Add "nol2x0" early param to avoid initialisation of the L2 controller

Some development platforms may have issues with this controller, so
allow easy disabling from the kernel command line. The patch also adds
a check for l2x0_disabled in the realview_pbx.c code to avoid setting
additional L2x0 registers.

Change-Id: Icbbd3e054688811200a4c96bf7e0a81c9c0ab790
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm/include/asm/hardware/cache-l2x0.h b/arch/arm/include/asm/hardware/cache-l2x0.h
index 89e2ff8a3585c5c999737acb5112d15bb555083d..787c06ada55515acc298447427f103b7c9a7693d 100644 (file)
--- a/arch/arm/include/asm/hardware/cache-l2x0.h
+++ b/arch/arm/include/asm/hardware/cache-l2x0.h
@@ -59,6 +59,7 @@
 extern void __init l2x0_init(void __iomem *base, __u32 aux_val, __u32 aux_mask);
 extern void l2x0_shutdown(void);
 extern void l2x0_restart(void);
+extern bool l2x0_disabled;
 #endif
 
 #endif

diff --git a/arch/arm/mach-realview/realview_pbx.c b/arch/arm/mach-realview/realview_pbx.c
index 9428eff0b116addda238d99d492cbe9d80c6b8a5..af13eb6e553c1ef8085977b69f4820317b4cf6d1 100644 (file)
--- a/arch/arm/mach-realview/realview_pbx.c
+++ b/arch/arm/mach-realview/realview_pbx.c
@@ -382,7 +382,7 @@ static void __init realview_pbx_init(void)
        int i;
 
 #ifdef CONFIG_CACHE_L2X0
-       if (core_tile_pbxa9mp()) {
+       if (!l2x0_disabled && core_tile_pbxa9mp()) {
                void __iomem *l2x0_base =
                        __io_address(REALVIEW_PBX_TILE_L220_BASE);
 

diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
index 9eb79d84b4602983371d7c7f06a551a16fb10a84..9abfa5d2b750654faf823ae6e74c12dec6396f45 100644 (file)
--- a/arch/arm/mm/cache-l2x0.c
+++ b/arch/arm/mm/cache-l2x0.c
@@ -27,6 +27,7 @@
 
 static void __iomem *l2x0_base;
 static uint32_t l2x0_way_mask; /* Bitmask of active ways */
+bool l2x0_disabled;
 
 static inline void cache_wait_always(void __iomem *reg, unsigned long mask)
 {
@@ -249,6 +250,9 @@ void l2x0_shutdown(void)
 {
        unsigned long flags;
 
+       if (l2x0_disabled)
+               return;
+
        BUG_ON(num_online_cpus() > 1);
 
        local_irq_save(flags);
@@ -282,6 +286,9 @@ static void l2x0_enable(__u32 aux_val, __u32 aux_mask)
        int ways;
        const char *type;
 
+       if (l2x0_disabled)
+               return;
+
        cache_id = readl_relaxed(l2x0_base + L2X0_CACHE_ID);
        aux = readl_relaxed(l2x0_base + L2X0_AUX_CTRL);
 
@@ -338,6 +345,11 @@ void l2x0_restart(void)
 
 void __init l2x0_init(void __iomem *base, __u32 aux_val, __u32 aux_mask)
 {
+       if (l2x0_disabled) {
+               pr_info(L2CC_TYPE " cache controller disabled\n");
+               return;
+       }
+
        l2x0_base = base;
 
        l2x0_enable(aux_val, aux_mask);
@@ -347,3 +359,10 @@ void __init l2x0_init(void __iomem *base, __u32 aux_val, __u32 aux_mask)
        outer_cache.flush_range = l2x0_flush_range;
        outer_cache.sync = l2x0_cache_sync;
 }
+
+static int __init l2x0_disable(char *unused)
+{
+       l2x0_disabled = 1;
+       return 0;
+}
+early_param("nol2x0", l2x0_disable);