From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- arch/x86/kernel/i8237.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 arch/x86/kernel/i8237.c (limited to 'arch/x86/kernel/i8237.c') diff --git a/arch/x86/kernel/i8237.c b/arch/x86/kernel/i8237.c new file mode 100644 index 000000000..2cd124ad9 --- /dev/null +++ b/arch/x86/kernel/i8237.c @@ -0,0 +1,76 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * 8237A DMA controller suspend functions. + * + * Written by Pierre Ossman, 2005. + */ + +#include +#include +#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 void i8237A_resume(void) +{ + unsigned long flags; + int i; + + flags = claim_dma_lock(); + + dma_outb(0, DMA1_RESET_REG); + dma_outb(0, DMA2_RESET_REG); + + 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); +} + +static struct syscore_ops i8237_syscore_ops = { + .resume = i8237A_resume, +}; + +static int __init i8237A_init_ops(void) +{ + /* + * 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_ops(&i8237_syscore_ops); + return 0; +} +device_initcall(i8237A_init_ops); -- cgit v1.2.3