From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
To: robh+dt@kernel.org, catalin.marinas@arm.com, hch@lst.de,
robin.murphy@arm.com, devicetree@vger.kernel.org,
iommu@lists.linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Cc: will@kernel.org, linux-arm-kernel@lists.infradead.org,
linux-rpi-kernel@lists.infradead.org,
Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Subject: [PATCH 3/4] arm64: Default to 32-bit ZONE_DMA
Date: Thu, 1 Oct 2020 18:17:39 +0200 [thread overview]
Message-ID: <20201001161740.29064-4-nsaenzjulienne@suse.de> (raw)
In-Reply-To: <20201001161740.29064-1-nsaenzjulienne@suse.de>
The Raspberry Pi 4 needs two DMA zones as some of its devices can only
DMA into the 30-bit physical address space. We solved that by creating
an extra ZONE_DMA covering the 30-bit. It turns out that creating extra
zones unnecessarily broke Kdump on large systems. So default to a single
32-bit wide ZONE_DMA and only define both zones if running on RPi4.
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
arch/arm64/mm/init.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index e1a69a618832..3c3f462466eb 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -43,8 +43,6 @@
#include <asm/tlb.h>
#include <asm/alternative.h>
-#define ARM64_ZONE_DMA_BITS 30
-
/*
* We need to be able to catch inadvertent references to memstart_addr
* that occur (potentially in generic code) before arm64_memblock_init()
@@ -388,8 +386,14 @@ void __init arm64_memblock_init(void)
early_init_fdt_scan_reserved_mem();
if (IS_ENABLED(CONFIG_ZONE_DMA)) {
- zone_dma_bits = ARM64_ZONE_DMA_BITS;
- arm64_dma_phys_limit = max_zone_phys(ARM64_ZONE_DMA_BITS);
+ /*
+ * early_init_dt_scan() might alter zone_dma_bits based on the
+ * device's DT. Otherwise, have it cover the 32-bit address
+ * space.
+ */
+ if (zone_dma_bits == ZONE_DMA_BITS_DEFAULT)
+ zone_dma_bits = 32;
+ arm64_dma_phys_limit = max_zone_phys(zone_dma_bits);
}
if (IS_ENABLED(CONFIG_ZONE_DMA32))
--
2.28.0
next prev parent reply other threads:[~2020-10-01 16:18 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-01 16:17 [PATCH 0/4] arm64: Default to 32-bit wide ZONE_DMA Nicolas Saenz Julienne
2020-10-01 16:17 ` [PATCH 1/4] of/fdt: Update zone_dma_bits when running in bcm2711 Nicolas Saenz Julienne
2020-10-01 17:15 ` Catalin Marinas
2020-10-01 17:23 ` Catalin Marinas
2020-10-01 17:31 ` Nicolas Saenz Julienne
2020-10-01 20:02 ` Rob Herring
2020-10-02 11:55 ` Catalin Marinas
2020-10-08 10:05 ` Nicolas Saenz Julienne
2020-10-08 10:13 ` Catalin Marinas
2020-10-08 19:43 ` Ard Biesheuvel
2020-10-09 3:59 ` Jeremy Linton
2020-10-09 8:37 ` Nicolas Saenz Julienne
2020-10-09 7:10 ` Christoph Hellwig
2020-10-09 7:37 ` Ard Biesheuvel
2020-10-09 8:36 ` Nicolas Saenz Julienne
2020-10-09 9:13 ` Ard Biesheuvel
2020-10-09 13:33 ` Nicolas Saenz Julienne
2020-10-09 15:24 ` Lorenzo Pieralisi
2020-10-09 16:23 ` Ard Biesheuvel
2020-10-09 17:10 ` Catalin Marinas
2020-10-10 10:36 ` Ard Biesheuvel
2020-10-10 10:53 ` Nicolas Saenz Julienne
2020-10-10 12:38 ` Catalin Marinas
2020-10-12 6:47 ` Christoph Hellwig
2020-10-12 8:47 ` Catalin Marinas
2020-10-02 9:05 ` kernel test robot
2020-10-01 16:17 ` [PATCH 2/4] dma-direct: Turn zone_dma_bits default value into a define Nicolas Saenz Julienne
2020-10-01 16:17 ` Nicolas Saenz Julienne [this message]
2020-10-01 17:19 ` [PATCH 3/4] arm64: Default to 32-bit ZONE_DMA Catalin Marinas
2020-10-01 16:17 ` [PATCH 4/4] mm: Update DMA zones description Nicolas Saenz Julienne
2020-10-01 17:19 ` Catalin Marinas
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