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

From: Haren Myneni <[email-masked]>
Date: Sun, 03 Jun 2018 21:52:08 -0700

On 06/03/2018 09:08 PM, Stewart Smith wrote:
> 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.

Correct, does not work for HW bug or NX does not support different priorities. But the current skiboot and kernel code has to be modified to support new chip revision anyway. 

How about the following change - moved the OPAL caLL to nx842_powernv_probe_vas().

static int __init vas_cfg_coproc_info(struct device_node *dn, int chip_id,
-                                       int vasid)
+                                       int vasid, int *ct)
 {
        struct vas_window *rxwin = NULL;
        struct vas_rx_win_attr rxattr;
@@ -837,6 +839,15 @@ static int __init vas_cfg_coproc_info(struct device_node *dn, int chip_id,
        coproc->vas.id = vasid;
        nx842_add_coprocs_list(coproc, chip_id);

+       /*
+        * (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.
+        */
+       *ct = pid;
+
        return 0;

 err_out:
@@ -848,7 +859,7 @@ static int __init vas_cfg_coproc_info(struct device_node *dn, int chip_id,
 static int __init nx842_powernv_probe_vas(struct device_node *pn)
 {
        struct device_node *dn;
-       int chip_id, vasid, ret = 0;
+       int chip_id, vasid, ct, ret = 0;
        int nx_fifo_found = 0;

        chip_id = of_get_ibm_chip_id(pn);
@@ -865,7 +876,7 @@ static int __init nx842_powernv_probe_vas(struct device_node *pn)

        for_each_child_of_node(pn, dn) {
                if (of_device_is_compatible(dn, "ibm,p9-nx-842")) {
-                       ret = vas_cfg_coproc_info(dn, chip_id, vasid);
+                       ret = vas_cfg_coproc_info(dn, chip_id, vasid, &ct);
                        if (ret) {
                                of_node_put(dn);
                                return ret;
@@ -879,6 +890,16 @@ static int __init nx842_powernv_probe_vas(struct device_node *pn)
                ret = -EINVAL;
        }

+       /*
+        * Initialize each NX instance for both high and normal
+        * priority FIFOs.
+        */
+       ret = opal_nx_coproc_init(chip_id, ct);
+       if (ret) {
+               pr_err("Failed to initialize NX coproc: %d\n", ret);
+               ret = opal_error_code(ret);
+       }
+
        return ret;
 }