Subject: Re: [PATCH] crypto/nx: Initialize 842 high and normal RxFIFO control registers

From: Stewart Smith <[email-masked]>
Date: Mon, 04 Jun 2018 14:08:46 +1000

Haren Myneni <[email-masked]> writes:
> On 06/03/2018 05:41 PM, Stewart Smith wrote:
>> Haren Myneni <[email-masked]> writes:
>>> On 06/01/2018 12:41 AM, Stewart Smith wrote:
>>>> Haren Myneni <[email-masked]> writes:
>>>>> NX increments readOffset by FIFO size in receive FIFO control register
>>>>> when CRB is read. But the index in RxFIFO has to match with the
>>>>> corresponding entry in FIFO maintained by VAS in kernel. Otherwise NX
>>>>> may be processing incorrect CRBs and can cause CRB timeout.
>>>>>
>>>>> VAS FIFO offset is 0 when the receive window is opened during
>>>>> initialization. When the module is reloaded or in kexec boot, readOffset
>>>>> in FIFO control register may not match with VAS entry. This patch adds
>>>>> nx_coproc_init OPAL call to reset readOffset and queued entries in FIFO
>>>>> control register for both high and normal FIFOs.
>>>>>
>>>>> Signed-off-by: Haren Myneni <[email-masked]>
>>>>>
>>>>> diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
>>>>> index d886a5b..ff61e4b 100644
>>>>> --- a/arch/powerpc/include/asm/opal-api.h
>>>>> +++ b/arch/powerpc/include/asm/opal-api.h
>>>>> @@ -206,7 +206,8 @@
>>>>>  #define OPAL_NPU_TL_SET				161
>>>>>  #define OPAL_PCI_GET_PBCQ_TUNNEL_BAR		164
>>>>>  #define OPAL_PCI_SET_PBCQ_TUNNEL_BAR		165
>>>>> -#define OPAL_LAST				165
>>>>> +#define	OPAL_NX_COPROC_INIT			167
>>>>> +#define OPAL_LAST				167
>>>>>  
>>>>>  /* Device tree flags */
>>>>>  
>>>>> diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
>>>>> index 7159e1a..d79eb82 100644
>>>>> --- a/arch/powerpc/include/asm/opal.h
>>>>> +++ b/arch/powerpc/include/asm/opal.h
>>>>> @@ -288,6 +288,7 @@ int64_t opal_imc_counters_init(uint32_t type, uint64_t address,
>>>>>  int opal_get_power_shift_ratio(u32 handle, int token, u32 *psr);
>>>>>  int opal_set_power_shift_ratio(u32 handle, int token, u32 psr);
>>>>>  int opal_sensor_group_clear(u32 group_hndl, int token);
>>>>> +int opal_nx_coproc_init(uint32_t chip_id, uint32_t ct);
>>>>>  
>>>>>  s64 opal_signal_system_reset(s32 cpu);
>>>>>  
>>>>> diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
>>>>> index 3da30c2..c7541a9 100644
>>>>> --- a/arch/powerpc/platforms/powernv/opal-wrappers.S
>>>>> +++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
>>>>> @@ -325,3 +325,4 @@ OPAL_CALL(opal_npu_spa_clear_cache,		OPAL_NPU_SPA_CLEAR_CACHE);
>>>>>  OPAL_CALL(opal_npu_tl_set,			OPAL_NPU_TL_SET);
>>>>>  OPAL_CALL(opal_pci_get_pbcq_tunnel_bar,		OPAL_PCI_GET_PBCQ_TUNNEL_BAR);
>>>>>  OPAL_CALL(opal_pci_set_pbcq_tunnel_bar,		OPAL_PCI_SET_PBCQ_TUNNEL_BAR);
>>>>> +OPAL_CALL(opal_nx_coproc_init,			OPAL_NX_COPROC_INIT);
>>>>> diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
>>>>> index 48fbb41..5e13908 100644
>>>>> --- a/arch/powerpc/platforms/powernv/opal.c
>>>>> +++ b/arch/powerpc/platforms/powernv/opal.c
>>>>> @@ -1035,3 +1035,5 @@ void powernv_set_nmmu_ptcr(unsigned long ptcr)
>>>>>  EXPORT_SYMBOL_GPL(opal_int_set_mfrr);
>>>>>  EXPORT_SYMBOL_GPL(opal_int_eoi);
>>>>>  EXPORT_SYMBOL_GPL(opal_error_code);
>>>>> +/* Export the below symbol for NX compression */
>>>>> +EXPORT_SYMBOL(opal_nx_coproc_init);
>>>>> diff --git a/drivers/crypto/nx/nx-842-powernv.c b/drivers/crypto/nx/nx-842-powernv.c
>>>>> index 1e87637..6c4784d 100644
>>>>> --- a/drivers/crypto/nx/nx-842-powernv.c
>>>>> +++ b/drivers/crypto/nx/nx-842-powernv.c
>>>>> @@ -24,6 +24,8 @@
>>>>>  #include <asm/icswx.h>
>>>>>  #include <asm/vas.h>
>>>>>  #include <asm/reg.h>
>>>>> +#include <asm/opal-api.h>
>>>>> +#include <asm/opal.h>
>>>>>  
>>>>>  MODULE_LICENSE("GPL");
>>>>>  MODULE_AUTHOR("Dan Streetman <[email-masked]>");
>>>>> @@ -803,9 +805,26 @@ static int __init vas_cfg_coproc_info(struct device_node *dn, int chip_id,
>>>>>  	if (!coproc)
>>>>>  		return -ENOMEM;
>>>>>  
>>>>> -	if (!strcmp(priority, "High"))
>>>>> +	if (!strcmp(priority, "High")) {
>>>>> +		/*
>>>>> +		 * (lpid, pid, tid) combination has to be unique for each
>>>>> +		 * coprocessor instance in the system. So to make it
>>>>> +		 * unique, skiboot uses coprocessor type such as 842 or
>>>>> +		 * GZIP for pid and provides this value to kernel in pid
>>>>> +		 * device-tree property.
>>>>> +		 *
>>>>> +		 * Initialize each NX instance for both high and normal
>>>>> +		 * priority FIFOs.
>>>>> +		 */
>>>>> +		ret = opal_nx_coproc_init(chip_id, pid);
>>>>> +		if (ret) {
>>>>> +			pr_err("Failed to initialize NX coproc: %d\n", ret);
>>>>> +			ret = opal_error_code(ret);
>>>>> +			goto err_out;
>>>>> +		}
>>>>> +
>>>>>  		coproc->ct = VAS_COP_TYPE_842_HIPRI;
>>>>
>>>> I think this should be called for all priority queues as it would be at
>>>> least theoretically possible to only have Normal priority queues, in
>>>> which case this patch wouldn't fix the problem.
>>>
>>> device tree exports separate nodes for high and normal priority FIFOs
>>> per each NX instance. But NX init OPAL function is called once per
>>> each NX instance when high-FIFO device node is parsed to reset high
>>> and normal FIFO control registers. As you see in skiboot patch, resets
>>> both priority registers. Thought we should minimize the number of OPAL
>>> calla execution and also should have generic NX init OPAL call. We can
>>> extend this call to reset default values for any other registers if
>>> needed.
>> 
>> This code does'nt do that though, it calls it for "high" priority, so if
>> for whatever reason there was a DT without a "High" priority node there,
>> it'd not call it.
>
> Skiboot exports high and normal FIFO nodes for each coprocessor type
> per NX instance. We will never see only normal FIFO node without high
> FIFO node. As we see in skiboot code, configure high FIFO and export
> this node first, and then normal FIFO. In case if xscom read/ write
> for high FIFO failed, we do not proceed for normal FIFO.

Currently that's true, yes. But in the future it may not be. Imagine if
we found a hardware bug that would mean disabling the 'High' priority
one, or a future chip revision just had a single priority.

-- 
Stewart Smith
OPAL Architect, IBM.