atm: [he] rewrite buffer handling in receive path

Instead of a fixed list of buffers, use the buffer pool correctly and
keep track of the outstanding buffer indexes using a fixed table.
Resolves reported HBUF_ERR's -- failures due to lack of receive buffers.
Signed-off-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/atm/he.h

@@ -198,26 +198,33 @@ struct he_hsp {
 	} group[HE_NUM_GROUPS];
 };
 
-/* figure 2.9 receive buffer pools */
+/*
+ * figure 2.9 receive buffer pools
+ *
+ * since a virtual address might be more than 32 bits, we store an index
+ * in the virt member of he_rbp.  NOTE: the lower six bits in the  rbrq
+ * addr member are used for buffer status further limiting us to 26 bits.
+ */
 
 struct he_rbp {
 	volatile u32 phys;
-	volatile u32 status;
+	volatile u32 idx;	/* virt */
 };
 
-/* NOTE: it is suggested that virt be the virtual address of the host
-   buffer.  on a 64-bit machine, this would not work.  Instead, we
-   store the real virtual address in another list, and store an index
-   (and buffer status) in the virt member.
-*/
+#define RBP_IDX_OFFSET 6
+
+/*
+ * the he dma engine will try to hold an extra 16 buffers in its local
+ * caches.  and add a couple buffers for safety.
+ */
 
-#define RBP_INDEX_OFF	6
-#define RBP_INDEX(x)	(((long)(x) >> RBP_INDEX_OFF) & 0xffff)
-#define RBP_LOANED	0x80000000
-#define RBP_SMALLBUF	0x40000000
+#define RBPL_TABLE_SIZE (CONFIG_RBPL_SIZE + 16 + 2)
 
-struct he_virt {
-	void *virt;
+struct he_buff {
+	struct list_head entry;
+	dma_addr_t mapping;
+	unsigned long len;
+	u8 data[];
 };
 
 #ifdef notyet
@@ -286,10 +293,13 @@ struct he_dev {
 	struct he_rbrq *rbrq_base, *rbrq_head;
 	int rbrq_peak;
 
+	struct he_buff **rbpl_virt;
+	unsigned long *rbpl_table;
+	unsigned long rbpl_hint;
 	struct pci_pool *rbpl_pool;
 	dma_addr_t rbpl_phys;
 	struct he_rbp *rbpl_base, *rbpl_tail;
-	struct he_virt *rbpl_virt;
+	struct list_head rbpl_outstanding;
 	int rbpl_peak;
 
 	dma_addr_t tbrq_phys;
@@ -304,20 +314,12 @@ struct he_dev {
 	struct he_dev *next;
 };
 
-struct he_iovec
-{
-	u32 iov_base;
-	u32 iov_len;
-};
-
 #define HE_MAXIOV 20
 
 struct he_vcc
 {
-	struct he_iovec iov_head[HE_MAXIOV];
-	struct he_iovec *iov_tail;
+	struct list_head buffers;
 	int pdu_len;
-
 	int rc_index;
 
 	wait_queue_head_t rx_waitq;