Changeset 1adbf90 in mainline

Timestamp:

2011-12-08T14:09:24Z (13 years ago)

Author:

Martin Decky <martin@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

28f8f170, c5ebb59

Parents:

190c943

Message:

make the i8042 driver just a slightly more robust
(timeout if the device is not behaving as expected to avoid infinite loop)

File:

• kernel/genarch/src/drivers/i8042/i8042.c (modified) (7 diffs)

kernel/genarch/src/drivers/i8042/i8042.c

@@ -44 +44 @@
 #include <mm/slab.h>
 #include <ddi/device.h>
+#include <time/delay.h>
 
 #define i8042_SET_COMMAND  0x60
@@ -51 +52 @@
 #define i8042_BUFFER_FULL_MASK  0x01
 #define i8042_WAIT_MASK         0x02
+
+#define i8042_TIMEOUT  65536
 
 static irq_ownership_t i8042_claim(irq_t *irq)
@@ -77 +80 @@
 static void i8042_clear_buffer(i8042_t *dev)
 {
-        while (pio_read_8(&dev->status) & i8042_BUFFER_FULL_MASK)
+        for (uint32_t i = 0; i < i8042_TIMEOUT; i++) {
+                if ((pio_read_8(&dev->status) & i8042_BUFFER_FULL_MASK) == 0)
+                        break;
+                
                 (void) pio_read_8(&dev->data);
+                delay(50);  /* 50 us think time */
+        }
+}
+
+static void i8042_send_command(i8042_t *dev, uint8_t cmd)
+{
+        for (uint32_t i = 0; i < i8042_TIMEOUT; i++) {
+                if ((pio_read_8(&dev->status) & i8042_WAIT_MASK) == 0)
+                        break;
+                
+                delay(50);  /* 50 us think time */
+        }
+        
+        pio_write_8(&dev->status, cmd);
+        delay(10000);  /* 10 ms think time */
 }
 
@@ -84 +105 @@
 i8042_instance_t *i8042_init(i8042_t *dev, inr_t inr)
 {
-        i8042_instance_t *instance
-            = malloc(sizeof(i8042_instance_t), FRAME_ATOMIC);
+        i8042_instance_t *instance =
+            malloc(sizeof(i8042_instance_t), FRAME_ATOMIC);
         if (instance) {
                 instance->i8042 = dev;
@@ -96 +117 @@
                 instance->irq.handler = i8042_irq_handler;
                 instance->irq.instance = instance;
-                
         }
         
@@ -107 +127 @@
         ASSERT(kbrdin);
         
+        i8042_clear_buffer(instance->i8042);
+        
         instance->kbrdin = kbrdin;
         irq_register(&instance->irq);
-        i8042_clear_buffer(instance->i8042);
 }
 
@@ -116 +137 @@
 {
         interrupts_disable();
-        
         i8042_clear_buffer(dev);
-        
-        /* Reset CPU */
-        pio_write_8(&dev->status, i8042_CPU_RESET);
+        i8042_send_command(dev, i8042_CPU_RESET);
 }