driver: net: ethernet: cpsw: implement interrupt pacing via ethtool
authorMugunthan V N <mugunthanvnm@ti.com>
Mon, 11 Mar 2013 23:16:37 +0000 (23:16 +0000)
committerDavid S. Miller <davem@davemloft.net>
Wed, 13 Mar 2013 08:38:20 +0000 (04:38 -0400)
This patch implements support for interrupt pacing block of CPSW via ethtool
Inetrrupt pacing block is common of both the ethernet interface in
dual emac mode

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/ethernet/ti/cpsw.c

index 83ce890d6e971a58082cd7146c3d9ec72101050b..d6cf6982904e7f59b25d2ce08ddd91540f0a0f6c 100644 (file)
@@ -126,6 +126,13 @@ do {                                                               \
 #define CPSW_FIFO_DUAL_MAC_MODE                (1 << 15)
 #define CPSW_FIFO_RATE_LIMIT_MODE      (2 << 15)
 
+#define CPSW_INTPACEEN         (0x3f << 16)
+#define CPSW_INTPRESCALE_MASK  (0x7FF << 0)
+#define CPSW_CMINTMAX_CNT      63
+#define CPSW_CMINTMIN_CNT      2
+#define CPSW_CMINTMAX_INTVL    (1000 / CPSW_CMINTMIN_CNT)
+#define CPSW_CMINTMIN_INTVL    ((1000 / CPSW_CMINTMAX_CNT) + 1)
+
 #define cpsw_enable_irq(priv)  \
        do {                    \
                u32 i;          \
@@ -164,6 +171,15 @@ struct cpsw_wr_regs {
        u32     rx_en;
        u32     tx_en;
        u32     misc_en;
+       u32     mem_allign1[8];
+       u32     rx_thresh_stat;
+       u32     rx_stat;
+       u32     tx_stat;
+       u32     misc_stat;
+       u32     mem_allign2[8];
+       u32     rx_imax;
+       u32     tx_imax;
+
 };
 
 struct cpsw_ss_regs {
@@ -318,6 +334,8 @@ struct cpsw_priv {
        struct cpsw_host_regs __iomem   *host_port_regs;
        u32                             msg_enable;
        u32                             version;
+       u32                             coal_intvl;
+       u32                             bus_freq_mhz;
        struct net_device_stats         stats;
        int                             rx_packet_max;
        int                             host_port;
@@ -616,6 +634,77 @@ static void cpsw_adjust_link(struct net_device *ndev)
        }
 }
 
+static int cpsw_get_coalesce(struct net_device *ndev,
+                               struct ethtool_coalesce *coal)
+{
+       struct cpsw_priv *priv = netdev_priv(ndev);
+
+       coal->rx_coalesce_usecs = priv->coal_intvl;
+       return 0;
+}
+
+static int cpsw_set_coalesce(struct net_device *ndev,
+                               struct ethtool_coalesce *coal)
+{
+       struct cpsw_priv *priv = netdev_priv(ndev);
+       u32 int_ctrl;
+       u32 num_interrupts = 0;
+       u32 prescale = 0;
+       u32 addnl_dvdr = 1;
+       u32 coal_intvl = 0;
+
+       if (!coal->rx_coalesce_usecs)
+               return -EINVAL;
+
+       coal_intvl = coal->rx_coalesce_usecs;
+
+       int_ctrl =  readl(&priv->wr_regs->int_control);
+       prescale = priv->bus_freq_mhz * 4;
+
+       if (coal_intvl < CPSW_CMINTMIN_INTVL)
+               coal_intvl = CPSW_CMINTMIN_INTVL;
+
+       if (coal_intvl > CPSW_CMINTMAX_INTVL) {
+               /* Interrupt pacer works with 4us Pulse, we can
+                * throttle further by dilating the 4us pulse.
+                */
+               addnl_dvdr = CPSW_INTPRESCALE_MASK / prescale;
+
+               if (addnl_dvdr > 1) {
+                       prescale *= addnl_dvdr;
+                       if (coal_intvl > (CPSW_CMINTMAX_INTVL * addnl_dvdr))
+                               coal_intvl = (CPSW_CMINTMAX_INTVL
+                                               * addnl_dvdr);
+               } else {
+                       addnl_dvdr = 1;
+                       coal_intvl = CPSW_CMINTMAX_INTVL;
+               }
+       }
+
+       num_interrupts = (1000 * addnl_dvdr) / coal_intvl;
+       writel(num_interrupts, &priv->wr_regs->rx_imax);
+       writel(num_interrupts, &priv->wr_regs->tx_imax);
+
+       int_ctrl |= CPSW_INTPACEEN;
+       int_ctrl &= (~CPSW_INTPRESCALE_MASK);
+       int_ctrl |= (prescale & CPSW_INTPRESCALE_MASK);
+       writel(int_ctrl, &priv->wr_regs->int_control);
+
+       cpsw_notice(priv, timer, "Set coalesce to %d usecs.\n", coal_intvl);
+       if (priv->data.dual_emac) {
+               int i;
+
+               for (i = 0; i < priv->data.slaves; i++) {
+                       priv = netdev_priv(priv->slaves[i].ndev);
+                       priv->coal_intvl = coal_intvl;
+               }
+       } else {
+               priv->coal_intvl = coal_intvl;
+       }
+
+       return 0;
+}
+
 static inline int __show_stat(char *buf, int maxlen, const char *name, u32 val)
 {
        static char *leader = "........................................";
@@ -838,6 +927,14 @@ static int cpsw_ndo_open(struct net_device *ndev)
                cpsw_info(priv, ifup, "submitted %d rx descriptors\n", i);
        }
 
+       /* Enable Interrupt pacing if configured */
+       if (priv->coal_intvl != 0) {
+               struct ethtool_coalesce coal;
+
+               coal.rx_coalesce_usecs = (priv->coal_intvl << 4);
+               cpsw_set_coalesce(ndev, &coal);
+       }
+
        cpdma_ctlr_start(priv->dma);
        cpsw_intr_enable(priv);
        napi_enable(&priv->napi);
@@ -1279,6 +1376,8 @@ static const struct ethtool_ops cpsw_ethtool_ops = {
        .get_ts_info    = cpsw_get_ts_info,
        .get_settings   = cpsw_get_settings,
        .set_settings   = cpsw_set_settings,
+       .get_coalesce   = cpsw_get_coalesce,
+       .set_coalesce   = cpsw_set_coalesce,
 };
 
 static void cpsw_slave_init(struct cpsw_slave *slave, struct cpsw_priv *priv,
@@ -1466,6 +1565,9 @@ static int cpsw_probe_dual_emac(struct platform_device *pdev,
        priv_sl2->slaves = priv->slaves;
        priv_sl2->clk = priv->clk;
 
+       priv_sl2->coal_intvl = 0;
+       priv_sl2->bus_freq_mhz = priv->bus_freq_mhz;
+
        priv_sl2->cpsw_res = priv->cpsw_res;
        priv_sl2->regs = priv->regs;
        priv_sl2->host_port = priv->host_port;
@@ -1575,6 +1677,8 @@ static int cpsw_probe(struct platform_device *pdev)
                ret = -ENODEV;
                goto clean_slave_ret;
        }
+       priv->coal_intvl = 0;
+       priv->bus_freq_mhz = clk_get_rate(priv->clk) / 1000000;
 
        priv->cpsw_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!priv->cpsw_res) {