This is a note to let you know that I've just added the patch titled
MIPS: Loongson64: Enable DMA noncoherent support
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mips-loongson64-enable-dma-noncoherent-support.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From edc0378eee00200a5bedf1bb9f00ad390e0d1bd4 Mon Sep 17 00:00:00 2001
From: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
Date: Tue, 7 Nov 2023 11:15:19 +0000
Subject: MIPS: Loongson64: Enable DMA noncoherent support
From: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
commit edc0378eee00200a5bedf1bb9f00ad390e0d1bd4 upstream.
There are some Loongson64 systems come with broken coherent DMA
support, firmware will set a bit in boot_param and pass nocoherentio
in cmdline.
However nonconherent support was missed out when spin off Loongson-2EF
form Loongson64, and that boot_param change never made itself into
upstream.
Support DMA noncoherent properly to get those systems working.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 71e2f4dd5a65 ("MIPS: Fork loongson2ef from loongson64")
Signed-off-by: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
Signed-off-by: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/mips/Kconfig | 2 ++
arch/mips/include/asm/mach-loongson64/boot_param.h | 3 ++-
arch/mips/loongson64/env.c | 10 +++++++++-
3 files changed, 13 insertions(+), 2 deletions(-)
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -482,6 +482,7 @@ config MACH_LOONGSON2EF
config MACH_LOONGSON64
bool "Loongson 64-bit family of machines"
+ select ARCH_DMA_DEFAULT_COHERENT
select ARCH_SPARSEMEM_ENABLE
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_MIGHT_HAVE_PC_SERIO
@@ -1273,6 +1274,7 @@ config CPU_LOONGSON64
select CPU_SUPPORTS_MSA
select CPU_DIEI_BROKEN if !LOONGSON3_ENHANCEMENT
select CPU_MIPSR2_IRQ_VI
+ select DMA_NONCOHERENT
select WEAK_ORDERING
select WEAK_REORDERING_BEYOND_LLSC
select MIPS_ASID_BITS_VARIABLE
--- a/arch/mips/include/asm/mach-loongson64/boot_param.h
+++ b/arch/mips/include/asm/mach-loongson64/boot_param.h
@@ -121,7 +121,8 @@ struct irq_source_routing_table {
u64 pci_io_start_addr;
u64 pci_io_end_addr;
u64 pci_config_addr;
- u32 dma_mask_bits;
+ u16 dma_mask_bits;
+ u16 dma_noncoherent;
} __packed;
struct interface_info {
--- a/arch/mips/loongson64/env.c
+++ b/arch/mips/loongson64/env.c
@@ -13,6 +13,8 @@
* Copyright (C) 2009 Lemote Inc.
* Author: Wu Zhangjin, wuzhangjin@xxxxxxxxx
*/
+
+#include <linux/dma-map-ops.h>
#include <linux/export.h>
#include <linux/pci_ids.h>
#include <asm/bootinfo.h>
@@ -147,8 +149,14 @@ void __init prom_lefi_init_env(void)
loongson_sysconf.dma_mask_bits = eirq_source->dma_mask_bits;
if (loongson_sysconf.dma_mask_bits < 32 ||
- loongson_sysconf.dma_mask_bits > 64)
+ loongson_sysconf.dma_mask_bits > 64) {
loongson_sysconf.dma_mask_bits = 32;
+ dma_default_coherent = true;
+ } else {
+ dma_default_coherent = !eirq_source->dma_noncoherent;
+ }
+
+ pr_info("Firmware: Coherent DMA: %s\n", dma_default_coherent ? "on" : "off");
loongson_sysconf.restart_addr = boot_p->reset_system.ResetWarm;
loongson_sysconf.poweroff_addr = boot_p->reset_system.Shutdown;
Patches currently in stable-queue which might be from jiaxun.yang@xxxxxxxxxxx are
queue-6.6/mips-kernel-clear-fpu-states-when-setting-up-kernel-threads.patch
queue-6.6/mips-loongson64-handle-more-memory-types-passed-from-firmware.patch
queue-6.6/mips-loongson64-enable-dma-noncoherent-support.patch
queue-6.6/mips-loongson64-reserve-vgabios-memory-on-boot.patch
