kernel-ark/drivers/parport/parport_ax88796.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

444 lines
9.6 KiB
C

/* linux/drivers/parport/parport_ax88796.c
*
* (c) 2005,2006 Simtec Electronics
* Ben Dooks <ben@simtec.co.uk>
*
* 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/kernel.h>
#include <linux/parport.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/platform_device.h>
#include <asm/io.h>
#include <asm/irq.h>
#define AX_SPR_BUSY (1<<7)
#define AX_SPR_ACK (1<<6)
#define AX_SPR_PE (1<<5)
#define AX_SPR_SLCT (1<<4)
#define AX_SPR_ERR (1<<3)
#define AX_CPR_nDOE (1<<5)
#define AX_CPR_SLCTIN (1<<3)
#define AX_CPR_nINIT (1<<2)
#define AX_CPR_ATFD (1<<1)
#define AX_CPR_STRB (1<<0)
struct ax_drvdata {
struct parport *parport;
struct parport_state suspend;
struct device *dev;
struct resource *io;
unsigned char irq_enabled;
void __iomem *base;
void __iomem *spp_data;
void __iomem *spp_spr;
void __iomem *spp_cpr;
};
static inline struct ax_drvdata *pp_to_drv(struct parport *p)
{
return p->private_data;
}
static unsigned char
parport_ax88796_read_data(struct parport *p)
{
struct ax_drvdata *dd = pp_to_drv(p);
return readb(dd->spp_data);
}
static void
parport_ax88796_write_data(struct parport *p, unsigned char data)
{
struct ax_drvdata *dd = pp_to_drv(p);
writeb(data, dd->spp_data);
}
static unsigned char
parport_ax88796_read_control(struct parport *p)
{
struct ax_drvdata *dd = pp_to_drv(p);
unsigned int cpr = readb(dd->spp_cpr);
unsigned int ret = 0;
if (!(cpr & AX_CPR_STRB))
ret |= PARPORT_CONTROL_STROBE;
if (!(cpr & AX_CPR_ATFD))
ret |= PARPORT_CONTROL_AUTOFD;
if (cpr & AX_CPR_nINIT)
ret |= PARPORT_CONTROL_INIT;
if (!(cpr & AX_CPR_SLCTIN))
ret |= PARPORT_CONTROL_SELECT;
return ret;
}
static void
parport_ax88796_write_control(struct parport *p, unsigned char control)
{
struct ax_drvdata *dd = pp_to_drv(p);
unsigned int cpr = readb(dd->spp_cpr);
cpr &= AX_CPR_nDOE;
if (!(control & PARPORT_CONTROL_STROBE))
cpr |= AX_CPR_STRB;
if (!(control & PARPORT_CONTROL_AUTOFD))
cpr |= AX_CPR_ATFD;
if (control & PARPORT_CONTROL_INIT)
cpr |= AX_CPR_nINIT;
if (!(control & PARPORT_CONTROL_SELECT))
cpr |= AX_CPR_SLCTIN;
dev_dbg(dd->dev, "write_control: ctrl=%02x, cpr=%02x\n", control, cpr);
writeb(cpr, dd->spp_cpr);
if (parport_ax88796_read_control(p) != control) {
dev_err(dd->dev, "write_control: read != set (%02x, %02x)\n",
parport_ax88796_read_control(p), control);
}
}
static unsigned char
parport_ax88796_read_status(struct parport *p)
{
struct ax_drvdata *dd = pp_to_drv(p);
unsigned int status = readb(dd->spp_spr);
unsigned int ret = 0;
if (status & AX_SPR_BUSY)
ret |= PARPORT_STATUS_BUSY;
if (status & AX_SPR_ACK)
ret |= PARPORT_STATUS_ACK;
if (status & AX_SPR_ERR)
ret |= PARPORT_STATUS_ERROR;
if (status & AX_SPR_SLCT)
ret |= PARPORT_STATUS_SELECT;
if (status & AX_SPR_PE)
ret |= PARPORT_STATUS_PAPEROUT;
return ret;
}
static unsigned char
parport_ax88796_frob_control(struct parport *p, unsigned char mask,
unsigned char val)
{
struct ax_drvdata *dd = pp_to_drv(p);
unsigned char old = parport_ax88796_read_control(p);
dev_dbg(dd->dev, "frob: mask=%02x, val=%02x, old=%02x\n",
mask, val, old);
parport_ax88796_write_control(p, (old & ~mask) | val);
return old;
}
static void
parport_ax88796_enable_irq(struct parport *p)
{
struct ax_drvdata *dd = pp_to_drv(p);
unsigned long flags;
local_irq_save(flags);
if (!dd->irq_enabled) {
enable_irq(p->irq);
dd->irq_enabled = 1;
}
local_irq_restore(flags);
}
static void
parport_ax88796_disable_irq(struct parport *p)
{
struct ax_drvdata *dd = pp_to_drv(p);
unsigned long flags;
local_irq_save(flags);
if (dd->irq_enabled) {
disable_irq(p->irq);
dd->irq_enabled = 0;
}
local_irq_restore(flags);
}
static void
parport_ax88796_data_forward(struct parport *p)
{
struct ax_drvdata *dd = pp_to_drv(p);
void __iomem *cpr = dd->spp_cpr;
writeb((readb(cpr) & ~AX_CPR_nDOE), cpr);
}
static void
parport_ax88796_data_reverse(struct parport *p)
{
struct ax_drvdata *dd = pp_to_drv(p);
void __iomem *cpr = dd->spp_cpr;
writeb(readb(cpr) | AX_CPR_nDOE, cpr);
}
static void
parport_ax88796_init_state(struct pardevice *d, struct parport_state *s)
{
struct ax_drvdata *dd = pp_to_drv(d->port);
memset(s, 0, sizeof(struct parport_state));
dev_dbg(dd->dev, "init_state: %p: state=%p\n", d, s);
s->u.ax88796.cpr = readb(dd->spp_cpr);
}
static void
parport_ax88796_save_state(struct parport *p, struct parport_state *s)
{
struct ax_drvdata *dd = pp_to_drv(p);
dev_dbg(dd->dev, "save_state: %p: state=%p\n", p, s);
s->u.ax88796.cpr = readb(dd->spp_cpr);
}
static void
parport_ax88796_restore_state(struct parport *p, struct parport_state *s)
{
struct ax_drvdata *dd = pp_to_drv(p);
dev_dbg(dd->dev, "restore_state: %p: state=%p\n", p, s);
writeb(s->u.ax88796.cpr, dd->spp_cpr);
}
static irqreturn_t
parport_ax88796_interrupt(int irq, void *dev_id)
{
parport_generic_irq(irq, dev_id);
return IRQ_HANDLED;
}
static struct parport_operations parport_ax88796_ops = {
.write_data = parport_ax88796_write_data,
.read_data = parport_ax88796_read_data,
.write_control = parport_ax88796_write_control,
.read_control = parport_ax88796_read_control,
.frob_control = parport_ax88796_frob_control,
.read_status = parport_ax88796_read_status,
.enable_irq = parport_ax88796_enable_irq,
.disable_irq = parport_ax88796_disable_irq,
.data_forward = parport_ax88796_data_forward,
.data_reverse = parport_ax88796_data_reverse,
.init_state = parport_ax88796_init_state,
.save_state = parport_ax88796_save_state,
.restore_state = parport_ax88796_restore_state,
.epp_write_data = parport_ieee1284_epp_write_data,
.epp_read_data = parport_ieee1284_epp_read_data,
.epp_write_addr = parport_ieee1284_epp_write_addr,
.epp_read_addr = parport_ieee1284_epp_read_addr,
.ecp_write_data = parport_ieee1284_ecp_write_data,
.ecp_read_data = parport_ieee1284_ecp_read_data,
.ecp_write_addr = parport_ieee1284_ecp_write_addr,
.compat_write_data = parport_ieee1284_write_compat,
.nibble_read_data = parport_ieee1284_read_nibble,
.byte_read_data = parport_ieee1284_read_byte,
.owner = THIS_MODULE,
};
static int parport_ax88796_probe(struct platform_device *pdev)
{
struct device *_dev = &pdev->dev;
struct ax_drvdata *dd;
struct parport *pp = NULL;
struct resource *res;
unsigned long size;
int spacing;
int irq;
int ret;
dd = kzalloc(sizeof(struct ax_drvdata), GFP_KERNEL);
if (dd == NULL) {
dev_err(_dev, "no memory for private data\n");
return -ENOMEM;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res == NULL) {
dev_err(_dev, "no MEM specified\n");
ret = -ENXIO;
goto exit_mem;
}
size = (res->end - res->start) + 1;
spacing = size / 3;
dd->io = request_mem_region(res->start, size, pdev->name);
if (dd->io == NULL) {
dev_err(_dev, "cannot reserve memory\n");
ret = -ENXIO;
goto exit_mem;
}
dd->base = ioremap(res->start, size);
if (dd->base == NULL) {
dev_err(_dev, "cannot ioremap region\n");
ret = -ENXIO;
goto exit_res;
}
irq = platform_get_irq(pdev, 0);
if (irq <= 0)
irq = PARPORT_IRQ_NONE;
pp = parport_register_port((unsigned long)dd->base, irq,
PARPORT_DMA_NONE,
&parport_ax88796_ops);
if (pp == NULL) {
dev_err(_dev, "failed to register parallel port\n");
ret = -ENOMEM;
goto exit_unmap;
}
pp->private_data = dd;
dd->parport = pp;
dd->dev = _dev;
dd->spp_data = dd->base;
dd->spp_spr = dd->base + (spacing * 1);
dd->spp_cpr = dd->base + (spacing * 2);
/* initialise the port controls */
writeb(AX_CPR_STRB, dd->spp_cpr);
if (irq >= 0) {
/* request irq */
ret = request_irq(irq, parport_ax88796_interrupt,
IRQF_TRIGGER_FALLING, pdev->name, pp);
if (ret < 0)
goto exit_port;
dd->irq_enabled = 1;
}
platform_set_drvdata(pdev, pp);
dev_info(_dev, "attached parallel port driver\n");
parport_announce_port(pp);
return 0;
exit_port:
parport_remove_port(pp);
exit_unmap:
iounmap(dd->base);
exit_res:
release_resource(dd->io);
kfree(dd->io);
exit_mem:
kfree(dd);
return ret;
}
static int parport_ax88796_remove(struct platform_device *pdev)
{
struct parport *p = platform_get_drvdata(pdev);
struct ax_drvdata *dd = pp_to_drv(p);
free_irq(p->irq, p);
parport_remove_port(p);
iounmap(dd->base);
release_resource(dd->io);
kfree(dd->io);
kfree(dd);
return 0;
}
#ifdef CONFIG_PM
static int parport_ax88796_suspend(struct platform_device *dev,
pm_message_t state)
{
struct parport *p = platform_get_drvdata(dev);
struct ax_drvdata *dd = pp_to_drv(p);
parport_ax88796_save_state(p, &dd->suspend);
writeb(AX_CPR_nDOE | AX_CPR_STRB, dd->spp_cpr);
return 0;
}
static int parport_ax88796_resume(struct platform_device *dev)
{
struct parport *p = platform_get_drvdata(dev);
struct ax_drvdata *dd = pp_to_drv(p);
parport_ax88796_restore_state(p, &dd->suspend);
return 0;
}
#else
#define parport_ax88796_suspend NULL
#define parport_ax88796_resume NULL
#endif
static struct platform_driver axdrv = {
.driver = {
.name = "ax88796-pp",
.owner = THIS_MODULE,
},
.probe = parport_ax88796_probe,
.remove = parport_ax88796_remove,
.suspend = parport_ax88796_suspend,
.resume = parport_ax88796_resume,
};
static int __init parport_ax88796_init(void)
{
return platform_driver_register(&axdrv);
}
static void __exit parport_ax88796_exit(void)
{
platform_driver_unregister(&axdrv);
}
module_init(parport_ax88796_init)
module_exit(parport_ax88796_exit)
MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
MODULE_DESCRIPTION("AX88796 Parport parallel port driver");
MODULE_LICENSE("GPL");