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Subject: Re: [PATCH v2 05/16] remoteproc: modify rproc_handle_carveout to
 support preallocated region
To:     Loic PALLARDY <loic.pallardy@st.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>
CC:     "ohad@wizery.com" <ohad@wizery.com>,
        "linux-remoteproc@vger.kernel.org" <linux-remoteproc@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Arnaud POULIQUEN <arnaud.pouliquen@st.com>,
        "benjamin.gaignard@linaro.org" <benjamin.gaignard@linaro.org>
References: <1512060411-729-1-git-send-email-loic.pallardy@st.com>
 <1512060411-729-6-git-send-email-loic.pallardy@st.com>
 <20171214005917.GG17344@builder>
 <0bbc0455b6ee45cdb0ebab04117b6a40@SFHDAG7NODE2.st.com>
From:   Suman Anna <s-anna@ti.com>
Message-ID: <9ced2a8b-916e-9447-4be7-6316385ade0a@ti.com>
Date:   Tue, 23 Oct 2018 12:40:06 -0500
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>>
>> 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@st.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.

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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