From 795312e763569ce4df67e7a0ca726a9901358fa2 Mon Sep 17 00:00:00 2001 From: Pierre Ossman Date: Sat, 3 Sep 2005 15:56:54 -0700 Subject: [PATCH] [PATCH] ISA DMA suspend for i386 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/kernel/Makefile | 2 +- arch/i386/kernel/i8237.c | 67 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 68 insertions(+), 1 deletion(-) create mode 100644 arch/i386/kernel/i8237.c diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile index 4cc83b322b36..64682a0edacf 100644 --- a/arch/i386/kernel/Makefile +++ b/arch/i386/kernel/Makefile @@ -7,7 +7,7 @@ extra-y := head.o init_task.o vmlinux.lds obj-y := process.o semaphore.o signal.o entry.o traps.o irq.o vm86.o \ ptrace.o time.o ioport.o ldt.o setup.o i8259.o sys_i386.o \ pci-dma.o i386_ksyms.o i387.o dmi_scan.o bootflag.o \ - doublefault.o quirks.o + doublefault.o quirks.o i8237.o obj-y += cpu/ obj-y += timers/ diff --git a/arch/i386/kernel/i8237.c b/arch/i386/kernel/i8237.c new file mode 100644 index 000000000000..c36d1c006c2f --- /dev/null +++ b/arch/i386/kernel/i8237.c @@ -0,0 +1,67 @@ +/* + * i8237.c: 8237A DMA controller suspend functions. + * + * Written by Pierre Ossman, 2005. + */ + +#include +#include + +#include + +/* + * 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); -- GitLab