powerpc/ppc4xx: Add gdsys mclink interface

mclink is a serial interface for communication between gdsys FPGA.

Signed-off-by: Dirk Eibach <dirk.eibach@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>

board/gdsys/common/mclink.c

+/*
+ * (C) Copyright 2012
+ * Dirk Eibach,  Guntermann & Drunck GmbH, dirk.eibach@gdsys.cc
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <errno.h>
+
+#include <gdsys_fpga.h>
+
+enum {
+	MCINT_SLAVE_LINK_CHANGED_EV = 1 << 7,
+	MCINT_TX_ERROR_EV = 1 << 9,
+	MCINT_TX_BUFFER_FREE = 1 << 10,
+	MCINT_TX_PACKET_TRANSMITTED_EV = 1 << 11,
+	MCINT_RX_ERROR_EV = 1 << 13,
+	MCINT_RX_CONTENT_AVAILABLE = 1 << 14,
+	MCINT_RX_PACKET_RECEIVED_EV = 1 << 15,
+};
+
+int mclink_probe(void)
+{
+	unsigned int k;
+	int slaves = 0;
+
+	for (k = 0; k < CONFIG_SYS_MCLINK_MAX; ++k) {
+		int timeout = 0;
+		unsigned int ctr = 0;
+		u16 mc_status;
+
+		FPGA_GET_REG(k, mc_status, &mc_status);
+
+		if (!(mc_status & (1 << 15)))
+			break;
+
+		FPGA_SET_REG(k, mc_control, 0x8000);
+
+		FPGA_GET_REG(k, mc_status, &mc_status);
+		while (!(mc_status & (1 << 14))) {
+			udelay(100);
+			if (ctr++ > 500) {
+				timeout = 1;
+				break;
+			}
+			FPGA_GET_REG(k, mc_status, &mc_status);
+		}
+		if (timeout)
+			break;
+
+		printf("waited %d us for mclink %d to come up\n", ctr * 100, k);
+
+		slaves++;
+	}
+
+	return slaves;
+}
+
+int mclink_send(u8 slave, u16 addr, u16 data)
+{
+	unsigned int ctr = 0;
+	u16 int_status;
+	u16 rx_cmd_status;
+	u16 rx_cmd;
+
+	/* reset interrupt status */
+	FPGA_GET_REG(0, mc_int, &int_status);
+	FPGA_SET_REG(0, mc_int, int_status);
+
+	/* send */
+	FPGA_SET_REG(0, mc_tx_address, addr);
+	FPGA_SET_REG(0, mc_tx_data, data);
+	FPGA_SET_REG(0, mc_tx_cmd, (slave & 0x03) << 14);
+	FPGA_SET_REG(0, mc_control, 0x8001);
+
+	/* wait for reply */
+	FPGA_GET_REG(0, mc_int, &int_status);
+	while (!(int_status & MCINT_RX_PACKET_RECEIVED_EV)) {
+		udelay(100);
+		if (ctr++ > 3)
+			return -ETIMEDOUT;
+		FPGA_GET_REG(0, mc_int, &int_status);
+	}
+
+	FPGA_GET_REG(0, mc_rx_cmd_status, &rx_cmd_status);
+	rx_cmd = (rx_cmd_status >> 12) & 0x03;
+	if (rx_cmd != 0)
+		printf("mclink_send: received cmd %d, expected %d\n", rx_cmd,
+		       0);
+
+	return 0;
+}
+
+int mclink_receive(u8 slave, u16 addr, u16 *data)
+{
+	u16 rx_cmd_status;
+	u16 rx_cmd;
+	u16 int_status;
+	unsigned int ctr = 0;
+
+	/* send read request */
+	FPGA_SET_REG(0, mc_tx_address, addr);
+	FPGA_SET_REG(0, mc_tx_cmd,
+		     ((slave & 0x03) << 14) | (1 << 12) | (1 << 0));
+	FPGA_SET_REG(0, mc_control, 0x8001);
+
+
+	/* wait for reply */
+	FPGA_GET_REG(0, mc_int, &int_status);
+	while (!(int_status & MCINT_RX_CONTENT_AVAILABLE)) {
+		udelay(100);
+		if (ctr++ > 3)
+			return -ETIMEDOUT;
+		FPGA_GET_REG(0, mc_int, &int_status);
+	}
+
+	/* check reply */
+	FPGA_GET_REG(0, mc_rx_cmd_status, &rx_cmd_status);
+	if ((rx_cmd_status >> 14) != slave) {
+		printf("mclink_receive: reply from slave %d, expected %d\n",
+		       rx_cmd_status >> 14, slave);
+		return -EINVAL;
+	}
+
+	rx_cmd = (rx_cmd_status >> 12) & 0x03;
+	if (rx_cmd != 1) {
+		printf("mclink_send: received cmd %d, expected %d\n",
+		       rx_cmd, 1);
+		return -EIO;
+	}
+
+	FPGA_GET_REG(0, mc_rx_data, data);
+
+	return 0;
+}

board/gdsys/common/mclink.h

+/*
+ * (C) Copyright 2012
+ * Dirk Eibach,  Guntermann & Drunck GmbH, dirk.eibach@gdsys.cc
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#ifndef _MCLINK_H_
+#define _MCLINK_H_
+
+int mclink_probe(void);
+int mclink_send(u8 slave, u16 addr, u16 data);
+int mclink_receive(u8 slave, u16 addr, u16 *data);
+
+#endif