Changeset c657bd7 in mainline for uspace/drv/char

Timestamp:

2017-11-20T10:06:59Z (8 years ago)

Author:

Jiri Svoboda <jiri@…>

Branches:

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

Children:

19ea61d

Parents:

5d50c419

git-author:

Jiri Svoboda <jiri@…> (2017-11-19 22:05:26)

git-committer:

Jiri Svoboda <jiri@…> (2017-11-20 10:06:59)

Message:

Less is sometimes more. Need chardev_read to be able to return less bytes than requested if less is available. Otherwise cannot read variable-sized packets except yte-by-byte.

Location:

uspace/drv/char

Files:

• i8042/buffer.h (modified) (2 diffs)
• i8042/i8042.c (modified) (1 diff)
• pl050/pl050.c (modified) (2 diffs)

uspace/drv/char/i8042/buffer.h

@@ -113 +113 @@
  *
  * @param buffer Cyclic buffer to read from.
+ * @param rb Place to store byte read
+ * @param wait @c True to wait until byte is available
  *
- * @return Byte read.
+ * @return EOK on success, EAGAIN if @c wait is false and no data is available
  *
  */
-static inline uint8_t buffer_read(buffer_t *buffer)
+static inline int buffer_read(buffer_t *buffer, uint8_t *rb, bool wait)
 {
         fibril_mutex_lock(&buffer->guard);
         
         /* Buffer is empty. */
-        while (buffer->write_head == buffer->read_head)
+        while (wait && buffer->write_head == buffer->read_head)
                 fibril_condvar_wait(&buffer->change, &buffer->guard);
+        
+        if (buffer->write_head == buffer->read_head) {
+                fibril_mutex_unlock(&buffer->guard);
+                return EAGAIN;
+        }
         
         /* Next position. */
@@ -144 +151 @@
         
         fibril_mutex_unlock(&buffer->guard);
-        return data;
+        *rb = data;
+        return EOK;
 }
 

uspace/drv/char/i8042/i8042.c

@@ -374 +374 @@
         i8042_t *i8042 = port->ctl;
         uint8_t *destp = (uint8_t *)dest;
+        int rc;
+        size_t i;
         
         buffer_t *buffer = (port == i8042->aux) ?
             &i8042->aux_buffer : &i8042->kbd_buffer;
         
-        for (size_t i = 0; i < size; ++i)
-                *destp++ = buffer_read(buffer);
-        
-        return size;
+        for (i = 0; i < size; ++i) {
+                rc = buffer_read(buffer, destp, i == 0);
+                if (rc != EOK)
+                        break;
+                ++destp;
+        }
+        
+        return i;
 }
 

uspace/drv/char/pl050/pl050.c

@@ -246 +246 @@
         left = size;
         while (left > 0) {
-                while (pl050->buf_rp == pl050->buf_wp)
+                while (left == size && pl050->buf_rp == pl050->buf_wp)
                         fibril_condvar_wait(&pl050->buf_cv, &pl050->buf_lock);
+                if (pl050->buf_rp == pl050->buf_wp)
+                        break;
                 *bp++ = pl050->buffer[pl050->buf_rp];
                 --left;
@@ -255 +257 @@
         fibril_mutex_unlock(&pl050->buf_lock);
 
-        return size;
+        return size - left;
 }