barebox qemu-malta pci problem

barebox qemu-malta pci problem

[Antony Pavlov]

Hi!

It looks like qemu-malta barebox pci support is broken since

  commit b8a1bb1dd215770670108fe5b0de0e5e137bf8fd
  Author: Lucas Stach <dev@lynxeye.de>
  Date:   Sat Oct 4 19:40:12 2014 +0200

      pci: defer device registration until after bridge setup
    
      Otherwise the drivers for a device may probe before the
      devices parent bridge is fully configured, which leads
      to errors when accessing the BARs.

How to reproduce the problem:

 $ cd barebox.git
 $ export ARCH=mips
 $ export CROSS_COMPILE=<your favorite mips cross-compiler prefix>

 # first let's see working state

 $ git checkout b8a1bb1dd215770670108fe5b0de0e5e137bf8fd^
 $ make qemu-malta_defconfig && make clean && make
 $ qemu-system-mips -nodefaults -M malta -m 256       -nographic -serial stdio -monitor null       -bios barebox-flash-image -net nic,model=rtl8139

 ...
 
 barebox:/ devinfo

 ...

 `-- i2c
 `-- pci
   `-- pci0
   `-- pci1
   `-- pci2
   `-- pci3
   `-- pci4
      `-- eth0
         `-- miibus0
 `-- fs

 <stop qemu emulation (ctrl-c)>

 # devinfo shows eth0 device on pci4. good.
 # now let's see broken state

 $ git checkout b8a1bb1dd215770670108fe5b0de0e5e137bf8fd
 $ make qemu-malta_defconfig && make clean && make
 $ qemu-system-mips -nodefaults -M malta -m 256       -nographic -serial stdio -monitor null       -bios barebox-flash-image -net nic,model=rtl8139

 ...
 
 barebox:/ devinfo

 ...

 `-- i2c
 `-- pci
 `-- fs

 # As you can see there is no pci devices on pci bus.

-- 
Best regards,
  Antony Pavlov

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Re: barebox qemu-malta pci problem

[Lucas Stach]

Am Donnerstag, den 02.04.2015, 00:54 +0300 schrieb Antony Pavlov:
> Hi!
> 
> It looks like qemu-malta barebox pci support is broken since
> 
>   commit b8a1bb1dd215770670108fe5b0de0e5e137bf8fd
>   Author: Lucas Stach <dev@lynxeye.de>
>   Date:   Sat Oct 4 19:40:12 2014 +0200
> 
>       pci: defer device registration until after bridge setup
>     
>       Otherwise the drivers for a device may probe before the
>       devices parent bridge is fully configured, which leads
>       to errors when accessing the BARs.
> 

Thanks for the report and the detailed reproducer. I'll have a look at
this.

Regards,
Lucas

> How to reproduce the problem:
> 
>  $ cd barebox.git
>  $ export ARCH=mips
>  $ export CROSS_COMPILE=<your favorite mips cross-compiler prefix>
> 
>  # first let's see working state
> 
>  $ git checkout b8a1bb1dd215770670108fe5b0de0e5e137bf8fd^
>  $ make qemu-malta_defconfig && make clean && make
>  $ qemu-system-mips -nodefaults -M malta -m 256       -nographic -serial stdio -monitor null       -bios barebox-flash-image -net nic,model=rtl8139
> 
>  ...
>  
>  barebox:/ devinfo
> 
>  ...
> 
>  `-- i2c
>  `-- pci
>    `-- pci0
>    `-- pci1
>    `-- pci2
>    `-- pci3
>    `-- pci4
>       `-- eth0
>          `-- miibus0
>  `-- fs
> 
>  <stop qemu emulation (ctrl-c)>
> 
>  # devinfo shows eth0 device on pci4. good.
>  # now let's see broken state
> 
>  $ git checkout b8a1bb1dd215770670108fe5b0de0e5e137bf8fd
>  $ make qemu-malta_defconfig && make clean && make
>  $ qemu-system-mips -nodefaults -M malta -m 256       -nographic -serial stdio -monitor null       -bios barebox-flash-image -net nic,model=rtl8139
> 
>  ...
>  
>  barebox:/ devinfo
> 
>  ...
> 
>  `-- i2c
>  `-- pci
>  `-- fs
> 
>  # As you can see there is no pci devices on pci bus.
> 
> -- 
> Best regards,
>   Antony Pavlov

-- 
Pengutronix e.K.             | Lucas Stach                 |
Industrial Linux Solutions   | http://www.pengutronix.de/  |


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