[U-Boot] dfu: make data buffer size configurable

[Heiko Schocher <hs@denx.de>]

Hello Tom,

Am 04.06.2013 22:04, schrieb Tom Rini:
> On Tue, Jun 04, 2013 at 11:22:54AM +0200, Heiko Schocher wrote:
> 
>> Dfu transfer uses a buffer before writing data to the
>> raw storage device. Make the size (in bytes) of this buffer
>> configurable.
> 
> NAK.

:-(

>> +		CONFIG_SYS_DFU_DATA_BUF_SIZE
>> +		Dfu transfer uses a buffer before writing data to the
>> +		raw storage device. Make the size (in bytes) of this buffer
>> +		configurable.
>> +
>>  		CONFIG_SYS_DFU_MAX_FILE_SIZE
>>  		When updating files rather than the raw storage device,
>>  		we use a static buffer to copy the file into and then write
> 
> The point of the buffer being configurable is to allow for larger files,
> right?  We need to fix CONFIG_SYS_DFU_MAX_FILE_SIZE so that..

In current code CONFIG_SYS_DFU_MAX_FILE_SIZE is not used in dfu_nand.c,
as if buffer is full, it is immediately flushed to nand.
Also default value from CONFIG_SYS_DFU_MAX_FILE_SIZE is smaller (4MiB)
as default value of CONFIG_SYS_DFU_DATA_BUF_SIZE (8MiB) ...

I used on my upcoming board port a CONFIG_SYS_DFU_DATA_BUF_SIZE from
1MiB and that worked perfectly, when transferring a file > 200MB.
The default value from 8MiB sometimes caused an error on the host:

[]# date;dfu-util -a rootfs -D dxr2-org/dxr2.xx-release-image-UNKNOWN-dxr2.ubi;date
Di 28. Mai 14:20:44 CEST 2013
dfu-util 0.5
[...]
Copying data from PC to DFU device
Starting download: [#############################################dfu_download: libusb_control_transfer returned -7
Error during download

Why we have a buffersize from 8MiB for raw writes, but a max file size
from 4MiB only?


>> -#define DFU_DATA_BUF_SIZE		(1024*1024*8)	/* 8 MiB */
>> +#ifndef CONFIG_SYS_DFU_DATA_BUF_SIZE
>> +#define CONFIG_SYS_DFU_DATA_BUF_SIZE		(1024*1024*8)	/* 8 MiB */
>> +#endif
>>  #ifndef CONFIG_SYS_DFU_MAX_FILE_SIZE
>>  #define CONFIG_SYS_DFU_MAX_FILE_SIZE	(4 << 20)	/* 4 MiB */
>>  #endif
> 
> We use one variable for both spots.  Or is there some case I'm missing
> where we need to buffer 8MiB at a time for raw writes?  In which case we
> still need to make CONFIG_SYS_DFU_MAX_FILE_SIZE be used :)

I do not really know, why we have 2 defines here!

bye,
Heiko
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