[Qemu-devel] [PATCH V2 5/6] hw/mdio: Move bitbang clock state tracking into core

[Grant Likely]

No need for drivers to open code the check for clock state change. This
patch moves it into the common code.

Cc: Peter Maydell <peter.mayd...@linaro.org>
Cc: Paul Brook <p...@codesourcery.com>
Cc: Edgar E. Iglesias <edgar.igles...@gmail.com>
Cc: Anthony Liguori <aligu...@us.ibm.com>
Cc: Andreas Färber <afaer...@suse.de>
Signed-off-by: Grant Likely <grant.lik...@secretlab.ca>
---
 hw/etraxfs_eth.c |    7 ++-----
 hw/mdio.c        |   20 ++++++++++++--------
 hw/mdio.h        |    2 +-
 3 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/hw/etraxfs_eth.c b/hw/etraxfs_eth.c
index f26e338..1bcdd12 100644
--- a/hw/etraxfs_eth.c
+++ b/hw/etraxfs_eth.c
@@ -173,11 +173,8 @@ eth_write(void *opaque, hwaddr addr,
         if (value & 2) {
             eth->mdio_bus.mdio = value & 1;
         }
-        if (eth->mdio_bus.mdc != (value & 4)) {
-            mdio_cycle(&eth->mdio_bus);
-            eth_validate_duplex(eth);
-        }
-        eth->mdio_bus.mdc = !!(value & 4);
+        mdio_cycle(&eth->mdio_bus, value & 4);
+        eth_validate_duplex(eth);
         eth->regs[addr] = value;
         break;
 
diff --git a/hw/mdio.c b/hw/mdio.c
index ca55e21..5272656 100644
--- a/hw/mdio.c
+++ b/hw/mdio.c
@@ -173,15 +173,19 @@ void mdio_write_req(struct qemu_mdio *bus, uint8_t addr, 
uint8_t req,
     }
 }
 
-void mdio_cycle(struct qemu_mdio *bus)
+void mdio_cycle(struct qemu_mdio *bus, bool mdc)
 {
+    if (mdc == bus->mdc) {
+        return; /* Clock state hasn't changed; do nothing */
+    }
+    bus->mdc = mdc;
     bus->cnt++;
 
     D(printf("mdc=%d mdio=%d state=%d cnt=%d drv=%d\n",
              bus->mdc, bus->mdio, bus->state, bus->cnt, bus->output_enable));
     switch (bus->state) {
     case PREAMBLE:
-        if (bus->mdc) {
+        if (!mdc) {
             if (bus->cnt >= (32 * 2) && !bus->mdio) {
                 bus->cnt = 0;
                 bus->state = SOF;
@@ -190,7 +194,7 @@ void mdio_cycle(struct qemu_mdio *bus)
         }
         break;
     case SOF:
-        if (bus->mdc) {
+        if (!mdc) {
             if (bus->mdio != 1) {
                 printf("WARNING: no SOF\n");
             }
@@ -202,7 +206,7 @@ void mdio_cycle(struct qemu_mdio *bus)
         }
         break;
     case OPC:
-        if (bus->mdc) {
+        if (!mdc) {
             bus->opc <<= 1;
             bus->opc |= bus->mdio & 1;
             if (bus->cnt == 2*2) {
@@ -213,7 +217,7 @@ void mdio_cycle(struct qemu_mdio *bus)
         }
         break;
     case ADDR:
-        if (bus->mdc) {
+        if (!mdc) {
             bus->addr <<= 1;
             bus->addr |= bus->mdio & 1;
 
@@ -225,7 +229,7 @@ void mdio_cycle(struct qemu_mdio *bus)
         }
         break;
     case REQ:
-        if (bus->mdc) {
+        if (!mdc) {
             bus->req <<= 1;
             bus->req |= bus->mdio & 1;
             if (bus->cnt == 5*2) {
@@ -235,7 +239,7 @@ void mdio_cycle(struct qemu_mdio *bus)
         }
         break;
     case TURNAROUND:
-        if (bus->mdc && bus->cnt == 2*2) {
+        if (!mdc && bus->cnt == 2*2) {
             bus->mdio = 0;
             bus->cnt = 0;
 
@@ -248,7 +252,7 @@ void mdio_cycle(struct qemu_mdio *bus)
         }
         break;
     case DATA:
-        if (!bus->mdc) {
+        if (mdc) {
             if (bus->output_enable) {
                 bus->mdio = !!(bus->data & (1 << 15));
                 bus->data <<= 1;
diff --git a/hw/mdio.h b/hw/mdio.h
index 1cbb422..bd1d0a0 100644
--- a/hw/mdio.h
+++ b/hw/mdio.h
@@ -85,6 +85,6 @@ void mdio_attach(struct qemu_mdio *bus, struct qemu_phy *phy,
                  unsigned int addr);
 uint16_t mdio_read_req(struct qemu_mdio *bus, uint8_t addr, uint8_t req);
 void mdio_write_req(struct qemu_mdio *bus, uint8_t addr, uint8_t req, uint16_t 
data);
-void mdio_cycle(struct qemu_mdio *bus);
+void mdio_cycle(struct qemu_mdio *bus, bool mdc);
 
 #endif
-- 
1.7.10.4