From: Andrew Bresticker <[email protected]> Do not enable the big.LITTLE switcher on systems that do not have an ARM CCI (cache-coherent interconnect) present. Since the CCI is used to maintain cache coherency between multiple clusters and peripherals, it is unlikely that a system without CCI would support big.LITTLE.
Signed-off-by: Andrew Bresticker <[email protected]> Signed-off-by: Abhilash Kesavan <[email protected]> --- arch/arm/common/bL_switcher.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c index 5774b6e..c4fec1f 100644 --- a/arch/arm/common/bL_switcher.c +++ b/arch/arm/common/bL_switcher.c @@ -33,6 +33,7 @@ #include <linux/sysfs.h> #include <linux/irqchip/arm-gic.h> #include <linux/moduleparam.h> +#include <linux/of.h> #include <asm/smp_plat.h> #include <asm/cputype.h> @@ -796,6 +797,17 @@ core_param(no_bL_switcher, no_bL_switcher, bool, 0644); static int __init bL_switcher_init(void) { int ret; + struct device_node *dn; + + /* + * We don't want to set up the bL switcher if the machine doesn't + * support bL, so use the presence of a CCI to indicate whether or + * not bL is supported on this device. + */ + dn = of_find_compatible_node(NULL, NULL, "arm,cci-400"); + if (!dn) + return 0; + of_node_put(dn); if (MAX_NR_CLUSTERS != 2) { pr_err("%s: only dual cluster systems are supported\n", __func__); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
