[PATCH v4 1/1] staging: fpgaboot: Xilinx FPGA firmware download driver

[Insop Song]

On Sat, Jan 11, 2014 at 4:10 PM, Greg KH <gregkh at linuxfoundation.org> wrote:
> On Sat, Jan 11, 2014 at 03:56:48PM -0800, Insop Song wrote:
>> On Sat, Jan 11, 2014 at 1:05 PM, Greg KH <gregkh at linuxfoundation.org> wrote:
>> > On Sat, Jan 11, 2014 at 12:51:28PM -0800, Greg KH wrote:
>> >> On Thu, Jan 09, 2014 at 11:48:04AM -0800, Insop Song wrote:
>> >> > This driver downloads Xilinx FPGA firmware using gpio pins.
>> >> > It loads Xilinx FPGA bitstream format firmware image and
>> >> > program the Xilinx FPGA using SelectMAP (parallel) mode.
>> >> >
>> >> > Signed-off-by: Insop Song <insop.song at gainspeed.com>
>> >>
>> >> This patch breaks the build on my machine, please be more careful:
>> >>
>> >> drivers/staging/gs_fpgaboot/gs_fpgaboot.c:30:28: fatal error: include/asm/io.h: No such file or directory
>> >>  #include <include/asm/io.h>
>> >>
>> >> Please fix this up, test it, and resend.
>> >
>> > Also, while you are fixing things up, please just remove the character
>> > device node from the driver, you aren't doing anything with it, so it's
>> > not needed.
>> >
>>
>> Thank you for the suggestion, makes a lot of sense and code cleaner.
>>
>> Could you take a quick look?
>> If it is good, will send out a new patch, v5, shortly.
>>
>> Main change is
>>
>> +/* fake device for request_firmware */
>> +static struct platform_device        *firmware_pdev;
>>
>> + firmware_pdev = platform_device_register_simple("fpgaboot", -1,
>> +                                                  NULL, 0);
>
> Why do you need a platform device?  Don't you have something on the
> hardware that describes the fact that this device is in the system, or
> not?  Like a PCI id?  DMI id?  Device Tree entry?
>
> You must have something that you can trigger off of.
>

This driver is only to download fpga firmware, not intended to keep
managing the fpga device after the downloading. The device we use is
not part of the device tree or PCI.

It downloads the image and after that no need to be existing.
Here is how we use

$ insmod gs_fpga.ko file="xlinx_fpga_top_bitstream.bit"
$ rmmod gs_fpga

I still needed "device" to use request_firmware() even though I don't
use it. I've looked at other drivers which uses request_firmware()
after your suggestion of removing char device node, and I've found
platform_device can be a simple one to use.

What do you think?

Thank you,

ISS