From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Shreyas B. Prabhu" Subject: [PATCH 2/9] cpuidle/powernv: Populate cpuidle state details by querying the device-tree Date: Mon, 25 Aug 2014 23:31:06 +0530 Message-ID: <1408989673-14137-3-git-send-email-shreyas@linux.vnet.ibm.com> References: <1408989673-14137-1-git-send-email-shreyas@linux.vnet.ibm.com> Return-path: In-Reply-To: <1408989673-14137-1-git-send-email-shreyas@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: Preeti U Murthy , linux-pm@vger.kernel.org, "Rafael J. Wysocki" , Rob Herring , Grant Likely , devicetree@vger.kernel.org, "Shreyas B. Prabhu" List-Id: devicetree@vger.kernel.org From: Preeti U Murthy We hard code the metrics relevant for cpuidle states in the kernel today. Instead pick them up from the device tree so that they remain relevant and updated for the system that the kernel is running on. Cc: linux-pm@vger.kernel.org Cc: Rafael J. Wysocki Cc: Rob Herring Cc: Grant Likely Cc: devicetree@vger.kernel.org Signed-off-by: Preeti U. Murthy Signed-off-by: Shreyas B. Prabhu --- drivers/cpuidle/cpuidle-powernv.c | 27 ++++++++++++++++++++++----- 1 file changed, 22 insertions(+), 5 deletions(-) diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c index 23d2743..3ceff53 100644 --- a/drivers/cpuidle/cpuidle-powernv.c +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -162,7 +162,8 @@ static int powernv_add_idle_states(void) int nr_idle_states = 1; /* Snooze */ int dt_idle_states; const __be32 *idle_state_flags; - u32 len_flags, flags; + const __be32 *idle_state_latency; + u32 len_flags, flags, latency_ns; int i; /* Currently we have snooze statically defined */ @@ -178,19 +179,33 @@ static int powernv_add_idle_states(void) pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n"); return nr_idle_states; } + idle_state_latency = of_get_property(power_mgt, + "ibm,cpu-idle-state-latencies-ns", NULL); + if (!idle_state_latency) { + pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-latencies-ns\n"); + return nr_idle_states; + } dt_idle_states = len_flags / sizeof(u32); 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 best case + * target residency to be 10x exit_latency + */ + latency_ns = be32_to_cpu(idle_state_latency[i]); + if (flags & IDLE_INST_NAP) { /* 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 = CPUIDLE_FLAG_TIME_VALID; - powernv_states[nr_idle_states].exit_latency = 10; - powernv_states[nr_idle_states].target_residency = 100; + 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].enter = &nap_loop; nr_idle_states++; } @@ -201,8 +216,10 @@ static int powernv_add_idle_states(void) strcpy(powernv_states[nr_idle_states].desc, "FastSleep"); powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TIMER_STOP; - powernv_states[nr_idle_states].exit_latency = 300; - powernv_states[nr_idle_states].target_residency = 1000000; + 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].enter = &fastsleep_loop; nr_idle_states++; } -- 1.9.0