1 files changed, 94 insertions, 9 deletions

diff --git a/kernel/drivers/i2c/busses/i2c-i801.c b/kernel/drivers/i2c/busses/i2c-i801.c
index 27fa0cb09..85f39cc3e 100644
--- a/kernel/drivers/i2c/busses/i2c-i801.c
+++ b/kernel/drivers/i2c/busses/i2c-i801.c
@@ -244,6 +244,13 @@ struct i801_priv {
 	struct platform_device *mux_pdev;
 #endif
 	struct platform_device *tco_pdev;
+
+	/*
+	 * If set to true the host controller registers are reserved for
+	 * ACPI AML use. Protected by acpi_lock.
+	 */
+	bool acpi_reserved;
+	struct mutex acpi_lock;
 };
 
 #define FEATURE_SMBUS_PEC	(1 << 0)
@@ -714,9 +721,15 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
 {
 	int hwpec;
 	int block = 0;
-	int ret, xact = 0;
+	int ret = 0, xact = 0;
 	struct i801_priv *priv = i2c_get_adapdata(adap);
 
+	mutex_lock(&priv->acpi_lock);
+	if (priv->acpi_reserved) {
+		mutex_unlock(&priv->acpi_lock);
+		return -EBUSY;
+	}
+
 	hwpec = (priv->features & FEATURE_SMBUS_PEC) && (flags & I2C_CLIENT_PEC)
 		&& size != I2C_SMBUS_QUICK
 		&& size != I2C_SMBUS_I2C_BLOCK_DATA;
@@ -773,7 +786,8 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
 	default:
 		dev_err(&priv->pci_dev->dev, "Unsupported transaction %d\n",
 			size);
-		return -EOPNOTSUPP;
+		ret = -EOPNOTSUPP;
+		goto out;
 	}
 
 	if (hwpec)	/* enable/disable hardware PEC */
@@ -796,11 +810,11 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
 		       ~(SMBAUXCTL_CRC | SMBAUXCTL_E32B), SMBAUXCTL(priv));
 
 	if (block)
-		return ret;
+		goto out;
 	if (ret)
-		return ret;
+		goto out;
 	if ((read_write == I2C_SMBUS_WRITE) || (xact == I801_QUICK))
-		return 0;
+		goto out;
 
 	switch (xact & 0x7f) {
 	case I801_BYTE:	/* Result put in SMBHSTDAT0 */
@@ -812,7 +826,10 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
 			     (inb_p(SMBHSTDAT1(priv)) << 8);
 		break;
 	}
-	return 0;
+
+out:
+	mutex_unlock(&priv->acpi_lock);
+	return ret;
 }
 
 
@@ -1249,6 +1266,72 @@ static void i801_add_tco(struct i801_priv *priv)
 	priv->tco_pdev = pdev;
 }
 
+#ifdef CONFIG_ACPI
+static acpi_status
+i801_acpi_io_handler(u32 function, acpi_physical_address address, u32 bits,
+		     u64 *value, void *handler_context, void *region_context)
+{
+	struct i801_priv *priv = handler_context;
+	struct pci_dev *pdev = priv->pci_dev;
+	acpi_status status;
+
+	/*
+	 * Once BIOS AML code touches the OpRegion we warn and inhibit any
+	 * further access from the driver itself. This device is now owned
+	 * by the system firmware.
+	 */
+	mutex_lock(&priv->acpi_lock);
+
+	if (!priv->acpi_reserved) {
+		priv->acpi_reserved = true;
+
+		dev_warn(&pdev->dev, "BIOS is accessing SMBus registers\n");
+		dev_warn(&pdev->dev, "Driver SMBus register access inhibited\n");
+	}
+
+	if ((function & ACPI_IO_MASK) == ACPI_READ)
+		status = acpi_os_read_port(address, (u32 *)value, bits);
+	else
+		status = acpi_os_write_port(address, (u32)*value, bits);
+
+	mutex_unlock(&priv->acpi_lock);
+
+	return status;
+}
+
+static int i801_acpi_probe(struct i801_priv *priv)
+{
+	struct acpi_device *adev;
+	acpi_status status;
+
+	adev = ACPI_COMPANION(&priv->pci_dev->dev);
+	if (adev) {
+		status = acpi_install_address_space_handler(adev->handle,
+				ACPI_ADR_SPACE_SYSTEM_IO, i801_acpi_io_handler,
+				NULL, priv);
+		if (ACPI_SUCCESS(status))
+			return 0;
+	}
+
+	return acpi_check_resource_conflict(&priv->pci_dev->resource[SMBBAR]);
+}
+
+static void i801_acpi_remove(struct i801_priv *priv)
+{
+	struct acpi_device *adev;
+
+	adev = ACPI_COMPANION(&priv->pci_dev->dev);
+	if (!adev)
+		return;
+
+	acpi_remove_address_space_handler(adev->handle,
+		ACPI_ADR_SPACE_SYSTEM_IO, i801_acpi_io_handler);
+}
+#else
+static inline int i801_acpi_probe(struct i801_priv *priv) { return 0; }
+static inline void i801_acpi_remove(struct i801_priv *priv) { }
+#endif
+
 static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 {
 	unsigned char temp;
@@ -1266,6 +1349,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	priv->adapter.dev.parent = &dev->dev;
 	ACPI_COMPANION_SET(&priv->adapter.dev, ACPI_COMPANION(&dev->dev));
 	priv->adapter.retries = 3;
+	mutex_init(&priv->acpi_lock);
 
 	priv->pci_dev = dev;
 	switch (dev->device) {
@@ -1328,10 +1412,8 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 		return -ENODEV;
 	}
 
-	err = acpi_check_resource_conflict(&dev->resource[SMBBAR]);
-	if (err) {
+	if (i801_acpi_probe(priv))
 		return -ENODEV;
-	}
 
 	err = pcim_iomap_regions(dev, 1 << SMBBAR,
 				 dev_driver_string(&dev->dev));
@@ -1340,6 +1422,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 			"Failed to request SMBus region 0x%lx-0x%Lx\n",
 			priv->smba,
 			(unsigned long long)pci_resource_end(dev, SMBBAR));
+		i801_acpi_remove(priv);
 		return err;
 	}
 
@@ -1404,6 +1487,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	err = i2c_add_adapter(&priv->adapter);
 	if (err) {
 		dev_err(&dev->dev, "Failed to add SMBus adapter\n");
+		i801_acpi_remove(priv);
 		return err;
 	}
 
@@ -1422,6 +1506,7 @@ static void i801_remove(struct pci_dev *dev)
 
 	i801_del_mux(priv);
 	i2c_del_adapter(&priv->adapter);
+	i801_acpi_remove(priv);
 	pci_write_config_byte(dev, SMBHSTCFG, priv->original_hstcfg);
 
 	platform_device_unregister(priv->tco_pdev);