[PATCH 2/3] ARC: cache: check cache configuration on each CPU

[Eugeniy Paltsev]

ARC kernel code assumes that all cores have same cache config
but as of today we check cache configuration only on master CPU.
Fix that and check cache configuration on each CPU.

Also while I'm at it, split cache_init_master() for two parts:
 * checks/setups related to master L1 caches
 * the rest of cache checks/setups which need to be done once
   (like IOC / SLC / dma callbacks setup)

Both of these changes are prerequisites for autodetecting cache
line size in runtime.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
---
 arch/arc/mm/cache.c | 66 +++++++++++++++++++++++++++++++++++------------------
 1 file changed, 44 insertions(+), 22 deletions(-)

diff --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c
index 4135abec3fb0..1036bd56f518 100644
--- a/arch/arc/mm/cache.c
+++ b/arch/arc/mm/cache.c
@@ -1208,27 +1208,43 @@ noinline void __init arc_ioc_setup(void)
 	__dc_enable();
 }
 
+#if IS_ENABLED(CONFIG_ARC_HAS_ICACHE) || IS_ENABLED(CONFIG_ARC_HAS_DCACHE)
+static void arc_l1_line_check(unsigned int line_len, const char *cache_name)
+{
+	if (!line_len)
+		panic("%s support enabled but non-existent cache\n",
+		      cache_name);
+
+	if (line_len != L1_CACHE_BYTES)
+		panic("%s line size [%u] != expected [%u]",
+		      cache_name, line_len, L1_CACHE_BYTES);
+}
+#endif /* IS_ENABLED(CONFIG_ARC_HAS_ICACHE) || IS_ENABLED(CONFIG_ARC_HAS_DCACHE) */
+
 /*
- * Cache related boot time checks/setups only needed on master CPU:
- *  - Geometry checks (kernel build and hardware agree: e.g. L1_CACHE_BYTES)
- *    Assume SMP only, so all cores will have same cache config. A check on
- *    one core suffices for all
- *  - IOC setup / dma callbacks only need to be done once
+ * Cache related boot time checks needed on every CPU.
  */
-void __init arc_cache_init_master(void)
+static void arc_l1_cache_check(unsigned int cpu)
 {
-	unsigned int __maybe_unused cpu = smp_processor_id();
+	if (IS_ENABLED(CONFIG_ARC_HAS_ICACHE))
+		arc_l1_line_check(cpuinfo_arc700[cpu].icache.line_len, "ICache");
+
+	if (IS_ENABLED(CONFIG_ARC_HAS_DCACHE))
+		arc_l1_line_check(cpuinfo_arc700[cpu].dcache.line_len, "DCache");
+}
 
+/*
+ * L1 Cache related boot time checks/setups needed on master CPU:
+ * This checks/setups are done in assumption that all CPU have same cache
+ * configuration (we validate this in arc_cache_check()):
+ *  - Geometry checks
+ *  - L1 cache line loop callbacks
+ */
+void __init arc_l1_cache_init_master(unsigned int cpu)
+{
 	if (IS_ENABLED(CONFIG_ARC_HAS_ICACHE)) {
 		struct cpuinfo_arc_cache *ic = &cpuinfo_arc700[cpu].icache;
 
-		if (!ic->line_len)
-			panic("cache support enabled but non-existent cache\n");
-
-		if (ic->line_len != L1_CACHE_BYTES)
-			panic("ICache line [%d] != kernel Config [%d]",
-			      ic->line_len, L1_CACHE_BYTES);
-
 		/*
 		 * In MMU v4 (HS38x) the aliasing icache config uses IVIL/PTAG
 		 * pair to provide vaddr/paddr respectively, just as in MMU v3
@@ -1242,13 +1258,6 @@ void __init arc_cache_init_master(void)
 	if (IS_ENABLED(CONFIG_ARC_HAS_DCACHE)) {
 		struct cpuinfo_arc_cache *dc = &cpuinfo_arc700[cpu].dcache;
 
-		if (!dc->line_len)
-			panic("cache support enabled but non-existent cache\n");
-
-		if (dc->line_len != L1_CACHE_BYTES)
-			panic("DCache line [%d] != kernel Config [%d]",
-			      dc->line_len, L1_CACHE_BYTES);
-
 		/* check for D-Cache aliasing on ARCompact: ARCv2 has PIPT */
 		if (is_isa_arcompact()) {
 			int handled = IS_ENABLED(CONFIG_ARC_CACHE_VIPT_ALIASING);
@@ -1271,6 +1280,14 @@ void __init arc_cache_init_master(void)
 	 */
 	BUILD_BUG_ON_MSG(L1_CACHE_BYTES > SMP_CACHE_BYTES,
 			 "SMP_CACHE_BYTES must be >= any cache line length");
+}
+
+/*
+ * Cache related boot time checks/setups needed on master CPU:
+ *  - IOC setup / SLC setup / dma callbacks only need to be done once
+ */
+void __init arc_cache_init_master(void)
+{
 	if (is_isa_arcv2() && (l2_line_sz > SMP_CACHE_BYTES))
 		panic("L2 Cache line [%d] > kernel Config [%d]\n",
 		      l2_line_sz, SMP_CACHE_BYTES);
@@ -1301,11 +1318,16 @@ void __init arc_cache_init_master(void)
 
 void __ref arc_cache_init(void)
 {
-	unsigned int __maybe_unused cpu = smp_processor_id();
+	unsigned int cpu = smp_processor_id();
 	char str[256];
 
 	pr_info("%s", arc_cache_mumbojumbo(0, str, sizeof(str)));
 
+	if (!cpu)
+		arc_l1_cache_init_master(cpu);
+
+	arc_l1_cache_check(cpu);
+
 	if (!cpu)
 		arc_cache_init_master();
 
-- 
2.14.5