Date:   Tue, 23 Oct 2018 14:12:44 -0500
From:   Suman Anna <s-anna@...com>
To:     Loic PALLARDY <loic.pallardy@...com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>
CC:     "ohad@...ery.com" <ohad@...ery.com>,
        "linux-remoteproc@...r.kernel.org" <linux-remoteproc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Arnaud POULIQUEN <arnaud.pouliquen@...com>,
        "benjamin.gaignard@...aro.org" <benjamin.gaignard@...aro.org>
Subject: Re: [PATCH v2 05/16] remoteproc: modify rproc_handle_carveout to
 support preallocated region

On 10/23/18 2:09 PM, Loic PALLARDY wrote:
> 
> 
>> -----Original Message-----
>> From: Suman Anna <s-anna@...com>
>> Sent: mardi 23 octobre 2018 19:40
>> To: Loic PALLARDY <loic.pallardy@...com>; Bjorn Andersson
>> <bjorn.andersson@...aro.org>
>> Cc: ohad@...ery.com; linux-remoteproc@...r.kernel.org; linux-
>> kernel@...r.kernel.org; Arnaud POULIQUEN <arnaud.pouliquen@...com>;
>> benjamin.gaignard@...aro.org
>> Subject: Re: [PATCH v2 05/16] remoteproc: modify rproc_handle_carveout to
>> support preallocated region
>>
>>>>
>>>> On Thu 30 Nov 08:46 PST 2017, Loic Pallardy wrote:
>>>>
>>>>> In current version rproc_handle_carveout function support only dynamic
>>>>> region allocation.
>>>>> This patch extends rproc_handle_carveout function to support different
>>>> carveout
>>>>> configurations:
>>>>> - fixed DA and fixed PA: check if already part of pre-registered carveouts
>>>>> (platform driver). If no, return error.
>>>>> - fixed DA and any PA: check if already part of pre-allocated carveouts
>>>>> (platform driver). If not found and rproc supports iommu, continue with
>>>>> dynamic allocation (DA will be used for iommu programming), else
>> return
>>>>> error as no way to force DA.
>>>>> - any DA and any PA: use original dynamic allocation
>>>>>
>>>>> Signed-off-by: Loic Pallardy <loic.pallardy@...com>
>>>>> ---
>>>>>  drivers/remoteproc/remoteproc_core.c | 40
>>>> ++++++++++++++++++++++++++++++++++++
>>>>>  1 file changed, 40 insertions(+)
>>>>>
>>>>> diff --git a/drivers/remoteproc/remoteproc_core.c
>>>> b/drivers/remoteproc/remoteproc_core.c
>>>>> index 78525d1..515a17a 100644
>>>>> --- a/drivers/remoteproc/remoteproc_core.c
>>>>> +++ b/drivers/remoteproc/remoteproc_core.c
>>>>> @@ -184,6 +184,10 @@ void *rproc_da_to_va(struct rproc *rproc, u64
>> da,
>>>> int len)
>>>>>  	struct rproc_mem_entry *carveout;
>>>>>  	void *ptr = NULL;
>>>>>
>>>>> +	/*
>>>>> +	 * da_to_va platform driver is deprecated. Driver should register
>>>>> +	 * carveout thanks to rproc_add_carveout function
>>>>> +	 */
>>>>
>>>> I think this comment is unrelated to the rest of this patch. I also
>>>> think that at the end of the carveout-rework we should have a patch
>>>> removing this ops.
>>>
>>> I'll remove this comment and add a da_to_va clean-up patch at the end of
>> the series
>>
>> da_to_va platform ops is actually used to provide the remoteproc
>> internal memory translations for the most part, not restricted just to
>> fixed carveouts. Also, typically these do have multiple address-views -
>> one the regular bus-address view, and another a remote processor address
>> view.
> 
> da_to_va op sis still there. I was proposing to remove this ops as we were discussing to register all carveouts accessed by coprocessor in rproc core carveout list.
> This will allow to centralize all carveout definitions and to see all memory resources viewed by coprocessor (va, pa and da) via debugfs...

Yes, understood. I was commenting only on the future removal part, and
if it is really judicious to do that.

regards
Suman

> 
> Regards,
> Loic
>>
>> regards
>> Suman
>>
>>>
>>>>
>>>>>  	if (rproc->ops->da_to_va) {
>>>>>  		ptr = rproc->ops->da_to_va(rproc, da, len);
>>>>>  		if (ptr)
>>>>> @@ -677,6 +681,7 @@ static int rproc_handle_carveout(struct rproc
>>>> *rproc,
>>>>>  	struct rproc_mem_entry *carveout, *mapping;
>>>>>  	struct device *dev = &rproc->dev;
>>>>>  	dma_addr_t dma;
>>>>> +	phys_addr_t pa;
>>>>>  	void *va;
>>>>>  	int ret;
>>>>>
>>>>> @@ -698,6 +703,41 @@ static int rproc_handle_carveout(struct rproc
>>>> *rproc,
>>>>>  	if (!carveout)
>>>>>  		return -ENOMEM;
>>>>>
>>>>> +	/* Check carveout rsc already part of a registered carveout */
>>>>> +	if (rsc->da != FW_RSC_ADDR_ANY) {
>>>>
>>>> As mentioned before, I consider it perfectly viable for rsc->da to be
>>>> ANY and the driver providing a fixed carveout.
>>>
>>> Yes I'll change sequence to lookup by name first and then verify exact
>> parameters matching , not only da definition.
>>>
>>>>
>>>>> +		va = rproc_find_carveout_by_da(rproc, rsc->da, rsc->len);
>>>>> +
>>>>> +		if (va) {
>>>>
>>>> In a system with an iommu it's possible that rsc->len is larger than
>>>> some carveout->len and va is NULL here so we fall through, allocate some
>>>> memory and remap a segment of the carveout. (Or hopefully fails
>>>> attempting).
>>>>
>>>>> +			/* Registered region found */
>>>>> +			pa = rproc_va_to_pa(va);
>>>>> +			if (rsc->pa != FW_RSC_ADDR_ANY && rsc->pa !=
>>>> (u32)pa) {
>>>>> +				/* Carveout doesn't match request */
>>>>> +				dev_err(dev->parent,
>>>>> +					"Failed to find carveout fitting da and
>>>> pa\n");
>>>>> +				return -ENOMEM;
>>>>> +			}
>>>>> +
>>>>> +			/* Update rsc table with physical address */
>>>>> +			rsc->pa = (u32)pa;
>>>>> +
>>>>> +			/* Update carveouts list */
>>>>> +			carveout->va = va;
>>>>> +			carveout->len = rsc->len;
>>>>> +			carveout->da = rsc->da;
>>>>> +			carveout->priv = (void *)CARVEOUT_RSC;
>>>>> +
>>>>> +			list_add_tail(&carveout->node, &rproc->carveouts);
>>>>
>>>> rproc_find_carveout_by_da() will return a reference into a carveout, now
>>>> we add another overlapping carveout into the same list.
>>>>
>>>>
>>>> I think it would be saner to not allow the resource table to describe
>>>> subsets of carveouts registered by the driver.
>>>>
>>>> In which case this would better find a carveout by name or exact da,
>>>> then check that the pa, da, len and rsc->flags are adequate.
>>>
>>> Agree
>>> /Loic
>>>>
>>>>> +
>>>>> +			return 0;
>>>>> +		}
>>>>> +
>>>>> +		if (!rproc->domain) {
>>>>
>>>> Currently this function ignore invalid values of da when !domain, so I
>>>> think it would be good you can submit this sanity check in it's own
>>>> patch so that anyone bisecting this would know why their broken
>> firmware
>>>> suddenly isn't loadable.
>>>>
>>>>> +			dev_err(dev->parent,
>>>>> +				"Bad carveout rsc configuration\n");
>>>>> +			return -ENOMEM;
>>>>> +		}
>>>>> +	}
>>>>> +
>>>>
>>>> Regards,
>>>> Bjorn
>>> --
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> 

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