1 files changed, 54 insertions, 33 deletions

diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
index 2e5acfeb76c8..a26b74c71206 100644
--- a/drivers/i2c/busses/i2c-aspeed.c
+++ b/drivers/i2c/busses/i2c-aspeed.c
@@ -170,6 +170,13 @@ struct aspeed_i2c_bus {
 
 static int aspeed_i2c_reset(struct aspeed_i2c_bus *bus);
 
+/* precondition: bus.lock has been acquired. */
+static void aspeed_i2c_do_stop(struct aspeed_i2c_bus *bus)
+{
+	bus->master_state = ASPEED_I2C_MASTER_STOP;
+	writel(ASPEED_I2CD_M_STOP_CMD, bus->base + ASPEED_I2C_CMD_REG);
+}
+
 static int aspeed_i2c_recover_bus(struct aspeed_i2c_bus *bus)
 {
 	unsigned long time_left, flags;
@@ -187,7 +194,7 @@ static int aspeed_i2c_recover_bus(struct aspeed_i2c_bus *bus)
 			command);
 
 		reinit_completion(&bus->cmd_complete);
-		writel(ASPEED_I2CD_M_STOP_CMD, bus->base + ASPEED_I2C_CMD_REG);
+		aspeed_i2c_do_stop(bus);
 		spin_unlock_irqrestore(&bus->lock, flags);
 
 		time_left = wait_for_completion_timeout(
@@ -249,18 +256,46 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
 	if (!slave)
 		return 0;
 
-	command = readl(bus->base + ASPEED_I2C_CMD_REG);
+	/*
+	 * Handle stop conditions early, prior to SLAVE_MATCH. Some masters may drive
+	 * transfers with low enough latency between the nak/stop phase of the current
+	 * command and the start/address phase of the following command that the
+	 * interrupts are coalesced by the time we process them.
+	 */
+	if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
+		irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
+		bus->slave_state = ASPEED_I2C_SLAVE_STOP;
+	}
+
+	if (irq_status & ASPEED_I2CD_INTR_TX_NAK &&
+	    bus->slave_state == ASPEED_I2C_SLAVE_READ_PROCESSED) {
+		irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
+		bus->slave_state = ASPEED_I2C_SLAVE_STOP;
+	}
 
-	/* Slave was requested, restart state machine. */
+	/* Propagate any stop conditions to the slave implementation. */
+	if (bus->slave_state == ASPEED_I2C_SLAVE_STOP) {
+		i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
+		bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
+	}
+
+	/*
+	 * Now that we've dealt with any potentially coalesced stop conditions,
+	 * address any start conditions.
+	 */
 	if (irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH) {
 		irq_handled |= ASPEED_I2CD_INTR_SLAVE_MATCH;
 		bus->slave_state = ASPEED_I2C_SLAVE_START;
 	}
 
-	/* Slave is not currently active, irq was for someone else. */
+	/*
+	 * If the slave has been stopped and not started then slave interrupt
+	 * handling is complete.
+	 */
 	if (bus->slave_state == ASPEED_I2C_SLAVE_INACTIVE)
 		return irq_handled;
 
+	command = readl(bus->base + ASPEED_I2C_CMD_REG);
 	dev_dbg(bus->dev, "slave irq status 0x%08x, cmd 0x%08x\n",
 		irq_status, command);
 
@@ -279,17 +314,6 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
 		irq_handled |= ASPEED_I2CD_INTR_RX_DONE;
 	}
 
-	/* Slave was asked to stop. */
-	if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
-		irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
-		bus->slave_state = ASPEED_I2C_SLAVE_STOP;
-	}
-	if (irq_status & ASPEED_I2CD_INTR_TX_NAK &&
-	    bus->slave_state == ASPEED_I2C_SLAVE_READ_PROCESSED) {
-		irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
-		bus->slave_state = ASPEED_I2C_SLAVE_STOP;
-	}
-
 	switch (bus->slave_state) {
 	case ASPEED_I2C_SLAVE_READ_REQUESTED:
 		if (unlikely(irq_status & ASPEED_I2CD_INTR_TX_ACK))
@@ -324,8 +348,7 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
 		i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);
 		break;
 	case ASPEED_I2C_SLAVE_STOP:
-		i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
-		bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
+		/* Stop event handling is done early. Unreachable. */
 		break;
 	case ASPEED_I2C_SLAVE_START:
 		/* Slave was just started. Waiting for the next event. */;
@@ -375,13 +398,6 @@ static void aspeed_i2c_do_start(struct aspeed_i2c_bus *bus)
 }
 
 /* precondition: bus.lock has been acquired. */
-static void aspeed_i2c_do_stop(struct aspeed_i2c_bus *bus)
-{
-	bus->master_state = ASPEED_I2C_MASTER_STOP;
-	writel(ASPEED_I2CD_M_STOP_CMD, bus->base + ASPEED_I2C_CMD_REG);
-}
-
-/* precondition: bus.lock has been acquired. */
 static void aspeed_i2c_next_msg_or_stop(struct aspeed_i2c_bus *bus)
 {
 	if (bus->msgs_index + 1 < bus->msgs_count) {
@@ -429,6 +445,7 @@ static u32 aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
 			irq_status);
 		irq_handled |= (irq_status & ASPEED_I2CD_INTR_MASTER_ERRORS);
 		if (bus->master_state != ASPEED_I2C_MASTER_INACTIVE) {
+			irq_handled = irq_status;
 			bus->cmd_err = ret;
 			bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
 			goto out_complete;
@@ -698,13 +715,16 @@ static int aspeed_i2c_master_xfer(struct i2c_adapter *adap,
 
 	if (time_left == 0) {
 		/*
-		 * If timed out and bus is still busy in a multi master
-		 * environment, attempt recovery at here.
+		 * In a multi-master setup, if a timeout occurs, attempt
+		 * recovery. But if the bus is idle, we still need to reset the
+		 * i2c controller to clear the remaining interrupts.
 		 */
 		if (bus->multi_master &&
 		    (readl(bus->base + ASPEED_I2C_CMD_REG) &
 		     ASPEED_I2CD_BUS_BUSY_STS))
 			aspeed_i2c_recover_bus(bus);
+		else
+			aspeed_i2c_reset(bus);
 
 		/*
 		 * If timed out and the state is still pending, drop the pending
@@ -746,6 +766,8 @@ static void __aspeed_i2c_reg_slave(struct aspeed_i2c_bus *bus, u16 slave_addr)
 	func_ctrl_reg_val = readl(bus->base + ASPEED_I2C_FUN_CTRL_REG);
 	func_ctrl_reg_val |= ASPEED_I2CD_SLAVE_EN;
 	writel(func_ctrl_reg_val, bus->base + ASPEED_I2C_FUN_CTRL_REG);
+
+	bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
 }
 
 static int aspeed_i2c_reg_slave(struct i2c_client *client)
@@ -762,7 +784,6 @@ static int aspeed_i2c_reg_slave(struct i2c_client *client)
 	__aspeed_i2c_reg_slave(bus, client->addr);
 
 	bus->slave = client;
-	bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
 	spin_unlock_irqrestore(&bus->lock, flags);
 
 	return 0;
@@ -793,11 +814,11 @@ static int aspeed_i2c_unreg_slave(struct i2c_client *client)
 #endif /* CONFIG_I2C_SLAVE */
 
 static const struct i2c_algorithm aspeed_i2c_algo = {
-	.master_xfer	= aspeed_i2c_master_xfer,
-	.functionality	= aspeed_i2c_functionality,
+	.xfer = aspeed_i2c_master_xfer,
+	.functionality = aspeed_i2c_functionality,
 #if IS_ENABLED(CONFIG_I2C_SLAVE)
-	.reg_slave	= aspeed_i2c_reg_slave,
-	.unreg_slave	= aspeed_i2c_unreg_slave,
+	.reg_slave = aspeed_i2c_reg_slave,
+	.unreg_slave = aspeed_i2c_unreg_slave,
 #endif /* CONFIG_I2C_SLAVE */
 };
 
@@ -970,7 +991,7 @@ static const struct of_device_id aspeed_i2c_bus_of_table[] = {
 		.compatible = "aspeed,ast2600-i2c-bus",
 		.data = aspeed_i2c_25xx_get_clk_reg_val,
 	},
-	{ },
+	{ }
 };
 MODULE_DEVICE_TABLE(of, aspeed_i2c_bus_of_table);
 
@@ -1081,7 +1102,7 @@ static void aspeed_i2c_remove_bus(struct platform_device *pdev)
 
 static struct platform_driver aspeed_i2c_bus_driver = {
 	.probe		= aspeed_i2c_probe_bus,
-	.remove_new	= aspeed_i2c_remove_bus,
+	.remove		= aspeed_i2c_remove_bus,
 	.driver		= {
 		.name		= "aspeed-i2c-bus",
 		.of_match_table	= aspeed_i2c_bus_of_table,