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android_kernel_samsung_msm8976/drivers/parport/parport_sunbpp.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

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/* parport_sunbpp.c: Parallel-port routines for SBUS
*
* Author: Derrick J. Brashear <shadow@dementia.org>
*
* based on work by:
* Phil Blundell <philb@gnu.org>
* Tim Waugh <tim@cyberelk.demon.co.uk>
* Jose Renau <renau@acm.org>
* David Campbell <campbell@tirian.che.curtin.edu.au>
* Grant Guenther <grant@torque.net>
* Eddie C. Dost <ecd@skynet.be>
* Stephen Williams (steve@icarus.com)
* Gus Baldauf (gbaldauf@ix.netcom.com)
* Peter Zaitcev
* Tom Dyas
*
* Updated to new SBUS device framework: David S. Miller <davem@davemloft.net>
*
*/
#include <linux/string.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/parport.h>
#include <asm/ptrace.h>
#include <linux/interrupt.h>
#include <asm/io.h>
#include <asm/oplib.h> /* OpenProm Library */
#include <asm/sbus.h>
#include <asm/dma.h> /* BPP uses LSI 64854 for DMA */
#include <asm/irq.h>
#include <asm/sunbpp.h>
#undef __SUNBPP_DEBUG
#ifdef __SUNBPP_DEBUG
#define dprintk(x) printk x
#else
#define dprintk(x)
#endif
static irqreturn_t parport_sunbpp_interrupt(int irq, void *dev_id)
{
parport_generic_irq(irq, (struct parport *) dev_id, regs);
return IRQ_HANDLED;
}
static void parport_sunbpp_disable_irq(struct parport *p)
{
struct bpp_regs __iomem *regs = (struct bpp_regs __iomem *)p->base;
u32 tmp;
tmp = sbus_readl(&regs->p_csr);
tmp &= ~DMA_INT_ENAB;
sbus_writel(tmp, &regs->p_csr);
}
static void parport_sunbpp_enable_irq(struct parport *p)
{
struct bpp_regs __iomem *regs = (struct bpp_regs __iomem *)p->base;
u32 tmp;
tmp = sbus_readl(&regs->p_csr);
tmp |= DMA_INT_ENAB;
sbus_writel(tmp, &regs->p_csr);
}
static void parport_sunbpp_write_data(struct parport *p, unsigned char d)
{
struct bpp_regs __iomem *regs = (struct bpp_regs __iomem *)p->base;
sbus_writeb(d, &regs->p_dr);
dprintk((KERN_DEBUG "wrote 0x%x\n", d));
}
static unsigned char parport_sunbpp_read_data(struct parport *p)
{
struct bpp_regs __iomem *regs = (struct bpp_regs __iomem *)p->base;
return sbus_readb(&regs->p_dr);
}
#if 0
static void control_pc_to_sunbpp(struct parport *p, unsigned char status)
{
struct bpp_regs __iomem *regs = (struct bpp_regs __iomem *)p->base;
unsigned char value_tcr = sbus_readb(&regs->p_tcr);
unsigned char value_or = sbus_readb(&regs->p_or);
if (status & PARPORT_CONTROL_STROBE)
value_tcr |= P_TCR_DS;
if (status & PARPORT_CONTROL_AUTOFD)
value_or |= P_OR_AFXN;
if (status & PARPORT_CONTROL_INIT)
value_or |= P_OR_INIT;
if (status & PARPORT_CONTROL_SELECT)
value_or |= P_OR_SLCT_IN;
sbus_writeb(value_or, &regs->p_or);
sbus_writeb(value_tcr, &regs->p_tcr);
}
#endif
static unsigned char status_sunbpp_to_pc(struct parport *p)
{
struct bpp_regs __iomem *regs = (struct bpp_regs __iomem *)p->base;
unsigned char bits = 0;
unsigned char value_tcr = sbus_readb(&regs->p_tcr);
unsigned char value_ir = sbus_readb(&regs->p_ir);
if (!(value_ir & P_IR_ERR))
bits |= PARPORT_STATUS_ERROR;
if (!(value_ir & P_IR_SLCT))
bits |= PARPORT_STATUS_SELECT;
if (!(value_ir & P_IR_PE))
bits |= PARPORT_STATUS_PAPEROUT;
if (value_tcr & P_TCR_ACK)
bits |= PARPORT_STATUS_ACK;
if (!(value_tcr & P_TCR_BUSY))
bits |= PARPORT_STATUS_BUSY;
dprintk((KERN_DEBUG "tcr 0x%x ir 0x%x\n", regs->p_tcr, regs->p_ir));
dprintk((KERN_DEBUG "read status 0x%x\n", bits));
return bits;
}
static unsigned char control_sunbpp_to_pc(struct parport *p)
{
struct bpp_regs __iomem *regs = (struct bpp_regs __iomem *)p->base;
unsigned char bits = 0;
unsigned char value_tcr = sbus_readb(&regs->p_tcr);
unsigned char value_or = sbus_readb(&regs->p_or);
if (!(value_tcr & P_TCR_DS))
bits |= PARPORT_CONTROL_STROBE;
if (!(value_or & P_OR_AFXN))
bits |= PARPORT_CONTROL_AUTOFD;
if (!(value_or & P_OR_INIT))
bits |= PARPORT_CONTROL_INIT;
if (value_or & P_OR_SLCT_IN)
bits |= PARPORT_CONTROL_SELECT;
dprintk((KERN_DEBUG "tcr 0x%x or 0x%x\n", regs->p_tcr, regs->p_or));
dprintk((KERN_DEBUG "read control 0x%x\n", bits));
return bits;
}
static unsigned char parport_sunbpp_read_control(struct parport *p)
{
return control_sunbpp_to_pc(p);
}
static unsigned char parport_sunbpp_frob_control(struct parport *p,
unsigned char mask,
unsigned char val)
{
struct bpp_regs __iomem *regs = (struct bpp_regs __iomem *)p->base;
unsigned char value_tcr = sbus_readb(&regs->p_tcr);
unsigned char value_or = sbus_readb(&regs->p_or);
dprintk((KERN_DEBUG "frob1: tcr 0x%x or 0x%x\n", regs->p_tcr, regs->p_or));
if (mask & PARPORT_CONTROL_STROBE) {
if (val & PARPORT_CONTROL_STROBE) {
value_tcr &= ~P_TCR_DS;
} else {
value_tcr |= P_TCR_DS;
}
}
if (mask & PARPORT_CONTROL_AUTOFD) {
if (val & PARPORT_CONTROL_AUTOFD) {
value_or &= ~P_OR_AFXN;
} else {
value_or |= P_OR_AFXN;
}
}
if (mask & PARPORT_CONTROL_INIT) {
if (val & PARPORT_CONTROL_INIT) {
value_or &= ~P_OR_INIT;
} else {
value_or |= P_OR_INIT;
}
}
if (mask & PARPORT_CONTROL_SELECT) {
if (val & PARPORT_CONTROL_SELECT) {
value_or |= P_OR_SLCT_IN;
} else {
value_or &= ~P_OR_SLCT_IN;
}
}
sbus_writeb(value_or, &regs->p_or);
sbus_writeb(value_tcr, &regs->p_tcr);
dprintk((KERN_DEBUG "frob2: tcr 0x%x or 0x%x\n", regs->p_tcr, regs->p_or));
return parport_sunbpp_read_control(p);
}
static void parport_sunbpp_write_control(struct parport *p, unsigned char d)
{
const unsigned char wm = (PARPORT_CONTROL_STROBE |
PARPORT_CONTROL_AUTOFD |
PARPORT_CONTROL_INIT |
PARPORT_CONTROL_SELECT);
parport_sunbpp_frob_control (p, wm, d & wm);
}
static unsigned char parport_sunbpp_read_status(struct parport *p)
{
return status_sunbpp_to_pc(p);
}
static void parport_sunbpp_data_forward (struct parport *p)
{
struct bpp_regs __iomem *regs = (struct bpp_regs __iomem *)p->base;
unsigned char value_tcr = sbus_readb(&regs->p_tcr);
dprintk((KERN_DEBUG "forward\n"));
value_tcr &= ~P_TCR_DIR;
sbus_writeb(value_tcr, &regs->p_tcr);
}
static void parport_sunbpp_data_reverse (struct parport *p)
{
struct bpp_regs __iomem *regs = (struct bpp_regs __iomem *)p->base;
u8 val = sbus_readb(&regs->p_tcr);
dprintk((KERN_DEBUG "reverse\n"));
val |= P_TCR_DIR;
sbus_writeb(val, &regs->p_tcr);
}
static void parport_sunbpp_init_state(struct pardevice *dev, struct parport_state *s)
{
s->u.pc.ctr = 0xc;
s->u.pc.ecr = 0x0;
}
static void parport_sunbpp_save_state(struct parport *p, struct parport_state *s)
{
s->u.pc.ctr = parport_sunbpp_read_control(p);
}
static void parport_sunbpp_restore_state(struct parport *p, struct parport_state *s)
{
parport_sunbpp_write_control(p, s->u.pc.ctr);
}
static struct parport_operations parport_sunbpp_ops =
{
.write_data = parport_sunbpp_write_data,
.read_data = parport_sunbpp_read_data,
.write_control = parport_sunbpp_write_control,
.read_control = parport_sunbpp_read_control,
.frob_control = parport_sunbpp_frob_control,
.read_status = parport_sunbpp_read_status,
.enable_irq = parport_sunbpp_enable_irq,
.disable_irq = parport_sunbpp_disable_irq,
.data_forward = parport_sunbpp_data_forward,
.data_reverse = parport_sunbpp_data_reverse,
.init_state = parport_sunbpp_init_state,
.save_state = parport_sunbpp_save_state,
.restore_state = parport_sunbpp_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 __devinit init_one_port(struct sbus_dev *sdev)
{
struct parport *p;
/* at least in theory there may be a "we don't dma" case */
struct parport_operations *ops;
void __iomem *base;
int irq, dma, err = 0, size;
struct bpp_regs __iomem *regs;
unsigned char value_tcr;
irq = sdev->irqs[0];
base = sbus_ioremap(&sdev->resource[0], 0,
sdev->reg_addrs[0].reg_size,
"sunbpp");
if (!base)
return -ENODEV;
size = sdev->reg_addrs[0].reg_size;
dma = PARPORT_DMA_NONE;
ops = kmalloc(sizeof(struct parport_operations), GFP_KERNEL);
if (!ops)
goto out_unmap;
memcpy (ops, &parport_sunbpp_ops, sizeof (struct parport_operations));
dprintk(("register_port\n"));
if (!(p = parport_register_port((unsigned long)base, irq, dma, ops)))
goto out_free_ops;
p->size = size;
if ((err = request_irq(p->irq, parport_sunbpp_interrupt,
IRQF_SHARED, p->name, p)) != 0) {
goto out_put_port;
}
parport_sunbpp_enable_irq(p);
regs = (struct bpp_regs __iomem *)p->base;
value_tcr = sbus_readb(&regs->p_tcr);
value_tcr &= ~P_TCR_DIR;
sbus_writeb(value_tcr, &regs->p_tcr);
printk(KERN_INFO "%s: sunbpp at 0x%lx\n", p->name, p->base);
dev_set_drvdata(&sdev->ofdev.dev, p);
parport_announce_port(p);
return 0;
out_put_port:
parport_put_port(p);
out_free_ops:
kfree(ops);
out_unmap:
sbus_iounmap(base, size);
return err;
}
static int __devinit bpp_probe(struct of_device *dev, const struct of_device_id *match)
{
struct sbus_dev *sdev = to_sbus_device(&dev->dev);
return init_one_port(sdev);
}
static int __devexit bpp_remove(struct of_device *dev)
{
struct parport *p = dev_get_drvdata(&dev->dev);
struct parport_operations *ops = p->ops;
parport_remove_port(p);
if (p->irq != PARPORT_IRQ_NONE) {
parport_sunbpp_disable_irq(p);
free_irq(p->irq, p);
}
sbus_iounmap((void __iomem *) p->base, p->size);
parport_put_port(p);
kfree(ops);
dev_set_drvdata(&dev->dev, NULL);
return 0;
}
static struct of_device_id bpp_match[] = {
{
.name = "SUNW,bpp",
},
{},
};
MODULE_DEVICE_TABLE(of, bpp_match);
static struct of_platform_driver bpp_sbus_driver = {
.name = "bpp",
.match_table = bpp_match,
.probe = bpp_probe,
.remove = __devexit_p(bpp_remove),
};
static int __init parport_sunbpp_init(void)
{
return of_register_driver(&bpp_sbus_driver, &sbus_bus_type);
}
static void __exit parport_sunbpp_exit(void)
{
of_unregister_driver(&bpp_sbus_driver);
}
MODULE_AUTHOR("Derrick J Brashear");
MODULE_DESCRIPTION("Parport Driver for Sparc bidirectional Port");
MODULE_SUPPORTED_DEVICE("Sparc Bidirectional Parallel Port");
MODULE_VERSION("2.0");
MODULE_LICENSE("GPL");
module_init(parport_sunbpp_init)
module_exit(parport_sunbpp_exit)
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