Add alloc_iob() and free_iob(). (Direct search-and-replace

equivalents for alloc_pkb() and free_pkb(), which will be retired in
due course).

src/include/gpxe/iobuf.h

@@ -11,6 +11,26 @@
 #include <assert.h>
 #include <gpxe/list.h>
 
+/**
+ * I/O buffer alignment
+ *
+ * I/O buffers allocated via alloc_iob() are guaranteed to be
+ * physically aligned to this boundary.  Some cards cannot DMA across
+ * a 4kB boundary.  With a standard Ethernet MTU, aligning to a 2kB
+ * boundary is sufficient to guarantee no 4kB boundary crossings.  For
+ * a jumbo Ethernet MTU, a packet may be larger than 4kB anyway.
+ */
+#define IOB_ALIGN 2048
+
+/**
+ * Minimum I/O buffer length
+ *
+ * alloc_iob() will round up the allocated length to this size if
+ * necessary.  This is used on behalf of hardware that is not capable
+ * of auto-padding.
+ */
+#define IOB_ZLEN 64
+
 /**
  * A persistent I/O buffer
  *
@@ -40,109 +60,109 @@ struct io_buffer {
 /**
  * Reserve space at start of I/O buffer
  *
- * @v iob	I/O buffer
+ * @v iobuf	I/O buffer
  * @v len	Length to reserve
  * @ret data	Pointer to new start of buffer
  */
-static inline void * iob_reserve ( struct io_buffer *iob, size_t len ) {
-	iob->data += len;
-	iob->tail += len;
-	assert ( iob->tail <= iob->end );
-	return iob->data;
+static inline void * iob_reserve ( struct io_buffer *iobuf, size_t len ) {
+	iobuf->data += len;
+	iobuf->tail += len;
+	assert ( iobuf->tail <= iobuf->end );
+	return iobuf->data;
 }
 
 /**
  * Add data to start of I/O buffer
  *
- * @v iob	I/O buffer
+ * @v iobuf	I/O buffer
  * @v len	Length to add
  * @ret data	Pointer to new start of buffer
  */
-static inline void * iob_push ( struct io_buffer *iob, size_t len ) {
-	iob->data -= len;
-	assert ( iob->data >= iob->head );
-	return iob->data;
+static inline void * iob_push ( struct io_buffer *iobuf, size_t len ) {
+	iobuf->data -= len;
+	assert ( iobuf->data >= iobuf->head );
+	return iobuf->data;
 }
 
 /**
  * Remove data from start of I/O buffer
  *
- * @v iob	I/O buffer
+ * @v iobuf	I/O buffer
  * @v len	Length to remove
  * @ret data	Pointer to new start of buffer
  */
-static inline void * iob_pull ( struct io_buffer *iob, size_t len ) {
-	iob->data += len;
-	assert ( iob->data <= iob->tail );
-	return iob->data;
+static inline void * iob_pull ( struct io_buffer *iobuf, size_t len ) {
+	iobuf->data += len;
+	assert ( iobuf->data <= iobuf->tail );
+	return iobuf->data;
 }
 
 /**
  * Add data to end of I/O buffer
  *
- * @v iob	I/O buffer
+ * @v iobuf	I/O buffer
  * @v len	Length to add
  * @ret data	Pointer to newly added space
  */
-static inline void * iob_put ( struct io_buffer *iob, size_t len ) {
-	void *old_tail = iob->tail;
-	iob->tail += len;
-	assert ( iob->tail <= iob->end );
+static inline void * iob_put ( struct io_buffer *iobuf, size_t len ) {
+	void *old_tail = iobuf->tail;
+	iobuf->tail += len;
+	assert ( iobuf->tail <= iobuf->end );
 	return old_tail;
 }
 
 /**
  * Remove data from end of I/O buffer
  *
- * @v iob	I/O buffer
+ * @v iobuf	I/O buffer
  * @v len	Length to remove
  */
-static inline void iob_unput ( struct io_buffer *iob, size_t len ) {
-	iob->tail -= len;
-	assert ( iob->tail >= iob->data );
+static inline void iob_unput ( struct io_buffer *iobuf, size_t len ) {
+	iobuf->tail -= len;
+	assert ( iobuf->tail >= iobuf->data );
 }
 
 /**
  * Empty an I/O buffer
  *
- * @v iob	I/O buffer
+ * @v iobuf	I/O buffer
  */
-static inline void iob_empty ( struct io_buffer *iob ) {
-	iob->tail = iob->data;
+static inline void iob_empty ( struct io_buffer *iobuf ) {
+	iobuf->tail = iobuf->data;
 }
 
 /**
  * Calculate length of data in an I/O buffer
  *
- * @v iob	I/O buffer
+ * @v iobuf	I/O buffer
  * @ret len	Length of data in buffer
  */
-static inline size_t iob_len ( struct io_buffer *iob ) {
-	return ( iob->tail - iob->data );
+static inline size_t iob_len ( struct io_buffer *iobuf ) {
+	return ( iobuf->tail - iobuf->data );
 }
 
 /**
  * Calculate available space at start of an I/O buffer
  *
- * @v iob	I/O buffer
+ * @v iobuf	I/O buffer
  * @ret len	Length of data available at start of buffer
  */
-static inline size_t iob_headroom ( struct io_buffer *iob ) {
-	return ( iob->data - iob->head );
+static inline size_t iob_headroom ( struct io_buffer *iobuf ) {
+	return ( iobuf->data - iobuf->head );
 }
 
 /**
  * Calculate available space at end of an I/O buffer
  *
- * @v iob	I/O buffer
+ * @v iobuf	I/O buffer
  * @ret len	Length of data available at end of buffer
  */
-static inline size_t iob_tailroom ( struct io_buffer *iob ) {
-	return ( iob->end - iob->tail );
+static inline size_t iob_tailroom ( struct io_buffer *iobuf ) {
+	return ( iobuf->end - iobuf->tail );
 }
 
 extern struct io_buffer * alloc_iob ( size_t len );
-extern void free_iob ( struct io_buffer *iob );
-extern void iob_pad ( struct io_buffer *iob, size_t min_len );
+extern void free_iob ( struct io_buffer *iobuf );
+extern void iob_pad ( struct io_buffer *iobuf, size_t min_len );
 
 #endif /* _GPXE_IOBUF_H */