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Commit f9692b95 authored by Haavard Skinnemoen's avatar Haavard Skinnemoen
Browse files

[AVR32] Reserve framebuffer memory in early_parse_fbmem() 



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: default avatarHaavard Skinnemoen <hskinnemoen@atmel.com>
parent d8011768

arch/avr32/kernel/setup.c

+61 −7
Original line number Diff line number Diff line
@@ -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);