i2c: piix4: Fix probing of reserved ports on AMD Family 16h Model 30h

Prevent bus timeouts and resets on Family 16h Model 30h by not probing
reserved Ports 3 and 4.

According to the AMD BIOS and Kernel Developer's Guides (BKDG), Port 3
and Port 4 are reserved on the following devices:
 - Family 15h Model 60h-6Fh
 - Family 15h Model 70h-7Fh
 - Family 16h Model 30h-3Fh

Based on earlier work by Andrew Cooks.

Reported-by: Andrew Cooks <andrew.cooks@opengear.com>
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index c46c4bd..d9f7e77 100644 (file)
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -72,7 +72,8 @@
 #define PIIX4_BLOCK_DATA       0x14
 
 /* Multi-port constants */
-#define PIIX4_MAX_ADAPTERS 4
+#define PIIX4_MAX_ADAPTERS     4
+#define HUDSON2_MAIN_PORTS     2 /* HUDSON2, KERNCZ reserves ports 3, 4 */
 
 /* SB800 constants */
 #define SB800_PIIX4_SMB_IDX            0xcd6
@@ -808,6 +809,7 @@ MODULE_DEVICE_TABLE (pci, piix4_ids);
 
 static struct i2c_adapter *piix4_main_adapters[PIIX4_MAX_ADAPTERS];
 static struct i2c_adapter *piix4_aux_adapter;
+static int piix4_adapter_count;
 
 static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
                             bool sb800_main, u8 port, bool notify_imc,
@@ -867,7 +869,15 @@ static int piix4_add_adapters_sb800(struct pci_dev *dev, unsigned short smba,
        int port;
        int retval;
 
-       for (port = 0; port < PIIX4_MAX_ADAPTERS; port++) {
+       if (dev->device == PCI_DEVICE_ID_AMD_KERNCZ_SMBUS ||
+           (dev->device == PCI_DEVICE_ID_AMD_HUDSON2_SMBUS &&
+            dev->revision >= 0x1F)) {
+               piix4_adapter_count = HUDSON2_MAIN_PORTS;
+       } else {
+               piix4_adapter_count = PIIX4_MAX_ADAPTERS;
+       }
+
+       for (port = 0; port < piix4_adapter_count; port++) {
                retval = piix4_add_adapter(dev, smba, true, port, notify_imc,
                                           piix4_main_port_names_sb800[port],
                                           &piix4_main_adapters[port]);
@@ -989,7 +999,7 @@ static void piix4_adap_remove(struct i2c_adapter *adap)
 
 static void piix4_remove(struct pci_dev *dev)
 {
-       int port = PIIX4_MAX_ADAPTERS;
+       int port = piix4_adapter_count;
 
        while (--port >= 0) {
                if (piix4_main_adapters[port]) {