this patch allowing the arm64 DMA zone be configurable.
Signed-off-by: Alix Wu <alix...@mediatek.com>
Signed-off-by: YJ Chiang <yj.chi...@mediatek.com>
Signed-off-by: Phil Chang <phil.ch...@mediatek.com>
---
Hi
For some devices, the main memory split into 2 part due to the memory
architecture,
the efficient and less inefficient part.
One of the use case is fine-tune the dma32 size to contain all the
efficient part of memory block on this kind of architecture,
but in general, the DMA32 zone size is hardcode to 4G.
.../admin-guide/kernel-parameters.txt | 3 ++
arch/arm64/include/asm/memory.h | 2 ++
arch/arm64/mm/init.c | 33 +++++++++++++++++--
3 files changed, 35 insertions(+), 3 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt
b/Documentation/admin-guide/kernel-parameters.txt
index fb95fad81c79..441ad3cb8ee8 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -956,6 +956,9 @@
The filter can be disabled or changed to another
driver later using sysfs.
+ dma32_zone=nn [KMG] [KNL,BOOT]
+ Forces the DMA32 zone size of <nn> in mb, arm64 only.
+
driver_async_probe= [KNL]
List of driver names to be probed asynchronously.
Format: <driver_name1>,<driver_name2>...
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index a1871bb32bb1..377f2252618a 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -174,6 +174,8 @@ extern u64 kimage_vaddr;
/* the offset between the kernel virtual and physical mappings */
extern u64 kimage_voffset;
+extern phys_addr_t arm_dma_zone_size;
+
static inline unsigned long kaslr_offset(void)
{
return kimage_vaddr - KIMAGE_VADDR;
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 1e93cfc7c47a..642ab323392c 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -60,6 +60,9 @@ EXPORT_SYMBOL(physvirt_offset);
struct page *vmemmap __ro_after_init;
EXPORT_SYMBOL(vmemmap);
+phys_addr_t arm_dma_zone_size __ro_after_init;
+EXPORT_SYMBOL(arm_dma_zone_size);
+
/*
* 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
@@ -242,6 +245,25 @@ static int __init early_mem(char *p)
}
early_param("mem", early_mem);
+/*
+ * Setup the dma32 zone size
+ */
+static int __init setup_dma32_zone(char *p)
+{
+ if (!p)
+ return -EINVAL;
+
+ if (kstrtoull(p, 0, &arm_dma_zone_size))
+ return -EINVAL;
+
+ arm_dma_zone_size *= SZ_1M;
+ pr_notice("Setup dma32 zone size to %llu Mb\n", arm_dma_zone_size);
+
+ return 0;
+}
+
+early_param("dma32_zone", setup_dma32_zone);
+
static int __init early_init_dt_scan_usablemem(unsigned long node,
const char *uname, int depth, void *data)
{
@@ -392,10 +414,15 @@ void __init arm64_memblock_init(void)
arm64_dma_phys_limit = max_zone_phys(ARM64_ZONE_DMA_BITS);
}
- if (IS_ENABLED(CONFIG_ZONE_DMA32))
- arm64_dma32_phys_limit = max_zone_phys(32);
- else
+ if (IS_ENABLED(CONFIG_ZONE_DMA32)) {
+ if (arm_dma_zone_size)
+ arm64_dma32_phys_limit = arm_dma_zone_size +
+ memblock_start_of_DRAM();
+ else
+ arm64_dma32_phys_limit = max_zone_phys(32);
+ } else {
arm64_dma32_phys_limit = PHYS_MASK + 1;
+ }
reserve_crashkernel();
--
2.18.0
