From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 11 May 2007 17:57:35 -0700 From: "Mark A. Greer" To: Paul Mackerras Subject: [PATCH 10/13] powerpc: check cache coherency of kernel vs firmware Message-ID: <20070512005735.GJ3365@mag.az.mvista.com> References: <20070512004605.GA2808@mag.az.mvista.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20070512004605.GA2808@mag.az.mvista.com> Cc: linuxppc-dev List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Dale Farnsworth 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 --- arch/powerpc/Kconfig | 3 + arch/powerpc/kernel/setup-common.c | 41 +++++++++++++++++++ arch/powerpc/platforms/embedded6xx/Kconfig | 1 3 files changed, 45 insertions(+) Index: linux-2.6-powerpc-df/arch/powerpc/kernel/setup-common.c =================================================================== --- linux-2.6-powerpc-df.orig/arch/powerpc/kernel/setup-common.c +++ linux-2.6-powerpc-df/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 */ Index: linux-2.6-powerpc-df/arch/powerpc/Kconfig =================================================================== --- linux-2.6-powerpc-df.orig/arch/powerpc/Kconfig +++ linux-2.6-powerpc-df/arch/powerpc/Kconfig @@ -373,6 +373,9 @@ config NOT_COHERENT_CACHE bool depends on 4xx || 8xx || E200 default y + +config CONFIG_CHECK_CACHE_COHERENCY + bool endmenu source "init/Kconfig" Index: linux-2.6-powerpc-df/arch/powerpc/platforms/embedded6xx/Kconfig =================================================================== --- linux-2.6-powerpc-df.orig/arch/powerpc/platforms/embedded6xx/Kconfig +++ linux-2.6-powerpc-df/arch/powerpc/platforms/embedded6xx/Kconfig @@ -41,6 +41,7 @@ config MPC10X_BRIDGE config MV64X60 bool select PPC_INDIRECT_PCI + select CONFIG_CHECK_CACHE_COHERENCY config MPC10X_OPENPIC bool