korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-12-29 14:05:19 +08:00
Code Issues Packages Projects Releases Wiki Activity
c9ec87e512
linux/drivers/scsi/NCR_Q720.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

378 lines
9.2 KiB
C
Raw Blame History

/* -*- mode: c; c-basic-offset: 8 -*- */
/* NCR Quad 720 MCA SCSI Driver
*
* Copyright (C) 2003 by James.Bottomley@HansenPartnership.com
*/
#include <linux/blkdev.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mca.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <asm/io.h>
#include "scsi.h"
#include <scsi/scsi_host.h>
#include "ncr53c8xx.h"
#include "NCR_Q720.h"
static struct ncr_chip q720_chip __initdata = {
.revision_id = 0x0f,
.burst_max = 3,
.offset_max = 8,
.nr_divisor = 4,
.features = FE_WIDE | FE_DIFF | FE_VARCLK,
};
MODULE_AUTHOR("James Bottomley");
MODULE_DESCRIPTION("NCR Quad 720 SCSI Driver");
MODULE_LICENSE("GPL");
#define NCR_Q720_VERSION "0.9"
/* We needs this helper because we have up to four hosts per struct device */
struct NCR_Q720_private {
struct device *dev;
void __iomem * mem_base;
__u32 phys_mem_base;
__u32 mem_size;
__u8 irq;
__u8 siops;
__u8 irq_enable;
struct Scsi_Host *hosts[4];
};
static struct scsi_host_template NCR_Q720_tpnt = {
.module = THIS_MODULE,
.proc_name = "NCR_Q720",
};
static irqreturn_t
NCR_Q720_intr(int irq, void *data)
{
struct NCR_Q720_private *p = (struct NCR_Q720_private *)data;
__u8 sir = (readb(p->mem_base + 0x0d) & 0xf0) >> 4;
__u8 siop;
sir |= ~p->irq_enable;
if(sir == 0xff)
return IRQ_NONE;
while((siop = ffz(sir)) < p->siops) {
sir |= 1<<siop;
ncr53c8xx_intr(irq, p->hosts[siop]);
}
return IRQ_HANDLED;
}
static int __init
NCR_Q720_probe_one(struct NCR_Q720_private *p, int siop,
int irq, int slot, __u32 paddr, void __iomem *vaddr)
{
struct ncr_device device;
__u8 scsi_id;
static int unit = 0;
__u8 scsr1 = readb(vaddr + NCR_Q720_SCSR_OFFSET + 1);
__u8 differential = readb(vaddr + NCR_Q720_SCSR_OFFSET) & 0x20;
__u8 version;
int error;
scsi_id = scsr1 >> 4;
/* enable burst length 16 (FIXME: should allow this) */
scsr1 |= 0x02;
/* force a siop reset */
scsr1 |= 0x04;
writeb(scsr1, vaddr + NCR_Q720_SCSR_OFFSET + 1);
udelay(10);
version = readb(vaddr + 0x18) >> 4;
memset(&device, 0, sizeof(struct ncr_device));
/* Initialise ncr_device structure with items required by ncr_attach. */
device.chip = q720_chip;
device.chip.revision_id = version;
device.host_id = scsi_id;
device.dev = p->dev;
device.slot.base = paddr;
device.slot.base_c = paddr;
device.slot.base_v = vaddr;
device.slot.irq = irq;
device.differential = differential ? 2 : 0;
printk("Q720 probe unit %d (siop%d) at 0x%lx, diff = %d, vers = %d\n", unit, siop,
(unsigned long)paddr, differential, version);
p->hosts[siop] = ncr_attach(&NCR_Q720_tpnt, unit++, &device);
if (!p->hosts[siop])
goto fail;
p->irq_enable |= (1<<siop);
scsr1 = readb(vaddr + NCR_Q720_SCSR_OFFSET + 1);
/* clear the disable interrupt bit */
scsr1 &= ~0x01;
writeb(scsr1, vaddr + NCR_Q720_SCSR_OFFSET + 1);
error = scsi_add_host(p->hosts[siop], p->dev);
if (error)
ncr53c8xx_release(p->hosts[siop]);
else
scsi_scan_host(p->hosts[siop]);
return error;
fail:
return -ENODEV;
}
/* Detect a Q720 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 __init
NCR_Q720_probe(struct device *dev)
{
struct NCR_Q720_private *p;
static int banner = 1;
struct mca_device *mca_dev = to_mca_device(dev);
int slot = mca_dev->slot;
int found = 0;
int irq, i, siops;
__u8 pos2, pos4, asr2, asr9, asr10;
__u16 io_base;
__u32 base_addr, mem_size;
void __iomem *mem_base;
p = kmalloc(sizeof(*p), GFP_KERNEL);
if (!p)
return -ENOMEM;
memset(p, 0, sizeof(*p));
pos2 = mca_device_read_pos(mca_dev, 2);
/* enable device */
pos2 |= NCR_Q720_POS2_BOARD_ENABLE | NCR_Q720_POS2_INTERRUPT_ENABLE;
mca_device_write_pos(mca_dev, 2, pos2);
io_base = (pos2 & NCR_Q720_POS2_IO_MASK) << NCR_Q720_POS2_IO_SHIFT;
if(banner) {
printk(KERN_NOTICE "NCR Q720: Driver Version " NCR_Q720_VERSION "\n"
"NCR Q720: Copyright (c) 2003 by James.Bottomley@HansenPartnership.com\n"
"NCR Q720:\n");
banner = 0;
}
io_base = mca_device_transform_ioport(mca_dev, io_base);
/* OK, this is phase one of the bootstrap, we now know the
* I/O space base address. All the configuration registers
* are mapped here (including pos) */
/* sanity check I/O mapping */
i = inb(io_base) | (inb(io_base+1)<<8);
if(i != NCR_Q720_MCA_ID) {
printk(KERN_ERR "NCR_Q720, adapter failed to I/O map registers correctly at 0x%x(0x%x)\n", io_base, i);
kfree(p);
return -ENODEV;
}
/* Phase II, find the ram base and memory map the board register */
pos4 = inb(io_base + 4);
/* enable streaming data */
pos4 |= 0x01;
outb(pos4, io_base + 4);
base_addr = (pos4 & 0x7e) << 20;
base_addr += (pos4 & 0x80) << 23;
asr10 = inb(io_base + 0x12);
base_addr += (asr10 & 0x80) << 24;
base_addr += (asr10 & 0x70) << 23;
/* OK, got the base addr, now we need to find the ram size,
* enable and map it */
asr9 = inb(io_base + 0x11);
i = (asr9 & 0xc0) >> 6;
if(i == 0)
mem_size = 1024;
else
mem_size = 1 << (19 + i);
/* enable the sram mapping */
asr9 |= 0x20;
/* disable the rom mapping */
asr9 &= ~0x10;
outb(asr9, io_base + 0x11);
if(!request_mem_region(base_addr, mem_size, "NCR_Q720")) {
printk(KERN_ERR "NCR_Q720: Failed to claim memory region 0x%lx\n-0x%lx",
(unsigned long)base_addr,
(unsigned long)(base_addr + mem_size));
goto out_free;
}
if (dma_declare_coherent_memory(dev, base_addr, base_addr,
mem_size, DMA_MEMORY_MAP)
!= DMA_MEMORY_MAP) {
printk(KERN_ERR "NCR_Q720: DMA declare memory failed\n");
goto out_release_region;
}
/* The first 1k of the memory buffer is a memory map of the registers
*/
mem_base = dma_mark_declared_memory_occupied(dev, base_addr,
1024);
if (IS_ERR(mem_base)) {
printk("NCR_Q720 failed to reserve memory mapped region\n");
goto out_release;
}
/* now also enable accesses in asr 2 */
asr2 = inb(io_base + 0x0a);
asr2 |= 0x01;
outb(asr2, io_base + 0x0a);
/* get the number of SIOPs (this should be 2 or 4) */
siops = ((asr2 & 0xe0) >> 5) + 1;
/* sanity check mapping (again) */
i = readw(mem_base);
if(i != NCR_Q720_MCA_ID) {
printk(KERN_ERR "NCR_Q720, adapter failed to memory map registers correctly at 0x%lx(0x%x)\n", (unsigned long)base_addr, i);
goto out_release;
}
irq = readb(mem_base + 5) & 0x0f;
/* now do the bus related transforms */
irq = mca_device_transform_irq(mca_dev, irq);
printk(KERN_NOTICE "NCR Q720: found in slot %d irq = %d mem base = 0x%lx siops = %d\n", slot, irq, (unsigned long)base_addr, siops);
printk(KERN_NOTICE "NCR Q720: On board ram %dk\n", mem_size/1024);
p->dev = dev;
p->mem_base = mem_base;
p->phys_mem_base = base_addr;
p->mem_size = mem_size;
p->irq = irq;
p->siops = siops;
if (request_irq(irq, NCR_Q720_intr, IRQF_SHARED, "NCR_Q720", p)) {
printk(KERN_ERR "NCR_Q720: request irq %d failed\n", irq);
goto out_release;
}
/* disable all the siop interrupts */
for(i = 0; i < siops; i++) {
void __iomem *reg_scsr1 = mem_base + NCR_Q720_CHIP_REGISTER_OFFSET
+ i*NCR_Q720_SIOP_SHIFT + NCR_Q720_SCSR_OFFSET + 1;
__u8 scsr1 = readb(reg_scsr1);
scsr1 |= 0x01;
writeb(scsr1, reg_scsr1);
}
/* plumb in all 720 chips */
for (i = 0; i < siops; i++) {
void __iomem *siop_v_base = mem_base + NCR_Q720_CHIP_REGISTER_OFFSET
+ i*NCR_Q720_SIOP_SHIFT;
__u32 siop_p_base = base_addr + NCR_Q720_CHIP_REGISTER_OFFSET
+ i*NCR_Q720_SIOP_SHIFT;
__u16 port = io_base + NCR_Q720_CHIP_REGISTER_OFFSET
+ i*NCR_Q720_SIOP_SHIFT;
int err;
outb(0xff, port + 0x40);
outb(0x07, port + 0x41);
if ((err = NCR_Q720_probe_one(p, i, irq, slot,
siop_p_base, siop_v_base)) != 0)
printk("Q720: 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_Q720");
dev_set_drvdata(dev, p);
return 0;
out_release:
dma_release_declared_memory(dev);
out_release_region:
release_mem_region(base_addr, mem_size);
out_free:
kfree(p);
return -ENODEV;
}
static void __exit
NCR_Q720_remove_one(struct Scsi_Host *host)
{
scsi_remove_host(host);
ncr53c8xx_release(host);
}
static int __exit
NCR_Q720_remove(struct device *dev)
{
struct NCR_Q720_private *p = dev_get_drvdata(dev);
int i;
for (i = 0; i < p->siops; i++)
if(p->hosts[i])
NCR_Q720_remove_one(p->hosts[i]);
dma_release_declared_memory(dev);
release_mem_region(p->phys_mem_base, p->mem_size);
free_irq(p->irq, p);
kfree(p);
return 0;
}
static short NCR_Q720_id_table[] = { NCR_Q720_MCA_ID, 0 };
static struct mca_driver NCR_Q720_driver = {
.id_table = NCR_Q720_id_table,
.driver = {
.name = "NCR_Q720",
.bus = &mca_bus_type,
.probe = NCR_Q720_probe,
.remove = __devexit_p(NCR_Q720_remove),
},
};
static int __init
NCR_Q720_init(void)
{
int ret = ncr53c8xx_init();
if (!ret)
ret = mca_register_driver(&NCR_Q720_driver);
if (ret)
ncr53c8xx_exit();
return ret;
}
static void __exit
NCR_Q720_exit(void)
{
mca_unregister_driver(&NCR_Q720_driver);
ncr53c8xx_exit();
}
module_init(NCR_Q720_init);
module_exit(NCR_Q720_exit);
Reference in New Issue View Git Blame Copy Permalink