Changeset 2448

Timestamp:

04/18/04 02:38:28 (9 years ago)

Author:

mds

Message:

support detection of eeprom shadows we now know are

software write-protect registers.
prevent Vaio detection from running more than once.
update eeprom driver documentation.

Location:

lm-sensors/trunk

Files:

• CHANGES (modified) (1 diff)
• doc/chips/eeprom (modified) (4 diffs)
• prog/detect/sensors-detect (modified) (4 diffs)

lm-sensors/trunk/CHANGES

@@ -46 +46 @@
                           Scan all logical devices of PC87365 and PC87366
                           Detect LM92, LM76, MAX6633, MAX6634, MAX6635
+                          Detect eeproms with software write protect
 
 

lm-sensors/trunk/doc/chips/eeprom

@@ -8 +8 @@
     Prefix `eeprom'
     Addresses scanned: I2C 0x50 - 0x57 (inclusive)
-    Datasheets: Publicly available from Atmel (www.atmel.com),
-                Fairchild (www.fairchildsemi.com), and
-                Microchip (www.microchip.com)
+    Datasheets: Publicly available from:
+                Atmel (www.atmel.com),
+                Catalyst (www.catsemi.com),
+                Fairchild (www.fairchildsemi.com),
+                Microchip (www.microchip.com),
+                Philips (www.semiconductor.philips.com),
+                Rohm (www.rohm.com),
+                ST (www.st.com),        
+                Xicor (www.xicor.com)           
 
         Chip     Size (bits)    Address
@@ -22 +28 @@
         24C16    16K            0x50 (additional data at 0x51 - 0x57)
         Sony      2K            0x57
+        Microchip 24AA52  2K    0x50 - 0x57, SW write protect at 0x30-37
+        ST M34C02         2K    0x50 - 0x57, SW write protect at 0x30-37
 
 
@@ -73 +81 @@
 specification, so it is guess work and far from being complete.
 
+The Microchip 24AA52/24LCS52 and the ST M34C02 support an additional
+software write protect register at 0x30 - 0x37 (0x20 less than the
+memory location). The chip responds to "write quick" detection at this
+address but does not respond to byte reads.
+If this register is present, the lower 128 bytes of the memory
+array are not write protected. Any byte data write to this address
+will write protect the memory array permanently, and the device
+will no longer respond at the 0x30-37 address.
+The eeprom driver does not support this register.
 
 Lacking functionality:
@@ -85 +102 @@
 * Enable Writing.  Again, no technical reason why not, but making it easy
 to change the contents of the EEPROMs (on DIMMs anyway) also makes it easy
-to disable the DIMMs until the values are restored somehow.
+to disable the DIMMs (potentially preventing the computer from booting)
+until the values are restored somehow.
 
 

lm-sensors/trunk/prog/detect/sensors-detect

@@ -1245 +1245 @@
        i2c_addrs => [0x57],
        i2c_detect => sub { eeprom_detect 1, @_ },
+     },
+     {
+       name => "SPD EEPROM with Software Write-Protect",
+       driver => "eeprom",
+       i2c_addrs => [0x50..0x57],
+       i2c_detect => sub { eeprom_detect 2, @_ },
      },
      {
@@ -3673 +3679 @@
 }
 
-# $_[0]: Chip to detect (0 = SPD EEPROM, 1 = Sony Vaio EEPROM)
+# $_[0]: Chip to detect (0 = SPD EEPROM, 1 = Sony Vaio EEPROM
+#                        2 = SPD EEPROM with Software Write Protect)
 # $_[1]: A reference to the file descriptor to access this chip
 # $_[2]: Address
@@ -3688 +3695 @@
 {
   my ($chip,$file,$addr) = @_;
+  my $checksum = 0;
 
   # Check the checksum for validity (works for most DIMMs and RIMMs)
-  my $checksum = 0;
-  for (my $i = 0; $i <= 62; $i ++) {
-    $checksum += i2c_smbus_read_byte_data($file,$i);
-  }
-  $checksum &= 255;
-  return 8
-    if $chip == 0 and i2c_smbus_read_byte_data($file,63) == $checksum;
-
-  # Look for a Sony Vaio EEPROM
+  if ($chip != 1) {
+          for (my $i = 0; $i <= 62; $i ++) {
+            $checksum += i2c_smbus_read_byte_data($file,$i);
+          }
+          $checksum &= 255;
+          $checksum -= i2c_smbus_read_byte_data($file,63);
+  }     
+  if ($chip == 0) {
+        if($checksum == 0) {
+                return 8;
+        } else {
+                return 1;
+        }
+  }     
+  if ($chip == 2) {
+        # check for 'shadow' write-protect register at 0x30-37
+        i2c_set_slave_addr($file,$addr - 0x20);
+        if(i2c_smbus_write_quick($file,$SMBUS_WRITE) >= 0 &&
+           i2c_smbus_read_byte_data($file,0x80) == -1) {
+                if($checksum == 0) {
+                        return (9, $addr - 0x20);
+                } else {
+                        return (2, $addr - 0x20);
+                }
+        }
+  }
+
+  # Look for a Sony Vaio EEPROM ($chip == 1)
   my $vaioconf = 1;
   $vaioconf += 4
@@ -3719 +3746 @@
 
   if ($vaioconf > 1) {
-    return if $chip != 1;
     return $vaioconf;
   }
-
-  # Even if all tests fail, it still may be an eeprom
-  return if $chip != 0;
-  # Default to SPD EEPROM
-  return 1;
+  return;
 }