Messages in this thread Patch in this message | | | Date | Thu, 30 Jun 2005 19:58:19 +0200 | From | Pierre Ossman <> | 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 | |