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authorDale Farnsworth <dale@farnsworth.org>2007-05-12 10:57:35 +1000
committerPaul Mackerras <paulus@samba.org>2007-05-12 11:32:50 +1000
commit06cce43cf0980d0ed3581458fd23522ca2d24e42 (patch)
tree853deee52d58559515a846a8d316adba4c7ebf58
parent[POWERPC] Add Marvell mv64x60 PCI bridge support (diff)
downloadlinux-dev-06cce43cf0980d0ed3581458fd23522ca2d24e42.tar.xz
linux-dev-06cce43cf0980d0ed3581458fd23522ca2d24e42.zip
[POWERPC] Check cache coherency of kernel vs firmware
check_cache_coherency() verifies that the cache coherency setting of the kernel (CONFIG_NOT_COHERENT_CACHE) matches that left by the firmware, as indicated by coherency-off device tree property. Signed-off-by: Dale Farnsworth <dale@farnsworth.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
-rw-r--r--arch/powerpc/Kconfig3
-rw-r--r--arch/powerpc/kernel/setup-common.c41
-rw-r--r--arch/powerpc/platforms/embedded6xx/Kconfig1
3 files changed, 45 insertions, 0 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index ccc5410af996..64089b11a9ee 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -389,6 +389,9 @@ config NOT_COHERENT_CACHE
bool
depends on 4xx || 8xx || E200
default y
+
+config CONFIG_CHECK_CACHE_COHERENCY
+ bool
endmenu
source "init/Kconfig"
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 370803722e47..ed07a198f8d6 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -530,3 +530,44 @@ void __init setup_panic(void)
{
atomic_notifier_chain_register(&panic_notifier_list, &ppc_panic_block);
}
+
+#ifdef CONFIG_CHECK_CACHE_COHERENCY
+/*
+ * For platforms that have configurable cache-coherency. This function
+ * checks that the cache coherency setting of the kernel matches the setting
+ * left by the firmware, as indicated in the device tree. Since a mismatch
+ * will eventually result in DMA failures, we print * and error and call
+ * BUG() in that case.
+ */
+
+#ifdef CONFIG_NOT_COHERENT_CACHE
+#define KERNEL_COHERENCY 0
+#else
+#define KERNEL_COHERENCY 1
+#endif
+
+static int __init check_cache_coherency(void)
+{
+ struct device_node *np;
+ const void *prop;
+ int devtree_coherency;
+
+ np = of_find_node_by_path("/");
+ prop = of_get_property(np, "coherency-off", NULL);
+ of_node_put(np);
+
+ devtree_coherency = prop ? 0 : 1;
+
+ if (devtree_coherency != KERNEL_COHERENCY) {
+ printk(KERN_ERR
+ "kernel coherency:%s != device tree_coherency:%s\n",
+ KERNEL_COHERENCY ? "on" : "off",
+ devtree_coherency ? "on" : "off");
+ BUG();
+ }
+
+ return 0;
+}
+
+late_initcall(check_cache_coherency);
+#endif /* CONFIG_CHECK_CACHE_COHERENCY */
diff --git a/arch/powerpc/platforms/embedded6xx/Kconfig b/arch/powerpc/platforms/embedded6xx/Kconfig
index bafd05765a72..15a1e9a77872 100644
--- a/arch/powerpc/platforms/embedded6xx/Kconfig
+++ b/arch/powerpc/platforms/embedded6xx/Kconfig
@@ -49,6 +49,7 @@ config MPC10X_BRIDGE
config MV64X60
bool
select PPC_INDIRECT_PCI
+ select CONFIG_CHECK_CACHE_COHERENCY
config MPC10X_OPENPIC
bool