kernel-ark/drivers/pcmcia/at91_cf.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

420 lines
10 KiB
C

/*
* at91_cf.c -- AT91 CompactFlash controller driver
*
* Copyright (C) 2005 David Brownell
*
* 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/sched.h>
#include <linux/platform_device.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <pcmcia/ss.h>
#include <asm/hardware.h>
#include <asm/io.h>
#include <asm/sizes.h>
#include <asm/arch/at91rm9200.h>
#include <asm/arch/board.h>
#include <asm/arch/gpio.h>
/*
* A0..A10 work in each range; A23 indicates I/O space; A25 is CFRNW;
* some other bit in {A24,A22..A11} is nREG to flag memory access
* (vs attributes). So more than 2KB/region would just be waste.
*/
#define CF_ATTR_PHYS (AT91_CF_BASE)
#define CF_IO_PHYS (AT91_CF_BASE + (1 << 23))
#define CF_MEM_PHYS (AT91_CF_BASE + 0x017ff800)
/*--------------------------------------------------------------------------*/
static const char driver_name[] = "at91_cf";
struct at91_cf_socket {
struct pcmcia_socket socket;
unsigned present:1;
struct platform_device *pdev;
struct at91_cf_data *board;
};
#define SZ_2K (2 * SZ_1K)
static inline int at91_cf_present(struct at91_cf_socket *cf)
{
return !at91_get_gpio_value(cf->board->det_pin);
}
/*--------------------------------------------------------------------------*/
static int at91_cf_ss_init(struct pcmcia_socket *s)
{
return 0;
}
static irqreturn_t at91_cf_irq(int irq, void *_cf)
{
struct at91_cf_socket *cf = (struct at91_cf_socket *) _cf;
if (irq == cf->board->det_pin) {
unsigned present = at91_cf_present(cf);
/* kick pccard as needed */
if (present != cf->present) {
cf->present = present;
pr_debug("%s: card %s\n", driver_name,
present ? "present" : "gone");
pcmcia_parse_events(&cf->socket, SS_DETECT);
}
}
return IRQ_HANDLED;
}
static int at91_cf_get_status(struct pcmcia_socket *s, u_int *sp)
{
struct at91_cf_socket *cf;
if (!sp)
return -EINVAL;
cf = container_of(s, struct at91_cf_socket, socket);
/* NOTE: CF is always 3VCARD */
if (at91_cf_present(cf)) {
int rdy = cf->board->irq_pin; /* RDY/nIRQ */
int vcc = cf->board->vcc_pin;
*sp = SS_DETECT | SS_3VCARD;
if (!rdy || at91_get_gpio_value(rdy))
*sp |= SS_READY;
if (!vcc || at91_get_gpio_value(vcc))
*sp |= SS_POWERON;
} else
*sp = 0;
return 0;
}
static int
at91_cf_set_socket(struct pcmcia_socket *sock, struct socket_state_t *s)
{
struct at91_cf_socket *cf;
cf = container_of(sock, struct at91_cf_socket, socket);
/* switch Vcc if needed and possible */
if (cf->board->vcc_pin) {
switch (s->Vcc) {
case 0:
at91_set_gpio_value(cf->board->vcc_pin, 0);
break;
case 33:
at91_set_gpio_value(cf->board->vcc_pin, 1);
break;
default:
return -EINVAL;
}
}
/* toggle reset if needed */
at91_set_gpio_value(cf->board->rst_pin, s->flags & SS_RESET);
pr_debug("%s: Vcc %d, io_irq %d, flags %04x csc %04x\n",
driver_name, s->Vcc, s->io_irq, s->flags, s->csc_mask);
return 0;
}
static int at91_cf_ss_suspend(struct pcmcia_socket *s)
{
return at91_cf_set_socket(s, &dead_socket);
}
/* we already mapped the I/O region */
static int at91_cf_set_io_map(struct pcmcia_socket *s, struct pccard_io_map *io)
{
struct at91_cf_socket *cf;
u32 csr;
cf = container_of(s, struct at91_cf_socket, socket);
io->flags &= (MAP_ACTIVE | MAP_16BIT | MAP_AUTOSZ);
/*
* Use 16 bit accesses unless/until we need 8-bit i/o space.
* Always set CSR4 ... PCMCIA won't always unmap things.
*/
csr = at91_sys_read(AT91_SMC_CSR(4)) & ~AT91_SMC_DBW;
/*
* NOTE: this CF controller ignores IOIS16, so we can't really do
* MAP_AUTOSZ. The 16bit mode allows single byte access on either
* D0-D7 (even addr) or D8-D15 (odd), so it's close enough for many
* purposes (and handles ide-cs).
*
* The 8bit mode is needed for odd byte access on D0-D7. It seems
* some cards only like that way to get at the odd byte, despite
* CF 3.0 spec table 35 also giving the D8-D15 option.
*/
if (!(io->flags & (MAP_16BIT|MAP_AUTOSZ))) {
csr |= AT91_SMC_DBW_8;
pr_debug("%s: 8bit i/o bus\n", driver_name);
} else {
csr |= AT91_SMC_DBW_16;
pr_debug("%s: 16bit i/o bus\n", driver_name);
}
at91_sys_write(AT91_SMC_CSR(4), csr);
io->start = cf->socket.io_offset;
io->stop = io->start + SZ_2K - 1;
return 0;
}
/* pcmcia layer maps/unmaps mem regions */
static int
at91_cf_set_mem_map(struct pcmcia_socket *s, struct pccard_mem_map *map)
{
struct at91_cf_socket *cf;
if (map->card_start)
return -EINVAL;
cf = container_of(s, struct at91_cf_socket, socket);
map->flags &= MAP_ACTIVE|MAP_ATTRIB|MAP_16BIT;
if (map->flags & MAP_ATTRIB)
map->static_start = CF_ATTR_PHYS;
else
map->static_start = CF_MEM_PHYS;
return 0;
}
static struct pccard_operations at91_cf_ops = {
.init = at91_cf_ss_init,
.suspend = at91_cf_ss_suspend,
.get_status = at91_cf_get_status,
.set_socket = at91_cf_set_socket,
.set_io_map = at91_cf_set_io_map,
.set_mem_map = at91_cf_set_mem_map,
};
/*--------------------------------------------------------------------------*/
static int __init at91_cf_probe(struct platform_device *pdev)
{
struct at91_cf_socket *cf;
struct at91_cf_data *board = pdev->dev.platform_data;
struct resource *io;
unsigned int csa;
int status;
if (!board || !board->det_pin || !board->rst_pin)
return -ENODEV;
io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!io)
return -ENODEV;
cf = kcalloc(1, sizeof *cf, GFP_KERNEL);
if (!cf)
return -ENOMEM;
cf->board = board;
cf->pdev = pdev;
platform_set_drvdata(pdev, cf);
/* CF takes over CS4, CS5, CS6 */
csa = at91_sys_read(AT91_EBI_CSA);
at91_sys_write(AT91_EBI_CSA, csa | AT91_EBI_CS4A_SMC_COMPACTFLASH);
/* force poweron defaults for these pins ... */
(void) at91_set_A_periph(AT91_PIN_PC9, 0); /* A25/CFRNW */
(void) at91_set_A_periph(AT91_PIN_PC10, 0); /* NCS4/CFCS */
(void) at91_set_A_periph(AT91_PIN_PC11, 0); /* NCS5/CFCE1 */
(void) at91_set_A_periph(AT91_PIN_PC12, 0); /* NCS6/CFCE2 */
/* nWAIT is _not_ a default setting */
(void) at91_set_A_periph(AT91_PIN_PC6, 1); /* nWAIT */
/*
* Static memory controller timing adjustments.
* REVISIT: these timings are in terms of MCK cycles, so
* when MCK changes (cpufreq etc) so must these values...
*/
at91_sys_write(AT91_SMC_CSR(4),
AT91_SMC_ACSS_STD
| AT91_SMC_DBW_16
| AT91_SMC_BAT
| AT91_SMC_WSEN
| AT91_SMC_NWS_(32) /* wait states */
| AT91_SMC_RWSETUP_(6) /* setup time */
| AT91_SMC_RWHOLD_(4) /* hold time */
);
/* must be a GPIO; ergo must trigger on both edges */
status = request_irq(board->det_pin, at91_cf_irq,
IRQF_SAMPLE_RANDOM, driver_name, cf);
if (status < 0)
goto fail0;
device_init_wakeup(&pdev->dev, 1);
/*
* The card driver will request this irq later as needed.
* but it causes lots of "irqNN: nobody cared" messages
* unless we report that we handle everything (sigh).
* (Note: DK board doesn't wire the IRQ pin...)
*/
if (board->irq_pin) {
status = request_irq(board->irq_pin, at91_cf_irq,
IRQF_SHARED, driver_name, cf);
if (status < 0)
goto fail0a;
cf->socket.pci_irq = board->irq_pin;
} else
cf->socket.pci_irq = NR_IRQS + 1;
/* pcmcia layer only remaps "real" memory not iospace */
cf->socket.io_offset = (unsigned long) ioremap(CF_IO_PHYS, SZ_2K);
if (!cf->socket.io_offset)
goto fail1;
/* reserve CS4, CS5, and CS6 regions; but use just CS4 */
if (!request_mem_region(io->start, io->end + 1 - io->start,
driver_name))
goto fail1;
pr_info("%s: irqs det #%d, io #%d\n", driver_name,
board->det_pin, board->irq_pin);
cf->socket.owner = THIS_MODULE;
cf->socket.dev.dev = &pdev->dev;
cf->socket.ops = &at91_cf_ops;
cf->socket.resource_ops = &pccard_static_ops;
cf->socket.features = SS_CAP_PCCARD | SS_CAP_STATIC_MAP
| SS_CAP_MEM_ALIGN;
cf->socket.map_size = SZ_2K;
cf->socket.io[0].res = io;
status = pcmcia_register_socket(&cf->socket);
if (status < 0)
goto fail2;
return 0;
fail2:
iounmap((void __iomem *) cf->socket.io_offset);
release_mem_region(io->start, io->end + 1 - io->start);
fail1:
if (board->irq_pin)
free_irq(board->irq_pin, cf);
fail0a:
free_irq(board->det_pin, cf);
device_init_wakeup(&pdev->dev, 0);
fail0:
at91_sys_write(AT91_EBI_CSA, csa);
kfree(cf);
return status;
}
static int __exit at91_cf_remove(struct platform_device *pdev)
{
struct at91_cf_socket *cf = platform_get_drvdata(pdev);
struct at91_cf_data *board = cf->board;
struct resource *io = cf->socket.io[0].res;
unsigned int csa;
pcmcia_unregister_socket(&cf->socket);
if (board->irq_pin)
free_irq(board->irq_pin, cf);
free_irq(board->det_pin, cf);
device_init_wakeup(&pdev->dev, 0);
iounmap((void __iomem *) cf->socket.io_offset);
release_mem_region(io->start, io->end + 1 - io->start);
csa = at91_sys_read(AT91_EBI_CSA);
at91_sys_write(AT91_EBI_CSA, csa & ~AT91_EBI_CS4A);
kfree(cf);
return 0;
}
#ifdef CONFIG_PM
static int at91_cf_suspend(struct platform_device *pdev, pm_message_t mesg)
{
struct at91_cf_socket *cf = platform_get_drvdata(pdev);
struct at91_cf_data *board = cf->board;
pcmcia_socket_dev_suspend(&pdev->dev, mesg);
if (device_may_wakeup(&pdev->dev))
enable_irq_wake(board->det_pin);
else {
disable_irq_wake(board->det_pin);
disable_irq(board->det_pin);
}
if (board->irq_pin)
disable_irq(board->irq_pin);
return 0;
}
static int at91_cf_resume(struct platform_device *pdev)
{
struct at91_cf_socket *cf = platform_get_drvdata(pdev);
struct at91_cf_data *board = cf->board;
if (board->irq_pin)
enable_irq(board->irq_pin);
if (!device_may_wakeup(&pdev->dev))
enable_irq(board->det_pin);
pcmcia_socket_dev_resume(&pdev->dev);
return 0;
}
#else
#define at91_cf_suspend NULL
#define at91_cf_resume NULL
#endif
static struct platform_driver at91_cf_driver = {
.driver = {
.name = (char *) driver_name,
.owner = THIS_MODULE,
},
.probe = at91_cf_probe,
.remove = __exit_p(at91_cf_remove),
.suspend = at91_cf_suspend,
.resume = at91_cf_resume,
};
/*--------------------------------------------------------------------------*/
static int __init at91_cf_init(void)
{
return platform_driver_register(&at91_cf_driver);
}
module_init(at91_cf_init);
static void __exit at91_cf_exit(void)
{
platform_driver_unregister(&at91_cf_driver);
}
module_exit(at91_cf_exit);
MODULE_DESCRIPTION("AT91 Compact Flash Driver");
MODULE_AUTHOR("David Brownell");
MODULE_LICENSE("GPL");