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[AVR32] Reserve framebuffer memory in early_parse_fbmem()

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With the current strategy of using the bootmem allocator to allocate
or reserve framebuffer memory, there's a slight chance that the
requested area has been taken by the boot allocator bitmap before we
get around to reserving it.

By inserting the framebuffer region as a reserved region as early as
possible, we improve our chances for success and we make the region
visible as a reserved region in dmesg and /proc/iomem without any
extra work.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
This commit is contained in:
Haavard Skinnemoen 2007-03-21 16:16:50 +01:00
parent d8011768e6
commit f9692b9501
1 changed files with 61 additions and 7 deletions
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68
arch/avr32/kernel/setup.c
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@ -191,21 +191,45 @@ find_free_region(const struct resource *mem, resource_size_t size,
return target;
}
static int __init
alloc_reserved_region(resource_size_t *start, resource_size_t size,
resource_size_t align, const char *name)
{
struct resource *mem;
resource_size_t target;
int ret;
for (mem = system_ram; mem; mem = mem->sibling) {
target = find_free_region(mem, size, align);
if (target <= mem->end) {
ret = add_reserved_region(target, target + size - 1,
name);
if (!ret)
*start = target;
return ret;
}
}
return -ENOMEM;
}
/*
* Early framebuffer allocation. Works as follows:
* - If fbmem_size is zero, nothing will be allocated or reserved.
* - If fbmem_start is zero when setup_bootmem() is called,
* fbmem_size bytes will be allocated from the bootmem allocator.
* a block of fbmem_size bytes will be reserved before bootmem
* initialization. It will be aligned to the largest page size
* that fbmem_size is a multiple of.
* - If fbmem_start is nonzero, an area of size fbmem_size will be
* reserved at the physical address fbmem_start if necessary. If
* the area isn't in a memory region known to the kernel, it will
* be left alone.
* reserved at the physical address fbmem_start if possible. If
* it collides with other reserved memory, a different block of
* same size will be allocated, just as if fbmem_start was zero.
*
* Board-specific code may use these variables to set up platform data
* for the framebuffer driver if fbmem_size is nonzero.
*/
static unsigned long __initdata fbmem_start;
static unsigned long __initdata fbmem_size;
static resource_size_t __initdata fbmem_start;
static resource_size_t __initdata fbmem_size;
/*
* "fbmem=xxx[kKmM]" allocates the specified amount of boot memory for
@ -219,9 +243,39 @@ static unsigned long __initdata fbmem_size;
*/
static int __init early_parse_fbmem(char *p)
{
int ret;
unsigned long align;
fbmem_size = memparse(p, &p);
if (*p == '@')
if (*p == '@') {
fbmem_start = memparse(p, &p);
ret = add_reserved_region(fbmem_start,
fbmem_start + fbmem_size - 1,
"Framebuffer");
if (ret) {
printk(KERN_WARNING
"Failed to reserve framebuffer memory\n");
fbmem_start = 0;
}
}
if (!fbmem_start) {
if ((fbmem_size & 0x000fffffUL) == 0)
align = 0x100000; /* 1 MiB */
else if ((fbmem_size & 0x0000ffffUL) == 0)
align = 0x10000; /* 64 KiB */
else
align = 0x1000; /* 4 KiB */
ret = alloc_reserved_region(&fbmem_start, fbmem_size,
align, "Framebuffer");
if (ret) {
printk(KERN_WARNING
"Failed to allocate framebuffer memory\n");
fbmem_size = 0;
}
}
return 0;
}
early_param("fbmem", early_parse_fbmem);