Hi,
On Mon, Dec 11, 2023 at 07:22:24PM +0100, Greg Kroah-Hartman wrote:
> 5.10-stable review patch. If anyone has any objections, please let me know.
>
> ------------------
>
> 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
> @@ -468,6 +468,7 @@ 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
> @@ -1379,6 +1380,7 @@ 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
> @@ -117,7 +117,8 @@ 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>
> @@ -131,8 +133,14 @@ void __init prom_init_env(void)
> loongson_sysconf.pci_io_base = eirq_source->pci_io_start_addr;
> 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;
While preparing an update for Debian and finally building for all
supported architecture, the builds for mipsel and mips64el were
failing with:
/<<PKGBUILDDIR>>/arch/mips/loongson64/env.c: In function 'prom_init_env':
/<<PKGBUILDDIR>>/arch/mips/loongson64/env.c:138:3: error: 'dma_default_coherent' undeclared (first use in this function); did you mean 'dma_free_coherent'?
138 | dma_default_coherent = true;
| ^~~~~~~~~~~~~~~~~~~~
| dma_free_coherent
/<<PKGBUILDDIR>>/arch/mips/loongson64/env.c:138:3: note: each undeclared identifier is reported only once for each function it appears in
make[6]: *** [/<<PKGBUILDDIR>>/scripts/Makefile.build:291: arch/mips/loongson64/env.o] Error 1
make[6]: *** Waiting for unfinished jobs....
Is here a prerequisite missing for the commit?
Backporting though 6d4e9a8efe3d ("driver core: lift dma_default_coherent into
common code") which is from 5.12-rc1 though seems too intrusive, correct? Would
the alternative be to just revert the 3ee7e2faef87 ("MIPS: Loongson64: Enable
DMA noncoherent support") commit which landed in 5.10.204?
Regards,
Salvatore
