toradex: tdx-cfg-block: add support for EEPROM

This introduces support for EEPROM as a storage for the main Toradex
config block and additional config blocks on extra EEPROM chips (on
carrier board or video adapters).

To enable EEPROM as a storage for the main config block:
TDX_HAVE_EEPROM=y.

For additional EEPROMs please enable this Kconfig symbol:
TDX_CFG_BLOCK_EXTRA=y.

Information about existing EEPROM chips is provide via Device Tree using
aliases.

You can also write configuration for the carrier board using create_carrier
subcommand for cfgblock. Example:

Verdin iMX8MM # cfgblock create_carrier
Supported carrier boards:
UNKNOWN CARRIER                     = [0]
Verdin Carrier Board                = [1]
Choose your carrier board (provide ID): 1
Enter carrier board version (e.g. V1.1B): V1.0A
Enter carrier board serial number: 10622780

Also with barcode:
cVerdin iMX8MM # cfgblock create carrier -y 0156100010622780

Relates-to: ELB-1402
Signed-off-by: Igor Opaniuk <igor.opaniuk@toradex.com>

1 files changed, 110 insertions, 0 deletions

diff --git a/board/toradex/common/tdx-eeprom.c b/board/toradex/common/tdx-eeprom.c
new file mode 100644
index 0000000000..176302248d
--- /dev/null
+++ b/board/toradex/common/tdx-eeprom.c
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2020 Toradex
+ */
+
+#include <dm.h>
+#include <i2c_eeprom.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static int get_tdx_eeprom(u32 eeprom_id, struct udevice **devp)
+{
+	int ret = 0;
+	int node;
+	ofnode eeprom;
+	char eeprom_str[16];
+	const char *path;
+
+	if (gd->fdt_blob == NULL) {
+		printf("%s: don't have a valid gd->fdt_blob!\n", __func__);
+		return -EFAULT;
+	}
+
+	node = fdt_path_offset(gd->fdt_blob, "/aliases");
+	if (node < 0)
+		return -ENODEV;
+
+	sprintf(eeprom_str, "eeprom%d", eeprom_id);
+
+	path = fdt_getprop(gd->fdt_blob, node, eeprom_str, NULL);
+	if (!path) {
+		printf("%s: no alias for %s\n", __func__, eeprom_str);
+		return -ENODEV;
+	}
+
+	eeprom = ofnode_path(path);
+	if (!ofnode_valid(eeprom)) {
+		printf("%s: invalid hardware path to EEPROM\n", __func__);
+		return -ENODEV;
+	}
+
+	ret = uclass_get_device_by_ofnode(UCLASS_I2C_EEPROM, eeprom, devp);
+	if (ret) {
+		printf("%s: cannot find EEPROM by node\n", __func__);
+		return ret;
+	}
+
+	return ret;
+}
+
+#ifdef DEBUG
+static void print_tdx_hex(u8 *buf, int size)
+{
+        unsigned char *p = (unsigned char *)buf;
+
+	printf("Toradex config block: \n");
+	for (int i = 0; i < size; ++i) {
+		if (! (i % 16) && i)
+			printf("\n");
+
+		printf("0x%02x ", p[i]);
+	}
+        printf("\n\n");
+}
+#endif
+
+int read_tdx_eeprom_data(u32 eeprom_id, int offset, u8 *buf,
+			 int size)
+{
+	struct udevice *dev;
+	int ret;
+
+	ret = get_tdx_eeprom(eeprom_id, &dev);
+	if (ret)
+		return ret;
+
+	ret = i2c_eeprom_read(dev, 0x0, buf, size);
+	if (ret) {
+		printf("%s: error reading data from EEPROM id: %d!, ret = %d\n",
+		        __func__, eeprom_id, ret);
+		return ret;
+	}
+#ifdef DEBUG
+	print_tdx_hex(buf, size);
+#endif
+	return ret;
+}
+
+int write_tdx_eeprom_data(u32 eeprom_id, int offset, u8 *buf,
+			  int size)
+{
+	struct udevice *dev;
+	int ret;
+
+	ret = get_tdx_eeprom(eeprom_id, &dev);
+	if (ret)
+		return ret;
+
+#ifdef DEBUG
+	print_tdx_hex(buf, size);
+#endif
+	ret = i2c_eeprom_write(dev, 0x0, buf, size);
+	if (ret) {
+		printf("%s: error writing data to EEPROM id: %d, ret = %d\n",
+		        __func__, eeprom_id, ret);
+		return ret;
+	}
+
+	return ret;
+}