Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754582AbbKWObW (ORCPT ); Mon, 23 Nov 2015 09:31:22 -0500 Received: from foss.arm.com ([217.140.101.70]:56138 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754797AbbKWO27 (ORCPT ); Mon, 23 Nov 2015 09:28:59 -0500 From: Juri Lelli To: linux-kernel@vger.kernel.org Cc: linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, peterz@infradead.org, vincent.guittot@linaro.org, robh+dt@kernel.org, mark.rutland@arm.com, linux@arm.linux.org.uk, sudeep.holla@arm.com, lorenzo.pieralisi@arm.com, catalin.marinas@arm.com, will.deacon@arm.com, morten.rasmussen@arm.com, dietmar.eggemann@arm.com, juri.lelli@arm.com Subject: [RFC PATCH 3/8] arm: parse cpu capacity from DT Date: Mon, 23 Nov 2015 14:28:36 +0000 Message-Id: <1448288921-30307-4-git-send-email-juri.lelli@arm.com> X-Mailer: git-send-email 2.2.2 In-Reply-To: <1448288921-30307-1-git-send-email-juri.lelli@arm.com> References: <1448288921-30307-1-git-send-email-juri.lelli@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2994 Lines: 101 With the introduction of cpu capacity bindings, CPU capacities can now be extracted from DT. Add parsing of such information at boot time. We keep code that can produce same information, based on different DT properties and hard-coded values, as fall-back for backward compatibility. Cc: Russell King Signed-off-by: Juri Lelli --- arch/arm/kernel/topology.c | 50 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 49 insertions(+), 1 deletion(-) diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c index ec279d1..ecbff03 100644 --- a/arch/arm/kernel/topology.c +++ b/arch/arm/kernel/topology.c @@ -78,6 +78,35 @@ static unsigned long *__cpu_capacity; #define cpu_capacity(cpu) __cpu_capacity[cpu] static unsigned long middle_capacity = 1; +static bool capacity_from_dt = true; +static u32 capacity_scale = SCHED_CAPACITY_SCALE; + +static int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu) +{ + int ret = 1; + u32 cpu_capacity; + + ret = of_property_read_u32(cpu_node, + "capacity", + &cpu_capacity); + if (!ret) { + u64 capacity; + + /* + * Enforce capacity <= capacity-scale. + */ + cpu_capacity = cpu_capacity <= capacity_scale ? cpu_capacity : + capacity_scale; + capacity = (cpu_capacity << SCHED_CAPACITY_SHIFT) / + capacity_scale; + + set_capacity_scale(cpu, capacity); + pr_info("CPU%d: DT cpu capacity %lu\n", + cpu, arch_scale_cpu_capacity(NULL, cpu)); + } + + return !ret; +} /* * Iterate all CPUs' descriptor in DT and compute the efficiency @@ -99,6 +128,18 @@ static void __init parse_dt_topology(void) __cpu_capacity = kcalloc(nr_cpu_ids, sizeof(*__cpu_capacity), GFP_NOWAIT); + cn = of_find_node_by_path("/cpus"); + if (!cn) { + pr_err("No CPU information found in DT\n"); + return; + } + + if (!of_property_read_u32(cn, "capacity-scale", &capacity_scale)) + pr_info("DT cpus capacity-scale %u\n", capacity_scale); + else + pr_debug("DT cpus capacity-scale not found: assuming %u\n", + capacity_scale); + for_each_possible_cpu(cpu) { const u32 *rate; int len; @@ -110,6 +151,13 @@ static void __init parse_dt_topology(void) continue; } + if (parse_cpu_capacity(cn, cpu)) { + of_node_put(cn); + continue; + } + + capacity_from_dt = false; + for (cpu_eff = table_efficiency; cpu_eff->compatible; cpu_eff++) if (of_device_is_compatible(cn, cpu_eff->compatible)) break; @@ -160,7 +208,7 @@ static void __init parse_dt_topology(void) */ static void update_cpu_capacity(unsigned int cpu) { - if (!cpu_capacity(cpu)) + if (!cpu_capacity(cpu) || capacity_from_dt) return; set_capacity_scale(cpu, cpu_capacity(cpu) / middle_capacity); -- 2.2.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/