From 1fb65f4bc30fbadd0c89521985ff8142693c9631 Mon Sep 17 00:00:00 2001 From: Nicolas Saenz Julienne Date: Wed, 11 Sep 2019 20:25:45 +0200 Subject: [PATCH] arm64: use both ZONE_DMA and ZONE_DMA32 commit 1a8e1cef7603e218339ac63cb3178b25554524e5 upstream. 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 Reviewed-by: Catalin Marinas Signed-off-by: Catalin Marinas --- arch/arm64/Kconfig | 4 +++ arch/arm64/include/asm/page.h | 2 ++ arch/arm64/mm/init.c | 54 +++++++++++++++++++++++++---------- 3 files changed, 45 insertions(+), 15 deletions(-) --- 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 --- 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 +#define ARCH_ZONE_DMA_BITS 30 + #endif --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -50,6 +50,13 @@ s64 memstart_addr __ro_after_init = -1; EXPORT_SYMBOL(memstart_addr); +/* + * 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 @@ -163,15 +170,16 @@ static void __init reserve_elfcorehdr(vo { } #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()); + phys_addr_t offset = memblock_start_of_DRAM() & GENMASK_ULL(63, zone_bits); + return min(offset + (1ULL << zone_bits), memblock_end_of_DRAM()); } #ifdef CONFIG_NUMA @@ -180,6 +188,9 @@ static void __init zone_sizes_init(unsig { 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 @@ -195,13 +206,18 @@ static void __init zone_sizes_init(unsig 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; @@ -213,11 +229,17 @@ static void __init zone_sizes_init(unsig 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) { @@ -420,9 +442,11 @@ 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; @@ -432,7 +456,7 @@ 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) @@ -536,7 +560,7 @@ static void __init free_unused_memmap(vo void __init mem_init(void) { if (swiotlb_force == SWIOTLB_FORCE || - max_pfn > (arm64_dma32_phys_limit >> PAGE_SHIFT)) + max_pfn > PFN_DOWN(arm64_dma_phys_limit ? : arm64_dma32_phys_limit)) swiotlb_init(1); else swiotlb_force = SWIOTLB_NO_FORCE;