[PATCH] mipsnet: Virtual ethernet driver for MIPSsim.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

 drivers/net/Kconfig   |    8 +
 drivers/net/Makefile  |    1
 drivers/net/mipsnet.c |  371 ++++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/net/mipsnet.h |  127 +++++++++++++++++
 4 files changed, 507 insertions(+)
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

4 files changed, 507 insertions, 0 deletions

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 0a30368..5148d47 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -475,6 +475,14 @@ config SGI_IOC3_ETH_HW_TX_CSUM
 	  the moment only acceleration of IPv4 is supported.  This option
 	  enables offloading for checksums on transmit.  If unsure, say Y.
 
+config MIPS_SIM_NET
+	tristate "MIPS simulator Network device (EXPERIMENTAL)"
+	depends on NETDEVICES && MIPS_SIM && EXPERIMENTAL
+	help
+	  The MIPSNET device is a simple Ethernet network device which is
+	  emulated by the MIPS Simulator.
+	  If you are not using a MIPSsim or are unsure, say N.
+
 config SGI_O2MACE_ETH
 	tristate "SGI O2 MACE Fast Ethernet support"
 	depends on NET_ETHERNET && SGI_IP32=y
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 4c9477c..1a84e04 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -167,6 +167,7 @@ obj-$(CONFIG_EQUALIZER) += eql.o
 obj-$(CONFIG_MIPS_JAZZ_SONIC) += jazzsonic.o
 obj-$(CONFIG_MIPS_GT96100ETH) += gt96100eth.o
 obj-$(CONFIG_MIPS_AU1X00_ENET) += au1000_eth.o
+obj-$(CONFIG_MIPS_SIM_NET) += mipsnet.o
 obj-$(CONFIG_SGI_IOC3_ETH) += ioc3-eth.o
 obj-$(CONFIG_DECLANCE) += declance.o
 obj-$(CONFIG_ATARILANCE) += atarilance.o
diff --git a/drivers/net/mipsnet.c b/drivers/net/mipsnet.c
new file mode 100644
index 0000000..f79f7ee
--- /dev/null
+++ b/drivers/net/mipsnet.c
@@ -0,0 +1,371 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#define DEBUG
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/sched.h>
+#include <linux/etherdevice.h>
+#include <linux/netdevice.h>
+#include <asm/io.h>
+#include <asm/mips-boards/simint.h>
+
+#include "mipsnet.h"		/* actual device IO mapping */
+
+#define MIPSNET_VERSION "2005-06-20"
+
+#define mipsnet_reg_address(dev, field) (dev->base_addr + field_offset(field))
+
+struct mipsnet_priv {
+	struct net_device_stats stats;
+};
+
+static struct platform_device *mips_plat_dev;
+
+static char mipsnet_string[] = "mipsnet";
+
+/*
+ * Copy data from the MIPSNET rx data port
+ */
+static int ioiocpy_frommipsnet(struct net_device *dev, unsigned char *kdata,
+			int len)
+{
+	uint32_t available_len = inl(mipsnet_reg_address(dev, rxDataCount));
+	if (available_len < len)
+		return -EFAULT;
+
+	for (; len > 0; len--, kdata++) {
+		*kdata = inb(mipsnet_reg_address(dev, rxDataBuffer));
+	}
+
+	return inl(mipsnet_reg_address(dev, rxDataCount));
+}
+
+static inline ssize_t mipsnet_put_todevice(struct net_device *dev,
+	struct sk_buff *skb)
+{
+	int count_to_go = skb->len;
+	char *buf_ptr = skb->data;
+	struct mipsnet_priv *mp = netdev_priv(dev);
+
+	pr_debug("%s: %s(): telling MIPSNET txDataCount(%d)\n",
+	         dev->name, __FUNCTION__, skb->len);
+
+	outl(skb->len, mipsnet_reg_address(dev, txDataCount));
+
+	pr_debug("%s: %s(): sending data to MIPSNET txDataBuffer(%d)\n",
+	         dev->name, __FUNCTION__, skb->len);
+
+	for (; count_to_go; buf_ptr++, count_to_go--) {
+		outb(*buf_ptr, mipsnet_reg_address(dev, txDataBuffer));
+	}
+
+	mp->stats.tx_packets++;
+	mp->stats.tx_bytes += skb->len;
+
+	return skb->len;
+}
+
+static int mipsnet_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	pr_debug("%s:%s(): transmitting %d bytes\n",
+	         dev->name, __FUNCTION__, skb->len);
+
+	/* Only one packet at a time. Once TXDONE interrupt is serviced, the
+	 * queue will be restarted.
+	 */
+	netif_stop_queue(dev);
+	mipsnet_put_todevice(dev, skb);
+
+	return 0;
+}
+
+static inline ssize_t mipsnet_get_fromdev(struct net_device *dev, size_t count)
+{
+	struct sk_buff *skb;
+	size_t len = count;
+	struct mipsnet_priv *mp = netdev_priv(dev);
+
+	if (!(skb = alloc_skb(len + 2, GFP_KERNEL))) {
+		mp->stats.rx_dropped++;
+		return -ENOMEM;
+	}
+
+	skb_reserve(skb, 2);
+	if (ioiocpy_frommipsnet(dev, skb_put(skb, len), len))
+		return -EFAULT;
+
+	skb->dev = dev;
+	skb->protocol = eth_type_trans(skb, dev);
+	skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+	pr_debug("%s:%s(): pushing RXed data to kernel\n",
+	         dev->name, __FUNCTION__);
+	netif_rx(skb);
+
+	mp->stats.rx_packets++;
+	mp->stats.rx_bytes += len;
+
+	return count;
+}
+
+static irqreturn_t
+mipsnet_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+	struct net_device *dev = dev_id;
+
+	irqreturn_t retval = IRQ_NONE;
+	uint64_t interruptFlags;
+
+	if (irq == dev->irq) {
+		pr_debug("%s:%s(): irq %d for device\n",
+		         dev->name, __FUNCTION__, irq);
+
+		retval = IRQ_HANDLED;
+
+		interruptFlags =
+		    inl(mipsnet_reg_address(dev, interruptControl));
+		pr_debug("%s:%s(): intCtl=0x%016llx\n", dev->name,
+		         __FUNCTION__, interruptFlags);
+
+		if (interruptFlags & MIPSNET_INTCTL_TXDONE) {
+			pr_debug("%s:%s(): got TXDone\n",
+			         dev->name, __FUNCTION__);
+			outl(MIPSNET_INTCTL_TXDONE,
+			     mipsnet_reg_address(dev, interruptControl));
+			// only one packet at a time, we are done.
+			netif_wake_queue(dev);
+		} else if (interruptFlags & MIPSNET_INTCTL_RXDONE) {
+			pr_debug("%s:%s(): got RX data\n",
+			         dev->name, __FUNCTION__);
+			mipsnet_get_fromdev(dev,
+			            inl(mipsnet_reg_address(dev, rxDataCount)));
+			pr_debug("%s:%s(): clearing RX int\n",
+			         dev->name, __FUNCTION__);
+			outl(MIPSNET_INTCTL_RXDONE,
+			     mipsnet_reg_address(dev, interruptControl));
+
+		} else if (interruptFlags & MIPSNET_INTCTL_TESTBIT) {
+			pr_debug("%s:%s(): got test interrupt\n",
+			         dev->name, __FUNCTION__);
+			// TESTBIT is cleared on read.
+			//    And takes effect after a write with 0
+			outl(0, mipsnet_reg_address(dev, interruptControl));
+		} else {
+			pr_debug("%s:%s(): no valid fags 0x%016llx\n",
+			         dev->name, __FUNCTION__, interruptFlags);
+			// Maybe shared IRQ, just ignore, no clearing.
+			retval = IRQ_NONE;
+		}
+
+	} else {
+		printk(KERN_INFO "%s: %s(): irq %d for unknown device\n",
+		       dev->name, __FUNCTION__, irq);
+		retval = IRQ_NONE;
+	}
+	return retval;
+}				//mipsnet_interrupt()
+
+static int mipsnet_open(struct net_device *dev)
+{
+	int err;
+	pr_debug("%s: mipsnet_open\n", dev->name);
+
+	err = request_irq(dev->irq, &mipsnet_interrupt,
+			  SA_SHIRQ, dev->name, (void *) dev);
+
+	if (err) {
+		pr_debug("%s: %s(): can't get irq %d\n",
+		         dev->name, __FUNCTION__, dev->irq);
+		release_region(dev->base_addr, MIPSNET_IO_EXTENT);
+		return err;
+	}
+
+	pr_debug("%s: %s(): got IO region at 0x%04lx and irq %d for dev.\n",
+	         dev->name, __FUNCTION__, dev->base_addr, dev->irq);
+
+
+	netif_start_queue(dev);
+
+	// test interrupt handler
+	outl(MIPSNET_INTCTL_TESTBIT,
+	     mipsnet_reg_address(dev, interruptControl));
+
+
+	return 0;
+}
+
+static int mipsnet_close(struct net_device *dev)
+{
+	pr_debug("%s: %s()\n", dev->name, __FUNCTION__);
+	netif_stop_queue(dev);
+	return 0;
+}
+
+static struct net_device_stats *mipsnet_get_stats(struct net_device *dev)
+{
+	struct mipsnet_priv *mp = netdev_priv(dev);
+
+	return &mp->stats;
+}
+
+static void mipsnet_set_mclist(struct net_device *dev)
+{
+	// we don't do anything
+	return;
+}
+
+static int __init mipsnet_probe(struct device *dev)
+{
+	struct net_device *netdev;
+	int err;
+
+	netdev = alloc_etherdev(sizeof(struct mipsnet_priv));
+	if (!netdev) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	dev_set_drvdata(dev, netdev);
+
+	netdev->open			= mipsnet_open;
+	netdev->stop			= mipsnet_close;
+	netdev->hard_start_xmit		= mipsnet_xmit;
+	netdev->get_stats		= mipsnet_get_stats;
+	netdev->set_multicast_list	= mipsnet_set_mclist;
+
+	/*
+	 * TODO: probe for these or load them from PARAM
+	 */
+	netdev->base_addr = 0x4200;
+	netdev->irq = MIPSCPU_INT_BASE + MIPSCPU_INT_MB0 +
+	              inl(mipsnet_reg_address(netdev, interruptInfo));
+
+	// Get the io region now, get irq on open()
+	if (!request_region(netdev->base_addr, MIPSNET_IO_EXTENT, "mipsnet")) {
+		pr_debug("%s: %s(): IO region {start: 0x%04lux, len: %d} "
+		         "for dev is not availble.\n", netdev->name,
+		         __FUNCTION__, netdev->base_addr, MIPSNET_IO_EXTENT);
+		err = -EBUSY;
+		goto out_free_netdev;
+	}
+
+	/*
+	 * Lacking any better mechanism to allocate a MAC address we use a
+	 * random one ...
+	 */
+	random_ether_addr(netdev->dev_addr);
+
+	err = register_netdev(netdev);
+	if (err) {
+		printk(KERN_ERR "MIPSNet: failed to register netdev.\n");
+		goto out_free_region;
+	}
+
+	return 0;
+
+out_free_region:
+	release_region(netdev->base_addr, MIPSNET_IO_EXTENT);
+
+out_free_netdev:
+	free_netdev(netdev);
+
+out:
+	return err;
+}
+
+static int __devexit mipsnet_device_remove(struct device *device)
+{
+	struct net_device *dev = dev_get_drvdata(device);
+
+	unregister_netdev(dev);
+	release_region(dev->base_addr, MIPSNET_IO_EXTENT);
+	free_netdev(dev);
+	dev_set_drvdata(device, NULL);
+
+	return 0;
+}
+
+static struct device_driver mipsnet_driver = {
+	.name	= mipsnet_string,
+	.bus	= &platform_bus_type,
+	.probe	= mipsnet_probe,
+	.remove	= __devexit_p(mipsnet_device_remove),
+};
+
+static void mipsnet_platform_release(struct device *device)
+{
+	struct platform_device *pldev;
+
+	/* free device */
+	pldev = to_platform_device(device);
+	kfree(pldev);
+}
+
+static int __init mipsnet_init_module(void)
+{
+	struct platform_device *pldev;
+	int err;
+
+	printk(KERN_INFO "MIPSNet Ethernet driver. Version: %s. "
+	       "(c)2005 MIPS Technologies, Inc.\n", MIPSNET_VERSION);
+
+	if (driver_register(&mipsnet_driver)) {
+		printk(KERN_ERR "Driver registration failed\n");
+		err = -ENODEV;
+		goto out;
+	}
+
+        if (!(pldev = kmalloc (sizeof (*pldev), GFP_KERNEL))) {
+		err = -ENOMEM;
+		goto out_unregister_driver;
+	}
+
+	memset (pldev, 0, sizeof (*pldev));
+	pldev->name		= mipsnet_string;
+	pldev->id		= 0;
+	pldev->dev.release	= mipsnet_platform_release;
+
+	if (platform_device_register(pldev)) {
+		err = -ENODEV;
+		goto out_free_pldev;
+	}
+
+        if (!pldev->dev.driver) {
+		/*
+		 * The driver was not bound to this device, there was
+                 * no hardware at this address. Unregister it, as the
+		 * release fuction will take care of freeing the
+		 * allocated structure
+		 */
+		platform_device_unregister (pldev);
+	}
+
+	mips_plat_dev		= pldev;
+
+	return 0;
+
+out_free_pldev:
+	kfree(pldev);
+
+out_unregister_driver:
+	driver_unregister(&mipsnet_driver);
+out:
+	return err;
+}
+
+static void __exit mipsnet_exit_module(void)
+{
+	pr_debug("MIPSNet Ethernet driver exiting\n");
+
+	driver_unregister(&mipsnet_driver);
+}
+
+module_init(mipsnet_init_module);
+module_exit(mipsnet_exit_module);
diff --git a/drivers/net/mipsnet.h b/drivers/net/mipsnet.h
new file mode 100644
index 0000000..8785359
--- /dev/null
+++ b/drivers/net/mipsnet.h
@@ -0,0 +1,127 @@
+//
+// <COPYRIGHT CLASS="1B" YEAR="2005">
+// Unpublished work (c) MIPS Technologies, Inc.  All rights reserved.
+// Unpublished rights reserved under the copyright laws of the U.S.A. and
+//  other countries.
+//
+// PROPRIETARY / SECRET CONFIDENTIAL INFORMATION OF MIPS TECHNOLOGIES, INC.
+// FOR INTERNAL USE ONLY.
+//
+// Under no circumstances (contract or otherwise) may this information be
+// disclosed to, or copied, modified or used by anyone other than employees
+// or contractors of MIPS Technologies having a need to know.
+// </COPYRIGHT>
+//
+//++
+// File: MIPS_Net.h
+//
+// Description:
+//   The definition of the emulated MIPSNET device's interface.
+//
+// Notes: This include file needs to work from a Linux device drivers.
+//
+//--
+//
+
+#ifndef __MIPSNET_H
+#define __MIPSNET_H
+
+/*
+ *  Id of this Net device, as seen by the core.
+ */
+#define MIPS_NET_DEV_ID ((uint64_t)           \
+	                     ((uint64_t)'M'<< 0)| \
+	                     ((uint64_t)'I'<< 8)| \
+	                     ((uint64_t)'P'<<16)| \
+	                     ((uint64_t)'S'<<24)| \
+	                     ((uint64_t)'N'<<32)| \
+	                     ((uint64_t)'E'<<40)| \
+	                     ((uint64_t)'T'<<48)| \
+	                     ((uint64_t)'0'<<56))
+
+/*
+ * Net status/control block as seen by sw in the core.
+ * (Why not use bit fields? can't be bothered with cross-platform struct
+ *  packing.)
+ */
+typedef struct _net_control_block {
+	/// dev info for probing
+	///  reads as MIPSNET%d where %d is some form of version
+	uint64_t devId;		/*0x00 */
+
+	/*
+	 * read only busy flag.
+	 * Set and cleared by the Net Device to indicate that an rx or a tx
+	 * is in progress.
+	 */
+	uint32_t busy;		/*0x08 */
+
+	/*
+	 * Set by the Net Device.
+	 * The device will set it once data has been received.
+	 * The value is the number of bytes that should be read from
+	 * rxDataBuffer.  The value will decrease till 0 until all the data
+	 * from rxDataBuffer has been read.
+	 */
+	uint32_t rxDataCount;	/*0x0c */
+#define MIPSNET_MAX_RXTX_DATACOUNT (1<<16)
+
+	/*
+	 * Settable from the MIPS core, cleared by the Net Device.
+	 * The core should set the number of bytes it wants to send,
+	 *   then it should write those bytes of data to txDataBuffer.
+	 * The device will clear txDataCount has been processed (not necessarily sent).
+	 */
+	uint32_t txDataCount;	/*0x10 */
+
+	/*
+	 * Interrupt control
+	 *
+	 * Used to clear the interrupted generated by this dev.
+	 * Write a 1 to clear the interrupt. (except bit31).
+	 *
+	 * Bit0 is set if it was a tx-done interrupt.
+	 * Bit1 is set when new rx-data is available.
+	 *      Until this bit is cleared there will be no other RXs.
+	 *
+	 * Bit31 is used for testing, it clears after a read.
+	 *    Writing 1 to this bit will cause an interrupt to be generated.
+	 *    To clear the test interrupt, write 0 to this register.
+	 */
+	uint32_t interruptControl;	/*0x14 */
+#define MIPSNET_INTCTL_TXDONE     ((uint32_t)(1<< 0))
+#define MIPSNET_INTCTL_RXDONE     ((uint32_t)(1<< 1))
+#define MIPSNET_INTCTL_TESTBIT    ((uint32_t)(1<<31))
+#define MIPSNET_INTCTL_ALLSOURCES (MIPSNET_INTCTL_TXDONE|MIPSNET_INTCTL_RXDONE|MIPSNET_INTCTL_TESTBIT)
+
+	/*
+	 * Readonly core-specific interrupt info for the device to signal the core.
+	 * The meaning of the contents of this field might change.
+	 */
+	/*###\todo: the whole memIntf interrupt scheme is messy: the device should have
+	 *  no control what so ever of what VPE/register set is being used.
+	 *  The MemIntf should only expose interrupt lines, and something in the
+	 *  config should be responsible for the line<->core/vpe bindings.
+	 */
+	uint32_t interruptInfo;	/*0x18 */
+
+	/*
+	 *  This is where the received data is read out.
+	 *  There is more data to read until rxDataReady is 0.
+	 *  Only 1 byte at this regs offset is used.
+	 */
+	uint32_t rxDataBuffer;	/*0x1c */
+
+	/*
+	 * This is where the data to transmit is written.
+	 * Data should be written for the amount specified in the txDataCount register.
+	 *  Only 1 byte at this regs offset is used.
+	 */
+	uint32_t txDataBuffer;	/*0x20 */
+} MIPS_T_NetControl;
+
+#define MIPSNET_IO_EXTENT 0x40	/* being generous */
+
+#define field_offset(field) ((int)&((MIPS_T_NetControl*)(0))->field)
+
+#endif /* __MIPSNET_H */