Support multiplexed main SMBus interface on SB80

The SB800 chipset supports a multiplexed main SMBus controller with four ports. Therefore the static variable piix4_main_adapter is converted into a piix4_main_adapters array that can hold one i2c_adapter for each multiplexed port.

The auxiliary adapter remains unchanged since it represents the second (not multiplexed) SMBus controller on the SB800 chipset.

Signed-off-by Christian Fetzer <[email protected]>

The SB800 chipset supports a multiplexed main SMBus controller with four ports. Therefore the static variable piix4_main_adapter is converted into a piix4_main_adapters array that can hold one i2c_adapter for each multiplexed port.

The auxiliary adapter remains unchanged since it represents the second
(not multiplexed) SMBus controller on the SB800 chipset.

(quoted diff) +0 -0

@@ -675,9 +678,14 @@ static void piix4_adap_remove(struct i2c_adapter
 *adap, int free_smba)

 static void piix4_remove(struct pci_dev *dev)
 {

drivers/i2c/busses/i2c-piix4.c +8 -3

-	if (piix4_main_adapter) {
-		piix4_adap_remove(piix4_main_adapter, 1);
-		piix4_main_adapter = NULL;
+	int port;
+
+	for (port = PIIX4_MAX_ADAPTERS - 1; port >= 0; port--) {
+		if (piix4_main_adapters[port]) {
+			piix4_adap_remove(piix4_main_adapters[port],
+					  port == 0);
+			piix4_main_adapters[port] = NULL;
+		}

  }

Request the SMBus base address index region once in piix4_probe. This is particularly useful when using the multiplexed adapter in SB800 as it avoids requesting and releasing the region on every transfer.

Signed-off-by Christian Fetzer <[email protected]>

---
 drivers/i2c/busses/i2c-piix4.c | 35 ++++++++++++++++++++++-------------
 1 file changed, 22 insertions(+), 13 deletions(-)

drivers/i2c/busses/i2c-piix4.c +8 -11

index 35eeb0d..d866b58 100644
@@ -125,6 +125,9 @@ static const struct dmi_system_id piix4_dmi_ibm[] = {
 	{ },
 };
 
+/* SB800 globals */
+static unsigned short piix4_smb_idx_sb800;
+
 struct i2c_piix4_adapdata {
 	unsigned short smba;
 };

@@ -232,7 +235,6 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev,
 			     const struct pci_device_id *id, u8 aux)
 {
 	unsigned short piix4_smba;
-	unsigned short smba_idx = 0xcd6;
 	u8 smba_en_lo, smba_en_hi, smb_en, smb_en_status;
 	u8 i2ccfg, i2ccfg_offset = 0x10;
 

@@ -254,16 +256,10 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev,
 	else
 		smb_en = (aux) ? 0x28 : 0x2c;
 
-	if (!request_region(smba_idx, 2, "smba_idx")) {
-		dev_err(&PIIX4_dev->dev, "SMBus base address index region "
-			"0x%x already in use!\n", smba_idx);
-		return -EBUSY;
-	}
-	outb_p(smb_en, smba_idx);
-	smba_en_lo = inb_p(smba_idx + 1);
-	outb_p(smb_en + 1, smba_idx);
-	smba_en_hi = inb_p(smba_idx + 1);
-	release_region(smba_idx, 2);
+	outb_p(smb_en, piix4_smb_idx_sb800);
+	smba_en_lo = inb_p(piix4_smb_idx_sb800 + 1);
+	outb_p(smb_en + 1, piix4_smb_idx_sb800);
+	smba_en_hi = inb_p(piix4_smb_idx_sb800 + 1);
 
 	if (!smb_en) {
 		smb_en_status = smba_en_lo & 0x10;

@@ -616,16 +612,26 @@ static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
 
 static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id)
 {
+	unsigned short smba_idx = 0xcd6;
 	int retval;
 
 	if ((dev->vendor == PCI_VENDOR_ID_ATI &&
 	     dev->device == PCI_DEVICE_ID_ATI_SBX00_SMBUS &&

Request the SMBus base address index region once in piix4_probe. This is particularly useful when using the multiplexed adapter in SB800 as it avoids requesting and releasing the region on every transfer.

(quoted diff) +0 -0

@@ -616,16 +612,26 @@ static int piix4_add_adapter(struct pci_dev
 *dev, unsigned short smba,

 static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id)
 {

drivers/i2c/busses/i2c-piix4.c +1 -0

+	unsigned short smba_idx = 0xcd6;

  int retval;

  if ((dev->vendor == PCI_VENDOR_ID_ATI && dev->device == PCI_DEVICE_ID_ATI_SBX00_SMBUS && dev->revision >= 0x40) ||

drivers/i2c/busses/i2c-piix4.c +4 -0

+			return -EBUSY;
+		}
+		piix4_smb_idx_sb800 = smba_idx;
+

  /* base address location etc changed in SB800 */ retval = piix4_setup_sb800(dev, id, 0);

drivers/i2c/busses/i2c-piix4.c +1 -1

-	else
+	} else {

  retval = piix4_setup(dev, id);

(quoted diff) +1 -0

+	}

The SB800 chipset supports a multiplexed main SMBus controller with four ports. The multiplexed ports share the same SMBus address and register set. The port is selected by bits 2:1 of the smb_en register (0x2C).

Only one port can be active at any point in time therefore a mutex is needed in order to synchronize access.

Tested on HP ProLiant MicroServer G7 N54L (where this patch adds support to access sensor data from the w83795adg).

Cc Thomas Brandon <[email protected]>

Cc Eddi De Pieri <[email protected]>

Signed-off-by Christian Fetzer <[email protected]>

---
 drivers/i2c/busses/i2c-piix4.c | 102 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 97 insertions(+), 5 deletions(-)

drivers/i2c/busses/i2c-piix4.c +8 -0

index d866b58..54f8af5 100644
@@ -23,6 +23,9 @@
 
    Note: we assume there can only be one device, with one or more
    SMBus interfaces.
+   The device can register multiple i2c_adapters (up to PIIX4_MAX_ADAPTERS).
+   For devices supporting multiple ports the i2c_adapter should provide
+   an i2c_algorithm to access them.
 */
 
 #include <linux/module.h>

@@ -37,6 +40,7 @@
 #include <linux/dmi.h>
 #include <linux/acpi.h>
 #include <linux/io.h>
+#include <linux/mutex.h>
 
 
 /* PIIX4 SMBus address offsets */

@@ -126,10 +130,12 @@ static const struct dmi_system_id piix4_dmi_ibm[] = {
 };
 
 /* SB800 globals */
+DEFINE_MUTEX(piix4_mutex_sb800);
 static unsigned short piix4_smb_idx_sb800;
 
 struct i2c_piix4_adapdata {
 	unsigned short smba;
+	unsigned short port;
 };
 
 static int piix4_setup(struct pci_dev *PIIX4_dev,

@@ -309,6 +315,8 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev,
 	else
 		dev_dbg(&PIIX4_dev->dev, "Using SMI# for SMBus\n");
 
+	mutex_init(&piix4_mutex_sb800);
+
 	dev_info(&PIIX4_dev->dev,
 		 "SMBus Host Controller at 0x%x, revision %d\n",
 		 piix4_smba, i2ccfg >> 4);

drivers/i2c/busses/i2c-piix4.c +51 -0

+ *
+ * Note: The selected port must be returned to the initial selection to avoid
+ * problems on certain systems.
+ */
+static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
+		 unsigned short flags, char read_write,
+		 u8 command, int size, union i2c_smbus_data *data)
+{
+	struct i2c_piix4_adapdata *adapdata = i2c_get_adapdata(adap);
+	u8 smba_en_lo, smb_en = 0x2c;
+	u8 port;
+	int retval;
+
+	mutex_lock(&piix4_mutex_sb800);
+
+	outb_p(smb_en, piix4_smb_idx_sb800);
+	smba_en_lo = inb_p(piix4_smb_idx_sb800 + 1);
+
+	port = adapdata->port;
+	if ((smba_en_lo & 6) != (port << 1))
+		outb_p((smba_en_lo & ~6) | (port << 1),
+		       piix4_smb_idx_sb800 + 1);
+
+	retval = piix4_access(adap, addr, flags, read_write,
+			      command, size, data);
+
+	outb_p(smba_en_lo, piix4_smb_idx_sb800 + 1);
+
+	mutex_unlock(&piix4_mutex_sb800);
+
+	return retval;
+}
+
 static u32 piix4_func(struct i2c_adapter *adapter)
 {
 	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |

@@ -535,6 +579,11 @@ static const struct i2c_algorithm smbus_algorithm = {
 	.functionality	= piix4_func,
 };
 
+static const struct i2c_algorithm piix4_smbus_algorithm_sb800 = {
+	.smbus_xfer	= piix4_access_sb800,
+	.functionality	= piix4_func,
+};
+
 static const struct pci_device_id piix4_ids[] = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371AB_3) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82443MX_3) },

@@ -610,6 +659,42 @@ static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
 	return 0;
 }
 
+static int piix4_add_adapters_sb800(struct pci_dev *dev, unsigned short smba)
+{
+	unsigned short port;
+	int retval;
+	struct i2c_piix4_adapdata *adapdata;
+
+	for (port = 0; port < PIIX4_MAX_ADAPTERS; port++) {
+		retval = piix4_add_adapter(dev, smba,
+					   &piix4_main_adapters[port]);
+		if (retval < 0)
+			goto error;
+
+		piix4_main_adapters[port]->algo = &piix4_smbus_algorithm_sb800;

drivers/i2c/busses/i2c-piix4.c +25 -5

+	for (port--; port >= 0; port--) {
+		adapdata = i2c_get_adapdata(piix4_main_adapters[port]);
+		if (adapdata->smba) {
+			i2c_del_adapter(piix4_main_adapters[port]);
+			kfree(adapdata);
+			kfree(piix4_main_adapters[port]);
+			piix4_main_adapters[port] = NULL;
+		}
+	}
+
+	return retval;
+}
+
 static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id)
 {
 	unsigned short smba_idx = 0xcd6;

@@ -629,19 +714,26 @@ static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id)
 
 		/* base address location etc changed in SB800 */
 		retval = piix4_setup_sb800(dev, id, 0);
+		if (retval < 0)
+			return retval;
+
+		/* Try to register multiplexed main SMBus adapter,
+		 * give up if we can't */
+		retval = piix4_add_adapters_sb800(dev, retval);
 	} else {
 		retval = piix4_setup(dev, id);
+		if (retval < 0)
+			return retval;
+
+		/* Try to register main SMBus adapter, give up if we can't */
+		retval = piix4_add_adapter(dev, retval,
+					   &piix4_main_adapters[0]);
 	}
 
 	/* If no main SMBus found, give up */
 	if (retval < 0)
 		return retval;
 
-	/* Try to register main SMBus adapter, give up if we can't */
-	retval = piix4_add_adapter(dev, retval, &piix4_main_adapters[0]);
-	if (retval < 0)
-		return retval;
-
 	/* Check for auxiliary SMBus on some AMD chipsets */
 	retval = -ENODEV;
 

Signature · 1 line

1.9.1

The SB800 chipset supports a multiplexed main SMBus controller with four ports. The multiplexed ports share the same SMBus address and register set. The port is selected by bits 2:1 of the smb_en register (0x2C).

Only one port can be active at any point in time therefore a mutex is needed in order to synchronize access.

Tested on HP ProLiant MicroServer G7 N54L (where this patch adds support to access sensor data from the w83795adg).

+static int piix4_add_adapters_sb800(struct pci_dev *dev, unsigned short smba)

drivers/i2c/busses/i2c-piix4.c +8 -0

+{
+	unsigned short port;
+	int retval;
+	struct i2c_piix4_adapdata *adapdata;
+
+	for (port = 0; port < PIIX4_MAX_ADAPTERS; port++) {
+		retval = piix4_add_adapter(dev, smba,
+					   &piix4_main_adapters[port

]);

drivers/i2c/busses/i2c-piix4.c +4 -0

+		if (retval < 0)
+			goto error;
+
+		piix4_main_adapters[port]->algo =

&piix4_smbus_algorithm_sb800;

(quoted diff) +2 -0

+
+		adapdata =

i2c_get_adapdata(piix4_main_adapters[port]);

(quoted diff) +1 -0

+		adapdata =

i2c_get_adapdata(piix4_main_adapters[port]);

drivers/i2c/busses/i2c-piix4.c +11 -0

+		if (adapdata->smba) {
+			i2c_del_adapter(piix4_main_adapters[port]);
+			kfree(adapdata);
+			kfree(piix4_main_adapters[port]);
+			piix4_main_adapters[port] = NULL;
+		}
+	}
+
+	return retval;
+}
+

 static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id)
 {
  unsigned short smba_idx = 0xcd6;

(quoted diff) +0 -0

@@ -629,19 +714,26 @@ static int piix4_probe(struct pci_dev *dev,
 const struct pci_device_id *id)

  /* base address location etc changed in SB800 */ retval = piix4_setup_sb800(dev, id, 0);

drivers/i2c/busses/i2c-piix4.c +1 -0

+		retval = piix4_add_adapters_sb800(dev, retval);

  } else {
  retval = piix4_setup(dev, id);

drivers/i2c/busses/i2c-piix4.c +4 -0

+		if (retval < 0)
+			return retval;
+
+		/* Try to register main SMBus adapter, give up if we

can't */

drivers/i2c/busses/i2c-piix4.c +2 -0

+		retval = piix4_add_adapter(dev, retval,
+					   &piix4_main_adapters[0]);

  }

  /* If no main SMBus found, give up */
  if (retval < 0)
  return retval;

(quoted diff) +0 -1

-	/* Try to register main SMBus adapter, give up if we can't

*/

(quoted diff) +0 -1

-	retval = piix4_add_adapter(dev, retval,

&piix4_main_adapters[0]);

drivers/i2c/busses/i2c-piix4.c +0 -3

-	if (retval < 0)
-		return retval;
-

  /* Check for auxiliary SMBus on some AMD chipsets */ retval = -ENODEV;

This patch adds support for port names for the SB800 chipset. Since the chipset supports a multiplexed main SMBus controller, adding the channel name to the adapter name is necessary to differentiate the ports better (for example in sensors output).

Signed-off-by Christian Fetzer <[email protected]>

---
 drivers/i2c/busses/i2c-piix4.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

drivers/i2c/busses/i2c-piix4.c +7 -2

index 54f8af5..18ea5d7 100644
@@ -132,6 +132,10 @@ static const struct dmi_system_id piix4_dmi_ibm[] = {
 /* SB800 globals */
 DEFINE_MUTEX(piix4_mutex_sb800);
 static unsigned short piix4_smb_idx_sb800;
+static const char *piix4_main_port_names_sb800[4] = {
+	"SDA0", "SDA2", "SDA3", "SDA4"
+};
+static const char *piix4_aux_port_name_sb800 = "SDA1";
 
 struct i2c_piix4_adapdata {
 	unsigned short smba;

@@ -613,7 +617,7 @@ static struct i2c_adapter *piix4_main_adapters[PIIX4_MAX_ADAPTERS];
 static struct i2c_adapter *piix4_aux_adapter;
 
 static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
-			     struct i2c_adapter **padap)
+			     const char *name, struct i2c_adapter **padap)
 {
 	struct i2c_adapter *adap;
 	struct i2c_piix4_adapdata *adapdata;

@@ -642,7 +646,7 @@ static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
 	adap->dev.parent = &dev->dev;
 
 	snprintf(adap->name, sizeof(adap->name),
-		"SMBus PIIX4 adapter at %04x", smba);
+		"SMBus PIIX4 adapter %s at %04x", name, smba);
 
 	i2c_set_adapdata(adap, adapdata);
 

@@ -667,6 +671,7 @@ static int piix4_add_adapters_sb800(struct pci_dev *dev, unsigned short smba)
 
 	for (port = 0; port < PIIX4_MAX_ADAPTERS; port++) {
 		retval = piix4_add_adapter(dev, smba,
+					   piix4_main_port_names_sb800[port],
 					   &piix4_main_adapters[port]);
 		if (retval < 0)
 			goto error;

drivers/i2c/busses/i2c-piix4.c +2 -1

 					   &piix4_main_adapters[0]);
 	}
 

@@ -755,7 +760,8 @@ static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	if (retval > 0) {
 		/* Try to add the aux adapter if it exists,
 		 * piix4_add_adapter will clean up if this fails */
-		piix4_add_adapter(dev, retval, &piix4_aux_adapter);
+		piix4_add_adapter(dev, retval, piix4_aux_port_name_sb800,
+				  &piix4_aux_adapter);
 	}
 
 	return 0;

Signature · 1 line

1.9.1

This patch adds support for port names for the SB800 chipset. Since the chipset supports a multiplexed main SMBus controller, adding
the channel name to the adapter name is necessary to differentiate the
ports better (for example in sensors output).

+static const char *piix4_main_port_names_sb800[4] = {

drivers/i2c/busses/i2c-piix4.c +3 -0

+	"SDA0", "SDA2", "SDA3", "SDA4"
 
 
+};
+static const char *piix4_aux_port_name_sb800 = "SDA1";