PECI: Move non-chipset specific PECI code to common folder

The Platform Environment Control Interface (PECI) is a thermal management
standard with one-wire bus interface that provides a communication channel
between Intel processor and chipset components to external monitoring or
control devices.

As we can read the CPU temperature over PECI more accurately than the
thermistors, we can eliminate usage of thermistors for reading CPU
temperature.

BUG=b:128666114
BRANCH=none
TEST=Manually tested on Dragonegg, able read CPU temperature.

Change-Id: Ie0845ca776e6a7e14511dc9315d6d83cdd5f09a6
Signed-off-by: Vijay Hiremath <vijay.p.hiremath@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/1622740
Commit-Ready: Vijay P Hiremath <vijay.p.hiremath@intel.com>
Tested-by: Vijay P Hiremath <vijay.p.hiremath@intel.com>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Jett Rink <jettrink@chromium.org>

6 files changed, 233 insertions, 234 deletions

diff --git a/board/it83xx_evb/board.h b/board/it83xx_evb/board.h
index 379362d4c5..b3917a8c49 100644
--- a/board/it83xx_evb/board.h
+++ b/board/it83xx_evb/board.h
@@ -24,6 +24,7 @@
 #define CONFIG_LOW_POWER_IDLE
 #define CONFIG_LOW_POWER_S0
 #define CONFIG_PECI
+#define CONFIG_PECI_COMMON
 #define CONFIG_PECI_TJMAX 100
 #define CONFIG_POWER_BUTTON
 #define CONFIG_PWM
diff --git a/chip/it83xx/peci.c b/chip/it83xx/peci.c
index b8e0b7c451..07336eaaf6 100644
--- a/chip/it83xx/peci.c
+++ b/chip/it83xx/peci.c
@@ -5,46 +5,14 @@
 
 /* PECI interface for Chrome EC */
 
-#include "chipset.h"
 #include "clock.h"
-#include "common.h"
-#include "console.h"
-#include "gpio.h"
 #include "hooks.h"
 #include "peci.h"
 #include "registers.h"
-#include "temp_sensor.h"
 #include "util.h"
 #include "timer.h"
 #include "task.h"
 
-#define TEMP_AVG_LENGTH 4  /* Should be power of 2 */
-static int temp_vals[TEMP_AVG_LENGTH];
-static int temp_idx;
-
-#define PECI_TARGET_ADDRESS         0x30
-#define PECI_WRITE_DATA_FIFO_SIZE   15
-#define PECI_READ_DATA_FIFO_SIZE    16
-
-#define PECI_GET_TEMP_READ_LENGTH   2
-#define PECI_GET_TEMP_WRITE_LENGTH  0
-#define PECI_GET_TEMP_TIMEOUT_US    200
-
-/* PECI Command Code */
-enum peci_command_code {
-	PECI_CMD_PING             = 0x00,
-	PECI_CMD_GET_DIB          = 0xF7,
-	PECI_CMD_GET_TEMP         = 0x01,
-	PECI_CMD_RD_PKG_CFG       = 0xA1,
-	PECI_CMD_WR_PKG_CFG       = 0xA5,
-	PECI_CMD_RD_IAMSR         = 0xB1,
-	PECI_CMD_WR_IAMSR         = 0xB5,
-	PECI_CMD_RD_PCI_CFG       = 0x61,
-	PECI_CMD_WR_PCI_CFG       = 0x65,
-	PECI_CMD_RD_PCI_CFG_LOCAL = 0xE1,
-	PECI_CMD_WR_PCI_CFG_LOCAL = 0xE5,
-};
-
 enum peci_status {
 	PECI_STATUS_NO_ERR        = 0x00,
 	PECI_STATUS_HOBY          = 0x01,
@@ -103,23 +71,11 @@ static void peci_reset(void)
 /**
  * Start a PECI transaction
  *
- * @param  addr       client address
- * @param  w_len      write length (no include [Cmd Code] and [AW FCS])
- * @param  r_len      read length (no include [FCS])
- * @param  cmd_code   command code
- * @param  *w_buf How buffer pointer of write data
- * @param  *r_buf How buffer pointer of read data
- * @param  timeout_us transaction timeout unit:us
+ * @param  peci transaction data
  *
  * @return zero if successful, non-zero if error
  */
-static enum peci_status peci_transaction(uint8_t addr,
-				uint8_t w_len,
-				uint8_t r_len,
-				enum peci_command_code cmd_code,
-				uint8_t *w_buf,
-				uint8_t *r_buf,
-				int timeout_us)
+int peci_transaction(struct peci_data *peci)
 {
 	uint8_t status;
 	int index;
@@ -140,22 +96,22 @@ static enum peci_status peci_transaction(uint8_t addr,
 	IT83XX_PECI_HOCTLR |= 0x34;
 
 	/* This register is the target address field of the PECI protocol. */
-	IT83XX_PECI_HOTRADDR = addr;
+	IT83XX_PECI_HOTRADDR = peci->addr;
 
 	/* This register is the write length field of the PECI protocol. */
-	ASSERT(w_len <= PECI_WRITE_DATA_FIFO_SIZE);
+	ASSERT(peci->w_len <= PECI_WRITE_DATA_FIFO_SIZE);
 
-	if (cmd_code == PECI_CMD_PING) {
+	if (peci->cmd_code == PECI_CMD_PING) {
 		/* write length is 0 */
 		IT83XX_PECI_HOWRLR = 0x00;
 	} else {
-		if ((cmd_code == PECI_CMD_WR_PKG_CFG) ||
-			(cmd_code == PECI_CMD_WR_IAMSR) ||
-			(cmd_code == PECI_CMD_WR_PCI_CFG) ||
-			(cmd_code == PECI_CMD_WR_PCI_CFG_LOCAL)) {
+		if ((peci->cmd_code == PECI_CMD_WR_PKG_CFG) ||
+			(peci->cmd_code == PECI_CMD_WR_IAMSR) ||
+			(peci->cmd_code == PECI_CMD_WR_PCI_CFG) ||
+			(peci->cmd_code == PECI_CMD_WR_PCI_CFG_LOCAL)) {
 
 			/* write length include Cmd Code + AW FCS */
-			IT83XX_PECI_HOWRLR = w_len + 2;
+			IT83XX_PECI_HOWRLR = peci->w_len + 2;
 
 			/* bit1, The bit enables the AW_FCS hardwired mechanism
 			 * based on the PECI command. This bit is functional
@@ -167,22 +123,22 @@ static enum peci_status peci_transaction(uint8_t addr,
 			IT83XX_PECI_HOCTLR |= 0x02;
 		} else {
 			/* write length include Cmd Code */
-			IT83XX_PECI_HOWRLR = w_len + 1;
+			IT83XX_PECI_HOWRLR = peci->w_len + 1;
 
 			IT83XX_PECI_HOCTLR &= ~0x02;
 		}
 	}
 
 	/* This register is the read length field of the PECI protocol. */
-	ASSERT(r_len <= PECI_READ_DATA_FIFO_SIZE);
-	IT83XX_PECI_HORDLR = r_len;
+	ASSERT(peci->r_len <= PECI_READ_DATA_FIFO_SIZE);
+	IT83XX_PECI_HORDLR = peci->r_len;
 
 	/* This register is the command field of the PECI protocol. */
-	IT83XX_PECI_HOCMDR = cmd_code;
+	IT83XX_PECI_HOCMDR = peci->cmd_code;
 
 	/* The write data field of the PECI protocol. */
-	for (index = 0x00; index < w_len; index++)
-		IT83XX_PECI_HOWRDR = w_buf[index];
+	for (index = 0x00; index < peci->w_len; index++)
+		IT83XX_PECI_HOWRDR = peci->w_buf[index];
 
 	peci_current_task = task_get_current();
 	task_clear_pending_irq(IT83XX_IRQ_PECI);
@@ -192,15 +148,15 @@ static enum peci_status peci_transaction(uint8_t addr,
 	IT83XX_PECI_HOCTLR |= 0x01;
 
 	/* pre-set timeout */
-	index = timeout_us;
-	if (task_wait_event(timeout_us) != TASK_EVENT_TIMER)
+	index = peci->timeout_us;
+	if (task_wait_event(peci->timeout_us) != TASK_EVENT_TIMER)
 		index = 0;
 
 	task_disable_irq(IT83XX_IRQ_PECI);
 
 	peci_current_task = TASK_ID_INVALID;
 
-	if (index < timeout_us) {
+	if (index < peci->timeout_us) {
 
 		status = IT83XX_PECI_HOSTAR;
 
@@ -213,8 +169,8 @@ static enum peci_status peci_transaction(uint8_t addr,
 		} else if (IT83XX_PECI_HOSTAR & PECI_STATUS_FINISH) {
 
 			/* The read data field of the PECI protocol. */
-			for (index = 0x00; index < r_len; index++)
-				r_buf[index] = IT83XX_PECI_HORDDR;
+			for (index = 0x00; index < peci->r_len; index++)
+				peci->r_buf[index] = IT83XX_PECI_HORDDR;
 
 			/* W/C */
 			IT83XX_PECI_HOSTAR = PECI_STATUS_FINISH;
@@ -237,72 +193,6 @@ static enum peci_status peci_transaction(uint8_t addr,
 	return status;
 }
 
-int peci_get_cpu_temp(void)
-{
-	uint8_t r_buf[PECI_GET_TEMP_READ_LENGTH] = {0};
-	int cpu_temp = -1;
-
-	if (peci_transaction(PECI_TARGET_ADDRESS,
-				PECI_GET_TEMP_WRITE_LENGTH,
-				PECI_GET_TEMP_READ_LENGTH,
-				PECI_CMD_GET_TEMP,
-				NULL,
-				r_buf,
-				PECI_GET_TEMP_TIMEOUT_US) ==
-				PECI_STATUS_NO_ERR) {
-
-		/* Get relative raw data of temperature. */
-		cpu_temp = (r_buf[1] << 8) | r_buf[0];
-
-#ifdef CONFIG_PECI_TJMAX
-		/* Convert relative raw data to degrees C. */
-		cpu_temp = ((cpu_temp ^ 0xFFFF) + 1) >> 6;
-		/* temperature in K */
-		cpu_temp = (CONFIG_PECI_TJMAX - cpu_temp) + 273;
-#endif
-	}
-
-	return cpu_temp;
-}
-
-int peci_temp_sensor_get_val(int idx, int *temp_ptr)
-{
-	int sum = 0;
-	int success_cnt = 0;
-	int i;
-
-	if (!chipset_in_state(CHIPSET_STATE_ON))
-		return EC_ERROR_NOT_POWERED;
-
-	for (i = 0; i < TEMP_AVG_LENGTH; ++i) {
-		if (temp_vals[i] >= 0) {
-			success_cnt++;
-			sum += temp_vals[i];
-		}
-	}
-
-	/*
-	 * Require at least two valid samples. When the AP transitions into S0,
-	 * it is possible, depending on the timing of the PECI sample, to read
-	 * an invalid temperature. This is very rare, but when it does happen
-	 * the temperature returned is CONFIG_PECI_TJMAX. Requiring two valid
-	 * samples here assures us that one bad maximum temperature reading
-	 * when entering S0 won't cause us to trigger an over temperature.
-	 */
-	if (success_cnt < 2)
-		return EC_ERROR_UNKNOWN;
-
-	*temp_ptr = sum / success_cnt;
-	return EC_SUCCESS;
-}
-
-static void peci_temp_sensor_poll(void)
-{
-	temp_vals[temp_idx] = peci_get_cpu_temp();
-	temp_idx = (temp_idx + 1) & (TEMP_AVG_LENGTH - 1);
-}
-DECLARE_HOOK(HOOK_TICK, peci_temp_sensor_poll, HOOK_PRIO_TEMP_SENSOR);
-
 void peci_interrupt(void)
 {
 	task_clear_pending_irq(IT83XX_IRQ_PECI);
@@ -314,8 +204,6 @@ void peci_interrupt(void)
 
 static void peci_init(void)
 {
-	int i;
-
 	clock_enable_peripheral(CGC_OFFSET_PECI, 0, 0);
 	peci_init_vtt_freq();
 
@@ -324,97 +212,5 @@ static void peci_init(void)
 
 	/* bit4, PECI enable */
 	IT83XX_GPIO_GRC2 |= 0x10;
-
-	/* Initialize temperature reading buffer to a sane value. */
-	for (i = 0; i < TEMP_AVG_LENGTH; ++i)
-		temp_vals[i] = 300; /* 27 C */
 }
 DECLARE_HOOK(HOOK_INIT, peci_init, HOOK_PRIO_DEFAULT);
-
-/*****************************************************************************/
-/* Console commands */
-
-static int peci_cmd(int argc, char **argv)
-{
-	uint8_t r_buf[PECI_READ_DATA_FIFO_SIZE] = {0};
-	uint8_t w_buf[PECI_WRITE_DATA_FIFO_SIZE] = {0};
-
-	int addr, wlen, rlen, cmd, time_us, param;
-	char *e;
-
-	if ((argc < 6) || (argc > 8))
-		return EC_ERROR_PARAM_COUNT;
-
-	addr = strtoi(argv[1], &e, 0);
-	if (*e)
-		return EC_ERROR_PARAM1;
-
-	wlen = strtoi(argv[2], &e, 0);
-	if (*e)
-		return EC_ERROR_PARAM2;
-
-	rlen = strtoi(argv[3], &e, 0);
-	if (*e)
-		return EC_ERROR_PARAM3;
-
-	cmd = strtoi(argv[4], &e, 0);
-	if (*e)
-		return EC_ERROR_PARAM4;
-
-	time_us = strtoi(argv[5], &e, 0);
-	if (*e)
-		return EC_ERROR_PARAM5;
-
-	if (argc > 6) {
-		param = strtoi(argv[6], &e, 0);
-		if (*e)
-			return EC_ERROR_PARAM6;
-
-		/* MSB of parameter */
-		w_buf[3] = (uint8_t)(param >> 24);
-		/* LSB of parameter */
-		w_buf[2] = (uint8_t)(param >> 16);
-		/* Index */
-		w_buf[1] = (uint8_t)(param >> 8);
-		/* Host ID[7:1] & Retry[0] */
-		w_buf[0] = (uint8_t)(param >> 0);
-
-		if (argc > 7) {
-			param = strtoi(argv[7], &e, 0);
-			if (*e)
-				return EC_ERROR_PARAM7;
-
-			/* Data (1, 2 or 4 bytes) */
-			w_buf[7] = (uint8_t)(param >> 24);
-			w_buf[6] = (uint8_t)(param >> 16);
-			w_buf[5] = (uint8_t)(param >> 8);
-			w_buf[4] = (uint8_t)(param >> 0);
-		}
-	} else {
-		wlen = 0x00;
-	}
-
-	if (peci_transaction(addr, wlen, rlen, cmd, w_buf, r_buf, time_us)) {
-		ccprintf("PECI transaction error\n");
-		return EC_ERROR_UNKNOWN;
-	}
-	ccprintf("PECI read data: %.*h\n", rlen, r_buf);
-	return EC_SUCCESS;
-}
-DECLARE_CONSOLE_COMMAND(peci, peci_cmd,
-			"addr wlen rlen cmd timeout(us)",
-			"PECI command");
-
-static int command_peci_temp(int argc, char **argv)
-{
-	int t = peci_get_cpu_temp();
-	if (t == -1) {
-		ccprintf("PECI get cpu temp error\n");
-		return EC_ERROR_UNKNOWN;
-	}
-	ccprintf("CPU temp = %d K = %d C\n", t, K_TO_C(t));
-	return EC_SUCCESS;
-}
-DECLARE_CONSOLE_COMMAND(pecitemp, command_peci_temp,
-			NULL,
-			"Print CPU temperature");
diff --git a/common/build.mk b/common/build.mk
index 78c97149c5..88b384bc51 100644
--- a/common/build.mk
+++ b/common/build.mk
@@ -92,6 +92,7 @@ common-$(CONFIG_HOSTCMD_X86)+=acpi.o port80.o ec_features.o
 common-$(CONFIG_MAG_CALIBRATE)+= mag_cal.o math_util.o vec3.o mat33.o mat44.o
 common-$(CONFIG_MKBP_EVENT)+=mkbp_event.o
 common-$(CONFIG_ONEWIRE)+=onewire.o
+common-$(CONFIG_PECI_COMMON)+=peci.o
 common-$(CONFIG_PHYSICAL_PRESENCE)+=physical_presence.o
 common-$(CONFIG_PINWEAVER)+=pinweaver.o
 common-$(CONFIG_POWER_BUTTON)+=power_button.o
diff --git a/common/peci.c b/common/peci.c
new file mode 100644
index 0000000000..b4422de05e
--- /dev/null
+++ b/common/peci.c
@@ -0,0 +1,165 @@
+/* Copyright 2019 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.
+ */
+
+/* PECI interface for Chrome EC */
+
+#include "chipset.h"
+#include "console.h"
+#include "peci.h"
+#include "util.h"
+
+static int peci_get_cpu_temp(int *cpu_temp)
+{
+	int rv;
+	uint8_t r_buf[PECI_GET_TEMP_READ_LENGTH] = {0};
+	struct peci_data peci = {
+		.cmd_code = PECI_CMD_GET_TEMP,
+		.addr = PECI_TARGET_ADDRESS,
+		.w_len = PECI_GET_TEMP_WRITE_LENGTH,
+		.r_len = PECI_GET_TEMP_READ_LENGTH,
+		.w_buf = NULL,
+		.r_buf = r_buf,
+		.timeout_us = PECI_GET_TEMP_TIMEOUT_US,
+	};
+
+	rv = peci_transaction(&peci);
+	if (rv)
+		return rv;
+
+	/* Get relative raw data of temperature. */
+	*cpu_temp = (r_buf[1] << 8) | r_buf[0];
+
+	/* Convert relative raw data to degrees C. */
+	*cpu_temp = ((*cpu_temp ^ 0xFFFF) + 1) >> 6;
+
+	/*
+	 * When the AP transitions into S0, it is possible, depending on the
+	 * timing of the PECI sample, to read an invalid temperature. This is
+	 * very rare, but when it does happen the temperature returned is
+	 * greater than or equal to CONFIG_PECI_TJMAX.
+	 */
+	if (*cpu_temp >= CONFIG_PECI_TJMAX)
+		return EC_ERROR_UNKNOWN;
+
+	/* temperature in K */
+	*cpu_temp = CONFIG_PECI_TJMAX - *cpu_temp + 273;
+
+	return EC_SUCCESS;
+}
+
+int peci_temp_sensor_get_val(int idx, int *temp_ptr)
+{
+	int i, rv;
+
+	if (!chipset_in_state(CHIPSET_STATE_ON | CHIPSET_STATE_STANDBY))
+		return EC_ERROR_NOT_POWERED;
+
+	/*
+	 * Retry reading PECI CPU temperature if the first sample is
+	 * invalid or failed to obtain.
+	 */
+	for (i = 0; i < 2; i++) {
+		rv = peci_get_cpu_temp(temp_ptr);
+		if (!rv)
+			break;
+	}
+
+	return rv;
+}
+
+/*****************************************************************************/
+/* Console commands */
+#ifdef CONFIG_CMD_PECI
+static int peci_cmd(int argc, char **argv)
+{
+	uint8_t r_buf[PECI_READ_DATA_FIFO_SIZE] = {0};
+	uint8_t w_buf[PECI_WRITE_DATA_FIFO_SIZE] = {0};
+	struct peci_data peci = {
+		.w_buf = w_buf,
+		.r_buf = r_buf,
+	};
+
+	int param;
+	char *e;
+
+	if ((argc < 6) || (argc > 8))
+		return EC_ERROR_PARAM_COUNT;
+
+	peci.addr = strtoi(argv[1], &e, 0);
+	if (*e)
+		return EC_ERROR_PARAM1;
+
+	peci.w_len = strtoi(argv[2], &e, 0);
+	if (*e)
+		return EC_ERROR_PARAM2;
+
+	peci.r_len = strtoi(argv[3], &e, 0);
+	if (*e)
+		return EC_ERROR_PARAM3;
+
+	peci.cmd_code = strtoi(argv[4], &e, 0);
+	if (*e)
+		return EC_ERROR_PARAM4;
+
+	peci.timeout_us = strtoi(argv[5], &e, 0);
+	if (*e)
+		return EC_ERROR_PARAM5;
+
+	if (argc > 6) {
+		param = strtoi(argv[6], &e, 0);
+		if (*e)
+			return EC_ERROR_PARAM6;
+
+		/* MSB of parameter */
+		w_buf[3] = (uint8_t)(param >> 24);
+		/* LSB of parameter */
+		w_buf[2] = (uint8_t)(param >> 16);
+		/* Index */
+		w_buf[1] = (uint8_t)(param >> 8);
+		/* Host ID[7:1] & Retry[0] */
+		w_buf[0] = (uint8_t)(param >> 0);
+
+		if (argc > 7) {
+			param = strtoi(argv[7], &e, 0);
+			if (*e)
+				return EC_ERROR_PARAM7;
+
+			/* Data (1, 2 or 4 bytes) */
+			w_buf[7] = (uint8_t)(param >> 24);
+			w_buf[6] = (uint8_t)(param >> 16);
+			w_buf[5] = (uint8_t)(param >> 8);
+			w_buf[4] = (uint8_t)(param >> 0);
+		}
+	} else {
+		peci.w_len = 0x00;
+	}
+
+	if (peci_transaction(&peci)) {
+		ccprintf("PECI transaction error\n");
+		return EC_ERROR_UNKNOWN;
+	}
+	ccprintf("PECI read data: %.*h\n", peci.r_len, r_buf);
+	return EC_SUCCESS;
+}
+DECLARE_CONSOLE_COMMAND(peci, peci_cmd,
+			"addr wlen rlen cmd timeout(us)",
+			"PECI command");
+
+static int command_peci_temp(int argc, char **argv)
+{
+	int t;
+
+	if (peci_get_cpu_temp(&t) != EC_SUCCESS) {
+		ccprintf("PECI get cpu temp error\n");
+		return EC_ERROR_UNKNOWN;
+	}
+
+	ccprintf("CPU temp: %d K, %d C\n", t, K_TO_C(t));
+	return EC_SUCCESS;
+}
+DECLARE_CONSOLE_COMMAND(pecitemp, command_peci_temp,
+			NULL,
+			"Print CPU temperature");
+#endif /* CONFIG_CMD_PECI */
diff --git a/include/config.h b/include/config.h
index ca441d17cf..9745444353 100644
--- a/include/config.h
+++ b/include/config.h
@@ -1155,6 +1155,7 @@
 #undef  CONFIG_CMD_PD_CONTROL
 #undef  CONFIG_CMD_PD_DEV_DUMP_INFO
 #undef  CONFIG_CMD_PD_FLASH
+#define CONFIG_CMD_PECI
 #undef  CONFIG_CMD_PLL
 #undef  CONFIG_CMD_PMU
 #define CONFIG_CMD_POWERINDEBUG
@@ -2654,6 +2655,9 @@
 /* Support PECI interface to x86 processor */
 #undef CONFIG_PECI
 
+/* Common code for PECI interface to x86 processor */
+#undef CONFIG_PECI_COMMON
+
 /*
  * Maximum operating temperature in degrees Celcius used on some x86
  * processors. CPU chip temperature is reported relative to this value and
diff --git a/include/peci.h b/include/peci.h
index c3bb4d62b2..c553eac40d 100644
--- a/include/peci.h
+++ b/include/peci.h
@@ -10,15 +10,38 @@
 
 #include "common.h"
 
-/**
- * Get the current CPU temperature.
- *
- * Note that the PECI interface is currently a little flaky; if you get an
- * error, retry a bit later.
- *
- * @return the CPU temperature in degrees K, or -1 if error.
- */
-int peci_get_cpu_temp(void);
+#define PECI_TARGET_ADDRESS         0x30
+#define PECI_WRITE_DATA_FIFO_SIZE   15
+#define PECI_READ_DATA_FIFO_SIZE    16
+
+#define PECI_GET_TEMP_READ_LENGTH   2
+#define PECI_GET_TEMP_WRITE_LENGTH  0
+#define PECI_GET_TEMP_TIMEOUT_US    200
+
+/* PECI Command Code */
+enum peci_command_code {
+	PECI_CMD_PING             = 0x00,
+	PECI_CMD_GET_DIB          = 0xF7,
+	PECI_CMD_GET_TEMP         = 0x01,
+	PECI_CMD_RD_PKG_CFG       = 0xA1,
+	PECI_CMD_WR_PKG_CFG       = 0xA5,
+	PECI_CMD_RD_IAMSR         = 0xB1,
+	PECI_CMD_WR_IAMSR         = 0xB5,
+	PECI_CMD_RD_PCI_CFG       = 0x61,
+	PECI_CMD_WR_PCI_CFG       = 0x65,
+	PECI_CMD_RD_PCI_CFG_LOCAL = 0xE1,
+	PECI_CMD_WR_PCI_CFG_LOCAL = 0xE5,
+};
+
+struct peci_data {
+	enum peci_command_code cmd_code; /* command code */
+	uint8_t addr;	/* client address */
+	uint8_t w_len;	/* write length */
+	uint8_t r_len;	/* read length */
+	uint8_t *w_buf;	/* buffer pointer of write data */
+	uint8_t *r_buf;	/* buffer pointer of read data */
+	int timeout_us;	/* transaction timeout unit:us */
+};
 
 /**
  * Get the last polled value of the PECI temp sensor.
@@ -30,4 +53,13 @@ int peci_get_cpu_temp(void);
  */
 int peci_temp_sensor_get_val(int idx, int *temp_ptr);
 
+/**
+ * Start a PECI transaction
+ *
+ * @param  peci transaction data
+ *
+ * @return zero if successful, non-zero if error
+ */
+int peci_transaction(struct peci_data *peci);
+
 #endif  /* __CROS_EC_PECI_H */