msi.c
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/*
* arch/arm/mach-iop13xx/msi.c
*
* PCI MSI support for the iop13xx processor
*
* Copyright (c) 2006, Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
* Place - Suite 330, Boston, MA 02111-1307 USA.
*
*/
#include <linux/pci.h>
#include <linux/msi.h>
#include <asm/mach/irq.h>
#include <asm/irq.h>
#define IOP13XX_NUM_MSI_IRQS 128
static DECLARE_BITMAP(msi_irq_in_use, IOP13XX_NUM_MSI_IRQS);
/* IMIPR0 CP6 R8 Page 1
*/
static u32 read_imipr_0(void)
{
u32 val;
asm volatile("mrc p6, 0, %0, c8, c1, 0":"=r" (val));
return val;
}
static void write_imipr_0(u32 val)
{
asm volatile("mcr p6, 0, %0, c8, c1, 0"::"r" (val));
}
/* IMIPR1 CP6 R9 Page 1
*/
static u32 read_imipr_1(void)
{
u32 val;
asm volatile("mrc p6, 0, %0, c9, c1, 0":"=r" (val));
return val;
}
static void write_imipr_1(u32 val)
{
asm volatile("mcr p6, 0, %0, c9, c1, 0"::"r" (val));
}
/* IMIPR2 CP6 R10 Page 1
*/
static u32 read_imipr_2(void)
{
u32 val;
asm volatile("mrc p6, 0, %0, c10, c1, 0":"=r" (val));
return val;
}
static void write_imipr_2(u32 val)
{
asm volatile("mcr p6, 0, %0, c10, c1, 0"::"r" (val));
}
/* IMIPR3 CP6 R11 Page 1
*/
static u32 read_imipr_3(void)
{
u32 val;
asm volatile("mrc p6, 0, %0, c11, c1, 0":"=r" (val));
return val;
}
static void write_imipr_3(u32 val)
{
asm volatile("mcr p6, 0, %0, c11, c1, 0"::"r" (val));
}
static u32 (*read_imipr[])(void) = {
read_imipr_0,
read_imipr_1,
read_imipr_2,
read_imipr_3,
};
static void (*write_imipr[])(u32) = {
write_imipr_0,
write_imipr_1,
write_imipr_2,
write_imipr_3,
};
static void iop13xx_msi_handler(unsigned int irq, struct irq_desc *desc)
{
int i, j;
unsigned long status;
/* read IMIPR registers and find any active interrupts,
* then call ISR for each active interrupt
*/
for (i = 0; i < ARRAY_SIZE(read_imipr); i++) {
status = (read_imipr[i])();
if (!status)
continue;
do {
j = find_first_bit(&status, 32);
(write_imipr[i])(1 << j); /* write back to clear bit */
generic_handle_irq(IRQ_IOP13XX_MSI_0 + j + (32*i));
status = (read_imipr[i])();
} while (status);
}
}
void __init iop13xx_msi_init(void)
{
irq_set_chained_handler(IRQ_IOP13XX_INBD_MSI, iop13xx_msi_handler);
}
/*
* Dynamic irq allocate and deallocation
*/
int create_irq(void)
{
int irq, pos;
again:
pos = find_first_zero_bit(msi_irq_in_use, IOP13XX_NUM_MSI_IRQS);
irq = IRQ_IOP13XX_MSI_0 + pos;
if (irq > NR_IRQS)
return -ENOSPC;
/* test_and_set_bit operates on 32-bits at a time */
if (test_and_set_bit(pos, msi_irq_in_use))
goto again;
dynamic_irq_init(irq);
return irq;
}
void destroy_irq(unsigned int irq)
{
int pos = irq - IRQ_IOP13XX_MSI_0;
dynamic_irq_cleanup(irq);
clear_bit(pos, msi_irq_in_use);
}
void arch_teardown_msi_irq(unsigned int irq)
{
destroy_irq(irq);
}
static void iop13xx_msi_nop(struct irq_data *d)
{
return;
}
static struct irq_chip iop13xx_msi_chip = {
.name = "PCI-MSI",
.irq_ack = iop13xx_msi_nop,
.irq_enable = unmask_msi_irq,
.irq_disable = mask_msi_irq,
.irq_mask = mask_msi_irq,
.irq_unmask = unmask_msi_irq,
};
int arch_setup_msi_irq(struct pci_dev *pdev, struct msi_desc *desc)
{
int id, irq = create_irq();
struct msi_msg msg;
if (irq < 0)
return irq;
irq_set_msi_desc(irq, desc);
msg.address_hi = 0x0;
msg.address_lo = IOP13XX_MU_MIMR_PCI;
id = iop13xx_cpu_id();
msg.data = (id << IOP13XX_MU_MIMR_CORE_SELECT) | (irq & 0x7f);
write_msi_msg(irq, &msg);
irq_set_chip_and_handler(irq, &iop13xx_msi_chip, handle_simple_irq);
return 0;
}