[Skiboot] [PATCH v2] occ: Poll OCC throttle status and queue OCC events to host

[Shilpasri G Bhat]

On 05/12/2015 11:01 AM, Stewart Smith wrote:
> Shilpasri G Bhat <shilpa.bhat at linux.vnet.ibm.com> writes:
>> Add a new class of message definition OPAL_MSG_OCC to
>> opal_message_type to notify the following OCC events to host:
>> 1) OCC Reset
>> 2) OCC Load
>> 3) OCC Throttle Status Change
>>
>> Add an opal poller to periodically read throttle status updated by OCC
>> for each chip and notify any change in throttle status to host. The
>> throttle status indicates the reason why OCC may have limited the max
>> Pstate of the chip.
> 
> Major comment is that you need to add something to
> doc/opal-api/opal-messages.txt
> 
> Also include a description on how we may deal with future expansion
> (e.g. chip_id and throttle_status only valid for params[0] = 0,1,2 and
> if params is > 2 then rest of params is something defined in future OPAL
> version and host should just ignore the message)
> 

Okay will do

> Do we *really* have to poll? That kind of sucks if so (and how do we get
> that fixed?)

Currently polling seemed to be quick solution to periodically check throttle
status updated by OCC in shared opal-occ area.

> 
>> diff --git a/hw/occ.c b/hw/occ.c
>> index 34d6de5..d346394 100644
>> --- a/hw/occ.c
>> +++ b/hw/occ.c
>> @@ -24,6 +24,8 @@
>>  #include <timebase.h>
>>  #include <hostservices.h>
>>  #include <errorlog.h>
>> +#include <opal-api.h>
>> +#include <opal-msg.h>
>>  
>>  /* OCC Communication Area for PStates */
>>  
>> @@ -31,6 +33,16 @@
>>  
>>  #define MAX_PSTATES 256
>>  
>> +#define OCC_RESET	0
>> +#define OCC_LOAD	1
>> +#define OCC_THROTTLE	2
> 
> Part of ABI? Please add to opal-api.h and doc/
> 
>> +
>> +#define chip_occ_data(chip) \
>> +		((struct occ_pstate_table *)(chip->homer_base + \
>> +				P8_HOMER_SAPPHIRE_DATA_OFFSET))
>> +
>> +static bool occ_reset;
>> +
>>  struct occ_pstate_entry {
>>  	s8 id;
>>  	u8 flags;
>> @@ -302,6 +314,61 @@ static bool cpu_pstates_prepare_core(struct proc_chip *chip, struct cpu_thread *
>>  	return true;
>>  }
>>  
>> +/* occ_throttle_poll: This function will queue a meassage of type
>> + * OPAL_MSG_OCC to notify any change in the throttle status of the
>> + * chip. Throttle status indicates the reason why OCC may have limited
>> + * the max Pstate of the chip.
>> + * 0x00 = No throttle
>> + * 0x01 = Power Cap
>> + * 0x02 = Processor Over Temperature
>> + * 0x03 = Power Supply Failure (currently not used)
>> + * 0x04 = Over current (currently not used)
>> + * 0x05 = OCC Reset (not reliable as some failures will not allow for
>> + * OCC to update throttle status, so use 'occ_reset')
> 
> Looks like these are part of ABI - please add to opal-api.h and document.
> 
>> + */
>> +static void occ_throttle_poll(void *data __unused)
>> +{
>> +	struct proc_chip *chip;
>> +	struct occ_pstate_table *occ_data;
>> +	int rc;
>> +
>> +	if (occ_reset) {
>> +		int inactive = 0;
>> +
>> +		for_each_chip(chip) {
>> +			occ_data = chip_occ_data(chip);
>> +			if (occ_data->valid != 1) {
>> +				inactive = 1;
>> +				break;
>> +			}
>> +		}
>> +		if (!inactive) {
>> +			/*
>> +			 * Queue OCC_THROTTLE with throttle status as 0 to
>> +			 * indicate all OCCs are active after a reset.
>> +			 */
>> +			rc = opal_queue_msg(OPAL_MSG_OCC, NULL, NULL,
>> +						OCC_THROTTLE, 0, 0);
>> +			if (!rc)
>> +				occ_reset = false;
>> +		}
>> +	} else {
>> +		for_each_chip(chip) {
>> +			occ_data = chip_occ_data(chip);
>> +			if ((occ_data->valid == 1) &&
>> +			    (chip->prev_throttle != occ_data->throttle) &&
>> +			    (occ_data->throttle <= 5)) {
>> +				rc = opal_queue_msg(OPAL_MSG_OCC, NULL, NULL,
>> +						OCC_THROTTLE, chip->id,
>> +						occ_data->throttle);
>> +				if (!rc)
>> +					chip->prev_throttle =
>> +						occ_data->throttle;
>> +			}
>> +		}
>> +	}
>> +}
>> +
>>  /* CPU-OCC PState init */
>>  /* Called after OCC init on P8 */
>>  void occ_pstates_init(void)
>> @@ -345,6 +412,11 @@ void occ_pstates_init(void)
>>  			cpu_pstates_prepare_core(chip, c, pstate_nom);
>>  		}
>>  	}
>> +
>> +	/* Add opal_poller to poll OCC throttle status of each chip */
>> +	for_each_chip(chip)
>> +		chip->prev_throttle = 0;
>> +	opal_add_poller(occ_throttle_poll, NULL);
>>  }
>>  
>>  struct occ_load_req {
>> @@ -386,6 +458,11 @@ static void __occ_do_load(u8 scope, u32 dbob_id __unused, u32 seq_id)
>>  		prlog(PR_INFO, "OCC: Load: Fallback to preloaded image\n");
>>  		rc = 0;
>>  	} else if (!rc) {
>> +		rc = opal_queue_msg(OPAL_MSG_OCC, NULL, NULL, OCC_LOAD);
>> +		if (rc)
>> +			prlog(PR_INFO, "OCC: Failed to queue message %d\n",
>> +						OCC_LOAD);
>> +
>>  		/* Success, start OCC */
>>  		rc = host_services_occ_start();
>>  	}
>> @@ -509,6 +586,24 @@ static void occ_do_reset(u8 scope, u32 dbob_id, u32 seq_id)
>>  		rc = 0;
>>  	}
>>  	if (!rc) {
>> +		rc = opal_queue_msg(OPAL_MSG_OCC, NULL, NULL, OCC_RESET);
>> +		if (rc)
>> +			prlog(PR_INFO, "OCC: Failed to queue message %d\n",
>> +						OCC_RESET);
>> +		/*
>> +		 * Set 'valid' byte of chip_occ_data to 0 since OCC
>> +		 * may not clear this byte on a reset.
>> +		 * OCC will set the 'valid' byte to 1 when it becomes
>> +		 * active again.
>> +		 */
>> +		for_each_chip(chip) {
>> +			struct occ_pstate_table *occ_data;
>> +
>> +			occ_data = chip_occ_data(chip);
>> +			occ_data->valid = 0;
>> +			chip->prev_throttle = 0;
>> +		}
>> +		occ_reset = true;
>>  		/* Send a single success response for all chips */
>>  		stat = fsp_mkmsg(FSP_CMD_RESET_OCC_STAT, 2, 0, seq_id);
>>  		if (stat)
>> diff --git a/include/chip.h b/include/chip.h
>> index 0547902..340fdfc 100644
>> --- a/include/chip.h
>> +++ b/include/chip.h
>> @@ -147,6 +147,7 @@ struct proc_chip {
>>  	uint64_t		homer_size;
>>  	uint64_t		occ_common_base;
>>  	uint64_t		occ_common_size;
>> +	u8			prev_throttle;
>>  
>>  	/* Must hold capi_lock to change */
>>  	u8			capp_phb3_attached_mask;
>> diff --git a/include/opal-api.h b/include/opal-api.h
>> index 1698311..abe798e 100644
>> --- a/include/opal-api.h
>> +++ b/include/opal-api.h
>> @@ -417,6 +417,13 @@ enum opal_msg_type {
>>  	OPAL_MSG_HMI_EVT,
>>  	OPAL_MSG_DPO,
>>  	OPAL_MSG_PRD,
>> +	OPAL_MSG_OCC,			/*
>> +					 * params[0] =	0 reset,
>> +					 *		1 load,
>> +					 *		2 throttle
>> +					 * params[1] = chip_id,
>> +					 * params[2] = throttle_status
>> +					 */
> 
> Perhaps define this in a struct/union somewhere too?
> 

Agree on all the above comments. Will move/add to opal-api/doc appropriately.

Thanks and Regards,
Shilpa