stmmac: review RX/TX ring management

This patch is to rework the ring management now optimized.
The indexes into the ring buffer are always incremented, and
the entry is accessed via doing a modulo to find the "real"
position in the ring.
It is inefficient, modulo is an expensive operation.

The formula [(entry + 1) & (size - 1)] is now adopted on
a ring that is power-of-2 in size.
Then, the number of elements cannot be set by command line but
it is fixed.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: Alexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
index cf28daba4346f0c288d1718513554b38e4de2176..2763772ef1d481b28e37a1a73c0fd9974506a3c7 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
+++ b/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
@@ -31,8 +31,7 @@
 static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
 {
        struct stmmac_priv *priv = (struct stmmac_priv *)p;
-       unsigned int txsize = priv->dma_tx_size;
-       unsigned int entry = priv->cur_tx % txsize;
+       unsigned int entry = priv->cur_tx;
        struct dma_desc *desc = priv->dma_tx + entry;
        unsigned int nopaged_len = skb_headlen(skb);
        unsigned int bmax;
@@ -54,7 +53,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
 
        while (len != 0) {
                priv->tx_skbuff[entry] = NULL;
-               entry = (++priv->cur_tx) % txsize;
+               entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
                desc = priv->dma_tx + entry;
 
                if (len > bmax) {
@@ -82,6 +81,9 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
                        len = 0;
                }
        }
+
+       priv->cur_tx = entry;
+
        return entry;
 }
 
@@ -138,7 +140,7 @@ static void stmmac_refill_desc3(void *priv_ptr, struct dma_desc *p)
                 */
                p->des3 = (unsigned int)(priv->dma_rx_phy +
                                         (((priv->dirty_rx) + 1) %
-                                         priv->dma_rx_size) *
+                                         DMA_RX_SIZE) *
                                         sizeof(struct dma_desc));
 }
 
@@ -151,10 +153,9 @@ static void stmmac_clean_desc3(void *priv_ptr, struct dma_desc *p)
                 * 1588-2002 time stamping is enabled, hence reinitialize it
                 * to keep explicit chaining in the descriptor.
                 */
-               p->des3 = (unsigned int)(priv->dma_tx_phy +
-                                        (((priv->dirty_tx + 1) %
-                                          priv->dma_tx_size) *
-                                         sizeof(struct dma_desc)));
+               p->des3 = (unsigned int)((priv->dma_tx_phy +
+                                         ((priv->dirty_tx + 1) % DMA_TX_SIZE))
+                                         * sizeof(struct dma_desc));
 }
 
 const struct stmmac_mode_ops chain_mode_ops = {

diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
index 586a33624dd23a5f38dc8b4e6bcdf72a2b609ac3..09291af1903950a814e95dc6fc53c910f3da8dc4 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/common.h
+++ b/drivers/net/ethernet/stmicro/stmmac/common.h
@@ -42,6 +42,10 @@
 #define        DWMAC_CORE_3_40 0x34
 #define        DWMAC_CORE_3_50 0x35
 
+#define DMA_TX_SIZE 512
+#define DMA_RX_SIZE 512
+#define STMMAC_GET_ENTRY(x, size)      ((x + 1) & (size - 1))
+
 #undef FRAME_FILTER_DEBUG
 /* #define FRAME_FILTER_DEBUG */
 

diff --git a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
index 5dd50c6cda5be0280e235152057a329a89fb187c..4358a87fbc6e9190cabd2db09d2eb7789b5a775e 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
+++ b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
@@ -31,8 +31,7 @@
 static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
 {
        struct stmmac_priv *priv = (struct stmmac_priv *)p;
-       unsigned int txsize = priv->dma_tx_size;
-       unsigned int entry = priv->cur_tx % txsize;
+       unsigned int entry = priv->cur_tx;
        struct dma_desc *desc;
        unsigned int nopaged_len = skb_headlen(skb);
        unsigned int bmax, len;
@@ -62,7 +61,7 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
                                                STMMAC_RING_MODE);
                wmb();
                priv->tx_skbuff[entry] = NULL;
-               entry = (++priv->cur_tx) % txsize;
+               entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
 
                if (priv->extend_desc)
                        desc = (struct dma_desc *)(priv->dma_etx + entry);
@@ -90,6 +89,8 @@ static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
                                                STMMAC_RING_MODE);
        }
 
+       priv->cur_tx = entry;
+
        return entry;
 }
 

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index 1f3b33a6c6a8f8bd68f1b2313bc9ea93eb470ed4..7ae7c6430a3fe9054a821012df95b683cc848289 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -54,7 +54,6 @@ struct stmmac_priv {
        struct sk_buff **tx_skbuff;
        unsigned int cur_tx;
        unsigned int dirty_tx;
-       unsigned int dma_tx_size;
        u32 tx_count_frames;
        u32 tx_coal_frames;
        u32 tx_coal_timer;
@@ -71,7 +70,6 @@ struct stmmac_priv {
        struct sk_buff **rx_skbuff;
        unsigned int cur_rx;
        unsigned int dirty_rx;
-       unsigned int dma_rx_size;
        unsigned int dma_buf_sz;
        u32 rx_riwt;
        int hwts_rx_en;

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 89c26268822e8742a51853d7f4563c16e33b33c5..eb555f0fe81585d107c1a445a432175869e68d4c 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -71,15 +71,7 @@ static int phyaddr = -1;
 module_param(phyaddr, int, S_IRUGO);
 MODULE_PARM_DESC(phyaddr, "Physical device address");
 
-#define DMA_TX_SIZE 256
-static int dma_txsize = DMA_TX_SIZE;
-module_param(dma_txsize, int, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(dma_txsize, "Number of descriptors in the TX list");
-
-#define DMA_RX_SIZE 256
-static int dma_rxsize = DMA_RX_SIZE;
-module_param(dma_rxsize, int, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(dma_rxsize, "Number of descriptors in the RX list");
+#define STMMAC_TX_THRESH       (DMA_TX_SIZE / 4)
 
 static int flow_ctrl = FLOW_OFF;
 module_param(flow_ctrl, int, S_IRUGO | S_IWUSR);
@@ -134,10 +126,6 @@ static void stmmac_verify_args(void)
 {
        if (unlikely(watchdog < 0))
                watchdog = TX_TIMEO;
-       if (unlikely(dma_rxsize < 0))
-               dma_rxsize = DMA_RX_SIZE;
-       if (unlikely(dma_txsize < 0))
-               dma_txsize = DMA_TX_SIZE;
        if (unlikely((buf_sz < DEFAULT_BUFSIZE) || (buf_sz > BUF_SIZE_16KiB)))
                buf_sz = DEFAULT_BUFSIZE;
        if (unlikely(flow_ctrl > 1))
@@ -197,12 +185,28 @@ static void print_pkt(unsigned char *buf, int len)
        print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, buf, len);
 }
 
-/* minimum number of free TX descriptors required to wake up TX process */
-#define STMMAC_TX_THRESH(x)    (x->dma_tx_size/4)
-
 static inline u32 stmmac_tx_avail(struct stmmac_priv *priv)
 {
-       return priv->dirty_tx + priv->dma_tx_size - priv->cur_tx - 1;
+       unsigned avail;
+
+       if (priv->dirty_tx > priv->cur_tx)
+               avail = priv->dirty_tx - priv->cur_tx - 1;
+       else
+               avail = DMA_TX_SIZE - priv->cur_tx + priv->dirty_tx - 1;
+
+       return avail;
+}
+
+static inline u32 stmmac_rx_dirty(struct stmmac_priv *priv)
+{
+       unsigned dirty;
+
+       if (priv->dirty_rx <= priv->cur_rx)
+               dirty = priv->cur_rx - priv->dirty_rx;
+       else
+               dirty = DMA_RX_SIZE - priv->dirty_rx + priv->cur_rx;
+
+       return dirty;
 }
 
 /**
@@ -906,19 +910,16 @@ static void stmmac_display_ring(void *head, int size, int extend_desc)
 
 static void stmmac_display_rings(struct stmmac_priv *priv)
 {
-       unsigned int txsize = priv->dma_tx_size;
-       unsigned int rxsize = priv->dma_rx_size;
-
        if (priv->extend_desc) {
                pr_info("Extended RX descriptor ring:\n");
-               stmmac_display_ring((void *)priv->dma_erx, rxsize, 1);
+               stmmac_display_ring((void *)priv->dma_erx, DMA_RX_SIZE, 1);
                pr_info("Extended TX descriptor ring:\n");
-               stmmac_display_ring((void *)priv->dma_etx, txsize, 1);
+               stmmac_display_ring((void *)priv->dma_etx, DMA_TX_SIZE, 1);
        } else {
                pr_info("RX descriptor ring:\n");
-               stmmac_display_ring((void *)priv->dma_rx, rxsize, 0);
+               stmmac_display_ring((void *)priv->dma_rx, DMA_RX_SIZE, 0);
                pr_info("TX descriptor ring:\n");
-               stmmac_display_ring((void *)priv->dma_tx, txsize, 0);
+               stmmac_display_ring((void *)priv->dma_tx, DMA_TX_SIZE, 0);
        }
 }
 
@@ -947,28 +948,26 @@ static int stmmac_set_bfsize(int mtu, int bufsize)
 static void stmmac_clear_descriptors(struct stmmac_priv *priv)
 {
        int i;
-       unsigned int txsize = priv->dma_tx_size;
-       unsigned int rxsize = priv->dma_rx_size;
 
        /* Clear the Rx/Tx descriptors */
-       for (i = 0; i < rxsize; i++)
+       for (i = 0; i < DMA_RX_SIZE; i++)
                if (priv->extend_desc)
                        priv->hw->desc->init_rx_desc(&priv->dma_erx[i].basic,
                                                     priv->use_riwt, priv->mode,
-                                                    (i == rxsize - 1));
+                                                    (i == DMA_RX_SIZE - 1));
                else
                        priv->hw->desc->init_rx_desc(&priv->dma_rx[i],
                                                     priv->use_riwt, priv->mode,
-                                                    (i == rxsize - 1));
-       for (i = 0; i < txsize; i++)
+                                                    (i == DMA_RX_SIZE - 1));
+       for (i = 0; i < DMA_TX_SIZE; i++)
                if (priv->extend_desc)
                        priv->hw->desc->init_tx_desc(&priv->dma_etx[i].basic,
                                                     priv->mode,
-                                                    (i == txsize - 1));
+                                                    (i == DMA_TX_SIZE - 1));
                else
                        priv->hw->desc->init_tx_desc(&priv->dma_tx[i],
                                                     priv->mode,
-                                                    (i == txsize - 1));
+                                                    (i == DMA_TX_SIZE - 1));
 }
 
 /**
@@ -1031,8 +1030,6 @@ static int init_dma_desc_rings(struct net_device *dev, gfp_t flags)
 {
        int i;
        struct stmmac_priv *priv = netdev_priv(dev);
-       unsigned int txsize = priv->dma_tx_size;
-       unsigned int rxsize = priv->dma_rx_size;
        unsigned int bfsize = 0;
        int ret = -ENOMEM;
 
@@ -1044,10 +1041,6 @@ static int init_dma_desc_rings(struct net_device *dev, gfp_t flags)
 
        priv->dma_buf_sz = bfsize;
 
-       if (netif_msg_probe(priv))
-               pr_debug("%s: txsize %d, rxsize %d, bfsize %d\n", __func__,
-                        txsize, rxsize, bfsize);
-
        if (netif_msg_probe(priv)) {
                pr_debug("(%s) dma_rx_phy=0x%08x dma_tx_phy=0x%08x\n", __func__,
                         (u32) priv->dma_rx_phy, (u32) priv->dma_tx_phy);
@@ -1055,7 +1048,7 @@ static int init_dma_desc_rings(struct net_device *dev, gfp_t flags)
                /* RX INITIALIZATION */
                pr_debug("\tSKB addresses:\nskb\t\tskb data\tdma data\n");
        }
-       for (i = 0; i < rxsize; i++) {
+       for (i = 0; i < DMA_RX_SIZE; i++) {
                struct dma_desc *p;
                if (priv->extend_desc)
                        p = &((priv->dma_erx + i)->basic);
@@ -1072,26 +1065,26 @@ static int init_dma_desc_rings(struct net_device *dev, gfp_t flags)
                                 (unsigned int)priv->rx_skbuff_dma[i]);
        }
        priv->cur_rx = 0;
-       priv->dirty_rx = (unsigned int)(i - rxsize);
+       priv->dirty_rx = (unsigned int)(i - DMA_RX_SIZE);
        buf_sz = bfsize;
 
        /* Setup the chained descriptor addresses */
        if (priv->mode == STMMAC_CHAIN_MODE) {
                if (priv->extend_desc) {
                        priv->hw->mode->init(priv->dma_erx, priv->dma_rx_phy,
-                                            rxsize, 1);
+                                            DMA_RX_SIZE, 1);
                        priv->hw->mode->init(priv->dma_etx, priv->dma_tx_phy,
-                                            txsize, 1);
+                                            DMA_TX_SIZE, 1);
                } else {
                        priv->hw->mode->init(priv->dma_rx, priv->dma_rx_phy,
-                                            rxsize, 0);
+                                            DMA_RX_SIZE, 0);
                        priv->hw->mode->init(priv->dma_tx, priv->dma_tx_phy,
-                                            txsize, 0);
+                                            DMA_TX_SIZE, 0);
                }
        }
 
        /* TX INITIALIZATION */
-       for (i = 0; i < txsize; i++) {
+       for (i = 0; i < DMA_TX_SIZE; i++) {
                struct dma_desc *p;
                if (priv->extend_desc)
                        p = &((priv->dma_etx + i)->basic);
@@ -1123,7 +1116,7 @@ static void dma_free_rx_skbufs(struct stmmac_priv *priv)
 {
        int i;
 
-       for (i = 0; i < priv->dma_rx_size; i++)
+       for (i = 0; i < DMA_RX_SIZE; i++)
                stmmac_free_rx_buffers(priv, i);
 }
 
@@ -1131,7 +1124,7 @@ static void dma_free_tx_skbufs(struct stmmac_priv *priv)
 {
        int i;
 
-       for (i = 0; i < priv->dma_tx_size; i++) {
+       for (i = 0; i < DMA_TX_SIZE; i++) {
                struct dma_desc *p;
 
                if (priv->extend_desc)
@@ -1171,33 +1164,31 @@ static void dma_free_tx_skbufs(struct stmmac_priv *priv)
  */
 static int alloc_dma_desc_resources(struct stmmac_priv *priv)
 {
-       unsigned int txsize = priv->dma_tx_size;
-       unsigned int rxsize = priv->dma_rx_size;
        int ret = -ENOMEM;
 
-       priv->rx_skbuff_dma = kmalloc_array(rxsize, sizeof(dma_addr_t),
+       priv->rx_skbuff_dma = kmalloc_array(DMA_RX_SIZE, sizeof(dma_addr_t),
                                            GFP_KERNEL);
        if (!priv->rx_skbuff_dma)
                return -ENOMEM;
 
-       priv->rx_skbuff = kmalloc_array(rxsize, sizeof(struct sk_buff *),
+       priv->rx_skbuff = kmalloc_array(DMA_RX_SIZE, sizeof(struct sk_buff *),
                                        GFP_KERNEL);
        if (!priv->rx_skbuff)
                goto err_rx_skbuff;
 
-       priv->tx_skbuff_dma = kmalloc_array(txsize,
+       priv->tx_skbuff_dma = kmalloc_array(DMA_TX_SIZE,
                                            sizeof(*priv->tx_skbuff_dma),
                                            GFP_KERNEL);
        if (!priv->tx_skbuff_dma)
                goto err_tx_skbuff_dma;
 
-       priv->tx_skbuff = kmalloc_array(txsize, sizeof(struct sk_buff *),
+       priv->tx_skbuff = kmalloc_array(DMA_TX_SIZE, sizeof(struct sk_buff *),
                                        GFP_KERNEL);
        if (!priv->tx_skbuff)
                goto err_tx_skbuff;
 
        if (priv->extend_desc) {
-               priv->dma_erx = dma_zalloc_coherent(priv->device, rxsize *
+               priv->dma_erx = dma_zalloc_coherent(priv->device, DMA_RX_SIZE *
                                                    sizeof(struct
                                                           dma_extended_desc),
                                                    &priv->dma_rx_phy,
@@ -1205,31 +1196,31 @@ static int alloc_dma_desc_resources(struct stmmac_priv *priv)
                if (!priv->dma_erx)
                        goto err_dma;
 
-               priv->dma_etx = dma_zalloc_coherent(priv->device, txsize *
+               priv->dma_etx = dma_zalloc_coherent(priv->device, DMA_TX_SIZE *
                                                    sizeof(struct
                                                           dma_extended_desc),
                                                    &priv->dma_tx_phy,
                                                    GFP_KERNEL);
                if (!priv->dma_etx) {
-                       dma_free_coherent(priv->device, priv->dma_rx_size *
+                       dma_free_coherent(priv->device, DMA_RX_SIZE *
                                          sizeof(struct dma_extended_desc),
                                          priv->dma_erx, priv->dma_rx_phy);
                        goto err_dma;
                }
        } else {
-               priv->dma_rx = dma_zalloc_coherent(priv->device, rxsize *
+               priv->dma_rx = dma_zalloc_coherent(priv->device, DMA_RX_SIZE *
                                                   sizeof(struct dma_desc),
                                                   &priv->dma_rx_phy,
                                                   GFP_KERNEL);
                if (!priv->dma_rx)
                        goto err_dma;
 
-               priv->dma_tx = dma_zalloc_coherent(priv->device, txsize *
+               priv->dma_tx = dma_zalloc_coherent(priv->device, DMA_TX_SIZE *
                                                   sizeof(struct dma_desc),
                                                   &priv->dma_tx_phy,
                                                   GFP_KERNEL);
                if (!priv->dma_tx) {
-                       dma_free_coherent(priv->device, priv->dma_rx_size *
+                       dma_free_coherent(priv->device, DMA_RX_SIZE *
                                          sizeof(struct dma_desc),
                                          priv->dma_rx, priv->dma_rx_phy);
                        goto err_dma;
@@ -1258,16 +1249,16 @@ static void free_dma_desc_resources(struct stmmac_priv *priv)
        /* Free DMA regions of consistent memory previously allocated */
        if (!priv->extend_desc) {
                dma_free_coherent(priv->device,
-                                 priv->dma_tx_size * sizeof(struct dma_desc),
+                                 DMA_TX_SIZE * sizeof(struct dma_desc),
                                  priv->dma_tx, priv->dma_tx_phy);
                dma_free_coherent(priv->device,
-                                 priv->dma_rx_size * sizeof(struct dma_desc),
+                                 DMA_RX_SIZE * sizeof(struct dma_desc),
                                  priv->dma_rx, priv->dma_rx_phy);
        } else {
-               dma_free_coherent(priv->device, priv->dma_tx_size *
+               dma_free_coherent(priv->device, DMA_TX_SIZE *
                                  sizeof(struct dma_extended_desc),
                                  priv->dma_etx, priv->dma_tx_phy);
-               dma_free_coherent(priv->device, priv->dma_rx_size *
+               dma_free_coherent(priv->device, DMA_RX_SIZE *
                                  sizeof(struct dma_extended_desc),
                                  priv->dma_erx, priv->dma_rx_phy);
        }
@@ -1312,16 +1303,15 @@ static void stmmac_dma_operation_mode(struct stmmac_priv *priv)
  */
 static void stmmac_tx_clean(struct stmmac_priv *priv)
 {
-       unsigned int txsize = priv->dma_tx_size;
        unsigned int bytes_compl = 0, pkts_compl = 0;
+       unsigned int entry = priv->dirty_tx;
 
        spin_lock(&priv->tx_lock);
 
        priv->xstats.tx_clean++;
 
-       while (priv->dirty_tx != priv->cur_tx) {
+       while (entry != priv->cur_tx) {
                int last;
-               unsigned int entry = priv->dirty_tx % txsize;
                struct sk_buff *skb = priv->tx_skbuff[entry];
                struct dma_desc *p;
 
@@ -1378,16 +1368,17 @@ static void stmmac_tx_clean(struct stmmac_priv *priv)
 
                priv->hw->desc->release_tx_desc(p, priv->mode);
 
-               priv->dirty_tx++;
+               entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
+               priv->dirty_tx = entry;
        }
 
        netdev_completed_queue(priv->dev, pkts_compl, bytes_compl);
 
        if (unlikely(netif_queue_stopped(priv->dev) &&
-                    stmmac_tx_avail(priv) > STMMAC_TX_THRESH(priv))) {
+                    stmmac_tx_avail(priv) > STMMAC_TX_THRESH)) {
                netif_tx_lock(priv->dev);
                if (netif_queue_stopped(priv->dev) &&
-                   stmmac_tx_avail(priv) > STMMAC_TX_THRESH(priv)) {
+                   stmmac_tx_avail(priv) > STMMAC_TX_THRESH) {
                        if (netif_msg_tx_done(priv))
                                pr_debug("%s: restart transmit\n", __func__);
                        netif_wake_queue(priv->dev);
@@ -1421,20 +1412,19 @@ static inline void stmmac_disable_dma_irq(struct stmmac_priv *priv)
 static void stmmac_tx_err(struct stmmac_priv *priv)
 {
        int i;
-       int txsize = priv->dma_tx_size;
        netif_stop_queue(priv->dev);
 
        priv->hw->dma->stop_tx(priv->ioaddr);
        dma_free_tx_skbufs(priv);
-       for (i = 0; i < txsize; i++)
+       for (i = 0; i < DMA_TX_SIZE; i++)
                if (priv->extend_desc)
                        priv->hw->desc->init_tx_desc(&priv->dma_etx[i].basic,
                                                     priv->mode,
-                                                    (i == txsize - 1));
+                                                    (i == DMA_TX_SIZE - 1));
                else
                        priv->hw->desc->init_tx_desc(&priv->dma_tx[i],
                                                     priv->mode,
-                                                    (i == txsize - 1));
+                                                    (i == DMA_TX_SIZE - 1));
        priv->dirty_tx = 0;
        priv->cur_tx = 0;
        netdev_reset_queue(priv->dev);
@@ -1811,9 +1801,6 @@ static int stmmac_open(struct net_device *dev)
        memset(&priv->xstats, 0, sizeof(struct stmmac_extra_stats));
        priv->xstats.threshold = tc;
 
-       /* Create and initialize the TX/RX descriptors chains. */
-       priv->dma_tx_size = STMMAC_ALIGN(dma_txsize);
-       priv->dma_rx_size = STMMAC_ALIGN(dma_rxsize);
        priv->dma_buf_sz = STMMAC_ALIGN(buf_sz);
 
        ret = alloc_dma_desc_resources(priv);
@@ -1955,7 +1942,6 @@ static int stmmac_release(struct net_device *dev)
 static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 {
        struct stmmac_priv *priv = netdev_priv(dev);
-       unsigned int txsize = priv->dma_tx_size;
        int entry;
        int i, csum_insertion = 0, is_jumbo = 0;
        int nfrags = skb_shinfo(skb)->nr_frags;
@@ -1978,7 +1964,8 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
        if (priv->tx_path_in_lpi_mode)
                stmmac_disable_eee_mode(priv);
 
-       entry = priv->cur_tx % txsize;
+       entry = priv->cur_tx;
+
 
        csum_insertion = (skb->ip_summed == CHECKSUM_PARTIAL);
 
@@ -2013,7 +2000,8 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
                int len = skb_frag_size(frag);
 
                priv->tx_skbuff[entry] = NULL;
-               entry = (++priv->cur_tx) % txsize;
+               entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
+
                if (priv->extend_desc)
                        desc = (struct dma_desc *)(priv->dma_etx + entry);
                else
@@ -2056,17 +2044,21 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
        priv->hw->desc->set_tx_owner(first);
        wmb();
 
-       priv->cur_tx++;
+       entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
+
+       priv->cur_tx = entry;
 
        if (netif_msg_pktdata(priv)) {
                pr_debug("%s: curr %d dirty=%d entry=%d, first=%p, nfrags=%d",
-                       __func__, (priv->cur_tx % txsize),
-                       (priv->dirty_tx % txsize), entry, first, nfrags);
+                       __func__, (priv->cur_tx % DMA_TX_SIZE),
+                       (priv->dirty_tx % DMA_TX_SIZE), entry, first, nfrags);
 
                if (priv->extend_desc)
-                       stmmac_display_ring((void *)priv->dma_etx, txsize, 1);
+                       stmmac_display_ring((void *)priv->dma_etx,
+                                           DMA_TX_SIZE, 1);
                else
-                       stmmac_display_ring((void *)priv->dma_tx, txsize, 0);
+                       stmmac_display_ring((void *)priv->dma_tx,
+                                           DMA_TX_SIZE, 0);
 
                pr_debug(">>> frame to be transmitted: ");
                print_pkt(skb->data, skb->len);
@@ -2128,11 +2120,11 @@ static void stmmac_rx_vlan(struct net_device *dev, struct sk_buff *skb)
  */
 static inline void stmmac_rx_refill(struct stmmac_priv *priv)
 {
-       unsigned int rxsize = priv->dma_rx_size;
        int bfsize = priv->dma_buf_sz;
+       unsigned int entry = priv->dirty_rx;
+       int dirty = stmmac_rx_dirty(priv);
 
-       for (; priv->cur_rx - priv->dirty_rx > 0; priv->dirty_rx++) {
-               unsigned int entry = priv->dirty_rx % rxsize;
+       while (dirty-- > 0) {
                struct dma_desc *p;
 
                if (priv->extend_desc)
@@ -2168,7 +2160,10 @@ static inline void stmmac_rx_refill(struct stmmac_priv *priv)
                wmb();
                priv->hw->desc->set_rx_owner(p);
                wmb();
+
+               entry = STMMAC_GET_ENTRY(entry, DMA_RX_SIZE);
        }
+       priv->dirty_rx = entry;
 }
 
 /**
@@ -2180,8 +2175,7 @@ static inline void stmmac_rx_refill(struct stmmac_priv *priv)
  */
 static int stmmac_rx(struct stmmac_priv *priv, int limit)
 {
-       unsigned int rxsize = priv->dma_rx_size;
-       unsigned int entry = priv->cur_rx % rxsize;
+       unsigned int entry = priv->cur_rx;
        unsigned int next_entry;
        unsigned int count = 0;
        int coe = priv->hw->rx_csum;
@@ -2189,9 +2183,11 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit)
        if (netif_msg_rx_status(priv)) {
                pr_debug("%s: descriptor ring:\n", __func__);
                if (priv->extend_desc)
-                       stmmac_display_ring((void *)priv->dma_erx, rxsize, 1);
+                       stmmac_display_ring((void *)priv->dma_erx,
+                                           DMA_RX_SIZE, 1);
                else
-                       stmmac_display_ring((void *)priv->dma_rx, rxsize, 0);
+                       stmmac_display_ring((void *)priv->dma_rx,
+                                           DMA_RX_SIZE, 0);
        }
        while (count < limit) {
                int status;
@@ -2207,7 +2203,9 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit)
 
                count++;
 
-               next_entry = (++priv->cur_rx) % rxsize;
+               priv->cur_rx = STMMAC_GET_ENTRY(priv->cur_rx, DMA_RX_SIZE);
+               next_entry = priv->cur_rx;
+
                if (priv->extend_desc)
                        prefetch(priv->dma_erx + next_entry);
                else
@@ -2567,19 +2565,17 @@ static int stmmac_sysfs_ring_read(struct seq_file *seq, void *v)
 {
        struct net_device *dev = seq->private;
        struct stmmac_priv *priv = netdev_priv(dev);
-       unsigned int txsize = priv->dma_tx_size;
-       unsigned int rxsize = priv->dma_rx_size;
 
        if (priv->extend_desc) {
                seq_printf(seq, "Extended RX descriptor ring:\n");
-               sysfs_display_ring((void *)priv->dma_erx, rxsize, 1, seq);
+               sysfs_display_ring((void *)priv->dma_erx, DMA_RX_SIZE, 1, seq);
                seq_printf(seq, "Extended TX descriptor ring:\n");
-               sysfs_display_ring((void *)priv->dma_etx, txsize, 1, seq);
+               sysfs_display_ring((void *)priv->dma_etx, DMA_TX_SIZE, 1, seq);
        } else {
                seq_printf(seq, "RX descriptor ring:\n");
-               sysfs_display_ring((void *)priv->dma_rx, rxsize, 0, seq);
+               sysfs_display_ring((void *)priv->dma_rx, DMA_RX_SIZE, 0, seq);
                seq_printf(seq, "TX descriptor ring:\n");
-               sysfs_display_ring((void *)priv->dma_tx, txsize, 0, seq);
+               sysfs_display_ring((void *)priv->dma_tx, DMA_TX_SIZE, 0, seq);
        }
 
        return 0;
@@ -3149,12 +3145,6 @@ static int __init stmmac_cmdline_opt(char *str)
                } else if (!strncmp(opt, "phyaddr:", 8)) {
                        if (kstrtoint(opt + 8, 0, &phyaddr))
                                goto err;
-               } else if (!strncmp(opt, "dma_txsize:", 11)) {
-                       if (kstrtoint(opt + 11, 0, &dma_txsize))
-                               goto err;
-               } else if (!strncmp(opt, "dma_rxsize:", 11)) {
-                       if (kstrtoint(opt + 11, 0, &dma_rxsize))
-                               goto err;
                } else if (!strncmp(opt, "buf_sz:", 7)) {
                        if (kstrtoint(opt + 7, 0, &buf_sz))
                                goto err;