1 /* 2 * 8237A DMA controller suspend functions. 3 * 4 * Written by Pierre Ossman, 2005. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or (at 9 * your option) any later version. 10 */ 11 12 #include <linux/init.h> 13 #include <linux/syscore_ops.h> 14 15 #include <asm/dma.h> 16 17 /* 18 * This module just handles suspend/resume issues with the 19 * 8237A DMA controller (used for ISA and LPC). 20 * Allocation is handled in kernel/dma.c and normal usage is 21 * in asm/dma.h. 22 */ 23 24 static void i8237A_resume(void) 25 { 26 unsigned long flags; 27 int i; 28 29 flags = claim_dma_lock(); 30 31 dma_outb(0, DMA1_RESET_REG); 32 dma_outb(0, DMA2_RESET_REG); 33 34 for (i = 0; i < 8; i++) { 35 set_dma_addr(i, 0x000000); 36 /* DMA count is a bit weird so this is not 0 */ 37 set_dma_count(i, 1); 38 } 39 40 /* Enable cascade DMA or channel 0-3 won't work */ 41 enable_dma(4); 42 43 release_dma_lock(flags); 44 } 45 46 static struct syscore_ops i8237_syscore_ops = { 47 .resume = i8237A_resume, 48 }; 49 50 static int __init i8237A_init_ops(void) 51 { 52 register_syscore_ops(&i8237_syscore_ops); 53 return 0; 54 } 55 device_initcall(i8237A_init_ops); 56