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: Albert Herranz <albert_herranz@yahoo.es>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This commit is contained in:
Albert Herranz 2009-12-12 06:31:53 +00:00 committed by Grant Likely
parent 02d748a9ee
commit de32400dd2
5 changed files with 106 additions and 7 deletions

View File

@ -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;

View File

@ -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

View File

@ -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

View File

@ -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;

View File

@ -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();