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linux/drivers/scsi/arm/powertec.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

470 lines
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/*
* linux/drivers/acorn/scsi/powertec.c
*
* Copyright (C) 1997-2005 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/ioport.h>
#include <linux/sched.h>
#include <linux/proc_fs.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/dma-mapping.h>
#include <asm/dma.h>
#include <asm/ecard.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include "../scsi.h"
#include <scsi/scsi_host.h>
#include "fas216.h"
#include "scsi.h"
#include <scsi/scsicam.h>
#define POWERTEC_FAS216_OFFSET 0x3000
#define POWERTEC_FAS216_SHIFT 6
#define POWERTEC_INTR_STATUS 0x2000
#define POWERTEC_INTR_BIT 0x80
#define POWERTEC_RESET_CONTROL 0x1018
#define POWERTEC_RESET_BIT 1
#define POWERTEC_TERM_CONTROL 0x2018
#define POWERTEC_TERM_ENABLE 1
#define POWERTEC_INTR_CONTROL 0x101c
#define POWERTEC_INTR_ENABLE 1
#define POWERTEC_INTR_DISABLE 0
#define VERSION "1.10 (19/01/2003 2.5.59)"
/*
* Use term=0,1,0,0,0 to turn terminators on/off.
* One entry per slot.
*/
static int term[MAX_ECARDS] = { 1, 1, 1, 1, 1, 1, 1, 1 };
#define NR_SG 256
struct powertec_info {
FAS216_Info info;
struct expansion_card *ec;
void __iomem *base;
unsigned int term_ctl;
struct scatterlist sg[NR_SG];
};
/* Prototype: void powertecscsi_irqenable(ec, irqnr)
* Purpose : Enable interrupts on Powertec SCSI card
* Params : ec - expansion card structure
* : irqnr - interrupt number
*/
static void
powertecscsi_irqenable(struct expansion_card *ec, int irqnr)
{
struct powertec_info *info = ec->irq_data;
writeb(POWERTEC_INTR_ENABLE, info->base + POWERTEC_INTR_CONTROL);
}
/* Prototype: void powertecscsi_irqdisable(ec, irqnr)
* Purpose : Disable interrupts on Powertec SCSI card
* Params : ec - expansion card structure
* : irqnr - interrupt number
*/
static void
powertecscsi_irqdisable(struct expansion_card *ec, int irqnr)
{
struct powertec_info *info = ec->irq_data;
writeb(POWERTEC_INTR_DISABLE, info->base + POWERTEC_INTR_CONTROL);
}
static const expansioncard_ops_t powertecscsi_ops = {
.irqenable = powertecscsi_irqenable,
.irqdisable = powertecscsi_irqdisable,
};
/* Prototype: void powertecscsi_terminator_ctl(host, on_off)
* Purpose : Turn the Powertec SCSI terminators on or off
* Params : host - card to turn on/off
* : on_off - !0 to turn on, 0 to turn off
*/
static void
powertecscsi_terminator_ctl(struct Scsi_Host *host, int on_off)
{
struct powertec_info *info = (struct powertec_info *)host->hostdata;
info->term_ctl = on_off ? POWERTEC_TERM_ENABLE : 0;
writeb(info->term_ctl, info->base + POWERTEC_TERM_CONTROL);
}
/* Prototype: void powertecscsi_intr(irq, *dev_id, *regs)
* Purpose : handle interrupts from Powertec SCSI card
* Params : irq - interrupt number
* dev_id - user-defined (Scsi_Host structure)
*/
static irqreturn_t powertecscsi_intr(int irq, void *dev_id)
{
struct powertec_info *info = dev_id;
return fas216_intr(&info->info);
}
/* Prototype: fasdmatype_t powertecscsi_dma_setup(host, SCpnt, direction, min_type)
* Purpose : initialises DMA/PIO
* Params : host - host
* SCpnt - command
* direction - DMA on to/off of card
* min_type - minimum DMA support that we must have for this transfer
* Returns : type of transfer to be performed
*/
static fasdmatype_t
powertecscsi_dma_setup(struct Scsi_Host *host, struct scsi_pointer *SCp,
fasdmadir_t direction, fasdmatype_t min_type)
{
struct powertec_info *info = (struct powertec_info *)host->hostdata;
struct device *dev = scsi_get_device(host);
int dmach = info->info.scsi.dma;
if (info->info.ifcfg.capabilities & FASCAP_DMA &&
min_type == fasdma_real_all) {
int bufs, map_dir, dma_dir;
bufs = copy_SCp_to_sg(&info->sg[0], SCp, NR_SG);
if (direction == DMA_OUT)
map_dir = DMA_TO_DEVICE,
dma_dir = DMA_MODE_WRITE;
else
map_dir = DMA_FROM_DEVICE,
dma_dir = DMA_MODE_READ;
dma_map_sg(dev, info->sg, bufs + 1, map_dir);
disable_dma(dmach);
set_dma_sg(dmach, info->sg, bufs + 1);
set_dma_mode(dmach, dma_dir);
enable_dma(dmach);
return fasdma_real_all;
}
/*
* If we're not doing DMA,
* we'll do slow PIO
*/
return fasdma_pio;
}
/* Prototype: int powertecscsi_dma_stop(host, SCpnt)
* Purpose : stops DMA/PIO
* Params : host - host
* SCpnt - command
*/
static void
powertecscsi_dma_stop(struct Scsi_Host *host, struct scsi_pointer *SCp)
{
struct powertec_info *info = (struct powertec_info *)host->hostdata;
if (info->info.scsi.dma != NO_DMA)
disable_dma(info->info.scsi.dma);
}
/* Prototype: const char *powertecscsi_info(struct Scsi_Host * host)
* Purpose : returns a descriptive string about this interface,
* Params : host - driver host structure to return info for.
* Returns : pointer to a static buffer containing null terminated string.
*/
const char *powertecscsi_info(struct Scsi_Host *host)
{
struct powertec_info *info = (struct powertec_info *)host->hostdata;
static char string[150];
sprintf(string, "%s (%s) in slot %d v%s terminators o%s",
host->hostt->name, info->info.scsi.type, info->ec->slot_no,
VERSION, info->term_ctl ? "n" : "ff");
return string;
}
/* Prototype: int powertecscsi_set_proc_info(struct Scsi_Host *host, char *buffer, int length)
* Purpose : Set a driver specific function
* Params : host - host to setup
* : buffer - buffer containing string describing operation
* : length - length of string
* Returns : -EINVAL, or 0
*/
static int
powertecscsi_set_proc_info(struct Scsi_Host *host, char *buffer, int length)
{
int ret = length;
if (length >= 12 && strncmp(buffer, "POWERTECSCSI", 12) == 0) {
buffer += 12;
length -= 12;
if (length >= 5 && strncmp(buffer, "term=", 5) == 0) {
if (buffer[5] == '1')
powertecscsi_terminator_ctl(host, 1);
else if (buffer[5] == '0')
powertecscsi_terminator_ctl(host, 0);
else
ret = -EINVAL;
} else
ret = -EINVAL;
} else
ret = -EINVAL;
return ret;
}
/* Prototype: int powertecscsi_proc_info(char *buffer, char **start, off_t offset,
* int length, int host_no, int inout)
* Purpose : Return information about the driver to a user process accessing
* the /proc filesystem.
* Params : buffer - a buffer to write information to
* start - a pointer into this buffer set by this routine to the start
* of the required information.
* offset - offset into information that we have read upto.
* length - length of buffer
* inout - 0 for reading, 1 for writing.
* Returns : length of data written to buffer.
*/
int powertecscsi_proc_info(struct Scsi_Host *host, char *buffer, char **start, off_t offset,
int length, int inout)
{
struct powertec_info *info;
char *p = buffer;
int pos;
if (inout == 1)
return powertecscsi_set_proc_info(host, buffer, length);
info = (struct powertec_info *)host->hostdata;
p += sprintf(p, "PowerTec SCSI driver v%s\n", VERSION);
p += fas216_print_host(&info->info, p);
p += sprintf(p, "Term : o%s\n",
info->term_ctl ? "n" : "ff");
p += fas216_print_stats(&info->info, p);
p += fas216_print_devices(&info->info, p);
*start = buffer + offset;
pos = p - buffer - offset;
if (pos > length)
pos = length;
return pos;
}
static ssize_t powertecscsi_show_term(struct device *dev, struct device_attribute *attr, char *buf)
{
struct expansion_card *ec = ECARD_DEV(dev);
struct Scsi_Host *host = ecard_get_drvdata(ec);
struct powertec_info *info = (struct powertec_info *)host->hostdata;
return sprintf(buf, "%d\n", info->term_ctl ? 1 : 0);
}
static ssize_t
powertecscsi_store_term(struct device *dev, struct device_attribute *attr, const char *buf, size_t len)
{
struct expansion_card *ec = ECARD_DEV(dev);
struct Scsi_Host *host = ecard_get_drvdata(ec);
if (len > 1)
powertecscsi_terminator_ctl(host, buf[0] != '0');
return len;
}
static DEVICE_ATTR(bus_term, S_IRUGO | S_IWUSR,
powertecscsi_show_term, powertecscsi_store_term);
static struct scsi_host_template powertecscsi_template = {
.module = THIS_MODULE,
.proc_info = powertecscsi_proc_info,
.name = "PowerTec SCSI",
.info = powertecscsi_info,
.queuecommand = fas216_queue_command,
.eh_host_reset_handler = fas216_eh_host_reset,
.eh_bus_reset_handler = fas216_eh_bus_reset,
.eh_device_reset_handler = fas216_eh_device_reset,
.eh_abort_handler = fas216_eh_abort,
.can_queue = 8,
.this_id = 7,
.sg_tablesize = SG_ALL,
.cmd_per_lun = 2,
.use_clustering = ENABLE_CLUSTERING,
.proc_name = "powertec",
};
static int __devinit
powertecscsi_probe(struct expansion_card *ec, const struct ecard_id *id)
{
struct Scsi_Host *host;
struct powertec_info *info;
unsigned long resbase, reslen;
void __iomem *base;
int ret;
ret = ecard_request_resources(ec);
if (ret)
goto out;
resbase = ecard_resource_start(ec, ECARD_RES_IOCFAST);
reslen = ecard_resource_len(ec, ECARD_RES_IOCFAST);
base = ioremap(resbase, reslen);
if (!base) {
ret = -ENOMEM;
goto out_region;
}
host = scsi_host_alloc(&powertecscsi_template,
sizeof (struct powertec_info));
if (!host) {
ret = -ENOMEM;
goto out_unmap;
}
ecard_set_drvdata(ec, host);
info = (struct powertec_info *)host->hostdata;
info->base = base;
powertecscsi_terminator_ctl(host, term[ec->slot_no]);
info->info.scsi.io_base = base + POWERTEC_FAS216_OFFSET;
info->info.scsi.io_shift = POWERTEC_FAS216_SHIFT;
info->info.scsi.irq = ec->irq;
info->info.scsi.dma = ec->dma;
info->info.ifcfg.clockrate = 40; /* MHz */
info->info.ifcfg.select_timeout = 255;
info->info.ifcfg.asyncperiod = 200; /* ns */
info->info.ifcfg.sync_max_depth = 7;
info->info.ifcfg.cntl3 = CNTL3_BS8 | CNTL3_FASTSCSI | CNTL3_FASTCLK;
info->info.ifcfg.disconnect_ok = 1;
info->info.ifcfg.wide_max_size = 0;
info->info.ifcfg.capabilities = 0;
info->info.dma.setup = powertecscsi_dma_setup;
info->info.dma.pseudo = NULL;
info->info.dma.stop = powertecscsi_dma_stop;
ec->irqaddr = base + POWERTEC_INTR_STATUS;
ec->irqmask = POWERTEC_INTR_BIT;
ec->irq_data = info;
ec->ops = &powertecscsi_ops;
device_create_file(&ec->dev, &dev_attr_bus_term);
ret = fas216_init(host);
if (ret)
goto out_free;
ret = request_irq(ec->irq, powertecscsi_intr,
IRQF_DISABLED, "powertec", info);
if (ret) {
printk("scsi%d: IRQ%d not free: %d\n",
host->host_no, ec->irq, ret);
goto out_release;
}
if (info->info.scsi.dma != NO_DMA) {
if (request_dma(info->info.scsi.dma, "powertec")) {
printk("scsi%d: DMA%d not free, using PIO\n",
host->host_no, info->info.scsi.dma);
info->info.scsi.dma = NO_DMA;
} else {
set_dma_speed(info->info.scsi.dma, 180);
info->info.ifcfg.capabilities |= FASCAP_DMA;
}
}
ret = fas216_add(host, &ec->dev);
if (ret == 0)
goto out;
if (info->info.scsi.dma != NO_DMA)
free_dma(info->info.scsi.dma);
free_irq(ec->irq, host);
out_release:
fas216_release(host);
out_free:
device_remove_file(&ec->dev, &dev_attr_bus_term);
scsi_host_put(host);
out_unmap:
iounmap(base);
out_region:
ecard_release_resources(ec);
out:
return ret;
}
static void __devexit powertecscsi_remove(struct expansion_card *ec)
{
struct Scsi_Host *host = ecard_get_drvdata(ec);
struct powertec_info *info = (struct powertec_info *)host->hostdata;
ecard_set_drvdata(ec, NULL);
fas216_remove(host);
device_remove_file(&ec->dev, &dev_attr_bus_term);
if (info->info.scsi.dma != NO_DMA)
free_dma(info->info.scsi.dma);
free_irq(ec->irq, info);
iounmap(info->base);
fas216_release(host);
scsi_host_put(host);
ecard_release_resources(ec);
}
static const struct ecard_id powertecscsi_cids[] = {
{ MANU_ALSYSTEMS, PROD_ALSYS_SCSIATAPI },
{ 0xffff, 0xffff },
};
static struct ecard_driver powertecscsi_driver = {
.probe = powertecscsi_probe,
.remove = __devexit_p(powertecscsi_remove),
.id_table = powertecscsi_cids,
.drv = {
.name = "powertecscsi",
},
};
static int __init powertecscsi_init(void)
{
return ecard_register_driver(&powertecscsi_driver);
}
static void __exit powertecscsi_exit(void)
{
ecard_remove_driver(&powertecscsi_driver);
}
module_init(powertecscsi_init);
module_exit(powertecscsi_exit);
MODULE_AUTHOR("Russell King");
MODULE_DESCRIPTION("Powertec SCSI driver");
module_param_array(term, int, NULL, 0);
MODULE_PARM_DESC(term, "SCSI bus termination");
MODULE_LICENSE("GPL");
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