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authorMika Westerberg <mika.westerberg@linux.intel.com>2016-06-09 16:56:28 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-08-16 09:30:48 +0200
commit3088903a55f218c0d3758de086ede3901b8711b0 (patch)
treeb08b17923e07e64bfa16febdfe67a8efe30b5914 /drivers/i2c/busses
parent979a61a02992e2029fcedcdf32c05050aa652c9c (diff)
i2c: i801: Allow ACPI SystemIO OpRegion to conflict with PCI BAR
commit a7ae81952cdab56a1277bd2f9ed7284c0f575120 upstream. Many Intel systems the BIOS declares a SystemIO OpRegion below the SMBus PCI device as can be seen in ACPI DSDT table from Lenovo Yoga 900: Device (SBUS) { OperationRegion (SMBI, SystemIO, (SBAR << 0x05), 0x10) Field (SMBI, ByteAcc, NoLock, Preserve) { HSTS, 8, Offset (0x02), HCON, 8, HCOM, 8, TXSA, 8, DAT0, 8, DAT1, 8, HBDR, 8, PECR, 8, RXSA, 8, SDAT, 16 } There are also bunch of AML methods that that the BIOS can use to access these fields. Most of the systems in question AML methods accessing the SMBI OpRegion are never used. Now, because of this SMBI OpRegion many systems fail to load the SMBus driver with an error looking like one below: ACPI Warning: SystemIO range 0x0000000000003040-0x000000000000305F conflicts with OpRegion 0x0000000000003040-0x000000000000304F (\_SB.PCI0.SBUS.SMBI) (20160108/utaddress-255) ACPI: If an ACPI driver is available for this device, you should use it instead of the native driver The reason is that this SMBI OpRegion conflicts with the PCI BAR used by the SMBus driver. It turns out that we can install a custom SystemIO address space handler for the SMBus device to intercept all accesses through that OpRegion. This allows us to share the PCI BAR with the AML code if it for some reason is using it. We do not expect that this OpRegion handler will ever be called but if it is we print a warning and prevent all access from the SMBus driver itself. Link: https://bugzilla.kernel.org/show_bug.cgi?id=110041 Reported-by: Andy Lutomirski <luto@kernel.org> Reported-by: Pali Rohár <pali.rohar@gmail.com> Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Jean Delvare <jdelvare@suse.de> Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Tested-by: Pali Rohár <pali.rohar@gmail.com> Tested-by: Jean Delvare <jdelvare@suse.de> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/i2c/busses')
-rw-r--r--drivers/i2c/busses/i2c-i801.c103
1 files changed, 94 insertions, 9 deletions
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 27fa0cb09538..85f39cc3e276 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/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);