via-velocity: Add ethtool interrupt coalescing support

(Partially from the upstream VIA driver). Tweaking the number of
frames-per-interrupt and timer-until-interrupt can reduce the amount of
CPU work quite a lot.

Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 165 insertions, 2 deletions

diff --git a/drivers/net/via-velocity.c b/drivers/net/via-velocity.c
index 04d3836bfa5d..7c362b242704 100644
--- a/drivers/net/via-velocity.c
+++ b/drivers/net/via-velocity.c
@@ -1246,6 +1246,66 @@ static void mii_init(struct velocity_info *vptr, u32 mii_status)
         }
 }
 
+/**
+ * setup_queue_timers   -       Setup interrupt timers
+ *
+ * Setup interrupt frequency during suppression (timeout if the frame
+ * count isn't filled).
+ */
+static void setup_queue_timers(struct velocity_info *vptr)
+{
+        /* Only for newer revisions */
+        if (vptr->rev_id >= REV_ID_VT3216_A0) {
+                u8 txqueue_timer = 0;
+                u8 rxqueue_timer = 0;
+
+                if (vptr->mii_status & (VELOCITY_SPEED_1000 |
+                                VELOCITY_SPEED_100)) {
+                        txqueue_timer = vptr->options.txqueue_timer;
+                        rxqueue_timer = vptr->options.rxqueue_timer;
+                }
+
+                writeb(txqueue_timer, &vptr->mac_regs->TQETMR);
+                writeb(rxqueue_timer, &vptr->mac_regs->RQETMR);
+        }
+}
+/**
+ * setup_adaptive_interrupts  -  Setup interrupt suppression
+ *
+ * @vptr velocity adapter
+ *
+ * The velocity is able to suppress interrupt during high interrupt load.
+ * This function turns on that feature.
+ */
+static void setup_adaptive_interrupts(struct velocity_info *vptr)
+{
+        struct mac_regs __iomem *regs = vptr->mac_regs;
+        u16 tx_intsup = vptr->options.tx_intsup;
+        u16 rx_intsup = vptr->options.rx_intsup;
+
+        /* Setup default interrupt mask (will be changed below) */
+        vptr->int_mask = INT_MASK_DEF;
+
+        /* Set Tx Interrupt Suppression Threshold */
+        writeb(CAMCR_PS0, &regs->CAMCR);
+        if (tx_intsup != 0) {
+                vptr->int_mask &= ~(ISR_PTXI | ISR_PTX0I | ISR_PTX1I |
+                                ISR_PTX2I | ISR_PTX3I);
+                writew(tx_intsup, &regs->ISRCTL);
+        } else
+                writew(ISRCTL_TSUPDIS, &regs->ISRCTL);
+
+        /* Set Rx Interrupt Suppression Threshold */
+        writeb(CAMCR_PS1, &regs->CAMCR);
+        if (rx_intsup != 0) {
+                vptr->int_mask &= ~ISR_PRXI;
+                writew(rx_intsup, &regs->ISRCTL);
+        } else
+                writew(ISRCTL_RSUPDIS, &regs->ISRCTL);
+
+        /* Select page to interrupt hold timer */
+        writeb(0, &regs->CAMCR);
+}
 
 /**
  *      velocity_init_registers -       initialise MAC registers
@@ -1332,7 +1392,7 @@ static void velocity_init_registers(struct velocity_info *vptr,
                  */
                 enable_mii_autopoll(regs);
 
-                vptr->int_mask = INT_MASK_DEF;
+                setup_adaptive_interrupts(vptr);
 
                 writel(vptr->rx.pool_dma, &regs->RDBaseLo);
                 writew(vptr->options.numrx - 1, &regs->RDCSize);
@@ -1789,6 +1849,8 @@ static void velocity_error(struct velocity_info *vptr, int status)
                                 BYTE_REG_BITS_OFF(TESTCFG_HBDIS, &regs->TESTCFG);
                         else
                                 BYTE_REG_BITS_ON(TESTCFG_HBDIS, &regs->TESTCFG);
+
+                        setup_queue_timers(vptr);
                 }
                 /*
                  *      Get link status from PHYSR0
@@ -3199,6 +3261,100 @@ static void velocity_set_msglevel(struct net_device *dev, u32 value)
          msglevel = value;
 }
 
+static int get_pending_timer_val(int val)
+{
+        int mult_bits = val >> 6;
+        int mult = 1;
+
+        switch (mult_bits)
+        {
+        case 1:
+                mult = 4; break;
+        case 2:
+                mult = 16; break;
+        case 3:
+                mult = 64; break;
+        case 0:
+        default:
+                break;
+        }
+
+        return (val & 0x3f) * mult;
+}
+
+static void set_pending_timer_val(int *val, u32 us)
+{
+        u8 mult = 0;
+        u8 shift = 0;
+
+        if (us >= 0x3f) {
+                mult = 1; /* mult with 4 */
+                shift = 2;
+        }
+        if (us >= 0x3f * 4) {
+                mult = 2; /* mult with 16 */
+                shift = 4;
+        }
+        if (us >= 0x3f * 16) {
+                mult = 3; /* mult with 64 */
+                shift = 6;
+        }
+
+        *val = (mult << 6) | ((us >> shift) & 0x3f);
+}
+
+
+static int velocity_get_coalesce(struct net_device *dev,
+                struct ethtool_coalesce *ecmd)
+{
+        struct velocity_info *vptr = netdev_priv(dev);
+
+        ecmd->tx_max_coalesced_frames = vptr->options.tx_intsup;
+        ecmd->rx_max_coalesced_frames = vptr->options.rx_intsup;
+
+        ecmd->rx_coalesce_usecs = get_pending_timer_val(vptr->options.rxqueue_timer);
+        ecmd->tx_coalesce_usecs = get_pending_timer_val(vptr->options.txqueue_timer);
+
+        return 0;
+}
+
+static int velocity_set_coalesce(struct net_device *dev,
+                struct ethtool_coalesce *ecmd)
+{
+        struct velocity_info *vptr = netdev_priv(dev);
+        int max_us = 0x3f * 64;
+
+        /* 6 bits of  */
+        if (ecmd->tx_coalesce_usecs > max_us)
+                return -EINVAL;
+        if (ecmd->rx_coalesce_usecs > max_us)
+                return -EINVAL;
+
+        if (ecmd->tx_max_coalesced_frames > 0xff)
+                return -EINVAL;
+        if (ecmd->rx_max_coalesced_frames > 0xff)
+                return -EINVAL;
+
+        vptr->options.rx_intsup = ecmd->rx_max_coalesced_frames;
+        vptr->options.tx_intsup = ecmd->tx_max_coalesced_frames;
+
+        set_pending_timer_val(&vptr->options.rxqueue_timer,
+                        ecmd->rx_coalesce_usecs);
+        set_pending_timer_val(&vptr->options.txqueue_timer,
+                        ecmd->tx_coalesce_usecs);
+
+        /* Setup the interrupt suppression and queue timers */
+        mac_disable_int(vptr->mac_regs);
+        .set_coalesce   =       velocity_set_coalesce,
         .begin          =       velocity_ethtool_up,
         .complete       =       velocity_ethtool_down
 };
diff --git a/drivers/net/via-velocity.h b/drivers/net/via-velocity.h
index ce894ffa7c91..499da64773ee 100644
--- a/drivers/net/via-velocity.h
+++ b/drivers/net/via-velocity.h
@@ -1005,7 +1005,8 @@ struct mac_regs {
 
         volatile __le32 RDBaseLo;       /* 0x38 */
         volatile __le16 RDIdx;          /* 0x3C */
-        volatile __le16 reserved_3E;
+        volatile u8 TQETMR;             /* 0x3E, VT3216 and above only */
+        volatile u8 RQETMR;             /* 0x3F, VT3216 and above only */
 
         volatile __le32 TDBaseLo[4];    /* 0x40 */
 
@@ -1491,6 +1492,10 @@ struct velocity_opt {
         int rx_bandwidth_hi;
         int rx_bandwidth_lo;
         int rx_bandwidth_en;
+        int rxqueue_timer;
+        int txqueue_timer;
+        int tx_intsup;
+        int rx_intsup;
         u32 flags;
 };