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Commit fded332b authored by Michael Schmitz's avatar Michael Schmitz Committed by Geert Uytterhoeven
Browse files

m68k/atari - stram: alloc ST-RAM pool even if kernel not in ST-RAM 



With the kernel loaded to FastRAM (TT-RAM), none of the ST-RAM
address range is mapped by init_mem, and ST-RAM is not accessible
through the normal allocation pathways as a result.

Implement ST-RAM pool allocation to be based on physical addresses
always (it already was when the kernel was loaded in ST-RAM).
Return kernel virtual addresses as per normal.

The current test for the kernel residing in ST-RAM always returns
true. Use the bootinfo memory chunk order instead - with the kernel
in FastRAM, ST-RAM (phys. 0x0) is not the first chunk.

In case the kernel is running from FastRAM, delay mapping of ST-RAM
pool until after mem_init.

Provide helper functions for those users of ST-RAM that need
to be aware of the backing physical addresses.

Kudos to Geert for his hints on getting this started.

Signed-off-by: default avatarMichael Schmitz <schmitz@debian.org>
Signed-off-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
parent c7208164

arch/m68k/atari/stram.c

+54 −17
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ static struct resource stram_pool = { 


static unsigned long pool_size = 1024*1024;



static unsigned long stram_virt_offset;



static int __init atari_stram_setup(char *arg)

{
@@ -67,14 +68,12 @@ early_param("stram_pool", atari_stram_setup); 
void __init atari_stram_init(void)

{

	int i;

	void *stram_start;



	/*

	 * determine whether kernel code resides in ST-RAM

	 * (then ST-RAM is the first memory block at virtual 0x0)

	 */

	stram_start = phys_to_virt(0);

	kernel_in_stram = (stram_start == 0);

	kernel_in_stram = (m68k_memory[0].addr == 0);



	for (i = 0; i < m68k_num_memory; ++i) {

		if (m68k_memory[i].addr == 0) {
@@ -89,24 +88,62 @@ void __init atari_stram_init(void) 


/*

 * This function is called from setup_arch() to reserve the pages needed for

 * ST-RAM management.

 * ST-RAM management, if the kernel resides in ST-RAM.

 */

void __init atari_stram_reserve_pages(void *start_mem)

{

	/*

	 * always reserve first page of ST-RAM, the first 2 KiB are

	 * supervisor-only!

	 */

	if (!kernel_in_stram)

		reserve_bootmem(0, PAGE_SIZE, BOOTMEM_DEFAULT);



	if (kernel_in_stram) {

		pr_debug("atari_stram pool: kernel in ST-RAM, using alloc_bootmem!\n");

		stram_pool.start = (resource_size_t)alloc_bootmem_low_pages(pool_size);

		stram_pool.end = stram_pool.start + pool_size - 1;

		request_resource(&iomem_resource, &stram_pool);

		stram_virt_offset = 0;

		pr_debug("atari_stram pool: size = %lu bytes, resource = %pR\n",

			pool_size, &stram_pool);

		pr_debug("atari_stram pool: stram_virt_offset = %lx\n",

			stram_virt_offset);

	}

}





/*

 * This function is called as arch initcall to reserve the pages needed for

 * ST-RAM management, if the kernel does not reside in ST-RAM.

 */

int __init atari_stram_map_pages(void)

{

	if (!kernel_in_stram) {

		/*

		 * Skip page 0, as the fhe first 2 KiB are supervisor-only!

		 */

		pr_debug("atari_stram pool: kernel not in ST-RAM, using ioremap!\n");

		stram_pool.start = PAGE_SIZE;

		stram_pool.end = stram_pool.start + pool_size - 1;

		request_resource(&iomem_resource, &stram_pool);

		stram_virt_offset = (unsigned long) ioremap(stram_pool.start,

				resource_size(&stram_pool)) - stram_pool.start;

		pr_debug("atari_stram pool: size = %lu bytes, resource = %pR\n",

			pool_size, &stram_pool);

		pr_debug("atari_stram pool: stram_virt_offset = %lx\n",

			stram_virt_offset);

	}

	return 0;

}

arch_initcall(atari_stram_map_pages);





void *atari_stram_to_virt(unsigned long phys)

{

	return (void *)(phys + stram_virt_offset);

}

EXPORT_SYMBOL(atari_stram_to_virt);





unsigned long atari_stram_to_phys(void *virt)

{

	return (unsigned long)(virt - stram_virt_offset);

}

EXPORT_SYMBOL(atari_stram_to_phys);





void *atari_stram_alloc(unsigned long size, const char *owner)
@@ -134,14 +171,14 @@ void *atari_stram_alloc(unsigned long size, const char *owner) 
	}



	pr_debug("atari_stram_alloc: returning %pR\n", res);

	return (void *)res->start;

	return atari_stram_to_virt(res->start);

}

EXPORT_SYMBOL(atari_stram_alloc);





void atari_stram_free(void *addr)

{

	unsigned long start = (unsigned long)addr;

	unsigned long start = atari_stram_to_phys(addr);

	struct resource *res;

	unsigned long size;

arch/m68k/include/asm/atari_stram.h

+2 −0
Original line number Diff line number Diff line
@@ -8,6 +8,8 @@ 
/* public interface */

void *atari_stram_alloc(unsigned long size, const char *owner);

void atari_stram_free(void *);

void *atari_stram_to_virt(unsigned long phys);

unsigned long atari_stram_to_phys(void *);



/* functions called internally by other parts of the kernel */

void atari_stram_init(void);