From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
To: catalin.marinas@arm.com, hch@lst.de, wahrenst@gmx.net,
marc.zyngier@arm.com, robh+dt@kernel.org,
linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
linux-riscv@lists.infradead.org, Will Deacon <will@kernel.org>
Cc: f.fainelli@gmail.com, robin.murphy@arm.com,
nsaenzjulienne@suse.de, linux-kernel@vger.kernel.org,
mbrugger@suse.com, linux-rpi-kernel@lists.infradead.org,
phill@raspberrypi.org, m.szyprowski@samsung.com
Subject: [PATCH v4 3/4] arm64: use both ZONE_DMA and ZONE_DMA32
Date: Fri, 6 Sep 2019 14:06:14 +0200 [thread overview]
Message-ID: <20190906120617.18836-4-nsaenzjulienne@suse.de> (raw)
In-Reply-To: <20190906120617.18836-1-nsaenzjulienne@suse.de>
So far all arm64 devices have supported 32 bit DMA masks for their
peripherals. This is not true anymore for the Raspberry Pi 4 as most of
it's peripherals can only address the first GB of memory on a total of
up to 4 GB.
This goes against ZONE_DMA32's intent, as it's expected for ZONE_DMA32
to be addressable with a 32 bit mask. So it was decided to re-introduce
ZONE_DMA in arm64.
ZONE_DMA will contain the lower 1G of memory, which is currently the
memory area addressable by any peripheral on an arm64 device.
ZONE_DMA32 will contain the rest of the 32 bit addressable memory.
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
Changes in v4:
- Fixed issue when NUMA=n and ZONE_DMA=n
- Merged two max_zone_dma*_phys() functions
Changes in v3:
- Used fixed size ZONE_DMA
- Fix check befor swiotlb_init()
Changes in v2:
- Update comment to reflect new zones split
- ZONE_DMA will never be left empty
arch/arm64/Kconfig | 4 +++
arch/arm64/include/asm/page.h | 2 ++
arch/arm64/mm/init.c | 51 ++++++++++++++++++++++++++---------
3 files changed, 44 insertions(+), 13 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 6b6362b83004..2dbe0165bd15 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -267,6 +267,10 @@ config GENERIC_CSUM
config GENERIC_CALIBRATE_DELAY
def_bool y
+config ZONE_DMA
+ bool "Support DMA zone" if EXPERT
+ default y
+
config ZONE_DMA32
bool "Support DMA32 zone" if EXPERT
default y
diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index d39ddb258a04..7b8c98830101 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -38,4 +38,6 @@ extern int pfn_valid(unsigned long);
#include <asm-generic/getorder.h>
+#define ARCH_ZONE_DMA_BITS 30
+
#endif
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 8e9bc64c5878..95ee7e839c75 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -56,6 +56,13 @@ EXPORT_SYMBOL(physvirt_offset);
struct page *vmemmap __ro_after_init;
EXPORT_SYMBOL(vmemmap);
+/*
+ * We create both ZONE_DMA and ZONE_DMA32. ZONE_DMA covers the first 1G of
+ * memory as some devices, namely the Raspberry Pi 4, have peripherals with
+ * this limited view of the memory. ZONE_DMA32 will cover the rest of the 32
+ * bit addressable memory area.
+ */
+phys_addr_t arm64_dma_phys_limit __ro_after_init;
phys_addr_t arm64_dma32_phys_limit __ro_after_init;
#ifdef CONFIG_KEXEC_CORE
@@ -169,15 +176,16 @@ static void __init reserve_elfcorehdr(void)
{
}
#endif /* CONFIG_CRASH_DUMP */
+
/*
- * Return the maximum physical address for ZONE_DMA32 (DMA_BIT_MASK(32)). It
- * currently assumes that for memory starting above 4G, 32-bit devices will
- * use a DMA offset.
+ * Return the maximum physical address for a zone with a given address size
+ * limit. It currently assumes that for memory starting above 4G, 32-bit
+ * devices will use a DMA offset.
*/
-static phys_addr_t __init max_zone_dma32_phys(void)
+static phys_addr_t __init max_zone_phys(unsigned int zone_bits)
{
phys_addr_t offset = memblock_start_of_DRAM() & GENMASK_ULL(63, 32);
- return min(offset + (1ULL << 32), memblock_end_of_DRAM());
+ return min(offset + (1ULL << zone_bits), memblock_end_of_DRAM());
}
#ifdef CONFIG_NUMA
@@ -186,6 +194,9 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
{
unsigned long max_zone_pfns[MAX_NR_ZONES] = {0};
+#ifdef CONFIG_ZONE_DMA
+ max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit);
+#endif
#ifdef CONFIG_ZONE_DMA32
max_zone_pfns[ZONE_DMA32] = PFN_DOWN(arm64_dma32_phys_limit);
#endif
@@ -201,13 +212,18 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
struct memblock_region *reg;
unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
unsigned long max_dma32 = min;
+ unsigned long max_dma = min;
memset(zone_size, 0, sizeof(zone_size));
- /* 4GB maximum for 32-bit only capable devices */
+#ifdef CONFIG_ZONE_DMA
+ max_dma = PFN_DOWN(arm64_dma_phys_limit);
+ zone_size[ZONE_DMA] = max_dma - min;
+ max_dma32 = max_dma;
+#endif
#ifdef CONFIG_ZONE_DMA32
max_dma32 = PFN_DOWN(arm64_dma32_phys_limit);
- zone_size[ZONE_DMA32] = max_dma32 - min;
+ zone_size[ZONE_DMA32] = max_dma32 - max_dma;
#endif
zone_size[ZONE_NORMAL] = max - max_dma32;
@@ -219,11 +235,17 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
if (start >= max)
continue;
-
+#ifdef CONFIG_ZONE_DMA
+ if (start < max_dma) {
+ unsigned long dma_end = min_not_zero(end, max_dma);
+ zhole_size[ZONE_DMA] -= dma_end - start;
+ }
+#endif
#ifdef CONFIG_ZONE_DMA32
if (start < max_dma32) {
- unsigned long dma_end = min(end, max_dma32);
- zhole_size[ZONE_DMA32] -= dma_end - start;
+ unsigned long dma32_end = min(end, max_dma32);
+ unsigned long dma32_start = max(start, max_dma);
+ zhole_size[ZONE_DMA32] -= dma32_end - dma32_start;
}
#endif
if (end > max_dma32) {
@@ -418,9 +440,11 @@ void __init arm64_memblock_init(void)
early_init_fdt_scan_reserved_mem();
- /* 4GB maximum for 32-bit only capable devices */
+ if (IS_ENABLED(CONFIG_ZONE_DMA))
+ arm64_dma_phys_limit = max_zone_phys(ARCH_ZONE_DMA_BITS);
+
if (IS_ENABLED(CONFIG_ZONE_DMA32))
- arm64_dma32_phys_limit = max_zone_dma32_phys();
+ arm64_dma32_phys_limit = max_zone_phys(32);
else
arm64_dma32_phys_limit = PHYS_MASK + 1;
@@ -430,7 +454,7 @@ void __init arm64_memblock_init(void)
high_memory = __va(memblock_end_of_DRAM() - 1) + 1;
- dma_contiguous_reserve(arm64_dma32_phys_limit);
+ dma_contiguous_reserve(arm64_dma_phys_limit ? : arm64_dma32_phys_limit);
}
void __init bootmem_init(void)
@@ -534,6 +558,7 @@ static void __init free_unused_memmap(void)
void __init mem_init(void)
{
if (swiotlb_force == SWIOTLB_FORCE ||
+ max_pfn > (arm64_dma_phys_limit >> PAGE_SHIFT) ||
max_pfn > (arm64_dma32_phys_limit >> PAGE_SHIFT))
swiotlb_init(1);
else
--
2.23.0
next prev parent reply other threads:[~2019-09-06 12:06 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-06 12:06 [PATCH v4 0/4] Raspberry Pi 4 DMA addressing support Nicolas Saenz Julienne
2019-09-06 12:06 ` [PATCH v4 1/4] arm64: mm: use arm64_dma_phys_limit instead of calling max_zone_dma_phys() Nicolas Saenz Julienne
2019-09-06 12:06 ` [PATCH v4 2/4] arm64: rename variables used to calculate ZONE_DMA32's size Nicolas Saenz Julienne
2019-09-06 12:06 ` Nicolas Saenz Julienne [this message]
2019-09-08 21:27 ` [PATCH v4 3/4] arm64: use both ZONE_DMA and ZONE_DMA32 Catalin Marinas
2019-09-09 8:46 ` Nicolas Saenz Julienne
2019-09-06 12:06 ` [PATCH v4 4/4] mm: refresh ZONE_DMA and ZONE_DMA32 comments in 'enum zone_type' Nicolas Saenz Julienne
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