powerpc: Dynamic DMA zone limits

Platform code can call limit_zone_pfn() to set appropriate limits
for ZONE_DMA and ZONE_DMA32, and dma_direct_alloc_coherent() will
select a suitable zone based on a device's mask and the pfn limits that
platform code has configured.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: Shaohui Xie <Shaohui.Xie@freescale.com>
This commit is contained in:
Scott Wood 2014-08-08 18:40:42 -05:00
Родитель 78eb9094ca
Коммит 1c98025c6c
4 изменённых файлов: 83 добавлений и 5 удалений

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@ -285,6 +285,10 @@ config PPC_EMULATE_SSTEP
bool
default y if KPROBES || UPROBES || XMON || HAVE_HW_BREAKPOINT
config ZONE_DMA32
bool
default y if PPC64
source "init/Kconfig"
source "kernel/Kconfig.freezer"

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@ -4,6 +4,7 @@
#ifndef __ASSEMBLY__
#include <linux/mmdebug.h>
#include <linux/mmzone.h>
#include <asm/processor.h> /* For TASK_SIZE */
#include <asm/mmu.h>
#include <asm/page.h>
@ -281,6 +282,8 @@ extern unsigned long empty_zero_page[];
extern pgd_t swapper_pg_dir[];
void limit_zone_pfn(enum zone_type zone, unsigned long max_pfn);
int dma_pfn_limit_to_zone(u64 pfn_limit);
extern void paging_init(void);
/*

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@ -40,6 +40,26 @@ void *dma_direct_alloc_coherent(struct device *dev, size_t size,
#else
struct page *page;
int node = dev_to_node(dev);
u64 pfn = (dev->coherent_dma_mask >> PAGE_SHIFT) + 1;
int zone;
zone = dma_pfn_limit_to_zone(pfn);
if (zone < 0) {
dev_err(dev, "%s: No suitable zone for pfn %#llx\n",
__func__, pfn);
return NULL;
}
switch (zone) {
case ZONE_DMA:
flag |= GFP_DMA;
break;
#ifdef CONFIG_ZONE_DMA32
case ZONE_DMA32:
flag |= GFP_DMA32;
break;
#endif
};
/* ignore region specifiers */
flag &= ~(__GFP_HIGHMEM);

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@ -260,6 +260,54 @@ static int __init mark_nonram_nosave(void)
return 0;
}
static bool zone_limits_final;
static unsigned long max_zone_pfns[MAX_NR_ZONES] = {
[0 ... MAX_NR_ZONES - 1] = ~0UL
};
/*
* Restrict the specified zone and all more restrictive zones
* to be below the specified pfn. May not be called after
* paging_init().
*/
void __init limit_zone_pfn(enum zone_type zone, unsigned long pfn_limit)
{
int i;
if (WARN_ON(zone_limits_final))
return;
for (i = zone; i >= 0; i--) {
if (max_zone_pfns[i] > pfn_limit)
max_zone_pfns[i] = pfn_limit;
}
}
/*
* Find the least restrictive zone that is entirely below the
* specified pfn limit. Returns < 0 if no suitable zone is found.
*
* pfn_limit must be u64 because it can exceed 32 bits even on 32-bit
* systems -- the DMA limit can be higher than any possible real pfn.
*/
int dma_pfn_limit_to_zone(u64 pfn_limit)
{
enum zone_type top_zone = ZONE_NORMAL;
int i;
#ifdef CONFIG_HIGHMEM
top_zone = ZONE_HIGHMEM;
#endif
for (i = top_zone; i >= 0; i--) {
if (max_zone_pfns[i] <= pfn_limit)
return i;
}
return -EPERM;
}
/*
* paging_init() sets up the page tables - in fact we've already done this.
*/
@ -267,7 +315,7 @@ void __init paging_init(void)
{
unsigned long long total_ram = memblock_phys_mem_size();
phys_addr_t top_of_ram = memblock_end_of_DRAM();
unsigned long max_zone_pfns[MAX_NR_ZONES];
enum zone_type top_zone;
#ifdef CONFIG_PPC32
unsigned long v = __fix_to_virt(__end_of_fixed_addresses - 1);
@ -289,13 +337,16 @@ void __init paging_init(void)
(unsigned long long)top_of_ram, total_ram);
printk(KERN_DEBUG "Memory hole size: %ldMB\n",
(long int)((top_of_ram - total_ram) >> 20));
memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
#ifdef CONFIG_HIGHMEM
max_zone_pfns[ZONE_DMA] = lowmem_end_addr >> PAGE_SHIFT;
max_zone_pfns[ZONE_HIGHMEM] = top_of_ram >> PAGE_SHIFT;
top_zone = ZONE_HIGHMEM;
limit_zone_pfn(ZONE_NORMAL, lowmem_end_addr >> PAGE_SHIFT);
#else
max_zone_pfns[ZONE_DMA] = top_of_ram >> PAGE_SHIFT;
top_zone = ZONE_NORMAL;
#endif
limit_zone_pfn(top_zone, top_of_ram >> PAGE_SHIFT);
zone_limits_final = true;
free_area_init_nodes(max_zone_pfns);
mark_nonram_nosave();