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Unverified Commit 5ec9c4ff authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Palmer Dabbelt
Browse files

riscv: add ZONE_DMA32 



This patch allows devices that require memory that can be addressed
using 32-bit addresses to work easily on RISC-V systems.  The newly
improved dma-direct ops will tap into this pool automatically for
32-bit addressing.

Based on an earlier patch from Wesley W. Terpstra.

CC: Wesley W. Terpstra <terpstra@sifive.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarPalmer Dabbelt <palmer@sifive.com>
parent f1b65f20

arch/riscv/Kconfig

+5 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ config RISCV 
	select GENERIC_ATOMIC64 if !64BIT || !RISCV_ISA_A

	select ARCH_WANT_OPTIONAL_GPIOLIB

	select HAVE_MEMBLOCK

	select HAVE_MEMBLOCK_NODE_MAP

	select HAVE_DMA_API_DEBUG

	select HAVE_DMA_CONTIGUOUS

	select HAVE_GENERIC_DMA_COHERENT
@@ -43,6 +44,10 @@ config MMU 
config ARCH_PHYS_ADDR_T_64BIT

	def_bool y



config ZONE_DMA32

	bool

	default y



config ARCH_DMA_ADDR_T_64BIT

	def_bool y

arch/riscv/kernel/setup.c

+9 −0
Original line number Diff line number Diff line
@@ -181,6 +181,15 @@ static void __init setup_bootmem(void) 
	early_init_fdt_scan_reserved_mem();

	memblock_allow_resize();

	memblock_dump_all();



	for_each_memblock(memory, reg) {

		unsigned long start_pfn = memblock_region_memory_base_pfn(reg);

		unsigned long end_pfn = memblock_region_memory_end_pfn(reg);



		memblock_set_node(PFN_PHYS(start_pfn),

		                  PFN_PHYS(end_pfn - start_pfn),

		                  &memblock.memory, 0);

	}

}



void __init setup_arch(char **cmdline_p)

arch/riscv/mm/init.c

+6 −4
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/initrd.h>

#include <linux/memblock.h>

#include <linux/swap.h>

#include <linux/sizes.h>



#include <asm/tlbflush.h>

#include <asm/sections.h>
@@ -25,11 +26,12 @@ 


static void __init zone_sizes_init(void)

{

	unsigned long zones_size[MAX_NR_ZONES];

	unsigned long max_zone_pfns[MAX_NR_ZONES] = { 0, };



	memset(zones_size, 0, sizeof(zones_size));

	zones_size[ZONE_NORMAL] = max_mapnr;

	free_area_init_node(0, zones_size, pfn_base, NULL);

	max_zone_pfns[ZONE_DMA32] = PFN_DOWN(min(4UL * SZ_1G, max_low_pfn));

	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;



	free_area_init_nodes(max_zone_pfns);

}



void setup_zero_page(void)