;
+}
+
+int fuse_sense(u32 bank, u32 word, u32 *val)
+{
+	s32 word_index;
+	bool redundancy;
+
+	if (bank >= FUSE_BANKS || word >= WORDS_PER_BANKS || !val)
+		return -EINVAL;
+
+	word_index = map_fsb_fuse_index(bank, word, &redundancy);
+	if (word_index >= 0) {
+		*val = readl((ulong)FSB_BASE_ADDR + 0x800 + (word_index << 2));
+		if (redundancy)
+			*val = (*val >> ((word % 2) * 16)) & 0xFFFF;
+
+		return 0;
+	}
+
+	word_index = map_s400_fuse_index(bank, word);
+	if (word_index >= 0) {
+		u32 data[4];
+		u32 res, size = 4;
+		int ret;
+
+		/* Only UID return 4 words */
+		if (word_index != 1)
+			size = 1;
+
+		ret = ahab_read_common_fuse(word_index, data, size, &res);
+		if (ret) {
+			printf("ahab read fuse failed %d, 0x%x\n", ret, res);
+			return ret;
+		}
+
+		if (word_index == 1) {
+			*val = data[word]; /* UID */
+		} else if (word_index == 2) {
+			/*
+			 * OTFAD 3 bits as follow:
+			 * bit 0: OTFAD_ENABLE
+			 * bit 1: OTFAD_DISABLE_OVERRIDE
+			 * bit 2: KEY_BLOB_EN
+			 */
+			*val = data[0] << 3;
+		} else {
+			*val = data[0];
+		}
+
+		return 0;
+	}
+
+	return -ENOENT;
+}
+
+int fuse_read(u32 bank, u32 word, u32 *val)
+{
+	return fuse_sense(bank, word, val);
+}
+
+int fuse_prog(u32 bank, u32 word, u32 val)
+{
+	u32 res;
+	int ret;
+
+	if (bank >= FUSE_BANKS || word >= WORDS_PER_BANKS || !val)
+		return -EINVAL;
+
+	ret = ahab_write_fuse((bank * 8 + word), val, false, &res);
+	if (ret) {
+		printf("ahab write fuse failed %d, 0x%x\n", ret, res);
+		return ret;
+	}
+
+	return 0;
+}
+
+int fuse_override(u32 bank, u32 word, u32 val)
+{
+	printf("Override fuse to i.MX8ULP in u-boot is forbidden\n");
+	return -EPERM;
+}