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author | Akinobu Mita <akinobu.mita@gmail.com> | 2014-06-04 16:06:54 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-06-04 16:53:57 -0700 |
commit | 5ea3b1b2f8ad9162684431ce6188102ca4c64b7a (patch) | |
tree | fe87b74396be16d20025673adf39ed607d7e3b92 /drivers/base | |
parent | 2bfc2862c4fe38379a2fb2cfba33fad32ccb4ff4 (diff) | |
download | linux-5ea3b1b2f8ad9162684431ce6188102ca4c64b7a.tar.gz linux-5ea3b1b2f8ad9162684431ce6188102ca4c64b7a.tar.bz2 linux-5ea3b1b2f8ad9162684431ce6188102ca4c64b7a.zip |
cma: add placement specifier for "cma=" kernel parameter
Currently, "cma=" kernel parameter is used to specify the size of CMA,
but we can't specify where it is located. We want to locate CMA below
4GB for devices only supporting 32-bit addressing on 64-bit systems
without iommu.
This enables to specify the placement of CMA by extending "cma=" kernel
parameter.
Examples:
1. locate 64MB CMA below 4GB by "cma=64M@0-4G"
2. locate 64MB CMA exact at 512MB by "cma=64M@512M"
Note that the DMA contiguous memory allocator on x86 assumes that
page_address() works for the pages to allocate. So this change requires
to limit end address of contiguous memory area upto max_pfn_mapped to
prevent from locating it on highmem area by the argument of
dma_contiguous_reserve().
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/base')
-rw-r--r-- | drivers/base/dma-contiguous.c | 42 |
1 files changed, 32 insertions, 10 deletions
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c index c34ec3364243..83969f8c5727 100644 --- a/drivers/base/dma-contiguous.c +++ b/drivers/base/dma-contiguous.c @@ -60,11 +60,22 @@ struct cma *dma_contiguous_default_area; */ static const phys_addr_t size_bytes = CMA_SIZE_MBYTES * SZ_1M; static phys_addr_t size_cmdline = -1; +static phys_addr_t base_cmdline; +static phys_addr_t limit_cmdline; static int __init early_cma(char *p) { pr_debug("%s(%s)\n", __func__, p); size_cmdline = memparse(p, &p); + if (*p != '@') + return 0; + base_cmdline = memparse(p + 1, &p); + if (*p != '-') { + limit_cmdline = base_cmdline + size_cmdline; + return 0; + } + limit_cmdline = memparse(p + 1, &p); + return 0; } early_param("cma", early_cma); @@ -108,11 +119,18 @@ static inline __maybe_unused phys_addr_t cma_early_percent_memory(void) void __init dma_contiguous_reserve(phys_addr_t limit) { phys_addr_t selected_size = 0; + phys_addr_t selected_base = 0; + phys_addr_t selected_limit = limit; + bool fixed = false; pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit); if (size_cmdline != -1) { selected_size = size_cmdline; + selected_base = base_cmdline; + selected_limit = min_not_zero(limit_cmdline, limit); + if (base_cmdline + size_cmdline == limit_cmdline) + fixed = true; } else { #ifdef CONFIG_CMA_SIZE_SEL_MBYTES selected_size = size_bytes; @@ -129,10 +147,12 @@ void __init dma_contiguous_reserve(phys_addr_t limit) pr_debug("%s: reserving %ld MiB for global area\n", __func__, (unsigned long)selected_size / SZ_1M); - dma_contiguous_reserve_area(selected_size, 0, limit, - &dma_contiguous_default_area); + dma_contiguous_reserve_area(selected_size, selected_base, + selected_limit, + &dma_contiguous_default_area, + fixed); } -}; +} static DEFINE_MUTEX(cma_mutex); @@ -189,15 +209,20 @@ core_initcall(cma_init_reserved_areas); * @base: Base address of the reserved area optional, use 0 for any * @limit: End address of the reserved memory (optional, 0 for any). * @res_cma: Pointer to store the created cma region. + * @fixed: hint about where to place the reserved area * * This function reserves memory from early allocator. It should be * called by arch specific code once the early allocator (memblock or bootmem) * has been activated and all other subsystems have already allocated/reserved * memory. This function allows to create custom reserved areas for specific * devices. + * + * If @fixed is true, reserve contiguous area at exactly @base. If false, + * reserve in range from @base to @limit. */ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base, - phys_addr_t limit, struct cma **res_cma) + phys_addr_t limit, struct cma **res_cma, + bool fixed) { struct cma *cma = &cma_areas[cma_area_count]; phys_addr_t alignment; @@ -223,18 +248,15 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base, limit &= ~(alignment - 1); /* Reserve memory */ - if (base) { + if (base && fixed) { if (memblock_is_region_reserved(base, size) || memblock_reserve(base, size) < 0) { ret = -EBUSY; goto err; } } else { - /* - * Use __memblock_alloc_base() since - * memblock_alloc_base() panic()s. - */ - phys_addr_t addr = __memblock_alloc_base(size, alignment, limit); + phys_addr_t addr = memblock_alloc_range(size, alignment, base, + limit); if (!addr) { ret = -ENOMEM; goto err; |