it83xx: i2c: add support for command queue mode

The mode eliminates byte interval from i2c single transaction.

BRANCH=none
BUG=b:208383454, b:197599515
TEST=buildall passes, cherry boots. EC console haven't prompt
     i2c error.

Change-Id: I860ff0d02f82cf395acccb4b149d11f8cc51520c
Signed-off-by: Dino Li <Dino.Li@ite.com.tw>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3314486
Reviewed-by: Ting Shen <phoenixshen@chromium.org>
Tested-by: Parker Lin <parkerlin@google.com>

5 files changed, 276 insertions, 13 deletions

diff --git a/chip/it83xx/clock.c b/chip/it83xx/clock.c
index 72cfa3e2b4..c1e9df4265 100644
--- a/chip/it83xx/clock.c
+++ b/chip/it83xx/clock.c
@@ -637,6 +637,12 @@ void __ram_code __idle(void)
 	while (1) {
 		/* Disable interrupts */
 		interrupt_disable();
+#ifdef CONFIG_IT83XX_I2C_CMD_QUEUE
+		if (i2c_idle_not_allowed()) {
+			interrupt_enable();
+			continue;
+		}
+#endif
 		/* Check if the EC can enter deep doze mode or not */
 		if (DEEP_SLEEP_ALLOWED && clock_allow_low_power_idle()) {
 			/* reset low power mode hw timer */
diff --git a/chip/it83xx/i2c.c b/chip/it83xx/i2c.c
index 5aa8f8a460..836ee7a82f 100644
--- a/chip/it83xx/i2c.c
+++ b/chip/it83xx/i2c.c
@@ -21,6 +21,48 @@
 /* Default maximum time we allow for an I2C transfer */
 #define I2C_TIMEOUT_DEFAULT_US (100 * MSEC)
 
+#ifdef CONFIG_IT83XX_I2C_CMD_QUEUE
+
+#ifdef CHIP_CORE_NDS32
+#error "Remapping DLM base is required on it8320 series"
+#endif
+
+/* It is allowed to configure the size up to 2K bytes. */
+#define I2C_CQ_MODE_MAX_PAYLOAD_SIZE     128
+/* reserved 5 bytes for ID and CMD_x */
+#define I2C_CQ_MODE_TX_MAX_PAYLOAD_SIZE  (I2C_CQ_MODE_MAX_PAYLOAD_SIZE - 5)
+uint8_t i2c_cq_mode_tx_dlm[I2C_ENHANCED_PORT_COUNT]
+			[I2C_CQ_MODE_MAX_PAYLOAD_SIZE] __aligned(4);
+uint8_t i2c_cq_mode_rx_dlm[I2C_ENHANCED_PORT_COUNT]
+			[I2C_CQ_MODE_MAX_PAYLOAD_SIZE] __aligned(4);
+
+/* Repeat Start */
+#define I2C_CQ_CMD_L_RS BIT(7)
+/*
+ * R/W (Read/ Write) decides the I2C read or write direction
+ * 1: read, 0: write
+ */
+#define I2C_CQ_CMD_L_RW BIT(6)
+/* P (STOP) is the I2C STOP condition */
+#define I2C_CQ_CMD_L_P  BIT(5)
+/* E (End) is this device end flag */
+#define I2C_CQ_CMD_L_E  BIT(4)
+/* LA (Last ACK) is Last ACK in master receiver */
+#define I2C_CQ_CMD_L_LA BIT(3)
+/* bit[2:0] are number of transfer out or receive data which depends on R/W. */
+#define I2C_CQ_CMD_L_NUM_BIT_2_0 GENMASK(2, 0)
+
+struct i2c_cq_packet {
+	uint8_t id;
+	uint8_t cmd_l;
+	uint8_t cmd_h;
+	uint8_t wdata[0];
+};
+
+/* Preventing CPU going into idle mode during command queue I2C transaction. */
+static uint32_t i2c_idle_disabled;
+#endif /* CONFIG_IT83XX_I2C_CMD_QUEUE */
+
 enum enhanced_i2c_transfer_direct {
 	TX_DIRECT,
 	RX_DIRECT,
@@ -98,6 +140,8 @@ enum enhanced_i2c_ctl {
 	E_START_ID = (E_INT_EN | E_MODE_SEL | E_ACK | E_START | E_HW_RST),
 	/* Generate stop condition */
 	E_FINISH = (E_INT_EN | E_MODE_SEL | E_ACK | E_STOP | E_HW_RST),
+	/* start with command queue mode */
+	E_START_CQ = (E_INT_EN | E_MODE_SEL | E_ACK | E_START),
 };
 
 enum i2c_reset_cause {
@@ -587,11 +631,199 @@ static int enhanced_i2c_error(int p)
 	return pd->err;
 }
 
-static int i2c_transaction(int p)
+#ifdef CONFIG_IT83XX_I2C_CMD_QUEUE
+static void enhanced_i2c_set_cmd_addr_regs(int p)
+{
+	int dlm_index = p - I2C_STANDARD_PORT_COUNT;
+	int p_ch = i2c_ch_reg_shift(p);
+	uint32_t dlm_base;
+
+	/* set "Address Register" to store the I2C data */
+	dlm_base = (uint32_t)&i2c_cq_mode_rx_dlm[dlm_index] & 0xffffff;
+	IT83XX_I2C_RAMH2A(p_ch) = (dlm_base >> 16) & 0xff;
+	IT83XX_I2C_RAMHA(p_ch) = (dlm_base >> 8) & 0xff;
+	IT83XX_I2C_RAMLA(p_ch) = dlm_base & 0xff;
+
+	/* Set "Command Address Register" to get commands */
+	dlm_base = (uint32_t)&i2c_cq_mode_tx_dlm[dlm_index] & 0xffffff;
+	IT83XX_I2C_CMD_ADDH2(p_ch) = (dlm_base >> 16) & 0xff;
+	IT83XX_I2C_CMD_ADDH(p_ch) = (dlm_base >> 8) & 0xff;
+	IT83XX_I2C_CMD_ADDL(p_ch) = dlm_base & 0xff;
+}
+
+static void i2c_enable_idle(int port)
+{
+	i2c_idle_disabled &= ~BIT(port);
+}
+
+static void i2c_disable_idle(int port)
+{
+	i2c_idle_disabled |= BIT(port);
+}
+
+uint32_t i2c_idle_not_allowed(void)
+{
+	return i2c_idle_disabled;
+}
+
+static int command_i2c_idle_mask(int argc, char **argv)
+{
+	ccprintf("i2c idle mask: %08x\n", i2c_idle_disabled);
+
+	return EC_SUCCESS;
+}
+DECLARE_SAFE_CONSOLE_COMMAND(i2cidlemask, command_i2c_idle_mask,
+			     NULL, "Display i2c idle mask");
+
+static void enhanced_i2c_cq_write(int p)
+{
+	struct i2c_port_data *pd = pdata + p;
+	struct i2c_cq_packet *i2c_cq_pckt;
+	uint8_t num_bit_2_0 = (pd->out_size - 1) & I2C_CQ_CMD_L_NUM_BIT_2_0;
+	uint8_t num_bit_10_3 = ((pd->out_size - 1) >> 3) & 0xff;
+	int dlm_index = p - I2C_STANDARD_PORT_COUNT;
+
+	i2c_cq_pckt = (struct i2c_cq_packet *)&i2c_cq_mode_tx_dlm[dlm_index];
+	/* Set commands in RAM. */
+	i2c_cq_pckt->id = pd->addr_8bit;
+	i2c_cq_pckt->cmd_l = I2C_CQ_CMD_L_P | I2C_CQ_CMD_L_E | num_bit_2_0;
+	i2c_cq_pckt->cmd_h = num_bit_10_3;
+	for (int i = 0; i < pd->out_size; i++)
+		i2c_cq_pckt->wdata[i] = pd->out[i];
+}
+
+static void enhanced_i2c_cq_read(int p)
+{
+	struct i2c_port_data *pd = pdata + p;
+	struct i2c_cq_packet *i2c_cq_pckt;
+	uint8_t num_bit_2_0 = (pd->in_size - 1) & I2C_CQ_CMD_L_NUM_BIT_2_0;
+	uint8_t num_bit_10_3 = ((pd->in_size - 1) >> 3) & 0xff;
+	int dlm_index = p - I2C_STANDARD_PORT_COUNT;
+
+	i2c_cq_pckt = (struct i2c_cq_packet *)&i2c_cq_mode_tx_dlm[dlm_index];
+	/* Set commands in RAM. */
+	i2c_cq_pckt->id = pd->addr_8bit;
+	i2c_cq_pckt->cmd_l = I2C_CQ_CMD_L_RW | I2C_CQ_CMD_L_P |
+				I2C_CQ_CMD_L_E | num_bit_2_0;
+	i2c_cq_pckt->cmd_h = num_bit_10_3;
+}
+
+static void enhanced_i2c_cq_write_to_read(int p)
+{
+	struct i2c_port_data *pd = pdata + p;
+	struct i2c_cq_packet *i2c_cq_pckt;
+	uint8_t num_bit_2_0 = (pd->out_size - 1) & I2C_CQ_CMD_L_NUM_BIT_2_0;
+	uint8_t num_bit_10_3 = ((pd->out_size - 1) >> 3) & 0xff;
+	int dlm_index = p - I2C_STANDARD_PORT_COUNT;
+	int i;
+
+	i2c_cq_pckt = (struct i2c_cq_packet *)&i2c_cq_mode_tx_dlm[dlm_index];
+	/* Set commands in RAM. (command byte for write) */
+	i2c_cq_pckt->id = pd->addr_8bit;
+	i2c_cq_pckt->cmd_l = num_bit_2_0;
+	i2c_cq_pckt->cmd_h = num_bit_10_3;
+	for (i = 0; i < pd->out_size; i++)
+		i2c_cq_pckt->wdata[i] = pd->out[i];
+	/* Set commands in RAM. (command byte for read) */
+	num_bit_2_0 = (pd->in_size - 1) & I2C_CQ_CMD_L_NUM_BIT_2_0;
+	num_bit_10_3 = ((pd->in_size - 1) >> 3) & 0xff;
+	i2c_cq_pckt->wdata[i++] = I2C_CQ_CMD_L_RS | I2C_CQ_CMD_L_RW |
+				I2C_CQ_CMD_L_P | I2C_CQ_CMD_L_E | num_bit_2_0;
+	i2c_cq_pckt->wdata[i] = num_bit_10_3;
+}
+
+static int enhanced_i2c_cmd_queue_trans(int p)
+{
+	struct i2c_port_data *pd = pdata + p;
+	int p_ch = i2c_ch_reg_shift(p);
+	int dlm_index = p - I2C_STANDARD_PORT_COUNT;
+
+	/* ISR of command queue mode */
+	if (in_interrupt_context()) {
+		/* device 1 finish IRQ */
+		if (IT83XX_I2C_FST(p_ch) & IT83XX_I2C_FST_DEV1_IRQ) {
+			/* get data if this is a read transaction */
+			for (int i = 0; i < pd->in_size; i++)
+				pd->in[i] = i2c_cq_mode_rx_dlm[dlm_index][i];
+		} else {
+			/* device 1 error have occurred. eg. nack, timeout... */
+			if (IT83XX_I2C_NST(p_ch) & IT83XX_I2C_NST_ID_NACK)
+				pd->err = E_HOSTA_ACK;
+			else
+				pd->err = IT83XX_I2C_STR(p_ch) &
+						E_HOSTA_ANY_ERROR;
+		}
+		/* reset bus */
+		IT83XX_I2C_CTR(p_ch) = E_STS_AND_HW_RST;
+		IT83XX_I2C_CTR1(p_ch) = 0;
+
+		return 0;
+	}
+
+	if ((pd->out_size > I2C_CQ_MODE_TX_MAX_PAYLOAD_SIZE) ||
+		(pd->in_size > I2C_CQ_MODE_MAX_PAYLOAD_SIZE)) {
+		pd->err = EC_ERROR_INVAL;
+		return 0;
+	}
+
+	/* State reset and hardware reset */
+	IT83XX_I2C_CTR(p_ch) = E_STS_AND_HW_RST;
+	/* Set "PSR" registers to decide the i2c speed. */
+	IT83XX_I2C_PSR(p_ch) = pdata[p].freq;
+	IT83XX_I2C_HSPR(p_ch) = pdata[p].freq;
+	/* Set time out register. port D, E, or F clock/data low timeout. */
+	IT83XX_I2C_TOR(p_ch) = I2C_CLK_LOW_TIMEOUT;
+
+	/* i2c write to read */
+	if (pd->out_size && pd->in_size)
+		enhanced_i2c_cq_write_to_read(p);
+	/* i2c write */
+	else if (pd->out_size)
+		enhanced_i2c_cq_write(p);
+	/* i2c read */
+	else if (pd->in_size)
+		enhanced_i2c_cq_read(p);
+
+	/* enable i2c module with command queue mode */
+	IT83XX_I2C_CTR1(p_ch) = IT83XX_I2C_MDL_EN | IT83XX_I2C_COMQ_EN;
+	/* one shot on device 1 */
+	IT83XX_I2C_MODE_SEL(p_ch) = 0;
+	IT83XX_I2C_CTR2(p_ch) = 1;
+	/* start */
+	i2c_disable_idle(p);
+	IT83XX_I2C_CTR(p_ch) = E_START_CQ;
+
+	return 0;
+}
+#endif /* CONFIG_IT83XX_I2C_CMD_QUEUE */
+
+static int enhanced_i2c_pio_trans(int p)
 {
 	struct i2c_port_data *pd = pdata + p;
 	int p_ch;
 
+	/* no error */
+	if (!(enhanced_i2c_error(p))) {
+		/* i2c write */
+		if (pd->out_size)
+			return enhanced_i2c_tran_write(p);
+		/* i2c read */
+		else if (pd->in_size)
+			return enhanced_i2c_tran_read(p);
+	}
+
+	p_ch = i2c_ch_reg_shift(p);
+	IT83XX_I2C_CTR(p_ch) = E_STS_AND_HW_RST;
+	IT83XX_I2C_CTR1(p_ch) = 0;
+
+	return 0;
+}
+
+static int i2c_transaction(int p)
+{
+	struct i2c_port_data *pd = pdata + p;
+	int ret;
+
 	if (p < I2C_STANDARD_PORT_COUNT) {
 		/* any error */
 		if (IT83XX_SMB_HOSTA(p) & HOSTA_ANY_ERROR) {
@@ -612,18 +844,13 @@ static int i2c_transaction(int p)
 		/* disable the SMBus host interface */
 		IT83XX_SMB_HOCTL2(p) = 0x00;
 	} else {
-		/* no error */
-		if (!(enhanced_i2c_error(p))) {
-			/* i2c write */
-			if (pd->out_size)
-				return enhanced_i2c_tran_write(p);
-			/* i2c read */
-			else if (pd->in_size)
-				return enhanced_i2c_tran_read(p);
-		}
-		p_ch = i2c_ch_reg_shift(p);
-		IT83XX_I2C_CTR(p_ch) = E_STS_AND_HW_RST;
-		IT83XX_I2C_CTR1(p_ch) = 0;
+#ifdef CONFIG_IT83XX_I2C_CMD_QUEUE
+		if (pd->flags == I2C_XFER_SINGLE)
+			ret = enhanced_i2c_cmd_queue_trans(p);
+		else
+#endif
+			ret = enhanced_i2c_pio_trans(p);
+		return ret;
 	}
 	/* done doing work */
 	return 0;
@@ -713,6 +940,10 @@ int chip_i2c_xfer(int port, uint16_t addr_flags,
 	if (pd->err)
 		pd->i2ccs = I2C_CH_NORMAL;
 
+#ifdef CONFIG_IT83XX_I2C_CMD_QUEUE
+	i2c_enable_idle(port);
+#endif
+
 	return pd->err;
 }
 
@@ -933,6 +1164,10 @@ void i2c_init(void)
 			IT83XX_I2C_CTR(p_ch) = E_STS_AND_HW_RST;
 			/* bit1, Module enable */
 			IT83XX_I2C_CTR1(p_ch) = 0;
+#ifdef CONFIG_IT83XX_I2C_CMD_QUEUE
+			/* set command address registers */
+			enhanced_i2c_set_cmd_addr_regs(p);
+#endif
 		}
 		pdata[i].task_waiting = TASK_ID_INVALID;
 	}
diff --git a/chip/it83xx/intc.h b/chip/it83xx/intc.h
index 62ceb34576..50d31999f9 100644
--- a/chip/it83xx/intc.h
+++ b/chip/it83xx/intc.h
@@ -50,5 +50,8 @@ void spi_peripheral_int_handler(void);
 void lpc_kbc_ibf_interrupt(void);
 void lpc_kbc_obe_interrupt(void);
 #endif
+#ifdef CONFIG_IT83XX_I2C_CMD_QUEUE
+uint32_t i2c_idle_not_allowed(void);
+#endif
 
 #endif /* __CROS_EC_INTC_H */
diff --git a/chip/it83xx/registers.h b/chip/it83xx/registers.h
index 39aba42315..b752f012d8 100644
--- a/chip/it83xx/registers.h
+++ b/chip/it83xx/registers.h
@@ -1552,7 +1552,20 @@ enum bram_ec_logs_status {
 #define IT83XX_I2C_IDR(ch)           REG8(IT83XX_I2C_BASE+0x06+(ch << 7))
 #define IT83XX_I2C_TOS(ch)           REG8(IT83XX_I2C_BASE+0x07+(ch << 7))
 #define IT83XX_I2C_CLK_STR           (1 << 7)
+#define IT83XX_I2C_STR2(ch)          REG8(IT83XX_I2C_BASE+0x12+(ch << 7))
+#define IT83XX_I2C_NST(ch)           REG8(IT83XX_I2C_BASE+0x13+(ch << 7))
+#define IT83XX_I2C_NST_CNS           BIT(7)
+#define IT83XX_I2C_NST_ID_NACK       BIT(3)
+#define IT83XX_I2C_TO_ARB_ST(ch)     REG8(IT83XX_I2C_BASE+0x18+(ch << 7))
+#define IT83XX_I2C_ERR_ST(ch)        REG8(IT83XX_I2C_BASE+0x19+(ch << 7))
+#define IT83XX_I2C_ERR_ST_DEV1_EIRQ  BIT(0)
+#define IT83XX_I2C_FST(ch)           REG8(IT83XX_I2C_BASE+0x1b+(ch << 7))
+#define IT83XX_I2C_FST_DEV1_IRQ      BIT(4)
+#define IT83XX_I2C_EM(ch)            REG8(IT83XX_I2C_BASE+0x1c+(ch << 7))
+#define IT83XX_I2C_EM_DEV1_IRQ       BIT(4)
+#define IT83XX_I2C_MODE_SEL(ch)      REG8(IT83XX_I2C_BASE+0x1d+(ch << 7))
 #define IT83XX_I2C_IDR2(ch)          REG8(IT83XX_I2C_BASE+0x1F+(ch << 7))
+#define IT83XX_I2C_CTR2(ch)          REG8(IT83XX_I2C_BASE+0x20+(ch << 7))
 #define IT83XX_I2C_RAMHA(ch)         REG8(IT83XX_I2C_BASE+0x23+(ch << 7))
 #define IT83XX_I2C_RAMLA(ch)         REG8(IT83XX_I2C_BASE+0x24+(ch << 7))
 #define IT83XX_I2C_RAMHA2(ch)        REG8(IT83XX_I2C_BASE+0x2B+(ch << 7))
diff --git a/include/config.h b/include/config.h
index 02f49f93ec..1c5fcdcb93 100644
--- a/include/config.h
+++ b/include/config.h
@@ -2794,6 +2794,12 @@
 #undef CONFIG_IT83XX_HARD_RESET_BY_GPG1
 
 /*
+ * Use i2c command queue mode for a single i2c transaction.
+ * (Applied to port D, E, and F)
+ */
+#undef CONFIG_IT83XX_I2C_CMD_QUEUE
+
+/*
  * Enable it if EC's VBAT won't go low when system's power isn't
  * presented (no battery and no AC)
  * If EC's VSTBY and VBAT(power source of BRAM) aren't connected to the same