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linux-next/drivers/scsi/NCR_D700.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

406 lines
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/* -*- mode: c; c-basic-offset: 8 -*- */
/* NCR Dual 700 MCA SCSI Driver
*
* Copyright (C) 2001 by James.Bottomley@HansenPartnership.com
**-----------------------------------------------------------------------------
**
** 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., 675 Mass Ave, Cambridge, MA 02139, USA.
**
**-----------------------------------------------------------------------------
*/
/* Notes:
*
* Most of the work is done in the chip specific module, 53c700.o
*
* TODO List:
*
* 1. Extract the SCSI ID from the voyager CMOS table (necessary to
* support multi-host environments.
*
* */
/* CHANGELOG
*
* Version 2.2
*
* Added mca_set_adapter_name().
*
* Version 2.1
*
* Modularise the driver into a Board piece (this file) and a chip
* piece 53c700.[ch] and 53c700.scr, added module options. You can
* now specify the scsi id by the parameters
*
* NCR_D700=slot:<n> [siop:<n>] id:<n> ....
*
* They need to be comma separated if compiled into the kernel
*
* Version 2.0
*
* Initial implementation of TCQ (Tag Command Queueing). TCQ is full
* featured and uses the clock algorithm to keep track of outstanding
* tags and guard against individual tag starvation. Also fixed a bug
* in all of the 1.x versions where the D700_data_residue() function
* was returning results off by 32 bytes (and thus causing the same 32
* bytes to be written twice corrupting the data block). It turns out
* the 53c700 only has a 6 bit DBC and DFIFO registers not 7 bit ones
* like the 53c710 (The 710 is the only data manual still available,
* which I'd been using to program the 700).
*
* Version 1.2
*
* Much improved message handling engine
*
* Version 1.1
*
* Add code to handle selection reasonably correctly. By the time we
* get the selection interrupt, we've already responded, but drop off the
* bus and hope the selector will go away.
*
* Version 1.0:
*
* Initial release. Fully functional except for procfs and tag
* command queueing. Has only been tested on cards with 53c700-66
* chips and only single ended. Features are
*
* 1. Synchronous data transfers to offset 8 (limit of 700-66) and
* 100ns (10MHz) limit of SCSI-2
*
* 2. Disconnection and reselection
*
* Testing:
*
* I've only really tested this with the 700-66 chip, but have done
* soak tests in multi-device environments to verify that
* disconnections and reselections are being processed correctly.
* */
#define NCR_D700_VERSION "2.2"
#include <linux/blkdev.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mca.h>
#include <linux/interrupt.h>
#include <asm/io.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_spi.h>
#include "53c700.h"
#include "NCR_D700.h"
static char *NCR_D700; /* command line from insmod */
MODULE_AUTHOR("James Bottomley");
MODULE_DESCRIPTION("NCR Dual700 SCSI Driver");
MODULE_LICENSE("GPL");
module_param(NCR_D700, charp, 0);
static __u8 __devinitdata id_array[2*(MCA_MAX_SLOT_NR + 1)] =
{ [0 ... 2*(MCA_MAX_SLOT_NR + 1)-1] = 7 };
#ifdef MODULE
#define ARG_SEP ' '
#else
#define ARG_SEP ','
#endif
static int __init
param_setup(char *string)
{
char *pos = string, *next;
int slot = -1, siop = -1;
while(pos != NULL && (next = strchr(pos, ':')) != NULL) {
int val = (int)simple_strtoul(++next, NULL, 0);
if(!strncmp(pos, "slot:", 5))
slot = val;
else if(!strncmp(pos, "siop:", 5))
siop = val;
else if(!strncmp(pos, "id:", 3)) {
if(slot == -1) {
printk(KERN_WARNING "NCR D700: Must specify slot for id parameter\n");
} else if(slot > MCA_MAX_SLOT_NR) {
printk(KERN_WARNING "NCR D700: Illegal slot %d for id %d\n", slot, val);
} else {
if(siop != 0 && siop != 1) {
id_array[slot*2] = val;
id_array[slot*2 + 1] =val;
} else {
id_array[slot*2 + siop] = val;
}
}
}
if((pos = strchr(pos, ARG_SEP)) != NULL)
pos++;
}
return 1;
}
/* Host template. The 53c700 routine NCR_700_detect will
* fill in all of the missing routines */
static struct scsi_host_template NCR_D700_driver_template = {
.module = THIS_MODULE,
.name = "NCR Dual 700 MCA",
.proc_name = "NCR_D700",
.this_id = 7,
};
/* We needs this helper because we have two hosts per struct device */
struct NCR_D700_private {
struct device *dev;
struct Scsi_Host *hosts[2];
char name[30];
char pad;
};
static int __devinit
NCR_D700_probe_one(struct NCR_D700_private *p, int siop, int irq,
int slot, u32 region, int differential)
{
struct NCR_700_Host_Parameters *hostdata;
struct Scsi_Host *host;
int ret;
hostdata = kmalloc(sizeof(*hostdata), GFP_KERNEL);
if (!hostdata) {
printk(KERN_ERR "NCR D700: SIOP%d: Failed to allocate host"
"data, detatching\n", siop);
return -ENOMEM;
}
memset(hostdata, 0, sizeof(*hostdata));
if (!request_region(region, 64, "NCR_D700")) {
printk(KERN_ERR "NCR D700: Failed to reserve IO region 0x%x\n",
region);
ret = -ENODEV;
goto region_failed;
}
/* Fill in the three required pieces of hostdata */
hostdata->base = ioport_map(region, 64);
hostdata->differential = (((1<<siop) & differential) != 0);
hostdata->clock = NCR_D700_CLOCK_MHZ;
/* and register the siop */
host = NCR_700_detect(&NCR_D700_driver_template, hostdata, p->dev);
if (!host) {
ret = -ENOMEM;
goto detect_failed;
}
p->hosts[siop] = host;
/* FIXME: read this from SUS */
host->this_id = id_array[slot * 2 + siop];
host->irq = irq;
host->base = region;
scsi_scan_host(host);
return 0;
detect_failed:
release_region(region, 64);
region_failed:
kfree(hostdata);
return ret;
}
static int
NCR_D700_intr(int irq, void *data)
{
struct NCR_D700_private *p = (struct NCR_D700_private *)data;
int i, found = 0;
for (i = 0; i < 2; i++)
if (p->hosts[i] &&
NCR_700_intr(irq, p->hosts[i]) == IRQ_HANDLED)
found++;
return found ? IRQ_HANDLED : IRQ_NONE;
}
/* Detect a D700 card. Note, because of the setup --- the chips are
* essentially connectecd to the MCA bus independently, it is easier
* to set them up as two separate host adapters, rather than one
* adapter with two channels */
static int __devinit
NCR_D700_probe(struct device *dev)
{
struct NCR_D700_private *p;
int differential;
static int banner = 1;
struct mca_device *mca_dev = to_mca_device(dev);
int slot = mca_dev->slot;
int found = 0;
int irq, i;
int pos3j, pos3k, pos3a, pos3b, pos4;
__u32 base_addr, offset_addr;
/* enable board interrupt */
pos4 = mca_device_read_pos(mca_dev, 4);
pos4 |= 0x4;
mca_device_write_pos(mca_dev, 4, pos4);
mca_device_write_pos(mca_dev, 6, 9);
pos3j = mca_device_read_pos(mca_dev, 3);
mca_device_write_pos(mca_dev, 6, 10);
pos3k = mca_device_read_pos(mca_dev, 3);
mca_device_write_pos(mca_dev, 6, 0);
pos3a = mca_device_read_pos(mca_dev, 3);
mca_device_write_pos(mca_dev, 6, 1);
pos3b = mca_device_read_pos(mca_dev, 3);
base_addr = ((pos3j << 8) | pos3k) & 0xfffffff0;
offset_addr = ((pos3a << 8) | pos3b) & 0xffffff70;
irq = (pos4 & 0x3) + 11;
if(irq >= 13)
irq++;
if(banner) {
printk(KERN_NOTICE "NCR D700: Driver Version " NCR_D700_VERSION "\n"
"NCR D700: Copyright (c) 2001 by James.Bottomley@HansenPartnership.com\n"
"NCR D700:\n");
banner = 0;
}
/* now do the bus related transforms */
irq = mca_device_transform_irq(mca_dev, irq);
base_addr = mca_device_transform_ioport(mca_dev, base_addr);
offset_addr = mca_device_transform_ioport(mca_dev, offset_addr);
printk(KERN_NOTICE "NCR D700: found in slot %d irq = %d I/O base = 0x%x\n", slot, irq, offset_addr);
/*outb(BOARD_RESET, base_addr);*/
/* clear any pending interrupts */
(void)inb(base_addr + 0x08);
/* get modctl, used later for setting diff bits */
switch(differential = (inb(base_addr + 0x08) >> 6)) {
case 0x00:
/* only SIOP1 differential */
differential = 0x02;
break;
case 0x01:
/* Both SIOPs differential */
differential = 0x03;
break;
case 0x03:
/* No SIOPs differential */
differential = 0x00;
break;
default:
printk(KERN_ERR "D700: UNEXPECTED DIFFERENTIAL RESULT 0x%02x\n",
differential);
differential = 0x00;
break;
}
p = kmalloc(sizeof(*p), GFP_KERNEL);
if (!p)
return -ENOMEM;
memset(p, '\0', sizeof(*p));
p->dev = dev;
snprintf(p->name, sizeof(p->name), "D700(%s)", dev->bus_id);
if (request_irq(irq, NCR_D700_intr, IRQF_SHARED, p->name, p)) {
printk(KERN_ERR "D700: request_irq failed\n");
kfree(p);
return -EBUSY;
}
/* plumb in both 700 chips */
for (i = 0; i < 2; i++) {
int err;
if ((err = NCR_D700_probe_one(p, i, irq, slot,
offset_addr + (0x80 * i),
differential)) != 0)
printk("D700: SIOP%d: probe failed, error = %d\n",
i, err);
else
found++;
}
if (!found) {
kfree(p);
return -ENODEV;
}
mca_device_set_claim(mca_dev, 1);
mca_device_set_name(mca_dev, "NCR_D700");
dev_set_drvdata(dev, p);
return 0;
}
static void __devexit
NCR_D700_remove_one(struct Scsi_Host *host)
{
scsi_remove_host(host);
NCR_700_release(host);
kfree((struct NCR_700_Host_Parameters *)host->hostdata[0]);
free_irq(host->irq, host);
release_region(host->base, 64);
}
static int __devexit
NCR_D700_remove(struct device *dev)
{
struct NCR_D700_private *p = dev_get_drvdata(dev);
int i;
for (i = 0; i < 2; i++)
NCR_D700_remove_one(p->hosts[i]);
kfree(p);
return 0;
}
static short NCR_D700_id_table[] = { NCR_D700_MCA_ID, 0 };
static struct mca_driver NCR_D700_driver = {
.id_table = NCR_D700_id_table,
.driver = {
.name = "NCR_D700",
.bus = &mca_bus_type,
.probe = NCR_D700_probe,
.remove = __devexit_p(NCR_D700_remove),
},
};
static int __init NCR_D700_init(void)
{
#ifdef MODULE
if (NCR_D700)
param_setup(NCR_D700);
#endif
return mca_register_driver(&NCR_D700_driver);
}
static void __exit NCR_D700_exit(void)
{
mca_unregister_driver(&NCR_D700_driver);
}
module_init(NCR_D700_init);
module_exit(NCR_D700_exit);
__setup("NCR_D700=", param_setup);
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