diff options
Diffstat (limited to 'arch/x86/kernel/i8237.c')
| -rw-r--r-- | arch/x86/kernel/i8237.c | 41 |
1 files changed, 33 insertions, 8 deletions
diff --git a/arch/x86/kernel/i8237.c b/arch/x86/kernel/i8237.c index 8eeaa81de066..896d46b44284 100644 --- a/arch/x86/kernel/i8237.c +++ b/arch/x86/kernel/i8237.c @@ -1,18 +1,16 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * 8237A DMA controller suspend functions. * * Written by Pierre Ossman, 2005. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or (at - * your option) any later version. */ +#include <linux/dmi.h> #include <linux/init.h> #include <linux/syscore_ops.h> #include <asm/dma.h> +#include <asm/x86_init.h> /* * This module just handles suspend/resume issues with the @@ -21,7 +19,7 @@ * in asm/dma.h. */ -static void i8237A_resume(void) +static void i8237A_resume(void *data) { unsigned long flags; int i; @@ -43,13 +41,40 @@ static void i8237A_resume(void) release_dma_lock(flags); } -static struct syscore_ops i8237_syscore_ops = { +static const struct syscore_ops i8237_syscore_ops = { .resume = i8237A_resume, }; +static struct syscore i8237_syscore = { + .ops = &i8237_syscore_ops, +}; + static int __init i8237A_init_ops(void) { - register_syscore_ops(&i8237_syscore_ops); + /* + * From SKL PCH onwards, the legacy DMA device is removed in which the + * I/O ports (81h-83h, 87h, 89h-8Bh, 8Fh) related to it are removed + * as well. All removed ports must return 0xff for a inb() request. + * + * Note: DMA_PAGE_2 (port 0x81) should not be checked for detecting + * the presence of DMA device since it may be used by BIOS to decode + * LPC traffic for POST codes. Original LPC only decodes one byte of + * port 0x80 but some BIOS may choose to enhance PCH LPC port 0x8x + * decoding. + */ + if (dma_inb(DMA_PAGE_0) == 0xFF) + return -ENODEV; + + /* + * It is not required to load this driver as newer SoC may not + * support 8237 DMA or bus mastering from LPC. Platform firmware + * must announce the support for such legacy devices via + * ACPI_FADT_LEGACY_DEVICES field in FADT table. + */ + if (x86_pnpbios_disabled() && dmi_get_bios_year() >= 2017) + return -ENODEV; + + register_syscore(&i8237_syscore); return 0; } device_initcall(i8237A_init_ops); |