[PATCH] spidernet: rework tx queue handling

With this patch TX queue descriptors are not chained per default any more.
The pointer to next descriptor is set only when next descriptor is prepaired
for transfer. Also the mechanism of checking wether Spider is ready has been
changed: it checks not for CARDOWNED flag in status of previous descriptor
but for a TXDMAENABLED flag in Spider's register.
Signed-off-by: Maxim Shchetynin <maxim@de.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Jens Osterkamp <Jens.Osterkamp@de.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/spider_net.h

@@ -208,7 +208,10 @@ extern char spider_net_driver_name[];
 #define SPIDER_NET_DMA_RX_VALUE		0x80000000
 #define SPIDER_NET_DMA_RX_FEND_VALUE	0x00030003
 /* to set TX_DMA_EN */
-#define SPIDER_NET_DMA_TX_VALUE		0x80000000
+#define SPIDER_NET_TX_DMA_EN		0x80000000
+#define SPIDER_NET_GDTDCEIDIS		0x00000002
+#define SPIDER_NET_DMA_TX_VALUE		SPIDER_NET_TX_DMA_EN | \
+					SPIDER_NET_GDTDCEIDIS
 #define SPIDER_NET_DMA_TX_FEND_VALUE	0x00030003
 
 /* SPIDER_NET_UA_DESCR_VALUE is OR'ed with the unicast address */
@@ -332,52 +335,20 @@ enum spider_net_int2_status {
 #define SPIDER_NET_GPREXEC			0x80000000
 #define SPIDER_NET_GPRDAT_MASK			0x0000ffff
 
-/* descriptor bits
- *
- * 1010					descriptor ready
- *     0				descr in middle of chain
- *      000				fixed to 0
- *
- *         0				no interrupt on completion
- *          000				fixed to 0
- *             1			no ipsec processing
- *              1			last descriptor for this frame
- *               00			no checksum
- *               10			tcp checksum
- *               11			udp checksum
- *
- *                 00			fixed to 0
- *                   0			fixed to 0
- *                    0			no interrupt on response errors
- *                     0		no interrupt on invalid descr
- *                      0		no interrupt on dma process termination
- *                       0		no interrupt on descr chain end
- *                        0		no interrupt on descr complete
- *
- *                         000		fixed to 0
- *                            0		response error interrupt status
- *                             0	invalid descr status
- *                              0	dma termination status
- *                               0	descr chain end status
- *                                0	descr complete status */
-#define SPIDER_NET_DMAC_CMDSTAT_NOCS	0xa00c0000
-#define SPIDER_NET_DMAC_CMDSTAT_TCPCS	0xa00e0000
-#define SPIDER_NET_DMAC_CMDSTAT_UDPCS	0xa00f0000
-#define SPIDER_NET_DESCR_IND_PROC_SHIFT	28
-#define SPIDER_NET_DESCR_IND_PROC_MASKO	0x0fffffff
-
-/* descr ready, descr is in middle of chain, get interrupt on completion */
-#define SPIDER_NET_DMAC_RX_CARDOWNED	0xa0800000
-
-enum spider_net_descr_status {
-	SPIDER_NET_DESCR_COMPLETE		= 0x00, /* used in rx and tx */
-	SPIDER_NET_DESCR_RESPONSE_ERROR		= 0x01, /* used in rx and tx */
-	SPIDER_NET_DESCR_PROTECTION_ERROR	= 0x02, /* used in rx and tx */
-	SPIDER_NET_DESCR_FRAME_END		= 0x04, /* used in rx */
-	SPIDER_NET_DESCR_FORCE_END		= 0x05, /* used in rx and tx */
-	SPIDER_NET_DESCR_CARDOWNED		= 0x0a, /* used in rx and tx */
-	SPIDER_NET_DESCR_NOT_IN_USE /* any other value */
-};
+#define SPIDER_NET_DMAC_NOINTR_COMPLETE		0x00800000
+#define SPIDER_NET_DMAC_NOCS			0x00040000
+#define SPIDER_NET_DMAC_TCP			0x00020000
+#define SPIDER_NET_DMAC_UDP			0x00030000
+#define SPIDER_NET_TXDCEST			0x08000000
+
+#define SPIDER_NET_DESCR_IND_PROC_MASK		0xF0000000
+#define SPIDER_NET_DESCR_COMPLETE		0x00000000 /* used in rx and tx */
+#define SPIDER_NET_DESCR_RESPONSE_ERROR		0x10000000 /* used in rx and tx */
+#define SPIDER_NET_DESCR_PROTECTION_ERROR	0x20000000 /* used in rx and tx */
+#define SPIDER_NET_DESCR_FRAME_END		0x40000000 /* used in rx */
+#define SPIDER_NET_DESCR_FORCE_END		0x50000000 /* used in rx and tx */
+#define SPIDER_NET_DESCR_CARDOWNED		0xA0000000 /* used in rx and tx */
+#define SPIDER_NET_DESCR_NOT_IN_USE		0xF0000000
 
 struct spider_net_descr {
 	/* as defined by the hardware */
@@ -398,7 +369,7 @@ struct spider_net_descr {
 } __attribute__((aligned(32)));
 
 struct spider_net_descr_chain {
-	/* we walk from tail to head */
+	spinlock_t lock;
 	struct spider_net_descr *head;
 	struct spider_net_descr *tail;
 };
@@ -453,8 +424,6 @@ struct spider_net_card {
 
 	struct spider_net_descr_chain tx_chain;
 	struct spider_net_descr_chain rx_chain;
-	atomic_t rx_chain_refill;
-	atomic_t tx_chain_release;
 
 	struct net_device_stats netdev_stats;