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Message-ID: <54E2F4CE.2090205@linux.vnet.ibm.com>
Date: Tue, 17 Feb 2015 13:29:10 +0530
From: Preeti U Murthy <preeti@...ux.vnet.ibm.com>
To: mpe@...erman.id.au, rafael.j.wysocki@...el.com
CC: stewart@...ux.vnet.ibm.com, linuxppc-dev@...ts.ozlabs.org,
linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH V4] cpuidle/powernv: Read target_residency value of idle
states from DT if available
Hi Rafael,
Can you please pull this patch ?
Another patch based on top of this is waiting to be pulled:
[PATCH] driver/cpuidle-powernv: Avoid endianness conversions while parsing DT
Regards
Preeti U Murthy
On 02/03/2015 11:50 AM, Preeti U Murthy wrote:
> The device tree now exposes the residency values for different idle states. Read
> these values instead of calculating residency from the latency values. The values
> exposed in the DT are validated for optimal power efficiency. However to maintain
> compatibility with the older firmware code which does not expose residency
> values, use default values as a fallback mechanism. While at it, use better
> APIs to parse the powermgmt device tree node.
>
> Signed-off-by: Preeti U Murthy <preeti@...ux.vnet.ibm.com>
> Acked-by: Stewart Smith <stewart@...ux.vnet.ibm.com>
> Acked-by: Michael Ellerman <mpe@...erman.id.au>
> ---
> Changes from the previous versions: https://lkml.org/lkml/2015/2/2/12
> 1. Used better APIs
> 2. Code Cleanups
> 3. Reverted back to the V2 of this patch as suggested in the above link,
> in addition to a few cleanups and carried forward the Acks from V2
>
> drivers/cpuidle/cpuidle-powernv.c | 71 ++++++++++++++++++++++---------------
> 1 file changed, 42 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
> index 2726663..3aa27a0 100644
> --- a/drivers/cpuidle/cpuidle-powernv.c
> +++ b/drivers/cpuidle/cpuidle-powernv.c
> @@ -13,6 +13,7 @@
> #include <linux/notifier.h>
> #include <linux/clockchips.h>
> #include <linux/of.h>
> +#include <linux/slab.h>
>
> #include <asm/machdep.h>
> #include <asm/firmware.h>
> @@ -161,69 +162,81 @@ static int powernv_add_idle_states(void)
> int nr_idle_states = 1; /* Snooze */
> int dt_idle_states;
> const __be32 *idle_state_flags;
> - const __be32 *idle_state_latency;
> - u32 len_flags, flags, latency_ns;
> - int i;
> + u32 len_flags, flags;
> + u32 *latency_ns, *residency_ns;
> + int i, rc;
>
> /* Currently we have snooze statically defined */
>
> power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
> if (!power_mgt) {
> pr_warn("opal: PowerMgmt Node not found\n");
> - return nr_idle_states;
> + goto out;
> }
>
> - idle_state_flags = of_get_property(power_mgt, "ibm,cpu-idle-state-flags", &len_flags);
> + idle_state_flags = of_get_property(power_mgt,
> + "ibm,cpu-idle-state-flags", &len_flags);
> if (!idle_state_flags) {
> - pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n");
> - return nr_idle_states;
> + pr_warn("cpuidle-powernv : missing
> + ibm,cpu-idle-state-flags in DT\n");
> + goto out;
> }
>
> - 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);
> +
> + latency_ns = kzalloc(sizeof(*latency_ns) * dt_idle_states, GFP_KERNEL);
> + rc = of_property_read_u32_array(power_mgt,
> + "ibm,cpu-idle-state-latencies-ns", latency_ns, dt_idle_states);
> + if (rc) {
> + pr_warn("cpuidle-powernv: missing
> + ibm,cpu-idle-state-latencies-ns in DT\n");
> + goto out_free_latency;
> }
>
> - dt_idle_states = len_flags / sizeof(u32);
> + residency_ns = kzalloc(sizeof(*residency_ns) * dt_idle_states, GFP_KERNEL);
> + rc = of_property_read_u32_array(power_mgt,
> + "ibm,cpu-idle-state-residency-ns", residency_ns, dt_idle_states);
>
> 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++;
> - }
> -
> - if (flags & OPAL_PM_SLEEP_ENABLED ||
> + } else if (flags & OPAL_PM_SLEEP_ENABLED ||
> flags & OPAL_PM_SLEEP_ENABLED_ER1) {
> /* Add FASTSLEEP state */
> strcpy(powernv_states[nr_idle_states].name, "FastSleep");
> strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
> powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIMER_STOP;
> - 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 = 300000;
> powernv_states[nr_idle_states].enter = &fastsleep_loop;
> - nr_idle_states++;
> }
> +
> + powernv_states[nr_idle_states].exit_latency =
> + ((unsigned int)latency_ns[i]) / 1000;
> +
> + if (!rc) {
> + powernv_states[nr_idle_states].target_residency =
> + ((unsigned int)residency_ns[i]) / 1000;
> + }
> +
> + nr_idle_states++;
> }
>
> + kfree(residency_ns);
> +out_free_latency:
> + kfree(latency_ns);
> +out:
> return nr_idle_states;
> }
>
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@...ts.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
>
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