powerpc/fsl-booke: Make CAM entries used for lowmem configurable

On booke processors, the code that maps low memory only uses up to three
CAM entries, even though there are sixteen and nothing else uses them.

Make this number configurable in the advanced options menu along with max
low memory size.  If one wants 1 GB of lowmem, then it's typically
necessary to have four CAM entries.

Signed-off-by: Trent Piepho <tpiepho@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/arch/powerpc/mm/fsl_booke_mmu.c b/arch/powerpc/mm/fsl_booke_mmu.c
index dfd292748e6e..0b9ba6be49d9 100644
--- a/arch/powerpc/mm/fsl_booke_mmu.c
+++ b/arch/powerpc/mm/fsl_booke_mmu.c
@@ -56,10 +56,14 @@
 
 extern void loadcam_entry(unsigned int index);
 unsigned int tlbcam_index;
-static unsigned long cam[3];
+static unsigned long cam[CONFIG_LOWMEM_CAM_NUM];
 
 #define NUM_TLBCAMS     (16)
 
+#if defined(CONFIG_LOWMEM_CAM_NUM_BOOL) && (CONFIG_LOWMEM_CAM_NUM >= NUM_TLBCAMS)
+#error "LOWMEM_CAM_NUM must be less than NUM_TLBCAMS"
+#endif
+
 struct tlbcam TLBCAM[NUM_TLBCAMS];
 
 struct tlbcamrange {