r8169: improve rtl_get_coalesce

Use FIELD_GET() macro to make the code better readable. In addition
change the logic to round the time limit up, not down. Reason is that
a time limit <1us would be rounded to 0 currently, what would be
interpreted as "no time limit set".

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index 9932b6ffae02771d66bf96e1b2a9aa977054864a..a36a48f713faf58f73105589402edf534b4ed445 100644 (file)
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -27,6 +27,7 @@
 #include <linux/interrupt.h>
 #include <linux/dma-mapping.h>
 #include <linux/pm_runtime.h>
+#include <linux/bitfield.h>
 #include <linux/prefetch.h>
 #include <linux/ipv6.h>
 #include <net/ip6_checksum.h>
@@ -229,6 +230,11 @@ enum rtl_registers {
        CPlusCmd        = 0xe0,
        IntrMitigate    = 0xe2,
 
+#define RTL_COALESCE_TX_USECS  GENMASK(15, 12)
+#define RTL_COALESCE_TX_FRAMES GENMASK(11, 8)
+#define RTL_COALESCE_RX_USECS  GENMASK(7, 4)
+#define RTL_COALESCE_RX_FRAMES GENMASK(3, 0)
+
 #define RTL_COALESCE_MASK      0x0f
 #define RTL_COALESCE_SHIFT     4
 #define RTL_COALESCE_T_MAX     (RTL_COALESCE_MASK)
@@ -1815,16 +1821,8 @@ static int rtl_get_coalesce(struct net_device *dev, struct ethtool_coalesce *ec)
 {
        struct rtl8169_private *tp = netdev_priv(dev);
        const struct rtl_coalesce_info *ci;
-       struct {
-               u32 *max_frames;
-               u32 *usecs;
-       } coal_settings [] = {
-               { &ec->rx_max_coalesced_frames, &ec->rx_coalesce_usecs },
-               { &ec->tx_max_coalesced_frames, &ec->tx_coalesce_usecs }
-       }, *p = coal_settings;
-       u32 scale;
-       int i;
-       u16 w;
+       u32 scale, c_us, c_fr;
+       u16 intrmit;
 
        if (rtl_is_8125(tp))
                return -EOPNOTSUPP;
@@ -1838,24 +1836,20 @@ static int rtl_get_coalesce(struct net_device *dev, struct ethtool_coalesce *ec)
 
        scale = ci->scale_nsecs[tp->cp_cmd & INTT_MASK];
 
-       /* read IntrMitigate and adjust according to scale */
-       for (w = RTL_R16(tp, IntrMitigate); w; w >>= RTL_COALESCE_SHIFT, p++) {
-               *p->max_frames = (w & RTL_COALESCE_MASK) << 2;
-               w >>= RTL_COALESCE_SHIFT;
-               *p->usecs = w & RTL_COALESCE_MASK;
-       }
+       intrmit = RTL_R16(tp, IntrMitigate);
 
-       for (i = 0; i < 2; i++) {
-               p = coal_settings + i;
-               *p->usecs = (*p->usecs * scale) / 1000;
+       c_us = FIELD_GET(RTL_COALESCE_TX_USECS, intrmit);
+       ec->tx_coalesce_usecs = DIV_ROUND_UP(c_us * scale, 1000);
 
-               /*
-                * ethtool_coalesce says it is illegal to set both usecs and
-                * max_frames to 0.
-                */
-               if (!*p->usecs && !*p->max_frames)
-                       *p->max_frames = 1;
-       }
+       c_fr = FIELD_GET(RTL_COALESCE_TX_FRAMES, intrmit);
+       /* ethtool_coalesce states usecs and max_frames must not both be 0 */
+       ec->tx_max_coalesced_frames = (c_us || c_fr) ? c_fr * 4 : 1;
+
+       c_us = FIELD_GET(RTL_COALESCE_RX_USECS, intrmit);
+       ec->rx_coalesce_usecs = DIV_ROUND_UP(c_us * scale, 1000);
+
+       c_fr = FIELD_GET(RTL_COALESCE_RX_FRAMES, intrmit);
+       ec->rx_max_coalesced_frames = (c_us || c_fr) ? c_fr * 4 : 1;
 
        return 0;
 }