[mii] Add generic MII reset function

iPXE provides no support for manually configuring the link speed.
Provide a generic routine which should be able to reset any MII/GMII
PHY and enable autonegotiation.

Prototyped-by: Thomas Miletich <thomas.miletich@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/net/mii.c

@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <ipxe/mii.h>
+
+/** @file
+ *
+ * Media Independent Interface
+ *
+ */
+
+/**
+ * Reset MII interface
+ *
+ * @v mii		MII interface
+ * @ret rc		Return status code
+ */
+int mii_reset ( struct mii_interface *mii ) {
+	unsigned int i;
+	int bmcr;
+	int rc;
+
+	/* Power-up, enable autonegotiation and initiate reset */
+	if ( ( rc = mii_write ( mii, MII_BMCR,
+				( BMCR_RESET | BMCR_ANENABLE ) ) ) != 0 ) {
+		DBGC ( mii, "MII %p could not write BMCR: %s\n",
+		       mii, strerror ( rc ) );
+		return rc;
+	}
+
+	/* Wait for reset to complete */
+	for ( i = 0 ; i < MII_RESET_MAX_WAIT_MS ; i++ ) {
+
+		/* Check if reset has completed */
+		bmcr = mii_read ( mii, MII_BMCR );
+		if ( bmcr < 0 ) {
+			rc = bmcr;
+			DBGC ( mii, "MII %p could not read BMCR: %s\n",
+			       mii, strerror ( rc ) );
+			return rc;
+		}
+
+		/* If reset is not complete, delay 1ms and retry */
+		if ( bmcr & BMCR_RESET ) {
+			mdelay ( 1 );
+			continue;
+		}
+
+		/* Force autonegotation on again, in case it was
+		 * cleared by the reset.
+		 */
+		if ( ( rc = mii_write ( mii, MII_BMCR, BMCR_ANENABLE ) ) != 0 ){
+			DBGC ( mii, "MII %p could not write BMCR: %s\n",
+			       mii, strerror ( rc ) );
+			return rc;
+		}
+
+		DBGC ( mii, "MII %p reset after %dms\n", mii, i );
+		return 0;
+	}
+
+	DBGC ( mii, "MII %p timed out waiting for reset\n", mii );
+	return -ETIMEDOUT;
+}

src/include/ipxe/errfile.h

@@ -141,6 +141,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #define ERRFILE_ath9k		     ( ERRFILE_DRIVER | 0x005f0000 )
 #define ERRFILE_ath		     ( ERRFILE_DRIVER | 0x00600000 )
 #define ERRFILE_vmxnet3		     ( ERRFILE_DRIVER | 0x00610000 )
+#define ERRFILE_mii		     ( ERRFILE_DRIVER | 0x00620000 )
 
 #define ERRFILE_scsi		     ( ERRFILE_DRIVER | 0x00700000 )
 #define ERRFILE_arbel		     ( ERRFILE_DRIVER | 0x00710000 )

src/include/ipxe/mii.h

@@ -0,0 +1,86 @@
+#ifndef _IPXE_MII_H
+#define _IPXE_MII_H
+
+/** @file
+ *
+ * Media Independent Interface
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <mii.h>
+#include <ipxe/netdevice.h>
+
+struct mii_interface;
+
+/** MII interface operations */
+struct mii_operations {
+	/**
+	 * Read from MII register
+	 *
+	 * @v mii		MII interface
+	 * @v reg		Register address
+	 * @ret data		Data read, or negative error
+	 */
+	int ( * read ) ( struct mii_interface *mii, unsigned int reg );
+	/**
+	 * Write to MII register
+	 *
+	 * @v mii		MII interface
+	 * @v reg		Register address
+	 * @v data		Data to write
+	 * @ret rc		Return status code
+	 */
+	int ( * write ) ( struct mii_interface *mii, unsigned int reg,
+			  unsigned int data );
+};
+
+/** An MII interface */
+struct mii_interface {
+	/** Interface operations */
+	struct mii_operations *op;
+};
+
+/**
+ * Initialise MII interface
+ *
+ * @v mii		MII interface
+ * @v op		MII interface operations
+ */
+static inline __attribute__ (( always_inline )) void
+mii_init ( struct mii_interface *mii, struct mii_operations *op ) {
+	mii->op = op;
+}
+
+/**
+ * Read from MII register
+ *
+ * @v mii		MII interface
+ * @v reg		Register address
+ * @ret data		Data read, or negative error
+ */
+static inline __attribute__ (( always_inline )) int
+mii_read ( struct mii_interface *mii, unsigned int reg ) {
+	return mii->op->read ( mii, reg );
+}
+
+/**
+ * Write to MII register
+ *
+ * @v mii		MII interface
+ * @v reg		Register address
+ * @v data		Data to write
+ * @ret rc		Return status code
+ */
+static inline __attribute__ (( always_inline )) int
+mii_write ( struct mii_interface *mii, unsigned int reg, unsigned int data ) {
+	return mii->op->write ( mii, reg, data );
+}
+
+/** Maximum time to wait for a reset, in milliseconds */
+#define MII_RESET_MAX_WAIT_MS 500
+
+extern int mii_reset ( struct mii_interface *mii );
+
+#endif /* _IPXE_MII_H */