3 files changed, 107 insertions, 10 deletions

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 64b1208bca5e..4a60ad214747 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -245,6 +245,13 @@ 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)
@@ -718,6 +725,12 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
         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;
+        }
+
         pm_runtime_get_sync(&priv->pci_dev->dev);
 
         hwpec = (priv->features & FEATURE_SMBUS_PEC) && (flags & I2C_CLIENT_PEC)
@@ -820,6 +833,7 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
 out:
         pm_runtime_mark_last_busy(&priv->pci_dev->dev);
         pm_runtime_put_autosuspend(&priv->pci_dev->dev);
+        mutex_unlock(&priv->acpi_lock);
         return ret;
 }
 
@@ -1257,6 +1271,83 @@ 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");
+
+                /*
+                 * BIOS is accessing the host controller so prevent it from
+                 * suspending automatically from now on.
+                 */
+                pm_runtime_get_sync(&pdev->dev);
+        }
+
+        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);
+
+        mutex_lock(&priv->acpi_lock);
+        if (priv->acpi_reserved)
+                pm_runtime_put(&priv->pci_dev->dev);
+        mutex_unlock(&priv->acpi_lock);
+}
+#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;
@@ -1274,6 +1365,7 @@ 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) {
@@ -1336,10 +1428,8 @@ 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));
@@ -1348,6 +1438,7 @@ 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;
         }
 
@@ -1412,6 +1503,7 @@ 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;
         }
 
@@ -1438,6 +1530,7 @@ 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);
diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c
index aa5f01efd826..30ae35146723 100644
--- a/drivers/i2c/busses/i2c-octeon.c
+++ b/drivers/i2c/busses/i2c-octeon.c
@@ -934,8 +934,15 @@ static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
                 return result;
 
         for (i = 0; i < length; i++) {
-                /* for the last byte TWSI_CTL_AAK must not be set */
-                if (i + 1 == length)
+                /*
+                 * For the last byte to receive TWSI_CTL_AAK must not be set.
+                 *
+                 * A special case is I2C_M_RECV_LEN where we don't know the
+                 * additional length yet. If recv_len is set we assume we're
+                 * not reading the final byte and therefore need to set
+                 * TWSI_CTL_AAK.
+                 */
+                if ((i + 1 == length) && !(recv_len && i == 0))
                         final_read = true;
 
                 /* clear iflg to allow next event */
@@ -950,12 +957,8 @@ static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
 
                 data[i] = octeon_i2c_data_read(i2c);
                 if (recv_len && i == 0) {
-                        if (data[i] > I2C_SMBUS_BLOCK_MAX + 1) {
-                                dev_err(i2c->dev,
-                                        "%s: read len > I2C_SMBUS_BLOCK_MAX %d\n",
-                                        __func__, data[i]);
+                        if (data[i] > I2C_SMBUS_BLOCK_MAX + 1)
                                 return -EPROTO;
-                        }
                         length += data[i];
                 }
 
diff --git a/drivers/i2c/muxes/i2c-mux-reg.c b/drivers/i2c/muxes/i2c-mux-reg.c
index 6773cadf7c9f..26e7c5187a58 100644
--- a/drivers/i2c/muxes/i2c-mux-reg.c
+++ b/drivers/i2c/muxes/i2c-mux-reg.c
@@ -260,6 +260,7 @@ static struct platform_driver i2c_mux_reg_driver = {
         .remove = i2c_mux_reg_remove,
         .driver = {
                 .name   = "i2c-mux-reg",
+                .of_match_table = of_match_ptr(i2c_mux_reg_of_match),
         },
 };