[PATCH v2 20/22] wii: use both mem1 and mem2 as ram
Albert Herranz
albert_herranz at yahoo.es
Sun Dec 13 03:31:53 EST 2009
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 at yahoo.es>
Acked-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
---
RFC v2 -> v2
- add __init to page_aligned() function
Note that the patch was acked-by without the single change from
RFC v2 to v2.
arch/powerpc/mm/init_32.c | 4 ++
arch/powerpc/mm/mmu_decl.h | 10 ++++-
arch/powerpc/mm/pgtable_32.c | 32 +++++++++++++--
arch/powerpc/mm/ppc_mmu_32.c | 4 +-
arch/powerpc/platforms/embedded6xx/wii.c | 63 ++++++++++++++++++++++++++++++
5 files changed, 106 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index 9ddcfb4..703c7c2 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -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;
diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index d2e5321..9aa39fe 100644
--- a/arch/powerpc/mm/mmu_decl.h
+++ b/arch/powerpc/mm/mmu_decl.h
@@ -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
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index cb96cb2..b55bbe8 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -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
diff --git a/arch/powerpc/mm/ppc_mmu_32.c b/arch/powerpc/mm/ppc_mmu_32.c
index 2d2a87e..f11c2cd 100644
--- a/arch/powerpc/mm/ppc_mmu_32.c
+++ b/arch/powerpc/mm/ppc_mmu_32.c
@@ -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;
diff --git a/arch/powerpc/platforms/embedded6xx/wii.c b/arch/powerpc/platforms/embedded6xx/wii.c
index 1bd41cc..de0c1e3 100644
--- a/arch/powerpc/platforms/embedded6xx/wii.c
+++ b/arch/powerpc/platforms/embedded6xx/wii.c
@@ -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 at 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();
--
1.6.3.3
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