[mii] Add bit-bashing interface

Signed-off-by: Sylvie Barlow <sylvie.c.barlow@gmail.com>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/drivers/bitbash/mii_bit.c b/src/drivers/bitbash/mii_bit.c
new file mode 100644 (file)
index 0000000..5f0ec04
--- /dev/null
+++ b/src/drivers/bitbash/mii_bit.c
@@ -0,0 +1,162 @@
+/*
+ * Copyright (C) 2018 Sylvie Barlow <sylvie.c.barlow@gmail.com>.
+ *
+ * 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 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.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <stdint.h>
+#include <unistd.h>
+#include <ipxe/bitbash.h>
+#include <ipxe/mii_bit.h>
+
+/**
+ * Transfer bits over MII bit-bashing interface
+ *
+ * @v basher           Bit basher
+ * @v mask             Mask
+ * @v write            Data to write
+ * @ret read           Data read
+ */
+static uint32_t mii_bit_xfer ( struct bit_basher *basher,
+                              uint32_t mask, uint32_t write ) {
+       uint32_t read = 0;
+       int bit;
+
+       for ( ; mask ; mask >>= 1 ) {
+
+               /* Delay */
+               udelay ( 1 );
+
+               /* Write bit to basher */
+               write_bit ( basher, MII_BIT_MDIO, ( write & mask ) );
+
+               /* Read bit from basher */
+               bit = read_bit ( basher, MII_BIT_MDIO );
+               read <<= 1;
+               read |= ( bit & 1 );
+
+               /* Set clock high */
+               write_bit ( basher, MII_BIT_MDC, 1 );
+
+               /* Delay */
+               udelay ( 1 );
+
+               /* Set clock low */
+               write_bit ( basher, MII_BIT_MDC, 0 );
+       }
+       return read;
+}
+
+/**
+ * Read or write via MII bit-bashing interface
+ *
+ * @v basher           Bit basher
+ * @v phy              PHY address
+ * @v reg              Register address
+ * @v data             Data to write
+ * @v cmd              Command
+ * @ret data           Data read
+ */
+static unsigned int mii_bit_rw ( struct bit_basher *basher,
+                                unsigned int phy, unsigned int reg,
+                                unsigned int data, unsigned int cmd ) {
+
+       /* Initiate drive for write */
+       write_bit ( basher, MII_BIT_DRIVE, 1 );
+
+       /* Write start */
+       mii_bit_xfer ( basher, MII_BIT_START_MASK, MII_BIT_START );
+
+       /* Write command */
+       mii_bit_xfer ( basher, MII_BIT_CMD_MASK, cmd );
+
+       /* Write PHY address */
+       mii_bit_xfer ( basher, MII_BIT_PHY_MASK, phy );
+
+       /* Write register address */
+       mii_bit_xfer ( basher, MII_BIT_REG_MASK, reg );
+
+       /* Switch drive to read if applicable */
+       write_bit ( basher, MII_BIT_DRIVE, ( cmd & MII_BIT_CMD_RW ) );
+
+       /* Allow space for turnaround */
+       mii_bit_xfer ( basher, MII_BIT_SWITCH_MASK, MII_BIT_SWITCH );
+
+       /* Read or write data */
+       data = mii_bit_xfer (basher, MII_BIT_DATA_MASK, data );
+
+       /* Initiate drive for read */
+       write_bit ( basher, MII_BIT_DRIVE, 0 );
+
+       return data;
+}
+
+/**
+ * Read from MII register
+ *
+ * @v mdio             MII interface
+ * @v phy              PHY address
+ * @v reg              Register address
+ * @ret data           Data read, or negative error
+ */
+static int mii_bit_read ( struct mii_interface *mdio, unsigned int phy,
+                         unsigned int reg ) {
+       struct mii_bit_basher *miibit =
+               container_of ( mdio, struct mii_bit_basher, mdio );
+       struct bit_basher *basher = &miibit->basher;
+
+       return mii_bit_rw ( basher, phy, reg, 0, MII_BIT_CMD_READ );
+}
+
+/**
+ * Write to MII register
+ *
+ * @v mdio             MII interface
+ * @v phy              PHY address
+ * @v reg              Register address
+ * @v data             Data to write
+ * @ret rc             Return status code
+ */
+static int mii_bit_write ( struct mii_interface *mdio, unsigned int phy,
+                          unsigned int reg, unsigned int data ) {
+       struct mii_bit_basher *miibit =
+               container_of ( mdio, struct mii_bit_basher, mdio );
+       struct bit_basher *basher = &miibit->basher;
+
+       mii_bit_rw ( basher, phy, reg, data, MII_BIT_CMD_WRITE );
+       return 0;
+}
+
+/** MII bit basher operations */
+static struct mii_operations mii_bit_op = {
+       .read = mii_bit_read,
+       .write = mii_bit_write,
+};
+
+/**
+ * Initialise bit-bashing interface
+ *
+ * @v miibit           MII bit basher
+ */
+void init_mii_bit_basher ( struct mii_bit_basher *miibit ) {
+       mdio_init ( &miibit->mdio, &mii_bit_op );
+};

diff --git a/src/include/ipxe/mii_bit.h b/src/include/ipxe/mii_bit.h
new file mode 100644 (file)
index 0000000..0f797e9
--- /dev/null
+++ b/src/include/ipxe/mii_bit.h
@@ -0,0 +1,55 @@
+#ifndef _IPXE_MII_BIT_H
+#define _IPXE_MII_BIT_H
+
+/** @file
+ *
+ * MII bit-bashing interface
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/mii.h>
+#include <ipxe/bitbash.h>
+
+#define MII_BIT_START          0xffffffff      /**< Start */
+#define MII_BIT_START_MASK     0x80000000      /**< Start mask */
+
+#define MII_BIT_CMD_MASK       0x00000008      /**< Command mask */
+#define MII_BIT_CMD_READ       0x00000006      /**< Command read */
+#define MII_BIT_CMD_WRITE      0x00000005      /**< Command write */
+#define MII_BIT_CMD_RW         0x00000001      /**< Command read or write */
+
+#define MII_BIT_PHY_MASK       0x00000010      /**< PHY mask */
+
+#define MII_BIT_REG_MASK       0x00000010      /**< Register mask */
+
+#define MII_BIT_SWITCH         0x00000002      /**< Switch */
+#define MII_BIT_SWITCH_MASK    0x00000002      /**< Switch mask */
+
+#define MII_BIT_DATA_MASK      0x00008000      /**< Data mask */
+
+/** A bit-bashing MII interface */
+struct mii_bit_basher {
+       /** MII interface */
+       struct mii_interface mdio;
+       /** Bit-bashing interface */
+       struct bit_basher basher;
+};
+
+/** Bit indices used for MII bit-bashing interface */
+enum {
+       /** MII clock */
+       MII_BIT_MDC = 0,
+       /** MII data */
+       MII_BIT_MDIO,
+       /** MII data direction */
+       MII_BIT_DRIVE,
+};
+
+/** Delay between MDC transitions */
+#define MII_BIT_UDELAY 1
+
+extern void init_mii_bit_basher ( struct mii_bit_basher *miibit );
+
+#endif /* _IPXE_MII_BIT_H */