ar71xx: improve ethernet driver cache footprint by removing an unnecessary pointer

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@43588 3c298f89-4303-0410-b956-a3cf2f4a3e73

diff --git a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
index 2d7c963..b18c20b 100644 (file)
--- a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
+++ b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
@@ -90,7 +90,6 @@ struct ag71xx_buf {
                struct sk_buff  *skb;
                void            *rx_buf;
        };
-       struct ag71xx_desc      *desc;
        union {
                dma_addr_t      dma_addr;
                unsigned long   timestamp;
@@ -203,6 +202,12 @@ static inline int ag71xx_desc_empty(struct ag71xx_desc *desc)
        return (desc->ctrl & DESC_EMPTY) != 0;
 }
 
+static inline struct ag71xx_desc *
+ag71xx_ring_desc(struct ag71xx_ring *ring, int idx)
+{
+       return (struct ag71xx_desc *) &ring->descs_cpu[idx * ring->desc_size];
+}
+
 /* Register offsets */
 #define AG71XX_REG_MAC_CFG1    0x0000
 #define AG71XX_REG_MAC_CFG2    0x0004

diff --git a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_debugfs.c b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_debugfs.c
index 757a572..c480121 100644 (file)
--- a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_debugfs.c
+++ b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_debugfs.c
@@ -183,6 +183,7 @@ static ssize_t read_file_ring(struct file *file, char __user *user_buf,
        desc_hw = ag71xx_rr(ag, desc_reg);
        for (i = 0; i < ring->size; i++) {
                struct ag71xx_buf *ab = &ring->buf[i];
+               struct ag71xx_desc *desc = ag71xx_ring_desc(ring, i);
                u32 desc_dma = ((u32) ring->descs_dma) + i * ring->desc_size;
 
                len += snprintf(buf + len, buflen - len,
@@ -192,10 +193,10 @@ static ssize_t read_file_ring(struct file *file, char __user *user_buf,
                        (i == dirty) ? 'D' : ' ',
                        (desc_hw == desc_dma) ? 'H' : ' ',
                        desc_dma,
-                       ab->desc->next,
-                       ab->desc->data,
-                       ab->desc->ctrl,
-                       (ab->desc->ctrl & DESC_EMPTY) ? 'E' : '*',
+                       desc->next,
+                       desc->data,
+                       desc->ctrl,
+                       (desc->ctrl & DESC_EMPTY) ? 'E' : '*',
                        ab->timestamp);
        }
 

diff --git a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
index 259cc20..5ef324e 100644 (file)
--- a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
+++ b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
@@ -100,7 +100,6 @@ static void ag71xx_ring_free(struct ag71xx_ring *ring)
 static int ag71xx_ring_alloc(struct ag71xx_ring *ring)
 {
        int err;
-       int i;
 
        ring->desc_size = sizeof(struct ag71xx_desc);
        if (ring->desc_size % cache_line_size()) {
@@ -124,13 +123,6 @@ static int ag71xx_ring_alloc(struct ag71xx_ring *ring)
                goto err;
        }
 
-       for (i = 0; i < ring->size; i++) {
-               int idx = i * ring->desc_size;
-               ring->buf[i].desc = (struct ag71xx_desc *)&ring->descs_cpu[idx];
-               DBG("ag71xx: ring %p, desc %d at %p\n",
-                       ring, i, ring->buf[i].desc);
-       }
-
        return 0;
 
 err:
@@ -144,10 +136,12 @@ static void ag71xx_ring_tx_clean(struct ag71xx *ag)
        u32 bytes_compl = 0, pkts_compl = 0;
 
        while (ring->curr != ring->dirty) {
+               struct ag71xx_desc *desc;
                u32 i = ring->dirty % ring->size;
 
-               if (!ag71xx_desc_empty(ring->buf[i].desc)) {
-                       ring->buf[i].desc->ctrl = 0;
+               desc = ag71xx_ring_desc(ring, i);
+               if (!ag71xx_desc_empty(desc)) {
+                       desc->ctrl = 0;
                        dev->stats.tx_errors++;
                }
 
@@ -172,10 +166,12 @@ static void ag71xx_ring_tx_init(struct ag71xx *ag)
        int i;
 
        for (i = 0; i < ring->size; i++) {
-               ring->buf[i].desc->next = (u32) (ring->descs_dma +
+               struct ag71xx_desc *desc = ag71xx_ring_desc(ring, i);
+
+               desc->next = (u32) (ring->descs_dma +
                        ring->desc_size * ((i + 1) % ring->size));
 
-               ring->buf[i].desc->ctrl = DESC_EMPTY;
+               desc->ctrl = DESC_EMPTY;
                ring->buf[i].skb = NULL;
        }
 
@@ -222,6 +218,8 @@ static int ag71xx_buffer_offset(struct ag71xx *ag)
 static bool ag71xx_fill_rx_buf(struct ag71xx *ag, struct ag71xx_buf *buf,
                               int offset)
 {
+       struct ag71xx_ring *ring = &ag->rx_ring;
+       struct ag71xx_desc *desc = ag71xx_ring_desc(ring, buf - &ring->buf[0]);
        void *data;
 
        data = kmalloc(ag->rx_buf_size +
@@ -233,7 +231,7 @@ static bool ag71xx_fill_rx_buf(struct ag71xx *ag, struct ag71xx_buf *buf,
        buf->rx_buf = data;
        buf->dma_addr = dma_map_single(&ag->dev->dev, data, ag->rx_buf_size,
                                       DMA_FROM_DEVICE);
-       buf->desc->data = (u32) buf->dma_addr + offset;
+       desc->data = (u32) buf->dma_addr + offset;
        return true;
 }
 
@@ -246,21 +244,24 @@ static int ag71xx_ring_rx_init(struct ag71xx *ag)
 
        ret = 0;
        for (i = 0; i < ring->size; i++) {
-               ring->buf[i].desc->next = (u32) (ring->descs_dma +
+               struct ag71xx_desc *desc = ag71xx_ring_desc(ring, i);
+
+               desc->next = (u32) (ring->descs_dma +
                        ring->desc_size * ((i + 1) % ring->size));
 
                DBG("ag71xx: RX desc at %p, next is %08x\n",
-                       ring->buf[i].desc,
-                       ring->buf[i].desc->next);
+                       desc, desc->next);
        }
 
        for (i = 0; i < ring->size; i++) {
+               struct ag71xx_desc *desc = ag71xx_ring_desc(ring, i);
+
                if (!ag71xx_fill_rx_buf(ag, &ring->buf[i], offset)) {
                        ret = -ENOMEM;
                        break;
                }
 
-               ring->buf[i].desc->ctrl = DESC_EMPTY;
+               desc->ctrl = DESC_EMPTY;
        }
 
        /* flush descriptors */
@@ -280,15 +281,17 @@ static int ag71xx_ring_rx_refill(struct ag71xx *ag)
 
        count = 0;
        for (; ring->curr - ring->dirty > 0; ring->dirty++) {
+               struct ag71xx_desc *desc;
                unsigned int i;
 
                i = ring->dirty % ring->size;
+               desc = ag71xx_ring_desc(ring, i);
 
                if (!ring->buf[i].rx_buf &&
                    !ag71xx_fill_rx_buf(ag, &ring->buf[i], offset))
                        break;
 
-               ring->buf[i].desc->ctrl = DESC_EMPTY;
+               desc->ctrl = DESC_EMPTY;
                count++;
        }
 
@@ -697,7 +700,7 @@ static int ag71xx_fill_dma_desc(struct ag71xx_ring *ring, u32 addr, int len)
                unsigned int cur_len = len;
 
                i = (ring->curr + ndesc) % ring->size;
-               desc = ring->buf[i].desc;
+               desc = ag71xx_ring_desc(ring, i);
 
                if (!ag71xx_desc_empty(desc))
                        return -1;
@@ -752,7 +755,7 @@ static netdev_tx_t ag71xx_hard_start_xmit(struct sk_buff *skb,
                                  DMA_TO_DEVICE);
 
        i = ring->curr % ring->size;
-       desc = ring->buf[i].desc;
+       desc = ag71xx_ring_desc(ring, i);
 
        /* setup descriptor fields */
        n = ag71xx_fill_dma_desc(ring, (u32) dma_addr, skb->len & ag->desc_pktlen_mask);
@@ -907,7 +910,7 @@ static int ag71xx_tx_packets(struct ag71xx *ag)
 
        while (ring->dirty + n != ring->curr) {
                unsigned int i = (ring->dirty + n) % ring->size;
-               struct ag71xx_desc *desc = ring->buf[i].desc;
+               struct ag71xx_desc *desc = ag71xx_ring_desc(ring, i);
                struct sk_buff *skb = ring->buf[i].skb;
 
                if (!ag71xx_desc_empty(desc)) {
@@ -963,7 +966,7 @@ static int ag71xx_rx_packets(struct ag71xx *ag, int limit)
 
        while (done < limit) {
                unsigned int i = ring->curr % ring->size;
-               struct ag71xx_desc *desc = ring->buf[i].desc;
+               struct ag71xx_desc *desc = ag71xx_ring_desc(ring, i);
                struct sk_buff *skb;
                int pktlen;
                int err = 0;