Re: [PATCH v4] remoteproc: uclass: Add methods to load firmware to rproc and boot rproc

MD Danish Anwar
2024-02-06T05:31:33Z

On 05/02/24 6:07 pm, Roger Quadros wrote:
>
>
> On 05/02/2024 12:20, MD Danish Anwar wrote:
>>
>>
>> On 05/02/24 3:36 pm, Roger Quadros wrote:
>>>
>>>
>>> On 02/02/2024 18:40, Anwar, Md Danish wrote:
>>>> Hi Roger,
>>>>
>>>> On 2/2/2024 4:49 PM, Roger Quadros wrote:
>>>>>
>>>>>
>>>>> On 30/01/2024 08:33, MD Danish Anwar wrote:
>>>>>> Add APIs to set a firmware_name to a rproc and boot the rproc with the
>>>>>> same firmware.
>>>>>>

<snip>

>>>>
>>>>> How does caller know what firmware size to set to?
>>>>> This should already be private to the rproc as it knows
>>>>> how large is its program memory.
>>>>>
>>>>
>>>> Caller is trying to boot the rproc with a firmware binary. Caller should
>>>> know the size of binary that it wants to load to rproc core. Caller will
>>>> specify the binary size to rproc_boot(). Based on the size provided by
>>>> caller, rproc_boot() will then allocate that much memory and call
>>>> request_firmware_into_buf() with the size and allocated buffer. If the
>>>> caller doesn't provide minimum size rproc_load() will fail.
>>>
>>> Caller only knows the filename. It need not know more details.
>>
>> Caller is trying to load a file of it's choice to a rproc. Caller should
>> know the size of file it is trying to load or atleast the max size that
>> the firmware file could be of.
>>
>>
>>> Also see my comment below about rproc_boot() API.
>>>
>>>>
>>>> rproc_load() calls respective driver ops, for example: pru_load().
>>>> pru_load() [1] API checks the required size of firmware to load by
>>>> casting the buffer into Elf32_Ehdr and Elf32_Phdr and returns error if
>>>> size provided by caller is less than this.
>>>>
>>>>
>>>> if (offset + filesz > size) {
>>>> dev_dbg(dev, "truncated fw: need 0x%x avail 0x%zx\n",
>>>> offset + filesz, size);
>>>> ret = -EINVAL;
>>>> break;
>>>> }
>>>>
>>>>>> + *
>>>>>> + * Boot a remote processor (i.e. load its firmware, power it on, ...).
>>>>>> + *
>>>>>> + * This function first loads the firmware set in the uclass pdata of Remote
>>>>>> + * processor to a buffer and then loads firmware to the remote processor
>>>>>> + * using rproc_load().
>>>>>> + *
>>>>>> + * Return: 0 on success, and an appropriate error value otherwise
>>>>>> + */
>>>>>> +int rproc_boot(struct udevice *rproc_dev, size_t fw_size);
>>>>>
>>>>> Was wondering if you need separate API for rproc_set_firmware or we can just
>>>>> pass firmware name as argument to rproc_boot()?
>>>>>
>>>>
>>>> Technically we can. But when we discussed this approach first in v1, you
>>>> had asked to keep the APIs similar to upstream linux. Upstream linux has
>>>> these two APIs so I kept it that way. If you want I can drop the first
>>>> API. Please let me know.
>>>
>>> Sure you can keep it as it is in Linux, but there, rproc_boot doesn't
>>> take fw_size argument. So wondering why you should have it in u-boot.
>>>
>>
>> For loading firmware to a rproc core in u-boot, it's first neccassry to
>> load the firmware into buffer and then load that buffer into rproc core
>> using rproc_load() API. Now to load the firmware to a buffer ther is an
>> API request_firmware_into_buf(). This API takes size of firmware as one
>> of it's argument. So in order to call this API from rproc_boot() we need
>> to pass fw_size to rproc_boot()
>>
>> Other u-boot drivers using request_firmware_into_buf() are also passing
>> size of firmware from their driver.
>
> But in your driver you didn't use size of firmware but some 64K
> https://lore.kernel.org/all/20240124064930.1787929-8-danishanwar@ti.com/
>

Yes, in driver I am hardcoding the size to 64K. That's because I know
the size of ICSSG firmwares are less than 64K. Instead of hardcoding I
can also define macro or provide a config option where we set the size
and the driver will read the size from the config and call rproc_boot()
with size.

For example, fm.c driver reads the size from config option
CONFIG_SYS_QE_FMAN_FW_LENGTH [1] and calls request_firmware_into_buf()

[1]
https://elixir.bootlin.com/u-boot/latest/source/drivers/net/fm/fm.c#L458

> So neither does the caller have a clue of firmware size?
>
>>
>> If rproc_boot() doesn't take fw_size as argument then within
>> rproc_boot() we need to figure out the fw_size before calling
>> request_firmware_into_buf().
>>
>> If we don't know the size / maximum size of the firmware to load, how
>> will we call request_firmware_into_buf(). Someone has to tell
>> request_firmware_into_buf() the size of firmware. I am expecting that to
>> be the caller. Do you have any other way of getting the firmware size
>> before request_firmware_into_buf() is called?
>
> /**
> * request_firmware_into_buf - Load firmware into a previously allocated buffer.
> * @dev: An instance of a driver.
> * @name: Name of firmware file.
> * @buf: Address of buffer to load firmware into.
> * @size: Size of buffer.
> * @offset: Offset of a file for start reading into buffer.
>
> It needs size of pre-allocated buffer which can be smaller than file size.
> It also has the option of offset. So you can load portions of the file limited
> by buffer size.
>
> My suggestion is that Remoteproc layer should take care of how much buffer
> to allocate and pass that buffer size to request_firmware_into_buf().
> You are doing the malloc here itself anyways.
>

But how would the remoteproc driver know how much buffer it needs to
allocate before calling request_firmware_into_buf().

>>
>>>>
>>>>>> #else
>>>>>> static inline int rproc_init(void) { return -ENOSYS; }
>>>>>> static inline int rproc_dev_init(int id) { return -ENOSYS; }
>>>>>> @@ -744,6 +775,10 @@ static inline int rproc_elf_load_rsc_table(struct udevice *dev, ulong fw_addr,
>>>>>> ulong fw_size, ulong *rsc_addr,
>>>>>> ulong *rsc_size)
>>>>>> { return -ENOSYS; }
>>>>>> +static inline int rproc_set_firmware(struct udevice *rproc_dev, const char *fw_name)
>>>>>> +{ return -ENOSYS; }
>>>>>> +static inline int rproc_boot(struct udevice *rproc_dev, size_t fw_size)
>>>>>> +{ return -ENOSYS; }
>>>>>> #endif
>>>>>>
>>>>>> #endif /* _RPROC_H_ */
>>>>>
>>>>
>>>> [1]
>>>> https://elixir.bootlin.com/u-boot/latest/source/drivers/remoteproc/pru_rproc.c#L324
>>>>
>>>
>>
>

--
Thanks and Regards,
Danish