zephyr: provide unified method to get sku id and board version

Previously, functions for reading board version and sku id were defined
in board.c files which are not compiled in Zephyr builds.
Logic from board.c files should be moved to the DeviceTree files.
This commit adds support for defining board version and sku id
pins and numeral system used to decode them.

BRANCH=main
BUG=b:194136536
TEST=Call system_get_sku_id and system_get_board_version
     on CrOS EC and Zephyr, values should be correct and
     the same on both versions

Change-Id: I61b5e205cb2a2299ad86c5dff38c05a9659eb2d3
Signed-off-by: Michał Barnaś <mb@semihalf.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3048102
Reviewed-by: Wai-Hong Tam <waihong@google.com>
Reviewed-by: Keith Short <keithshort@chromium.org>
Commit-Queue: Wai-Hong Tam <waihong@google.com>
Tested-by: Wai-Hong Tam <waihong@google.com>

6 files changed, 171 insertions, 1 deletions

diff --git a/common/util.c b/common/util.c
index 7ed4c45c53..deaa62f37f 100644
--- a/common/util.c
+++ b/common/util.c
@@ -767,3 +767,27 @@ int binary_first_base3_from_bits(int *bits, int nbits)
 	/* binary_below is normal binary system value if !has_z. */
 	return binary_below;
 }
+
+int binary_from_bits(int *bits, int nbits)
+{
+	int value = 0;
+	int i;
+
+	/* Loop through every binary digit, from MSB to LSB. */
+	for (i = nbits - 1; i >= 0; i--)
+		value = (value << 1) | bits[i];
+
+	return value;
+}
+
+int ternary_from_bits(int *bits, int nbits)
+{
+	int value = 0;
+	int i;
+
+	/* Loop through every ternary digit, from MSB to LSB. */
+	for (i = nbits - 1; i >= 0; i--)
+		value = (value * 3) + bits[i];
+
+	return value;
+}
diff --git a/include/util.h b/include/util.h
index 4ed352f0d7..1b077d0f55 100644
--- a/include/util.h
+++ b/include/util.h
@@ -342,7 +342,7 @@ void wait_for_ready(volatile uint32_t *reg, uint32_t enable, uint32_t ready);
  * the normal ternary system order (skipping the values that were already used
  * up).
  *
- * This function is useful for converting BOARd ID, which is initially used a
+ * This function is useful for converting BOARD ID, which is initially used a
  * binary and later decided to switch to tri-state after some revisions have
  * already been built.
  *
@@ -365,6 +365,25 @@ void wait_for_ready(volatile uint32_t *reg, uint32_t enable, uint32_t ready);
  */
 int binary_first_base3_from_bits(int *bits, int nbits);
 
+/**
+ * Convert the binary bit array to integer value.
+ *
+ * @param bits    array of integers with values of 0 and 1
+ * @param nbits   number of bits to decode
+ * @return        integer decoded from bits
+ */
+int binary_from_bits(int *bits, int nbits);
+
+/**
+ * Convert the ternary bit array to integer value.
+ * This function is used to handle 'Z' state of gpio as value of '2'.
+ *
+ * @param bits    array of integers with values of 0, 1 or 2
+ * @param nbits   number of bits to decode
+ * @return        integer decoded from bits
+ */
+int ternary_from_bits(int *bits, int nbits);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/zephyr/dts/bindings/gpio/gpio-id.yaml b/zephyr/dts/bindings/gpio/gpio-id.yaml
new file mode 100644
index 0000000000..24322b3de8
--- /dev/null
+++ b/zephyr/dts/bindings/gpio/gpio-id.yaml
@@ -0,0 +1,27 @@
+description: Defines board version and sku id gpios
+
+compatible: cros-ec,gpio-id
+
+properties:
+  bits:
+    type: phandles
+    required: true
+    description: GPIO list to read, LSB to MSB
+
+  system:
+    type: string
+    description:
+      Numeral system used to decode values
+      - binary - expects array with values of 0 and 1.
+      - binary_first_base3 - non-standard ternary number system
+          where the first 2^n natural numbers are represented as
+          they would be in a binary system (without any Z digits)
+          and the following 3^n-2^n numbers use the remaining
+          ternary representations in the normal ternary system order
+      - ternary - expects array with values of 0, 1 and 2.
+          It treats 'Z' state as digit '2'.
+    enum:
+      - binary
+      - binary_first_base3
+      - ternary
+
diff --git a/zephyr/shim/src/CMakeLists.txt b/zephyr/shim/src/CMakeLists.txt
index 5fee14dfbd..e9f6f55eab 100644
--- a/zephyr/shim/src/CMakeLists.txt
+++ b/zephyr/shim/src/CMakeLists.txt
@@ -5,6 +5,7 @@
 zephyr_library_sources(console.c)
 zephyr_library_sources(crc.c)
 zephyr_library_sources(gpio.c)
+zephyr_library_sources(gpio_id.c)
 zephyr_library_sources(util.c)
 
 if (DEFINED CONFIG_ARCH_POSIX)
diff --git a/zephyr/shim/src/gpio_id.c b/zephyr/shim/src/gpio_id.c
new file mode 100644
index 0000000000..f07ea8bd22
--- /dev/null
+++ b/zephyr/shim/src/gpio_id.c
@@ -0,0 +1,75 @@
+/* Copyright 2021 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <devicetree.h>
+#include "gpio.h"
+#include "util.h"
+
+#define IS_BOARD_COMPATIBLE \
+	DT_NODE_HAS_COMPAT(DT_PATH(board), cros_ec_gpio_id)
+#define IS_SKU_COMPATIBLE \
+	DT_NODE_HAS_COMPAT(DT_PATH(sku), cros_ec_gpio_id)
+
+#define CONVERT_NUMERAL_SYSTEM_EVAL(system, bits, nbits) \
+	system##_from_bits(bits, nbits)
+#define CONVERT_NUMERAL_SYSTEM(system, bits, nbits) \
+	CONVERT_NUMERAL_SYSTEM_EVAL(system, bits, nbits)
+
+#define READ_PIN_FROM_PHANDLE(node_id, prop, idx) \
+	gpio_get_ternary(GPIO_SIGNAL(DT_PHANDLE_BY_IDX(node_id, prop, idx))),
+
+#if DT_NODE_EXISTS(DT_PATH(sku)) && IS_SKU_COMPATIBLE
+
+__override uint32_t board_get_sku_id(void)
+{
+	static uint32_t sku_id = (uint32_t)-1;
+
+	if (sku_id == (uint32_t)-1) {
+		int bits[] = {
+			DT_FOREACH_PROP_ELEM(DT_PATH(sku),
+					bits,
+					READ_PIN_FROM_PHANDLE)
+		};
+
+		if (sizeof(bits) == 0)
+			return (uint32_t)-1;
+
+		sku_id = CONVERT_NUMERAL_SYSTEM(
+				DT_ENUM_TOKEN(DT_PATH(sku), system),
+				bits,
+				ARRAY_SIZE(bits));
+	}
+
+	return sku_id;
+}
+
+#endif
+
+#if DT_NODE_EXISTS(DT_PATH(board)) && IS_BOARD_COMPATIBLE
+
+__override int board_get_version(void)
+{
+	static int board_version = -1;
+
+	if (board_version == -1) {
+		int bits[] = {
+			DT_FOREACH_PROP_ELEM(DT_PATH(board),
+					bits,
+					READ_PIN_FROM_PHANDLE)
+		};
+
+		if (sizeof(bits) == 0)
+			return -1;
+
+		board_version = CONVERT_NUMERAL_SYSTEM(
+					DT_ENUM_TOKEN(DT_PATH(board), system),
+					bits,
+					ARRAY_SIZE(bits));
+	}
+
+	return board_version;
+}
+
+#endif
diff --git a/zephyr/shim/src/util.c b/zephyr/shim/src/util.c
index 32f55e0581..af68838bec 100644
--- a/zephyr/shim/src/util.c
+++ b/zephyr/shim/src/util.c
@@ -329,3 +329,27 @@ int binary_first_base3_from_bits(int *bits, int nbits)
 	/* binary_below is normal binary system value if !has_z. */
 	return binary_below;
 }
+
+int binary_from_bits(int *bits, int nbits)
+{
+	int value = 0;
+	int i;
+
+	/* Loop through every binary digit, from MSB to LSB. */
+	for (i = nbits - 1; i >= 0; i--)
+		value = (value << 1) | bits[i];
+
+	return value;
+}
+
+int ternary_from_bits(int *bits, int nbits)
+{
+	int value = 0;
+	int i;
+
+	/* Loop through every ternary digit, from MSB to LSB. */
+	for (i = nbits - 1; i >= 0; i--)
+		value = (value * 3) + bits[i];
+
+	return value;
+}