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SubjectRe: [PATCHv3 05/15] remoteproc/omap: Add the rproc ops .da_to_va() implementation
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On 12/19/19 6:12 PM, Mathieu Poirier wrote:
> On Thu, 19 Dec 2019 at 06:18, Tero Kristo <t-kristo@ti.com> wrote:
>>
>> On 18/12/2019 02:38, Mathieu Poirier wrote:
>>> On Fri, Dec 13, 2019 at 02:55:27PM +0200, Tero Kristo wrote:
>>>> From: Suman Anna <s-anna@ti.com>
>>>>
>>>> An implementation for the rproc ops .da_to_va() has been added
>>>> that provides the address translation between device addresses
>>>> to kernel virtual addresses for internal RAMs present on that
>>>> particular remote processor device. The implementation provides
>>>> the translations based on the addresses parsed and stored during
>>>> the probe.
>>>>
>>>> This ops gets invoked by the exported rproc_da_to_va() function
>>>> and allows the remoteproc core's ELF loader to be able to load
>>>> program data directly into the internal memories.
>>>>
>>>> Signed-off-by: Suman Anna <s-anna@ti.com>
>>>> Signed-off-by: Tero Kristo <t-kristo@ti.com>
>>>> ---
>>>> drivers/remoteproc/omap_remoteproc.c | 39 ++++++++++++++++++++++++++++
>>>> 1 file changed, 39 insertions(+)
>>>>
>>>> diff --git a/drivers/remoteproc/omap_remoteproc.c b/drivers/remoteproc/omap_remoteproc.c
>>>> index 844703507a74..28f14e24b389 100644
>>>> --- a/drivers/remoteproc/omap_remoteproc.c
>>>> +++ b/drivers/remoteproc/omap_remoteproc.c
>>>> @@ -232,10 +232,49 @@ static int omap_rproc_stop(struct rproc *rproc)
>>>> return 0;
>>>> }
>>>>
>>>> +/**
>>>> + * omap_rproc_da_to_va() - internal memory translation helper
>>>> + * @rproc: remote processor to apply the address translation for
>>>> + * @da: device address to translate
>>>> + * @len: length of the memory buffer
>>>> + *
>>>> + * Custom function implementing the rproc .da_to_va ops to provide address
>>>> + * translation (device address to kernel virtual address) for internal RAMs
>>>> + * present in a DSP or IPU device). The translated addresses can be used
>>>> + * either by the remoteproc core for loading, or by any rpmsg bus drivers.
>>>> + * Returns the translated virtual address in kernel memory space, or NULL
>>>> + * in failure.
>>>> + */
>>>> +static void *omap_rproc_da_to_va(struct rproc *rproc, u64 da, int len)
>>>> +{
>>>> + struct omap_rproc *oproc = rproc->priv;
>>>> + int i;
>>>> + u32 offset;
>>>> +
>>>> + if (len <= 0)
>>>> + return NULL;
>>>> +
>>>> + if (!oproc->num_mems)
>>>> + return NULL;
>>>> +
>>>> + for (i = 0; i < oproc->num_mems; i++) {
>>>> + if (da >= oproc->mem[i].dev_addr && da + len <=
>>>
>>> Shouldn't this be '<' rather than '<=' ?
>>
>> No, I think <= is correct. You need to consider the initial byte in the
>> range also. Consider a simple case where you provide the exact da + len
>> corresponding to a specific memory range.
>
> For that specific case you are correct. On the flip side if @da falls
> somewhere after @mem[i].dev_addr, there is a possibility to clobber
> the first byte of the next range if <= is used.

Not really, you will miss out on the last byte actually if you use just
<. This is just address range check, any memcpy would actually end one
byte before.

Eg: 0x80000 of len 0x10000. I should perfectly be able to copy 0x1000
bytes at 0x8f000.

regards
Suman


>
> Thanks,
> Mathieu
>
>>
>>>
>>>> + oproc->mem[i].dev_addr + oproc->mem[i].size) {
>>>
>>> One space too many after the '+' .
>>
>> True, I wonder why checkpatch did not catch this.
>>
>>>
>>>> + offset = da - oproc->mem[i].dev_addr;
>>>
>>> One space too many after then '-' .
>>
>> Same, will fix these two.
>>
>> -Tero
>>
>>>
>>>> + /* __force to make sparse happy with type conversion */
>>>> + return (__force void *)(oproc->mem[i].cpu_addr +
>>>> + offset);
>>>> + }
>>>> + }
>>>> +
>>>> + return NULL;
>>>> +}
>>>> +
>>>> static const struct rproc_ops omap_rproc_ops = {
>>>> .start = omap_rproc_start,
>>>> .stop = omap_rproc_stop,
>>>> .kick = omap_rproc_kick,
>>>> + .da_to_va = omap_rproc_da_to_va,
>>>> };
>>>>
>>>> static const char * const ipu_mem_names[] = {
>>>> --
>>>> 2.17.1
>>>>
>>>> --
>>
>> --
>> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

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