ARM: l2c: realview: improve commentry about the L2 cache requirements

Add better commentry about the L2 cache requirements on these platforms.
Unfortunately, the auxiliary control register is not pre-set to indicate
the correct cache parameters, so we have to manually program these.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 21 insertions, 5 deletions

diff --git a/arch/arm/mach-realview/realview_eb.c b/arch/arm/mach-realview/realview_eb.c
index c85ddb2a0ad0..b575895037b8 100644
--- a/arch/arm/mach-realview/realview_eb.c
+++ b/arch/arm/mach-realview/realview_eb.c
@@ -442,8 +442,13 @@ static void __init realview_eb_init(void)
                 realview_eb11mp_fixup();
 
 #ifdef CONFIG_CACHE_L2X0
-                /* 1MB (128KB/way), 8-way associativity, evmon/parity/share enabled
-                 * Bits:  .... ...0 0111 1001 0000 .... .... .... */
+                /*
+                 * The PL220 needs to be manually configured as the hardware
+                 * doesn't report the correct sizes.
+                 * 1MB (128KB/way), 8-way associativity, event monitor and
+                 * parity enabled, ignore share bit, no force write allocate
+                 * Bits:  .... ...0 0111 1001 0000 .... .... ....
+                 */
                 l2x0_init(__io_address(REALVIEW_EB11MP_L220_BASE), 0x00790000, 0xfe000fff);
 #endif
                 platform_device_register(&pmu_device);
diff --git a/arch/arm/mach-realview/realview_pb1176.c b/arch/arm/mach-realview/realview_pb1176.c
index c5eade76461b..e3bddb5ab10f 100644
--- a/arch/arm/mach-realview/realview_pb1176.c
+++ b/arch/arm/mach-realview/realview_pb1176.c
@@ -355,7 +355,13 @@ static void __init realview_pb1176_init(void)
         int i;
 
 #ifdef CONFIG_CACHE_L2X0
-        /* 128Kb (16Kb/way) 8-way associativity. evmon/parity/share enabled. */
+        /*
+         * The PL220 needs to be manually configured as the hardware
+         * doesn't report the correct sizes.
+         * 128kB (16kB/way), 8-way associativity, event monitor and
+         * parity enabled, ignore share bit, no force write allocate
+         * Bits:  .... ...0 0111 0011 0000 .... .... ....
+         */
         l2x0_init(__io_address(REALVIEW_PB1176_L220_BASE), 0x00730000, 0xfe000fff);
 #endif
 
diff --git a/arch/arm/mach-realview/realview_pb11mp.c b/arch/arm/mach-realview/realview_pb11mp.c
index f4b0962578fe..101deaf2630b 100644
--- a/arch/arm/mach-realview/realview_pb11mp.c
+++ b/arch/arm/mach-realview/realview_pb11mp.c
@@ -337,8 +337,13 @@ static void __init realview_pb11mp_init(void)
         int i;
 
 #ifdef CONFIG_CACHE_L2X0
-        /* 1MB (128KB/way), 8-way associativity, evmon/parity/share enabled
-         * Bits:  .... ...0 0111 1001 0000 .... .... .... */
+        /*
+         * The PL220 needs to be manually configured as the hardware
+         * doesn't report the correct sizes.
+         * 1MB (128KB/way), 8-way associativity, event monitor and
+         * parity enabled, ignore share bit, no force write allocate
+         * Bits:  .... ...0 0111 1001 0000 .... .... ....
+         */
         l2x0_init(__io_address(REALVIEW_TC11MP_L220_BASE), 0x00790000, 0xfe000fff);
 #endif