[PATCH 70/75] ARM: l2c: add warnings for stuff modifying aux_ctrl register values
Russell King
rmk+kernel at arm.linux.org.uk
Fri Mar 28 11:20:24 EDT 2014
Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
---
arch/arm/mm/cache-l2x0.c | 27 +++++++++++++++++++++++----
1 file changed, 23 insertions(+), 4 deletions(-)
diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
index dd3de310b4ea..cbf036dff6d1 100644
--- a/arch/arm/mm/cache-l2x0.c
+++ b/arch/arm/mm/cache-l2x0.c
@@ -717,7 +717,15 @@ static void __init __l2c_init(const struct l2c_init_data *data,
{
struct outer_cache_fns fns;
unsigned way_size_bits, ways;
- u32 aux;
+ u32 aux, old_aux;
+
+ /*
+ * Sanity check the aux values. aux_mask is the bits we preserve
+ * from reading the hardware register, and aux_val is the bits we
+ * set.
+ */
+ if (aux_val & aux_mask)
+ pr_alert("L2C: platform provided aux values permit register corruption.\n");
/*
* It is strange to save the register state before initialisation,
@@ -726,11 +734,14 @@ static void __init __l2c_init(const struct l2c_init_data *data,
if (data->save)
data->save(l2x0_base);
- aux = readl_relaxed(l2x0_base + L2X0_AUX_CTRL);
-
+ old_aux = aux = readl_relaxed(l2x0_base + L2X0_AUX_CTRL);
aux &= aux_mask;
aux |= aux_val;
+ if (old_aux != aux)
+ pr_warn("L2C: DT/platform modifies aux control register: 0x%08x -> 0x%08x\n",
+ old_aux, aux);
+
/* Determine the number of ways */
switch (cache_id & L2X0_CACHE_ID_PART_MASK) {
case L2X0_CACHE_ID_PART_L310:
@@ -1363,7 +1374,7 @@ int __init l2x0_of_init(u32 aux_val, u32 aux_mask)
const struct l2c_init_data *data;
struct device_node *np;
struct resource res;
- u32 cache_id;
+ u32 cache_id, old_aux;
np = of_find_matching_node(NULL, l2x0_ids);
if (!np)
@@ -1380,6 +1391,14 @@ int __init l2x0_of_init(u32 aux_val, u32 aux_mask)
data = of_match_node(l2x0_ids, np)->data;
+ old_aux = readl_relaxed(l2x0_base + L2X0_AUX_CTRL);
+ if (old_aux != ((old_aux & aux_mask) | aux_val)) {
+ pr_warn("L2C: platform modifies aux control register: 0x%08x -> 0x%08x\n",
+ old_aux, (old_aux & aux_mask) | aux_val);
+ } else if (aux_mask != ~0U && aux_val != 0) {
+ pr_alert("L2C: platform provided aux values match the hardware, so have no effect. Please remove them.\n");
+ }
+
/* All L2 caches are unified, so this property should be specified */
if (!of_property_read_bool(np, "cache-unified"))
pr_err("L2C: device tree omits to specify unified cache\n");
--
1.8.3.1
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