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    Subject[PATCH 2/2] ISA DMA suspend for x86_64
    Reset the ISA DMA controller into a known state after a suspend. Primary
    concern was reenabling the cascading DMA channel (4).

    Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

    Word of warning, I haven't tested this platform since I don't have any
    x86_64 hardware. But it shouldn't differ from i386.

    Index: linux-wbsd/arch/x86_64/kernel/i8237.c
    ===================================================================
    --- linux-wbsd/arch/x86_64/kernel/i8237.c (revision 0)
    +++ linux-wbsd/arch/x86_64/kernel/i8237.c (revision 0)
    @@ -0,0 +1,67 @@
    +/*
    + * i8237.c: 8237A DMA controller suspend functions.
    + *
    + * Written by Pierre Ossman, 2005.
    + */
    +
    +#include <linux/init.h>
    +#include <linux/sysdev.h>
    +
    +#include <asm/dma.h>
    +
    +/*
    + * This module just handles suspend/resume issues with the
    + * 8237A DMA controller (used for ISA and LPC).
    + * Allocation is handled in kernel/dma.c and normal usage is
    + * in asm/dma.h.
    + */
    +
    +static int i8237A_resume(struct sys_device *dev)
    +{
    + unsigned long flags;
    + int i;
    +
    + flags = claim_dma_lock();
    +
    + dma_outb(DMA1_RESET_REG, 0);
    + dma_outb(DMA2_RESET_REG, 0);
    +
    + for (i = 0;i < 8;i++) {
    + set_dma_addr(i, 0x000000);
    + /* DMA count is a bit weird so this is not 0 */
    + set_dma_count(i, 1);
    + }
    +
    + /* Enable cascade DMA or channel 0-3 won't work */
    + enable_dma(4);
    +
    + release_dma_lock(flags);
    +
    + return 0;
    +}
    +
    +static int i8237A_suspend(struct sys_device *dev, pm_message_t state)
    +{
    + return 0;
    +}
    +
    +static struct sysdev_class i8237_sysdev_class = {
    + set_kset_name("i8237"),
    + .suspend = i8237A_suspend,
    + .resume = i8237A_resume,
    +};
    +
    +static struct sys_device device_i8237A = {
    + .id = 0,
    + .cls = &i8237_sysdev_class,
    +};
    +
    +static int __init i8237A_init_sysfs(void)
    +{
    + int error = sysdev_class_register(&i8237_sysdev_class);
    + if (!error)
    + error = sysdev_register(&device_i8237A);
    + return error;
    +}
    +
    +device_initcall(i8237A_init_sysfs);
    Index: linux-wbsd/arch/x86_64/kernel/Makefile
    ===================================================================
    --- linux-wbsd/arch/x86_64/kernel/Makefile (revision 153)
    +++ linux-wbsd/arch/x86_64/kernel/Makefile (working copy)
    @@ -7,7 +7,7 @@
    obj-y := process.o semaphore.o signal.o entry.o traps.o irq.o \
    ptrace.o time.o ioport.o ldt.o setup.o i8259.o sys_x86_64.o \
    x8664_ksyms.o i387.o syscall.o vsyscall.o \
    - setup64.o bootflag.o e820.o reboot.o quirks.o
    + setup64.o bootflag.o e820.o reboot.o quirks.o i8237.o

    obj-$(CONFIG_X86_MCE) += mce.o
    obj-$(CONFIG_X86_MCE_INTEL) += mce_intel.o
    \
     
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      Last update: 2005-06-30 20:15    [W:0.022 / U:31.348 seconds]
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