diff options
Diffstat (limited to 'arch/powerpc/kernel/setup-common.c')
| -rw-r--r-- | arch/powerpc/kernel/setup-common.c | 41 |
1 files changed, 41 insertions, 0 deletions
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 */ |