linux/drivers/net/mipsnet.c

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/*
* 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.
*/
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/platform_device.h>
#include <asm/mips-boards/simint.h>
#define MIPSNET_VERSION "2007-11-17"
/*
* Net status/control block as seen by sw in the core.
*/
struct mipsnet_regs {
/*
* Device info for probing, reads as MIPSNET%d where %d is some
* form of version.
*/
u64 devId; /*0x00 */
/*
* read only busy flag.
* Set and cleared by the Net Device to indicate that an rx or a tx
* is in progress.
*/
u32 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.
*/
u32 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).
*/
u32 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.
*/
u32 interruptControl; /*0x14 */
#define MIPSNET_INTCTL_TXDONE (1u << 0)
#define MIPSNET_INTCTL_RXDONE (1u << 1)
#define MIPSNET_INTCTL_TESTBIT (1u << 31)
/*
* Readonly core-specific interrupt info for the device to signal
* the core. The meaning of the contents of this field might change.
*/
/* XXX: 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.
*/
u32 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.
*/
u32 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.
*/
u32 txDataBuffer; /*0x20 */
};
#define regaddr(dev, field) \
(dev->base_addr + offsetof(struct mipsnet_regs, field))
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)
{
for (; len > 0; len--, kdata++)
*kdata = inb(regaddr(dev, rxDataBuffer));
return inl(regaddr(dev, rxDataCount));
}
static inline void mipsnet_put_todevice(struct net_device *dev,
struct sk_buff *skb)
{
int count_to_go = skb->len;
char *buf_ptr = skb->data;
outl(skb->len, regaddr(dev, txDataCount));
for (; count_to_go; buf_ptr++, count_to_go--)
outb(*buf_ptr, regaddr(dev, txDataBuffer));
dev->stats.tx_packets++;
dev->stats.tx_bytes += skb->len;
dev_kfree_skb(skb);
}
static int mipsnet_xmit(struct sk_buff *skb, struct net_device *dev)
{
/*
* 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 len)
{
struct sk_buff *skb;
if (!len)
return len;
skb = dev_alloc_skb(len + NET_IP_ALIGN);
if (!skb) {
dev->stats.rx_dropped++;
return -ENOMEM;
}
skb_reserve(skb, NET_IP_ALIGN);
if (ioiocpy_frommipsnet(dev, skb_put(skb, len), len))
return -EFAULT;
skb->protocol = eth_type_trans(skb, dev);
skb->ip_summed = CHECKSUM_UNNECESSARY;
netif_rx(skb);
dev->stats.rx_packets++;
dev->stats.rx_bytes += len;
return len;
}
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 13:55:46 +00:00
static irqreturn_t mipsnet_interrupt(int irq, void *dev_id)
{
struct net_device *dev = dev_id;
u32 int_flags;
irqreturn_t ret = IRQ_NONE;
if (irq != dev->irq)
goto out_badirq;
/* TESTBIT is cleared on read. */
int_flags = inl(regaddr(dev, interruptControl));
if (int_flags & MIPSNET_INTCTL_TESTBIT) {
/* TESTBIT takes effect after a write with 0. */
outl(0, regaddr(dev, interruptControl));
ret = IRQ_HANDLED;
} else if (int_flags & MIPSNET_INTCTL_TXDONE) {
/* Only one packet at a time, we are done. */
dev->stats.tx_packets++;
netif_wake_queue(dev);
outl(MIPSNET_INTCTL_TXDONE,
regaddr(dev, interruptControl));
ret = IRQ_HANDLED;
} else if (int_flags & MIPSNET_INTCTL_RXDONE) {
mipsnet_get_fromdev(dev, inl(regaddr(dev, rxDataCount)));
outl(MIPSNET_INTCTL_RXDONE, regaddr(dev, interruptControl));
ret = IRQ_HANDLED;
}
return ret;
out_badirq:
printk(KERN_INFO "%s: %s(): irq %d for unknown device\n",
dev->name, __func__, irq);
return ret;
}
static int mipsnet_open(struct net_device *dev)
{
int err;
err = request_irq(dev->irq, &mipsnet_interrupt,
IRQF_SHARED, dev->name, (void *) dev);
if (err) {
release_region(dev->base_addr, sizeof(struct mipsnet_regs));
return err;
}
netif_start_queue(dev);
/* test interrupt handler */
outl(MIPSNET_INTCTL_TESTBIT, regaddr(dev, interruptControl));
return 0;
}
static int mipsnet_close(struct net_device *dev)
{
netif_stop_queue(dev);
free_irq(dev->irq, dev);
return 0;
}
static void mipsnet_set_mclist(struct net_device *dev)
{
}
static int __init mipsnet_probe(struct platform_device *dev)
{
struct net_device *netdev;
int err;
netdev = alloc_etherdev(0);
if (!netdev) {
err = -ENOMEM;
goto out;
}
platform_set_drvdata(dev, netdev);
netdev->open = mipsnet_open;
netdev->stop = mipsnet_close;
netdev->hard_start_xmit = mipsnet_xmit;
netdev->set_multicast_list = mipsnet_set_mclist;
/*
* TODO: probe for these or load them from PARAM
*/
netdev->base_addr = 0x4200;
netdev->irq = MIPS_CPU_IRQ_BASE + MIPSCPU_INT_MB0 +
inl(regaddr(netdev, interruptInfo));
/* Get the io region now, get irq on open() */
if (!request_region(netdev->base_addr, sizeof(struct mipsnet_regs),
"mipsnet")) {
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, sizeof(struct mipsnet_regs));
out_free_netdev:
free_netdev(netdev);
out:
return err;
}
static int __devexit mipsnet_device_remove(struct platform_device *device)
{
struct net_device *dev = platform_get_drvdata(device);
unregister_netdev(dev);
release_region(dev->base_addr, sizeof(struct mipsnet_regs));
free_netdev(dev);
platform_set_drvdata(device, NULL);
return 0;
}
static struct platform_driver mipsnet_driver = {
.driver = {
.name = mipsnet_string,
.owner = THIS_MODULE,
},
.probe = mipsnet_probe,
.remove = __devexit_p(mipsnet_device_remove),
};
static int __init mipsnet_init_module(void)
{
int err;
printk(KERN_INFO "MIPSNet Ethernet driver. Version: %s. "
"(c)2005 MIPS Technologies, Inc.\n", MIPSNET_VERSION);
err = platform_driver_register(&mipsnet_driver);
if (err)
printk(KERN_ERR "Driver registration failed\n");
return err;
}
static void __exit mipsnet_exit_module(void)
{
platform_driver_unregister(&mipsnet_driver);
}
module_init(mipsnet_init_module);
module_exit(mipsnet_exit_module);