Commit de32400d authored by Albert Herranz's avatar Albert Herranz Committed by Grant Likely
Browse files

wii: use both mem1 and mem2 as ram 



The Nintendo Wii video game console has two discontiguous RAM regions:
- MEM1: 24MB @ 0x00000000
- MEM2: 64MB @ 0x10000000

Unfortunately, the kernel currently does not support discontiguous RAM
memory regions on 32-bit PowerPC platforms.

This patch adds a series of workarounds to allow the use of the second
memory region (MEM2) as RAM by the kernel.
Basically, a single range of memory from the beginning of MEM1 to the
end of MEM2 is reported to the kernel, and a memory reservation is
created for the hole between MEM1 and MEM2.

With this patch the system is able to use all the available RAM and not
just ~27% of it.

This will no longer be needed when proper discontig memory support
for 32-bit PowerPC is added to the kernel.

Signed-off-by: default avatarAlbert Herranz <albert_herranz@yahoo.es>
Acked-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent 02d748a9

arch/powerpc/mm/init_32.c

+4 −0
Original line number Diff line number Diff line
@@ -131,9 +131,13 @@ void __init MMU_init(void) 
	MMU_setup();



	if (lmb.memory.cnt > 1) {

#ifndef CONFIG_WII

		lmb.memory.cnt = 1;

		lmb_analyze();

		printk(KERN_WARNING "Only using first contiguous memory region");

#else

		wii_memory_fixups();

#endif

	}



	total_lowmem = total_memory = lmb_end_of_DRAM() - memstart_addr;

arch/powerpc/mm/mmu_decl.h

+9 −1
Original line number Diff line number Diff line
@@ -136,6 +136,14 @@ extern phys_addr_t total_lowmem; 
extern phys_addr_t memstart_addr;

extern phys_addr_t lowmem_end_addr;



#ifdef CONFIG_WII

extern unsigned long wii_hole_start;

extern unsigned long wii_hole_size;



extern unsigned long wii_mmu_mapin_mem2(unsigned long top);

extern void wii_memory_fixups(void);

#endif



/* ...and now those things that may be slightly different between processor

 * architectures.  -- Dan

 */
@@ -155,5 +163,5 @@ extern void adjust_total_lowmem(void); 
#elif defined(CONFIG_PPC32)

/* anything 32-bit except 4xx or 8xx */

extern void MMU_init_hw(void);

extern unsigned long mmu_mapin_ram(void);

extern unsigned long mmu_mapin_ram(unsigned long top);

#endif

arch/powerpc/mm/pgtable_32.c

+28 −4
Original line number Diff line number Diff line
@@ -283,18 +283,18 @@ int map_page(unsigned long va, phys_addr_t pa, int flags) 
}



/*

 * Map in a big chunk of physical memory starting at PAGE_OFFSET.

 * Map in a chunk of physical memory starting at start.

 */

void __init mapin_ram(void)

void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)

{

	unsigned long v, s, f;

	phys_addr_t p;

	int ktext;



	s = mmu_mapin_ram();

	s = offset;

	v = PAGE_OFFSET + s;

	p = memstart_addr + s;

	for (; s < total_lowmem; s += PAGE_SIZE) {

	for (; s < top; s += PAGE_SIZE) {

		ktext = ((char *) v >= _stext && (char *) v < etext);

		f = ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL;

		map_page(v, p, f);
@@ -307,6 +307,30 @@ void __init mapin_ram(void) 
	}

}



void __init mapin_ram(void)

{

	unsigned long s, top;



#ifndef CONFIG_WII

	top = total_lowmem;

	s = mmu_mapin_ram(top);

	__mapin_ram_chunk(s, top);

#else

	if (!wii_hole_size) {

		s = mmu_mapin_ram(total_lowmem);

		__mapin_ram_chunk(s, total_lowmem);

	} else {

		top = wii_hole_start;

		s = mmu_mapin_ram(top);

		__mapin_ram_chunk(s, top);



		top = lmb_end_of_DRAM();

		s = wii_mmu_mapin_mem2(top);

		__mapin_ram_chunk(s, top);

	}

#endif

}



/* Scan the real Linux page tables and return a PTE pointer for

 * a virtual address in a context.

 * Returns true (1) if PTE was found, zero otherwise.  The pointer to

arch/powerpc/mm/ppc_mmu_32.c

+2 −2
Original line number Diff line number Diff line
@@ -72,7 +72,7 @@ unsigned long p_mapped_by_bats(phys_addr_t pa) 
	return 0;

}



unsigned long __init mmu_mapin_ram(void)

unsigned long __init mmu_mapin_ram(unsigned long top)

{

	unsigned long tot, bl, done;

	unsigned long max_size = (256<<20);
@@ -86,7 +86,7 @@ unsigned long __init mmu_mapin_ram(void) 


	/* Make sure we don't map a block larger than the

	   smallest alignment of the physical address. */

	tot = total_lowmem;

	tot = top;

	for (bl = 128<<10; bl < max_size; bl <<= 1) {

		if (bl * 2 > tot)

			break;

arch/powerpc/platforms/embedded6xx/wii.c

+63 −0
Original line number Diff line number Diff line
@@ -20,6 +20,8 @@ 
#include <linux/seq_file.h>

#include <linux/kexec.h>

#include <linux/of_platform.h>

#include <linux/lmb.h>

#include <mm/mmu_decl.h>



#include <asm/io.h>

#include <asm/machdep.h>
@@ -52,6 +54,67 @@ 
static void __iomem *hw_ctrl;

static void __iomem *hw_gpio;



unsigned long wii_hole_start;

unsigned long wii_hole_size;





static int __init page_aligned(unsigned long x)

{

	return !(x & (PAGE_SIZE-1));

}



void __init wii_memory_fixups(void)

{

	struct lmb_property *p = lmb.memory.region;



	/*

	 * This is part of a workaround to allow the use of two

	 * discontiguous RAM ranges on the Wii, even if this is

	 * currently unsupported on 32-bit PowerPC Linux.

	 *

	 * We coealesce the two memory ranges of the Wii into a

	 * single range, then create a reservation for the "hole"

	 * between both ranges.

	 */



	BUG_ON(lmb.memory.cnt != 2);

	BUG_ON(!page_aligned(p[0].base) || !page_aligned(p[1].base));



	p[0].size = _ALIGN_DOWN(p[0].size, PAGE_SIZE);

	p[1].size = _ALIGN_DOWN(p[1].size, PAGE_SIZE);



	wii_hole_start = p[0].base + p[0].size;

	wii_hole_size = p[1].base - wii_hole_start;



	pr_info("MEM1: <%08llx %08llx>\n", p[0].base, p[0].size);

	pr_info("HOLE: <%08lx %08lx>\n", wii_hole_start, wii_hole_size);

	pr_info("MEM2: <%08llx %08llx>\n", p[1].base, p[1].size);



	p[0].size += wii_hole_size + p[1].size;



	lmb.memory.cnt = 1;

	lmb_analyze();



	/* reserve the hole */

	lmb_reserve(wii_hole_start, wii_hole_size);

}



unsigned long __init wii_mmu_mapin_mem2(unsigned long top)

{

	unsigned long delta, size, bl;

	unsigned long max_size = (256<<20);



	/* MEM2 64MB@0x10000000 */

	delta = wii_hole_start + wii_hole_size;

	size = top - delta;

	for (bl = 128<<10; bl < max_size; bl <<= 1) {

		if (bl * 2 > size)

			break;

	}

	setbat(4, PAGE_OFFSET+delta, delta, bl, PAGE_KERNEL_X);

	return delta + bl;

}



static void wii_spin(void)

{

	local_irq_disable();

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