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linux-2.6/drivers/net/ibm_emac/ibm_emac_mal.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

583 lines
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/*
* drivers/net/ibm_emac/ibm_emac_mal.c
*
* Memory Access Layer (MAL) support
*
* Copyright (c) 2004, 2005 Zultys Technologies.
* Eugene Surovegin <eugene.surovegin@zultys.com> or <ebs@ebshome.net>
*
* Based on original work by
* Benjamin Herrenschmidt <benh@kernel.crashing.org>,
* David Gibson <hermes@gibson.dropbear.id.au>,
*
* Armin Kuster <akuster@mvista.com>
* Copyright 2002 MontaVista Softare Inc.
*
* 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.
*
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <asm/ocp.h>
#include "ibm_emac_core.h"
#include "ibm_emac_mal.h"
#include "ibm_emac_debug.h"
int __init mal_register_commac(struct ibm_ocp_mal *mal,
struct mal_commac *commac)
{
unsigned long flags;
local_irq_save(flags);
MAL_DBG("%d: reg(%08x, %08x)" NL, mal->def->index,
commac->tx_chan_mask, commac->rx_chan_mask);
/* Don't let multiple commacs claim the same channel(s) */
if ((mal->tx_chan_mask & commac->tx_chan_mask) ||
(mal->rx_chan_mask & commac->rx_chan_mask)) {
local_irq_restore(flags);
printk(KERN_WARNING "mal%d: COMMAC channels conflict!\n",
mal->def->index);
return -EBUSY;
}
mal->tx_chan_mask |= commac->tx_chan_mask;
mal->rx_chan_mask |= commac->rx_chan_mask;
list_add(&commac->list, &mal->list);
local_irq_restore(flags);
return 0;
}
void __exit mal_unregister_commac(struct ibm_ocp_mal *mal,
struct mal_commac *commac)
{
unsigned long flags;
local_irq_save(flags);
MAL_DBG("%d: unreg(%08x, %08x)" NL, mal->def->index,
commac->tx_chan_mask, commac->rx_chan_mask);
mal->tx_chan_mask &= ~commac->tx_chan_mask;
mal->rx_chan_mask &= ~commac->rx_chan_mask;
list_del_init(&commac->list);
local_irq_restore(flags);
}
int mal_set_rcbs(struct ibm_ocp_mal *mal, int channel, unsigned long size)
{
struct ocp_func_mal_data *maldata = mal->def->additions;
BUG_ON(channel < 0 || channel >= maldata->num_rx_chans ||
size > MAL_MAX_RX_SIZE);
MAL_DBG("%d: set_rbcs(%d, %lu)" NL, mal->def->index, channel, size);
if (size & 0xf) {
printk(KERN_WARNING
"mal%d: incorrect RX size %lu for the channel %d\n",
mal->def->index, size, channel);
return -EINVAL;
}
set_mal_dcrn(mal, MAL_RCBS(channel), size >> 4);
return 0;
}
int mal_tx_bd_offset(struct ibm_ocp_mal *mal, int channel)
{
struct ocp_func_mal_data *maldata = mal->def->additions;
BUG_ON(channel < 0 || channel >= maldata->num_tx_chans);
return channel * NUM_TX_BUFF;
}
int mal_rx_bd_offset(struct ibm_ocp_mal *mal, int channel)
{
struct ocp_func_mal_data *maldata = mal->def->additions;
BUG_ON(channel < 0 || channel >= maldata->num_rx_chans);
return maldata->num_tx_chans * NUM_TX_BUFF + channel * NUM_RX_BUFF;
}
void mal_enable_tx_channel(struct ibm_ocp_mal *mal, int channel)
{
local_bh_disable();
MAL_DBG("%d: enable_tx(%d)" NL, mal->def->index, channel);
set_mal_dcrn(mal, MAL_TXCASR,
get_mal_dcrn(mal, MAL_TXCASR) | MAL_CHAN_MASK(channel));
local_bh_enable();
}
void mal_disable_tx_channel(struct ibm_ocp_mal *mal, int channel)
{
set_mal_dcrn(mal, MAL_TXCARR, MAL_CHAN_MASK(channel));
MAL_DBG("%d: disable_tx(%d)" NL, mal->def->index, channel);
}
void mal_enable_rx_channel(struct ibm_ocp_mal *mal, int channel)
{
local_bh_disable();
MAL_DBG("%d: enable_rx(%d)" NL, mal->def->index, channel);
set_mal_dcrn(mal, MAL_RXCASR,
get_mal_dcrn(mal, MAL_RXCASR) | MAL_CHAN_MASK(channel));
local_bh_enable();
}
void mal_disable_rx_channel(struct ibm_ocp_mal *mal, int channel)
{
set_mal_dcrn(mal, MAL_RXCARR, MAL_CHAN_MASK(channel));
MAL_DBG("%d: disable_rx(%d)" NL, mal->def->index, channel);
}
void mal_poll_add(struct ibm_ocp_mal *mal, struct mal_commac *commac)
{
local_bh_disable();
MAL_DBG("%d: poll_add(%p)" NL, mal->def->index, commac);
list_add_tail(&commac->poll_list, &mal->poll_list);
local_bh_enable();
}
void mal_poll_del(struct ibm_ocp_mal *mal, struct mal_commac *commac)
{
local_bh_disable();
MAL_DBG("%d: poll_del(%p)" NL, mal->def->index, commac);
list_del(&commac->poll_list);
local_bh_enable();
}
/* synchronized by mal_poll() */
static inline void mal_enable_eob_irq(struct ibm_ocp_mal *mal)
{
MAL_DBG2("%d: enable_irq" NL, mal->def->index);
set_mal_dcrn(mal, MAL_CFG, get_mal_dcrn(mal, MAL_CFG) | MAL_CFG_EOPIE);
}
/* synchronized by __LINK_STATE_RX_SCHED bit in ndev->state */
static inline void mal_disable_eob_irq(struct ibm_ocp_mal *mal)
{
set_mal_dcrn(mal, MAL_CFG, get_mal_dcrn(mal, MAL_CFG) & ~MAL_CFG_EOPIE);
MAL_DBG2("%d: disable_irq" NL, mal->def->index);
}
static irqreturn_t mal_serr(int irq, void *dev_instance)
{
struct ibm_ocp_mal *mal = dev_instance;
u32 esr = get_mal_dcrn(mal, MAL_ESR);
/* Clear the error status register */
set_mal_dcrn(mal, MAL_ESR, esr);
MAL_DBG("%d: SERR %08x" NL, mal->def->index, esr);
if (esr & MAL_ESR_EVB) {
if (esr & MAL_ESR_DE) {
/* We ignore Descriptor error,
* TXDE or RXDE interrupt will be generated anyway.
*/
return IRQ_HANDLED;
}
if (esr & MAL_ESR_PEIN) {
/* PLB error, it's probably buggy hardware or
* incorrect physical address in BD (i.e. bug)
*/
if (net_ratelimit())
printk(KERN_ERR
"mal%d: system error, PLB (ESR = 0x%08x)\n",
mal->def->index, esr);
return IRQ_HANDLED;
}
/* OPB error, it's probably buggy hardware or incorrect EBC setup */
if (net_ratelimit())
printk(KERN_ERR
"mal%d: system error, OPB (ESR = 0x%08x)\n",
mal->def->index, esr);
}
return IRQ_HANDLED;
}
static inline void mal_schedule_poll(struct ibm_ocp_mal *mal)
{
if (likely(netif_rx_schedule_prep(&mal->poll_dev))) {
MAL_DBG2("%d: schedule_poll" NL, mal->def->index);
mal_disable_eob_irq(mal);
__netif_rx_schedule(&mal->poll_dev);
} else
MAL_DBG2("%d: already in poll" NL, mal->def->index);
}
static irqreturn_t mal_txeob(int irq, void *dev_instance)
{
struct ibm_ocp_mal *mal = dev_instance;
u32 r = get_mal_dcrn(mal, MAL_TXEOBISR);
MAL_DBG2("%d: txeob %08x" NL, mal->def->index, r);
mal_schedule_poll(mal);
set_mal_dcrn(mal, MAL_TXEOBISR, r);
return IRQ_HANDLED;
}
static irqreturn_t mal_rxeob(int irq, void *dev_instance)
{
struct ibm_ocp_mal *mal = dev_instance;
u32 r = get_mal_dcrn(mal, MAL_RXEOBISR);
MAL_DBG2("%d: rxeob %08x" NL, mal->def->index, r);
mal_schedule_poll(mal);
set_mal_dcrn(mal, MAL_RXEOBISR, r);
return IRQ_HANDLED;
}
static irqreturn_t mal_txde(int irq, void *dev_instance)
{
struct ibm_ocp_mal *mal = dev_instance;
u32 deir = get_mal_dcrn(mal, MAL_TXDEIR);
set_mal_dcrn(mal, MAL_TXDEIR, deir);
MAL_DBG("%d: txde %08x" NL, mal->def->index, deir);
if (net_ratelimit())
printk(KERN_ERR
"mal%d: TX descriptor error (TXDEIR = 0x%08x)\n",
mal->def->index, deir);
return IRQ_HANDLED;
}
static irqreturn_t mal_rxde(int irq, void *dev_instance)
{
struct ibm_ocp_mal *mal = dev_instance;
struct list_head *l;
u32 deir = get_mal_dcrn(mal, MAL_RXDEIR);
MAL_DBG("%d: rxde %08x" NL, mal->def->index, deir);
list_for_each(l, &mal->list) {
struct mal_commac *mc = list_entry(l, struct mal_commac, list);
if (deir & mc->rx_chan_mask) {
mc->rx_stopped = 1;
mc->ops->rxde(mc->dev);
}
}
mal_schedule_poll(mal);
set_mal_dcrn(mal, MAL_RXDEIR, deir);
return IRQ_HANDLED;
}
static int mal_poll(struct net_device *ndev, int *budget)
{
struct ibm_ocp_mal *mal = ndev->priv;
struct list_head *l;
int rx_work_limit = min(ndev->quota, *budget), received = 0, done;
MAL_DBG2("%d: poll(%d) %d ->" NL, mal->def->index, *budget,
rx_work_limit);
again:
/* Process TX skbs */
list_for_each(l, &mal->poll_list) {
struct mal_commac *mc =
list_entry(l, struct mal_commac, poll_list);
mc->ops->poll_tx(mc->dev);
}
/* Process RX skbs.
* We _might_ need something more smart here to enforce polling fairness.
*/
list_for_each(l, &mal->poll_list) {
struct mal_commac *mc =
list_entry(l, struct mal_commac, poll_list);
int n = mc->ops->poll_rx(mc->dev, rx_work_limit);
if (n) {
received += n;
rx_work_limit -= n;
if (rx_work_limit <= 0) {
done = 0;
goto more_work; // XXX What if this is the last one ?
}
}
}
/* We need to disable IRQs to protect from RXDE IRQ here */
local_irq_disable();
__netif_rx_complete(ndev);
mal_enable_eob_irq(mal);
local_irq_enable();
done = 1;
/* Check for "rotting" packet(s) */
list_for_each(l, &mal->poll_list) {
struct mal_commac *mc =
list_entry(l, struct mal_commac, poll_list);
if (unlikely(mc->ops->peek_rx(mc->dev) || mc->rx_stopped)) {
MAL_DBG2("%d: rotting packet" NL, mal->def->index);
if (netif_rx_reschedule(ndev, received))
mal_disable_eob_irq(mal);
else
MAL_DBG2("%d: already in poll list" NL,
mal->def->index);
if (rx_work_limit > 0)
goto again;
else
goto more_work;
}
mc->ops->poll_tx(mc->dev);
}
more_work:
ndev->quota -= received;
*budget -= received;
MAL_DBG2("%d: poll() %d <- %d" NL, mal->def->index, *budget,
done ? 0 : 1);
return done ? 0 : 1;
}
static void mal_reset(struct ibm_ocp_mal *mal)
{
int n = 10;
MAL_DBG("%d: reset" NL, mal->def->index);
set_mal_dcrn(mal, MAL_CFG, MAL_CFG_SR);
/* Wait for reset to complete (1 system clock) */
while ((get_mal_dcrn(mal, MAL_CFG) & MAL_CFG_SR) && n)
--n;
if (unlikely(!n))
printk(KERN_ERR "mal%d: reset timeout\n", mal->def->index);
}
int mal_get_regs_len(struct ibm_ocp_mal *mal)
{
return sizeof(struct emac_ethtool_regs_subhdr) +
sizeof(struct ibm_mal_regs);
}
void *mal_dump_regs(struct ibm_ocp_mal *mal, void *buf)
{
struct emac_ethtool_regs_subhdr *hdr = buf;
struct ibm_mal_regs *regs = (struct ibm_mal_regs *)(hdr + 1);
struct ocp_func_mal_data *maldata = mal->def->additions;
int i;
hdr->version = MAL_VERSION;
hdr->index = mal->def->index;
regs->tx_count = maldata->num_tx_chans;
regs->rx_count = maldata->num_rx_chans;
regs->cfg = get_mal_dcrn(mal, MAL_CFG);
regs->esr = get_mal_dcrn(mal, MAL_ESR);
regs->ier = get_mal_dcrn(mal, MAL_IER);
regs->tx_casr = get_mal_dcrn(mal, MAL_TXCASR);
regs->tx_carr = get_mal_dcrn(mal, MAL_TXCARR);
regs->tx_eobisr = get_mal_dcrn(mal, MAL_TXEOBISR);
regs->tx_deir = get_mal_dcrn(mal, MAL_TXDEIR);
regs->rx_casr = get_mal_dcrn(mal, MAL_RXCASR);
regs->rx_carr = get_mal_dcrn(mal, MAL_RXCARR);
regs->rx_eobisr = get_mal_dcrn(mal, MAL_RXEOBISR);
regs->rx_deir = get_mal_dcrn(mal, MAL_RXDEIR);
for (i = 0; i < regs->tx_count; ++i)
regs->tx_ctpr[i] = get_mal_dcrn(mal, MAL_TXCTPR(i));
for (i = 0; i < regs->rx_count; ++i) {
regs->rx_ctpr[i] = get_mal_dcrn(mal, MAL_RXCTPR(i));
regs->rcbs[i] = get_mal_dcrn(mal, MAL_RCBS(i));
}
return regs + 1;
}
static int __init mal_probe(struct ocp_device *ocpdev)
{
struct ibm_ocp_mal *mal;
struct ocp_func_mal_data *maldata;
int err = 0, i, bd_size;
MAL_DBG("%d: probe" NL, ocpdev->def->index);
maldata = ocpdev->def->additions;
if (maldata == NULL) {
printk(KERN_ERR "mal%d: missing additional data!\n",
ocpdev->def->index);
return -ENODEV;
}
mal = kzalloc(sizeof(struct ibm_ocp_mal), GFP_KERNEL);
if (!mal) {
printk(KERN_ERR
"mal%d: out of memory allocating MAL structure!\n",
ocpdev->def->index);
return -ENOMEM;
}
mal->dcrbase = maldata->dcr_base;
mal->def = ocpdev->def;
INIT_LIST_HEAD(&mal->poll_list);
set_bit(__LINK_STATE_START, &mal->poll_dev.state);
mal->poll_dev.weight = CONFIG_IBM_EMAC_POLL_WEIGHT;
mal->poll_dev.poll = mal_poll;
mal->poll_dev.priv = mal;
atomic_set(&mal->poll_dev.refcnt, 1);
INIT_LIST_HEAD(&mal->list);
/* Load power-on reset defaults */
mal_reset(mal);
/* Set the MAL configuration register */
set_mal_dcrn(mal, MAL_CFG, MAL_CFG_DEFAULT | MAL_CFG_PLBB |
MAL_CFG_OPBBL | MAL_CFG_LEA);
mal_enable_eob_irq(mal);
/* Allocate space for BD rings */
BUG_ON(maldata->num_tx_chans <= 0 || maldata->num_tx_chans > 32);
BUG_ON(maldata->num_rx_chans <= 0 || maldata->num_rx_chans > 32);
bd_size = sizeof(struct mal_descriptor) *
(NUM_TX_BUFF * maldata->num_tx_chans +
NUM_RX_BUFF * maldata->num_rx_chans);
mal->bd_virt =
dma_alloc_coherent(&ocpdev->dev, bd_size, &mal->bd_dma, GFP_KERNEL);
if (!mal->bd_virt) {
printk(KERN_ERR
"mal%d: out of memory allocating RX/TX descriptors!\n",
mal->def->index);
err = -ENOMEM;
goto fail;
}
memset(mal->bd_virt, 0, bd_size);
for (i = 0; i < maldata->num_tx_chans; ++i)
set_mal_dcrn(mal, MAL_TXCTPR(i), mal->bd_dma +
sizeof(struct mal_descriptor) *
mal_tx_bd_offset(mal, i));
for (i = 0; i < maldata->num_rx_chans; ++i)
set_mal_dcrn(mal, MAL_RXCTPR(i), mal->bd_dma +
sizeof(struct mal_descriptor) *
mal_rx_bd_offset(mal, i));
err = request_irq(maldata->serr_irq, mal_serr, 0, "MAL SERR", mal);
if (err)
goto fail2;
err = request_irq(maldata->txde_irq, mal_txde, 0, "MAL TX DE", mal);
if (err)
goto fail3;
err = request_irq(maldata->txeob_irq, mal_txeob, 0, "MAL TX EOB", mal);
if (err)
goto fail4;
err = request_irq(maldata->rxde_irq, mal_rxde, 0, "MAL RX DE", mal);
if (err)
goto fail5;
err = request_irq(maldata->rxeob_irq, mal_rxeob, 0, "MAL RX EOB", mal);
if (err)
goto fail6;
/* Enable all MAL SERR interrupt sources */
set_mal_dcrn(mal, MAL_IER, MAL_IER_EVENTS);
/* Advertise this instance to the rest of the world */
ocp_set_drvdata(ocpdev, mal);
mal_dbg_register(mal->def->index, mal);
printk(KERN_INFO "mal%d: initialized, %d TX channels, %d RX channels\n",
mal->def->index, maldata->num_tx_chans, maldata->num_rx_chans);
return 0;
fail6:
free_irq(maldata->rxde_irq, mal);
fail5:
free_irq(maldata->txeob_irq, mal);
fail4:
free_irq(maldata->txde_irq, mal);
fail3:
free_irq(maldata->serr_irq, mal);
fail2:
dma_free_coherent(&ocpdev->dev, bd_size, mal->bd_virt, mal->bd_dma);
fail:
kfree(mal);
return err;
}
static void __exit mal_remove(struct ocp_device *ocpdev)
{
struct ibm_ocp_mal *mal = ocp_get_drvdata(ocpdev);
struct ocp_func_mal_data *maldata = mal->def->additions;
MAL_DBG("%d: remove" NL, mal->def->index);
/* Syncronize with scheduled polling,
stolen from net/core/dev.c:dev_close()
*/
clear_bit(__LINK_STATE_START, &mal->poll_dev.state);
netif_poll_disable(&mal->poll_dev);
if (!list_empty(&mal->list)) {
/* This is *very* bad */
printk(KERN_EMERG
"mal%d: commac list is not empty on remove!\n",
mal->def->index);
}
ocp_set_drvdata(ocpdev, NULL);
free_irq(maldata->serr_irq, mal);
free_irq(maldata->txde_irq, mal);
free_irq(maldata->txeob_irq, mal);
free_irq(maldata->rxde_irq, mal);
free_irq(maldata->rxeob_irq, mal);
mal_reset(mal);
mal_dbg_register(mal->def->index, NULL);
dma_free_coherent(&ocpdev->dev,
sizeof(struct mal_descriptor) *
(NUM_TX_BUFF * maldata->num_tx_chans +
NUM_RX_BUFF * maldata->num_rx_chans), mal->bd_virt,
mal->bd_dma);
kfree(mal);
}
/* Structure for a device driver */
static struct ocp_device_id mal_ids[] = {
{ .vendor = OCP_VENDOR_IBM, .function = OCP_FUNC_MAL },
{ .vendor = OCP_VENDOR_INVALID}
};
static struct ocp_driver mal_driver = {
.name = "mal",
.id_table = mal_ids,
.probe = mal_probe,
.remove = mal_remove,
};
int __init mal_init(void)
{
MAL_DBG(": init" NL);
return ocp_register_driver(&mal_driver);
}
void __exit mal_exit(void)
{
MAL_DBG(": exit" NL);
ocp_unregister_driver(&mal_driver);
}
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