From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e36.co.us.ibm.com (e36.co.us.ibm.com [32.97.110.154]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id B98EA1A0627 for ; Tue, 27 Jan 2015 15:02:50 +1100 (AEDT) Received: from /spool/local by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 26 Jan 2015 21:02:48 -0700 Received: from b03cxnp08027.gho.boulder.ibm.com (b03cxnp08027.gho.boulder.ibm.com [9.17.130.19]) by d03dlp02.boulder.ibm.com (Postfix) with ESMTP id 5BC6C3E40041 for ; Mon, 26 Jan 2015 21:02:46 -0700 (MST) Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t0R42kA032768222 for ; Mon, 26 Jan 2015 21:02:46 -0700 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t0R42ju6013546 for ; Mon, 26 Jan 2015 21:02:46 -0700 Message-ID: <54C70DDD.9040408@linux.vnet.ibm.com> Date: Tue, 27 Jan 2015 09:32:37 +0530 From: Preeti U Murthy MIME-Version: 1.0 To: Michael Ellerman , rafael.j.wysocki@intel.com Subject: Re: cpuidle/powernv: Read target_residency value of idle states from DT if available References: <20150123045906.D0086140297@ozlabs.org> In-Reply-To: <20150123045906.D0086140297@ozlabs.org> Content-Type: text/plain; charset=ISO-8859-6 Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 01/23/2015 10:29 AM, Michael Ellerman wrote: > On Tue, 2015-20-01 at 11:26:49 UTC, Preeti U Murthy wrote: >> @@ -177,34 +178,39 @@ static int powernv_add_idle_states(void) >> return nr_idle_states; >> } >> >> - idle_state_latency = of_get_property(power_mgt, >> - "ibm,cpu-idle-state-latencies-ns", NULL); >> - if (!idle_state_latency) { >> + dt_idle_states = len_flags / sizeof(u32); >> + >> + latency_ns = kzalloc(sizeof(*latency_ns) * dt_idle_states, GFP_KERNEL); >> + rc = of_property_read_u32(power_mgt, >> + "ibm,cpu-idle-state-latencies-ns", latency_ns); > > That's only reading the first value. > > If you want to read the full property you need the _array version. Right, thanks for pointing this out. > >> + if (rc) { >> pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-latencies-ns\n"); > > You missed my hint that "DT-PowerMgmt" is a weird and ugly prefix. Can you use > "cpuidle-powernv:" instead? Yes will change this. > >> >> - dt_idle_states = len_flags / sizeof(u32); >> + residency_ns = kzalloc(sizeof(*residency_ns) * dt_idle_states, GFP_KERNEL); >> + rc = of_property_read_u32(power_mgt, >> + "ibm,cpu-idle-state-residency-ns", residency_ns); >> + if (rc) { >> + pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-residency-ns\n"); >> + pr_warn("Falling back to default values\n"); > > I don't think this is worth a warning seeing as we know there are firmwares out > there which do not have the property. > >> for (i = 0; i < dt_idle_states; i++) { >> >> flags = be32_to_cpu(idle_state_flags[i]); >> - >> - /* Cpuidle accepts exit_latency in us and we estimate >> - * target residency to be 10x exit_latency >> + /* >> + * Cpuidle accepts exit_latency and target_residency in us. >> + * Use default target_residency values if f/w does not expose it. >> */ >> - latency_ns = be32_to_cpu(idle_state_latency[i]); >> if (flags & OPAL_PM_NAP_ENABLED) { >> /* Add NAP state */ >> strcpy(powernv_states[nr_idle_states].name, "Nap"); >> strcpy(powernv_states[nr_idle_states].desc, "Nap"); >> powernv_states[nr_idle_states].flags = 0; >> - powernv_states[nr_idle_states].exit_latency = >> - ((unsigned int)latency_ns) / 1000; >> - powernv_states[nr_idle_states].target_residency = >> - ((unsigned int)latency_ns / 100); >> + powernv_states[nr_idle_states].target_residency = 100; >> powernv_states[nr_idle_states].enter = &nap_loop; >> - nr_idle_states++; > > That looks wrong? Or do you mean to do that? Are you pointing at removing the lines that populate the exit_latency ? I read the latency value from the DT outside of these conditions because it is guaranteed to be present at this point. We return back from this function early on if we do not find it in the DT. If you are pointing at the lines that remove increment of nr_idle_states, it has to be done so towards the end of the iteration because we are yet to populate the exit_latency and target_residency outside of these conditions using this index. Regards Preeti U Murthy > > cheers >