GRETH: changed the PHY initialization sequence

1. read_mii() now returns 0xffff on failure. It is more robust when it
   comes to reading the reset bit in the control register, that is the
   first access.

2. write_mii() now has error printout like read_mii().

3. Additional (optional) PHY access debugging is now available by
   enabling GRETH_DEBUG_MII. Even successful accesses are printed.

4. Let PHY do power-down (not only reset) to get in a good state,
   this is just in case the PHY input pin settings are sampled only
   on PHY power-up on some PHYs.

5. PHY GBit advertisement is disabled if Gbit is not supported by MAC.
   Or forced if supported.

6. Auto-nego is started if supported by PHY, before it was started only
   if default set by PHY.

7. Reset Sequence updated:
     * one must wait until reset bit is self-cleared.
     * the DD (Disable Duplex Detection) bit is set, only affects
       EDCL capable devices. This lets RTEMS handle PHY initialization

1 files changed, 1 insertions, 0 deletions

diff --git a/c/src/lib/libbsp/sparc/shared/include/greth.h b/c/src/lib/libbsp/sparc/shared/include/greth.h
index c0c3b9a28b..8c88172b94 100644
--- a/c/src/lib/libbsp/sparc/shared/include/greth.h
+++ b/c/src/lib/libbsp/sparc/shared/include/greth.h
@@ -81,6 +81,7 @@ typedef struct _greth_regs {
 #define GRETH_CTRL_FULLD        0x00000010 /* Full Duplex */
 #define GRETH_CTRL_PRO          0x00000020 /* Promiscuous (receive all) */
 #define GRETH_CTRL_RST          0x00000040 /* Reset MAC */
+#define GRETH_CTRL_DD           0x00001000 /* Disable EDCL Duplex Detection */
 
 /* Status Register */
 #define GRETH_STATUS_RXERR      0x00000001 /* Receive Error */