net: ethernet: ti: cpsw: remove rx_descs property

There is no reason in rx_descs property because davinici_cpdma
driver splits pool of descriptors equally between tx and rx channels.
That is, if number of descriptors 256, 128 of them are for rx
channels. While receiving, the descriptor is freed to the pool and
then allocated with new skb. And if in DT the "rx_descs" is set to
64, then 128 - 64 = 64 descriptors are always in the pool and cannot
be used, for tx, for instance. It's not correct resource usage,
better to set it to half of pool, then the rx pool can be used in
full. It will not have any impact on performance, as anyway, the
"redundant" descriptors were unused.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
index f2a4cd6be14fde3ffee19a28cb6db5e9d3d88692..83273288aefc3bcfdbdc6c9a749b19e4e4dcc721 100644 (file)
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -1277,6 +1277,7 @@ static int cpsw_ndo_open(struct net_device *ndev)
 
        if (!cpsw_common_res_usage_state(priv)) {
                struct cpsw_priv *priv_sl0 = cpsw_get_slave_priv(priv, 0);
+               int buf_num;
 
                /* setup tx dma to fixed prio and zero offset */
                cpdma_control_set(priv->dma, CPDMA_TX_PRIO_FIXED, 1);
@@ -1304,10 +1305,8 @@ static int cpsw_ndo_open(struct net_device *ndev)
                        enable_irq(priv->irqs_table[0]);
                }
 
-               if (WARN_ON(!priv->data.rx_descs))
-                       priv->data.rx_descs = 128;
-
-               for (i = 0; i < priv->data.rx_descs; i++) {
+               buf_num = cpdma_chan_get_rx_buf_num(priv->dma);
+               for (i = 0; i < buf_num; i++) {
                        struct sk_buff *skb;
 
                        ret = -ENOMEM;
@@ -1998,12 +1997,6 @@ static int cpsw_probe_dt(struct cpsw_platform_data *data,
        }
        data->bd_ram_size = prop;
 
-       if (of_property_read_u32(node, "rx_descs", &prop)) {
-               dev_err(&pdev->dev, "Missing rx_descs property in the DT.\n");
-               return -EINVAL;
-       }
-       data->rx_descs = prop;
-
        if (of_property_read_u32(node, "mac_control", &prop)) {
                dev_err(&pdev->dev, "Missing mac_control property in the DT.\n");
                return -EINVAL;

diff --git a/drivers/net/ethernet/ti/cpsw.h b/drivers/net/ethernet/ti/cpsw.h
index e50afd1b2eda09d87a94b100646d774de52f32b5..16b54c6f32c2e32a48f24ee2c7b582623d0caa18 100644 (file)
--- a/drivers/net/ethernet/ti/cpsw.h
+++ b/drivers/net/ethernet/ti/cpsw.h
@@ -35,7 +35,6 @@ struct cpsw_platform_data {
        u32     cpts_clock_shift; /* convert input clock ticks to nanoseconds */
        u32     ale_entries;    /* ale table size */
        u32     bd_ram_size;  /*buffer descriptor ram size */
-       u32     rx_descs;       /* Number of Rx Descriptios */
        u32     mac_control;    /* Mac control register */
        u16     default_vlan;   /* Def VLAN for ALE lookup in VLAN aware mode*/
        bool    dual_emac;      /* Enable Dual EMAC mode */

diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c b/drivers/net/ethernet/ti/davinci_cpdma.c
index 18bf3a8fdc505ad2ed8a0fa3b81dfeb7d833b94d..bcd9e455457eea4d0acfe9c1e20f798451553700 100644 (file)
--- a/drivers/net/ethernet/ti/davinci_cpdma.c
+++ b/drivers/net/ethernet/ti/davinci_cpdma.c
@@ -543,6 +543,12 @@ struct cpdma_chan *cpdma_chan_create(struct cpdma_ctlr *ctlr, int chan_num,
 }
 EXPORT_SYMBOL_GPL(cpdma_chan_create);
 
+int cpdma_chan_get_rx_buf_num(struct cpdma_ctlr *ctlr)
+{
+       return ctlr->pool->num_desc / 2;
+}
+EXPORT_SYMBOL_GPL(cpdma_chan_get_rx_buf_num);
+
 int cpdma_chan_destroy(struct cpdma_chan *chan)
 {
        struct cpdma_ctlr *ctlr;

diff --git a/drivers/net/ethernet/ti/davinci_cpdma.h b/drivers/net/ethernet/ti/davinci_cpdma.h
index 86dee487f2f0e4aaa4c33ac17b7ad2f10f682e12..80c015cbbce5c4340a28179dc36aebce9d0d6215 100644 (file)
--- a/drivers/net/ethernet/ti/davinci_cpdma.h
+++ b/drivers/net/ethernet/ti/davinci_cpdma.h
@@ -81,6 +81,7 @@ int cpdma_ctlr_dump(struct cpdma_ctlr *ctlr);
 
 struct cpdma_chan *cpdma_chan_create(struct cpdma_ctlr *ctlr, int chan_num,
                                     cpdma_handler_fn handler);
+int cpdma_chan_get_rx_buf_num(struct cpdma_ctlr *ctlr);
 int cpdma_chan_destroy(struct cpdma_chan *chan);
 int cpdma_chan_start(struct cpdma_chan *chan);
 int cpdma_chan_stop(struct cpdma_chan *chan);