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linux-next/drivers/net/isa-skeleton.c
David Howells 7d12e780e0 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 15:10:12 +01:00

725 lines
18 KiB
C
Raw Blame History

/* isa-skeleton.c: A network driver outline for linux.
*
* Written 1993-94 by Donald Becker.
*
* Copyright 1993 United States Government as represented by the
* Director, National Security Agency.
*
* This software may be used and distributed according to the terms
* of the GNU General Public License, incorporated herein by reference.
*
* The author may be reached as becker@scyld.com, or C/O
* Scyld Computing Corporation
* 410 Severn Ave., Suite 210
* Annapolis MD 21403
*
* This file is an outline for writing a network device driver for the
* the Linux operating system.
*
* To write (or understand) a driver, have a look at the "loopback.c" file to
* get a feel of what is going on, and then use the code below as a skeleton
* for the new driver.
*
*/
static const char *version =
"isa-skeleton.c:v1.51 9/24/94 Donald Becker (becker@cesdis.gsfc.nasa.gov)\n";
/*
* Sources:
* List your sources of programming information to document that
* the driver is your own creation, and give due credit to others
* that contributed to the work. Remember that GNU project code
* cannot use proprietary or trade secret information. Interface
* definitions are generally considered non-copyrightable to the
* extent that the same names and structures must be used to be
* compatible.
*
* Finally, keep in mind that the Linux kernel is has an API, not
* ABI. Proprietary object-code-only distributions are not permitted
* under the GPL.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/bitops.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/dma.h>
/*
* The name of the card. Is used for messages and in the requests for
* io regions, irqs and dma channels
*/
static const char* cardname = "netcard";
/* First, a few definitions that the brave might change. */
/* A zero-terminated list of I/O addresses to be probed. */
static unsigned int netcard_portlist[] __initdata =
{ 0x200, 0x240, 0x280, 0x2C0, 0x300, 0x320, 0x340, 0};
/* use 0 for production, 1 for verification, >2 for debug */
#ifndef NET_DEBUG
#define NET_DEBUG 2
#endif
static unsigned int net_debug = NET_DEBUG;
/* The number of low I/O ports used by the ethercard. */
#define NETCARD_IO_EXTENT 32
#define MY_TX_TIMEOUT ((400*HZ)/1000)
/* Information that need to be kept for each board. */
struct net_local {
struct net_device_stats stats;
long open_time; /* Useless example local info. */
/* Tx control lock. This protects the transmit buffer ring
* state along with the "tx full" state of the driver. This
* means all netif_queue flow control actions are protected
* by this lock as well.
*/
spinlock_t lock;
};
/* The station (ethernet) address prefix, used for IDing the board. */
#define SA_ADDR0 0x00
#define SA_ADDR1 0x42
#define SA_ADDR2 0x65
/* Index to functions, as function prototypes. */
static int netcard_probe1(struct net_device *dev, int ioaddr);
static int net_open(struct net_device *dev);
static int net_send_packet(struct sk_buff *skb, struct net_device *dev);
static irqreturn_t net_interrupt(int irq, void *dev_id);
static void net_rx(struct net_device *dev);
static int net_close(struct net_device *dev);
static struct net_device_stats *net_get_stats(struct net_device *dev);
static void set_multicast_list(struct net_device *dev);
static void net_tx_timeout(struct net_device *dev);
/* Example routines you must write ;->. */
#define tx_done(dev) 1
static void hardware_send_packet(short ioaddr, char *buf, int length);
static void chipset_init(struct net_device *dev, int startp);
/*
* Check for a network adaptor of this type, and return '0' iff one exists.
* If dev->base_addr == 0, probe all likely locations.
* If dev->base_addr == 1, always return failure.
* If dev->base_addr == 2, allocate space for the device and return success
* (detachable devices only).
*/
static int __init do_netcard_probe(struct net_device *dev)
{
int i;
int base_addr = dev->base_addr;
int irq = dev->irq;
SET_MODULE_OWNER(dev);
if (base_addr > 0x1ff) /* Check a single specified location. */
return netcard_probe1(dev, base_addr);
else if (base_addr != 0) /* Don't probe at all. */
return -ENXIO;
for (i = 0; netcard_portlist[i]; i++) {
int ioaddr = netcard_portlist[i];
if (netcard_probe1(dev, ioaddr) == 0)
return 0;
dev->irq = irq;
}
return -ENODEV;
}
static void cleanup_card(struct net_device *dev)
{
#ifdef jumpered_dma
free_dma(dev->dma);
#endif
#ifdef jumpered_interrupts
free_irq(dev->irq, dev);
#endif
release_region(dev->base_addr, NETCARD_IO_EXTENT);
}
#ifndef MODULE
struct net_device * __init netcard_probe(int unit)
{
struct net_device *dev = alloc_etherdev(sizeof(struct net_local));
int err;
if (!dev)
return ERR_PTR(-ENOMEM);
sprintf(dev->name, "eth%d", unit);
netdev_boot_setup_check(dev);
err = do_netcard_probe(dev);
if (err)
goto out;
return dev;
out:
free_netdev(dev);
return ERR_PTR(err);
}
#endif
/*
* This is the real probe routine. Linux has a history of friendly device
* probes on the ISA bus. A good device probes avoids doing writes, and
* verifies that the correct device exists and functions.
*/
static int __init netcard_probe1(struct net_device *dev, int ioaddr)
{
struct net_local *np;
static unsigned version_printed;
int i;
int err = -ENODEV;
/* Grab the region so that no one else tries to probe our ioports. */
if (!request_region(ioaddr, NETCARD_IO_EXTENT, cardname))
return -EBUSY;
/*
* For ethernet adaptors the first three octets of the station address
* contains the manufacturer's unique code. That might be a good probe
* method. Ideally you would add additional checks.
*/
if (inb(ioaddr + 0) != SA_ADDR0
|| inb(ioaddr + 1) != SA_ADDR1
|| inb(ioaddr + 2) != SA_ADDR2)
goto out;
if (net_debug && version_printed++ == 0)
printk(KERN_DEBUG "%s", version);
printk(KERN_INFO "%s: %s found at %#3x, ", dev->name, cardname, ioaddr);
/* Fill in the 'dev' fields. */
dev->base_addr = ioaddr;
/* Retrieve and print the ethernet address. */
for (i = 0; i < 6; i++)
printk(" %2.2x", dev->dev_addr[i] = inb(ioaddr + i));
err = -EAGAIN;
#ifdef jumpered_interrupts
/*
* If this board has jumpered interrupts, allocate the interrupt
* vector now. There is no point in waiting since no other device
* can use the interrupt, and this marks the irq as busy. Jumpered
* interrupts are typically not reported by the boards, and we must
* used autoIRQ to find them.
*/
if (dev->irq == -1)
; /* Do nothing: a user-level program will set it. */
else if (dev->irq < 2) { /* "Auto-IRQ" */
unsigned long irq_mask = probe_irq_on();
/* Trigger an interrupt here. */
dev->irq = probe_irq_off(irq_mask);
if (net_debug >= 2)
printk(" autoirq is %d", dev->irq);
} else if (dev->irq == 2)
/*
* Fixup for users that don't know that IRQ 2 is really
* IRQ9, or don't know which one to set.
*/
dev->irq = 9;
{
int irqval = request_irq(dev->irq, &net_interrupt, 0, cardname, dev);
if (irqval) {
printk("%s: unable to get IRQ %d (irqval=%d).\n",
dev->name, dev->irq, irqval);
goto out;
}
}
#endif /* jumpered interrupt */
#ifdef jumpered_dma
/*
* If we use a jumpered DMA channel, that should be probed for and
* allocated here as well. See lance.c for an example.
*/
if (dev->dma == 0) {
if (request_dma(dev->dma, cardname)) {
printk("DMA %d allocation failed.\n", dev->dma);
goto out1;
} else
printk(", assigned DMA %d.\n", dev->dma);
} else {
short dma_status, new_dma_status;
/* Read the DMA channel status registers. */
dma_status = ((inb(DMA1_STAT_REG) >> 4) & 0x0f) |
(inb(DMA2_STAT_REG) & 0xf0);
/* Trigger a DMA request, perhaps pause a bit. */
outw(0x1234, ioaddr + 8);
/* Re-read the DMA status registers. */
new_dma_status = ((inb(DMA1_STAT_REG) >> 4) & 0x0f) |
(inb(DMA2_STAT_REG) & 0xf0);
/*
* Eliminate the old and floating requests,
* and DMA4 the cascade.
*/
new_dma_status ^= dma_status;
new_dma_status &= ~0x10;
for (i = 7; i > 0; i--)
if (test_bit(i, &new_dma_status)) {
dev->dma = i;
break;
}
if (i <= 0) {
printk("DMA probe failed.\n");
goto out1;
}
if (request_dma(dev->dma, cardname)) {
printk("probed DMA %d allocation failed.\n", dev->dma);
goto out1;
}
}
#endif /* jumpered DMA */
np = netdev_priv(dev);
spin_lock_init(&np->lock);
dev->open = net_open;
dev->stop = net_close;
dev->hard_start_xmit = net_send_packet;
dev->get_stats = net_get_stats;
dev->set_multicast_list = &set_multicast_list;
dev->tx_timeout = &net_tx_timeout;
dev->watchdog_timeo = MY_TX_TIMEOUT;
err = register_netdev(dev);
if (err)
goto out2;
return 0;
out2:
#ifdef jumpered_dma
free_dma(dev->dma);
#endif
out1:
#ifdef jumpered_interrupts
free_irq(dev->irq, dev);
#endif
out:
release_region(base_addr, NETCARD_IO_EXTENT);
return err;
}
static void net_tx_timeout(struct net_device *dev)
{
struct net_local *np = netdev_priv(dev);
printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,
tx_done(dev) ? "IRQ conflict" : "network cable problem");
/* Try to restart the adaptor. */
chipset_init(dev, 1);
np->stats.tx_errors++;
/* If we have space available to accept new transmit
* requests, wake up the queueing layer. This would
* be the case if the chipset_init() call above just
* flushes out the tx queue and empties it.
*
* If instead, the tx queue is retained then the
* netif_wake_queue() call should be placed in the
* TX completion interrupt handler of the driver instead
* of here.
*/
if (!tx_full(dev))
netif_wake_queue(dev);
}
/*
* Open/initialize the board. This is called (in the current kernel)
* sometime after booting when the 'ifconfig' program is run.
*
* This routine should set everything up anew at each open, even
* registers that "should" only need to be set once at boot, so that
* there is non-reboot way to recover if something goes wrong.
*/
static int
net_open(struct net_device *dev)
{
struct net_local *np = netdev_priv(dev);
int ioaddr = dev->base_addr;
/*
* This is used if the interrupt line can turned off (shared).
* See 3c503.c for an example of selecting the IRQ at config-time.
*/
if (request_irq(dev->irq, &net_interrupt, 0, cardname, dev)) {
return -EAGAIN;
}
/*
* Always allocate the DMA channel after the IRQ,
* and clean up on failure.
*/
if (request_dma(dev->dma, cardname)) {
free_irq(dev->irq, dev);
return -EAGAIN;
}
/* Reset the hardware here. Don't forget to set the station address. */
chipset_init(dev, 1);
outb(0x00, ioaddr);
np->open_time = jiffies;
/* We are now ready to accept transmit requeusts from
* the queueing layer of the networking.
*/
netif_start_queue(dev);
return 0;
}
/* This will only be invoked if your driver is _not_ in XOFF state.
* What this means is that you need not check it, and that this
* invariant will hold if you make sure that the netif_*_queue()
* calls are done at the proper times.
*/
static int net_send_packet(struct sk_buff *skb, struct net_device *dev)
{
struct net_local *np = netdev_priv(dev);
int ioaddr = dev->base_addr;
short length = ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN;
unsigned char *buf = skb->data;
/* If some error occurs while trying to transmit this
* packet, you should return '1' from this function.
* In such a case you _may not_ do anything to the
* SKB, it is still owned by the network queueing
* layer when an error is returned. This means you
* may not modify any SKB fields, you may not free
* the SKB, etc.
*/
#if TX_RING
/* This is the most common case for modern hardware.
* The spinlock protects this code from the TX complete
* hardware interrupt handler. Queue flow control is
* thus managed under this lock as well.
*/
spin_lock_irq(&np->lock);
add_to_tx_ring(np, skb, length);
dev->trans_start = jiffies;
/* If we just used up the very last entry in the
* TX ring on this device, tell the queueing
* layer to send no more.
*/
if (tx_full(dev))
netif_stop_queue(dev);
/* When the TX completion hw interrupt arrives, this
* is when the transmit statistics are updated.
*/
spin_unlock_irq(&np->lock);
#else
/* This is the case for older hardware which takes
* a single transmit buffer at a time, and it is
* just written to the device via PIO.
*
* No spin locking is needed since there is no TX complete
* event. If by chance your card does have a TX complete
* hardware IRQ then you may need to utilize np->lock here.
*/
hardware_send_packet(ioaddr, buf, length);
np->stats.tx_bytes += skb->len;
dev->trans_start = jiffies;
/* You might need to clean up and record Tx statistics here. */
if (inw(ioaddr) == /*RU*/81)
np->stats.tx_aborted_errors++;
dev_kfree_skb (skb);
#endif
return 0;
}
#if TX_RING
/* This handles TX complete events posted by the device
* via interrupts.
*/
void net_tx(struct net_device *dev)
{
struct net_local *np = netdev_priv(dev);
int entry;
/* This protects us from concurrent execution of
* our dev->hard_start_xmit function above.
*/
spin_lock(&np->lock);
entry = np->tx_old;
while (tx_entry_is_sent(np, entry)) {
struct sk_buff *skb = np->skbs[entry];
np->stats.tx_bytes += skb->len;
dev_kfree_skb_irq (skb);
entry = next_tx_entry(np, entry);
}
np->tx_old = entry;
/* If we had stopped the queue due to a "tx full"
* condition, and space has now been made available,
* wake up the queue.
*/
if (netif_queue_stopped(dev) && ! tx_full(dev))
netif_wake_queue(dev);
spin_unlock(&np->lock);
}
#endif
/*
* The typical workload of the driver:
* Handle the network interface interrupts.
*/
static irqreturn_t net_interrupt(int irq, void *dev_id)
{
struct net_device *dev = dev_id;
struct net_local *np;
int ioaddr, status;
int handled = 0;
ioaddr = dev->base_addr;
np = netdev_priv(dev);
status = inw(ioaddr + 0);
if (status == 0)
goto out;
handled = 1;
if (status & RX_INTR) {
/* Got a packet(s). */
net_rx(dev);
}
#if TX_RING
if (status & TX_INTR) {
/* Transmit complete. */
net_tx(dev);
np->stats.tx_packets++;
netif_wake_queue(dev);
}
#endif
if (status & COUNTERS_INTR) {
/* Increment the appropriate 'localstats' field. */
np->stats.tx_window_errors++;
}
out:
return IRQ_RETVAL(handled);
}
/* We have a good packet(s), get it/them out of the buffers. */
static void
net_rx(struct net_device *dev)
{
struct net_local *lp = netdev_priv(dev);
int ioaddr = dev->base_addr;
int boguscount = 10;
do {
int status = inw(ioaddr);
int pkt_len = inw(ioaddr);
if (pkt_len == 0) /* Read all the frames? */
break; /* Done for now */
if (status & 0x40) { /* There was an error. */
lp->stats.rx_errors++;
if (status & 0x20) lp->stats.rx_frame_errors++;
if (status & 0x10) lp->stats.rx_over_errors++;
if (status & 0x08) lp->stats.rx_crc_errors++;
if (status & 0x04) lp->stats.rx_fifo_errors++;
} else {
/* Malloc up new buffer. */
struct sk_buff *skb;
lp->stats.rx_bytes+=pkt_len;
skb = dev_alloc_skb(pkt_len);
if (skb == NULL) {
printk(KERN_NOTICE "%s: Memory squeeze, dropping packet.\n",
dev->name);
lp->stats.rx_dropped++;
break;
}
skb->dev = dev;
/* 'skb->data' points to the start of sk_buff data area. */
memcpy(skb_put(skb,pkt_len), (void*)dev->rmem_start,
pkt_len);
/* or */
insw(ioaddr, skb->data, (pkt_len + 1) >> 1);
netif_rx(skb);
dev->last_rx = jiffies;
lp->stats.rx_packets++;
lp->stats.rx_bytes += pkt_len;
}
} while (--boguscount);
return;
}
/* The inverse routine to net_open(). */
static int
net_close(struct net_device *dev)
{
struct net_local *lp = netdev_priv(dev);
int ioaddr = dev->base_addr;
lp->open_time = 0;
netif_stop_queue(dev);
/* Flush the Tx and disable Rx here. */
disable_dma(dev->dma);
/* If not IRQ or DMA jumpered, free up the line. */
outw(0x00, ioaddr+0); /* Release the physical interrupt line. */
free_irq(dev->irq, dev);
free_dma(dev->dma);
/* Update the statistics here. */
return 0;
}
/*
* Get the current statistics.
* This may be called with the card open or closed.
*/
static struct net_device_stats *net_get_stats(struct net_device *dev)
{
struct net_local *lp = netdev_priv(dev);
short ioaddr = dev->base_addr;
/* Update the statistics from the device registers. */
lp->stats.rx_missed_errors = inw(ioaddr+1);
return &lp->stats;
}
/*
* Set or clear the multicast filter for this adaptor.
* num_addrs == -1 Promiscuous mode, receive all packets
* num_addrs == 0 Normal mode, clear multicast list
* num_addrs > 0 Multicast mode, receive normal and MC packets,
* and do best-effort filtering.
*/
static void
set_multicast_list(struct net_device *dev)
{
short ioaddr = dev->base_addr;
if (dev->flags&IFF_PROMISC)
{
/* Enable promiscuous mode */
outw(MULTICAST|PROMISC, ioaddr);
}
else if((dev->flags&IFF_ALLMULTI) || dev->mc_count > HW_MAX_ADDRS)
{
/* Disable promiscuous mode, use normal mode. */
hardware_set_filter(NULL);
outw(MULTICAST, ioaddr);
}
else if(dev->mc_count)
{
/* Walk the address list, and load the filter */
hardware_set_filter(dev->mc_list);
outw(MULTICAST, ioaddr);
}
else
outw(0, ioaddr);
}
#ifdef MODULE
static struct net_device *this_device;
static int io = 0x300;
static int irq;
static int dma;
static int mem;
MODULE_LICENSE("GPL");
int init_module(void)
{
struct net_device *dev;
int result;
if (io == 0)
printk(KERN_WARNING "%s: You shouldn't use auto-probing with insmod!\n",
cardname);
dev = alloc_etherdev(sizeof(struct net_local));
if (!dev)
return -ENOMEM;
/* Copy the parameters from insmod into the device structure. */
dev->base_addr = io;
dev->irq = irq;
dev->dma = dma;
dev->mem_start = mem;
if (do_netcard_probe(dev) == 0) {
this_device = dev;
return 0;
}
free_netdev(dev);
return -ENXIO;
}
void
cleanup_module(void)
{
unregister_netdev(this_device);
cleanup_card(this_device);
free_netdev(this_device);
}
#endif /* MODULE */
/*
* Local variables:
* compile-command:
* gcc -D__KERNEL__ -Wall -Wstrict-prototypes -Wwrite-strings
* -Wredundant-decls -O2 -m486 -c skeleton.c
* version-control: t
* kept-new-versions: 5
* tab-width: 4
* c-indent-level: 4
* End:
*/
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