[Qemu-devel] [RFC PATCH v1 1/2] e1000: clean up set_phy_ctrl function

["Gabriel L. Somlo" <gsomlo@gmail.com>]

set_phy_ctrl() runs the same autonegotiation availability checks
that were factored out into have_autoneg() in an earlier commit
(d7a4155265416a1c8f3067b59e68bf5fda1d6215), except it runs them
on the value about to be written into the phy_ctrl register, and
then does not actually write the register.

This patch moves the have_autoneg() function in front of
set_phy_ctrl(), then updates the latter to actually write
the register with the given value, and use the factored-out
check to determine whether the link should be bounced.

Also, fix indentation/line width when setting up the timer.

Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
---

I'm not 100% sure whether "val" in set_phy_ctrl() is not written
to phy_reg[PHY_CTRL] by mistake, or whether there's an ulterior
motive (in which case we should add a comment as to why that is).

Assuming it's a mistake, and we *should* have been writing it (as
per my patch below), we can then use have_autoneg() to also simplify
the code significantly :)

Thanks,
  Gabriel

 hw/net/e1000.c | 27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/hw/net/e1000.c b/hw/net/e1000.c
index 0fc29a0..2376910 100644
--- a/hw/net/e1000.c
+++ b/hw/net/e1000.c
@@ -186,6 +186,14 @@ e1000_link_up(E1000State *s)
     s->phy_reg[PHY_STATUS] |= MII_SR_LINK_STATUS;
 }
 
+static bool
+have_autoneg(E1000State *s)
+{
+    return (s->compat_flags & E1000_FLAG_AUTONEG) &&
+           (s->phy_reg[PHY_CTRL] & MII_CR_AUTO_NEG_EN) &&
+           (s->phy_reg[PHY_CTRL] & MII_CR_RESTART_AUTO_NEG);
+}
+
 static void
 set_phy_ctrl(E1000State *s, int index, uint16_t val)
 {
@@ -194,13 +202,14 @@ set_phy_ctrl(E1000State *s, int index, uint16_t val)
      * migrate during auto negotiation, after migration the link will be
      * down.
      */
-    if (!(s->compat_flags & E1000_FLAG_AUTONEG)) {
-        return;
-    }
-    if ((val & MII_CR_AUTO_NEG_EN) && (val & MII_CR_RESTART_AUTO_NEG)) {
+
+    s->phy_reg[PHY_CTRL] = val;
+
+    if (have_autoneg(s)) {
         e1000_link_down(s);
         DBGOUT(PHY, "Start link auto negotiation\n");
-        timer_mod(s->autoneg_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 500);
+        timer_mod(s->autoneg_timer,
+                  qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 500);
     }
 }
 
@@ -848,14 +857,6 @@ receive_filter(E1000State *s, const uint8_t *buf, int size)
     return 0;
 }
 
-static bool
-have_autoneg(E1000State *s)
-{
-    return (s->compat_flags & E1000_FLAG_AUTONEG) &&
-           (s->phy_reg[PHY_CTRL] & MII_CR_AUTO_NEG_EN) &&
-           (s->phy_reg[PHY_CTRL] & MII_CR_RESTART_AUTO_NEG);
-}
-
 static void
 e1000_set_link_status(NetClientState *nc)
 {
-- 
1.9.3