Hi Preeti,
On 04/23/2015 05:28 PM, Preeti U Murthy wrote:
> Hi Shilpa,
>
> On 04/22/2015 10:34 PM, Shilpasri G Bhat wrote:
>> OCC is an On-Chip-Controller which takes care of power and thermal
>> safety of the chip. During runtime due to power failure or
>> overtemperature the OCC may throttle the frequencies of the CPUs to
>> remain within the power budget.
>>
>> We want the cpufreq driver to be aware of such situations to be able
>> to report it to the user. We register to opal_message_notifier to
>> receive OCC messages from opal.
>>
>> powernv_cpufreq_throttle_check() reports any frequency throttling and
>> this patch will report the reason or event that caused throttling. We
>> can be throttled if OCC is reset or OCC limits Pmax due to power or
>> thermal reasons. We are also notified of unthrottling after an OCC
>> reset or if OCC restores Pmax on the chip.
>>
>> Signed-off-by: Shilpasri G Bhat <shilpa.b...@linux.vnet.ibm.com>
>> CC: "Rafael J. Wysocki" <r...@rjwysocki.net>
>> CC: Viresh Kumar <viresh.ku...@linaro.org>
>> CC: linux...@vger.kernel.org
>> ---
>> drivers/cpufreq/powernv-cpufreq.c | 70
>> ++++++++++++++++++++++++++++++++++++++-
>> 1 file changed, 69 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/cpufreq/powernv-cpufreq.c
>> b/drivers/cpufreq/powernv-cpufreq.c
>> index ebef0d8..5718765 100644
>> --- a/drivers/cpufreq/powernv-cpufreq.c
>> +++ b/drivers/cpufreq/powernv-cpufreq.c
>> @@ -32,6 +32,7 @@
>> #include <asm/firmware.h>
>> #include <asm/reg.h>
>> #include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */
>> +#include <asm/opal.h>
>>
>> #define POWERNV_MAX_PSTATES 256
>> #define PMSR_PSAFE_ENABLE (1UL << 30)
>> @@ -40,7 +41,7 @@
>> #define PMSR_LP(x) ((x >> 48) & 0xFF)
>>
>> static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
>> -static bool rebooting, throttled;
>> +static bool rebooting, throttled, occ_reset;
>>
>> /*
>> * Note: The set of pstates consists of contiguous integers, the
>> @@ -395,6 +396,72 @@ static struct notifier_block powernv_cpufreq_reboot_nb
>> = {
>> .notifier_call = powernv_cpufreq_reboot_notifier,
>> };
>>
>> +static char throttle_reason[6][50] = { "No throttling",
>> + "Power Cap",
>> + "Processor Over Temperature",
>> + "Power Supply Failure",
>> + "OverCurrent",
>> + "OCC Reset"
>> + };
>> +
>> +static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
>> + unsigned long msg_type, void *msg)
>> +{
>> + struct opal_msg *occ_msg = msg;
>> + uint64_t token;
>> + uint64_t chip_id, reason;
>> +
>> + if (msg_type != OPAL_MSG_OCC)
>> + return 0;
>> + token = be64_to_cpu(occ_msg->params[0]);
>> + switch (token) {
>> + case 0:
>> + occ_reset = true;
>> + /*
>> + * powernv_cpufreq_throttle_check() is called in
>> + * target() callback which can detect the throttle state
>> + * for governors like ondemand.
>> + * But static governors will not call target() often thus
>> + * report throttling here.
>> + */
>> + if (!throttled) {
>> + throttled = true;
>> + pr_crit("CPU Frequency is throttled\n");
>> + }
>> + pr_info("OCC in Reset\n");
>> + break;
>> + case 1:
>> + pr_info("OCC is Loaded\n");
>> + break;
>> + case 2:
>
> You may want to replace the numbers with macros. Like
> OCC_RESET,OCC_LOAD, OCC_THROTTLE for better readability.
Okay will do.
>
>> + chip_id = be64_to_cpu(occ_msg->params[1]);
>> + reason = be64_to_cpu(occ_msg->params[2]);
>> + if (occ_reset) {
>> + occ_reset = false;
>> + throttled = false;
>> + pr_info("OCC is Active\n");
>> + /* Sanity check for static governors */
>> + powernv_cpufreq_throttle_check(smp_processor_id());
>> + } else if (reason) {
>> + throttled = true;
>> + pr_info("Pmax reduced due to %s on chip %x\n",
>> + throttle_reason[reason], (int)chip_id);
>> + } else {
>> + throttled = false;
>> + pr_info("%s on chip %x\n",
>> + throttle_reason[reason], (int)chip_id);
>
> Don't you need a powernv_cpufreq_throttle_check() here? Or is it ok to
> rely on the OCC notification for unthrottle ?
Yes we need to check. Fixing this in v2.
Thanks and Regards,
Shilpa
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