1 files changed, 101 insertions, 12 deletions

diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c
index 10f00a82ec9d..59d5cf376f6a 100644
--- a/drivers/i2c/i2c-core-smbus.c
+++ b/drivers/i2c/i2c-core-smbus.c
@@ -17,6 +17,8 @@
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/i2c.h>
+#include <linux/i2c-smbus.h>
+#include <linux/slab.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/smbus.h>
@@ -290,6 +292,22 @@ s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
 }
 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
 
+static void i2c_smbus_try_get_dmabuf(struct i2c_msg *msg, u8 init_val)
+{
+	bool is_read = msg->flags & I2C_M_RD;
+	unsigned char *dma_buf;
+
+	dma_buf = kzalloc(I2C_SMBUS_BLOCK_MAX + (is_read ? 2 : 3), GFP_KERNEL);
+	if (!dma_buf)
+		return;
+
+	msg->buf = dma_buf;
+	msg->flags |= I2C_M_DMA_SAFE;
+
+	if (init_val)
+		msg->buf[0] = init_val;
+}
+
 /* Simulate a SMBus command using the i2c protocol
    No checking of parameters is done!  */
 static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
@@ -367,6 +385,7 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
 			msg[1].flags |= I2C_M_RECV_LEN;
 			msg[1].len = 1; /* block length will be added by
 					   the underlying bus driver */
+			i2c_smbus_try_get_dmabuf(&msg[1], 0);
 		} else {
 			msg[0].len = data->block[0] + 2;
 			if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
@@ -375,8 +394,10 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
 					data->block[0]);
 				return -EINVAL;
 			}
+
+			i2c_smbus_try_get_dmabuf(&msg[0], command);
 			for (i = 1; i < msg[0].len; i++)
-				msgbuf0[i] = data->block[i-1];
+				msg[0].buf[i] = data->block[i - 1];
 		}
 		break;
 	case I2C_SMBUS_BLOCK_PROC_CALL:
@@ -388,26 +409,34 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
 				data->block[0]);
 			return -EINVAL;
 		}
+
 		msg[0].len = data->block[0] + 2;
+		i2c_smbus_try_get_dmabuf(&msg[0], command);
 		for (i = 1; i < msg[0].len; i++)
-			msgbuf0[i] = data->block[i-1];
+			msg[0].buf[i] = data->block[i - 1];
+
 		msg[1].flags |= I2C_M_RECV_LEN;
 		msg[1].len = 1; /* block length will be added by
 				   the underlying bus driver */
+		i2c_smbus_try_get_dmabuf(&msg[1], 0);
 		break;
 	case I2C_SMBUS_I2C_BLOCK_DATA:
+		if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
+			dev_err(&adapter->dev, "Invalid block %s size %d\n",
+				read_write == I2C_SMBUS_READ ? "read" : "write",
+				data->block[0]);
+			return -EINVAL;
+		}
+
 		if (read_write == I2C_SMBUS_READ) {
 			msg[1].len = data->block[0];
+			i2c_smbus_try_get_dmabuf(&msg[1], 0);
 		} else {
 			msg[0].len = data->block[0] + 1;
-			if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
-				dev_err(&adapter->dev,
-					"Invalid block write size %d\n",
-					data->block[0]);
-				return -EINVAL;
-			}
+
+			i2c_smbus_try_get_dmabuf(&msg[0], command);
 			for (i = 1; i <= data->block[0]; i++)
-				msgbuf0[i] = data->block[i];
+				msg[0].buf[i] = data->block[i];
 		}
 		break;
 	default:
@@ -455,14 +484,20 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
 			break;
 		case I2C_SMBUS_I2C_BLOCK_DATA:
 			for (i = 0; i < data->block[0]; i++)
-				data->block[i+1] = msgbuf1[i];
+				data->block[i + 1] = msg[1].buf[i];
 			break;
 		case I2C_SMBUS_BLOCK_DATA:
 		case I2C_SMBUS_BLOCK_PROC_CALL:
-			for (i = 0; i < msgbuf1[0] + 1; i++)
-				data->block[i] = msgbuf1[i];
+			for (i = 0; i < msg[1].buf[0] + 1; i++)
+				data->block[i] = msg[1].buf[i];
 			break;
 		}
+
+	if (msg[0].flags & I2C_M_DMA_SAFE)
+		kfree(msg[0].buf);
+	if (msg[1].flags & I2C_M_DMA_SAFE)
+		kfree(msg[1].buf);
+
 	return 0;
 }
 
@@ -592,3 +627,57 @@ s32 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
 	return i;
 }
 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data_or_emulated);
+
+/**
+ * i2c_setup_smbus_alert - Setup SMBus alert support
+ * @adapter: the target adapter
+ * @setup: setup data for the SMBus alert handler
+ * Context: can sleep
+ *
+ * Setup handling of the SMBus alert protocol on a given I2C bus segment.
+ *
+ * Handling can be done either through our IRQ handler, or by the
+ * adapter (from its handler, periodic polling, or whatever).
+ *
+ * NOTE that if we manage the IRQ, we *MUST* know if it's level or
+ * edge triggered in order to hand it to the workqueue correctly.
+ * If triggering the alert seems to wedge the system, you probably
+ * should have said it's level triggered.
+ *
+ * This returns the ara client, which should be saved for later use with
+ * i2c_handle_smbus_alert() and ultimately i2c_unregister_device(); or NULL
+ * to indicate an error.
+ */
+struct i2c_client *i2c_setup_smbus_alert(struct i2c_adapter *adapter,
+					 struct i2c_smbus_alert_setup *setup)
+{
+	struct i2c_board_info ara_board_info = {
+		I2C_BOARD_INFO("smbus_alert", 0x0c),
+		.platform_data = setup,
+	};
+
+	return i2c_new_device(adapter, &ara_board_info);
+}
+EXPORT_SYMBOL_GPL(i2c_setup_smbus_alert);
+
+#if IS_ENABLED(CONFIG_I2C_SMBUS) && IS_ENABLED(CONFIG_OF)
+int of_i2c_setup_smbus_alert(struct i2c_adapter *adapter)
+{
+	struct i2c_client *client;
+	int irq;
+
+	irq = of_property_match_string(adapter->dev.of_node, "interrupt-names",
+				       "smbus_alert");
+	if (irq == -EINVAL || irq == -ENODATA)
+		return 0;
+	else if (irq < 0)
+		return irq;
+
+	client = i2c_setup_smbus_alert(adapter, NULL);
+	if (!client)
+		return -ENODEV;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(of_i2c_setup_smbus_alert);
+#endif