Re: Need some guidance on i2c-ocores driver

[Lee Jones]

On Fri, 17 Apr 2015, York Sun wrote:

> Resend to LKML
> 
> Lee,
> 
> This question is actually more about MFD. Can you point me to the possible
> causes for my failure below?

It's hard to tell exactly without code, but it looks like you're
trying to allocate overlapping memory regions.  Double check all of
your addresses.  For DT you need to take a look at your 'reg'
properties, for traditional platform data it's best to grep for
IORESOURCE_MEM.

> Thanks.
> 
> York
> 
> 
> On 04/16/2015 05:02 PM, York Sun wrote:
> > Julia and other experts,
> > 
> > I am seeking for help on my device driver.
> > 
> > I am working on a module driver for a FPGA design with open core I2C controller
> > memory-mapped to BAR2. I have searched up and down and found only one driver
> > (drivers/mfd/timberdale.c) with similar implementation. Following timberdale
> > driver, I am able to load the driver, but blocked by devm_ioremap_resource(). It
> > is always in conflict with my BAR2. I wonder if I did something wrong. Here is
> > the flow I tracked so far. (By the way, I am using an older kernel 3.12. The new
> > 4.0 kernel crashes when booting on my platform. I plan to move to newer kernel
> > later).
> > 
> > mfd_add_devices()
> > |
> > |--mfd_add_device()
> >     |
> >     |--platform_device_add()
> >         |
> >         |--insert_resource()  /* this passed */
> >         |   |
> >         |   |--insert_resource_conflict()
> >         |
> >         |--device_add()
> >             |
> >             |--bus_probe_device()
> >                 |
> >                 |--devm_ioremap_resource()
> >                     |
> >                     |--devm_request_mem_region()
> >                         |
> >                         |--__request_region() /* this always conflicts */
> >                             |
> >                             |--__request_resource()
> > 
> > My driver is called RedStone DMA. Here is my debug output
> > 
> >> root@p1022ds:~# insmod redstone_mfd.ko 
> >> RedStone DMA 0002:05:00.0: pci_enable_device() successful
> >> RedStone DMA 0002:05:00.0: MSI-X init successful
> >> York kernel: Calling devm_ioremap_resource()
> >> York kernel kernel/resource.c __request_region 977: conflict=[??? 0xc00080000-0xc00087fff flags 0x80000000]
> >> ocores-i2c ocores-i2c: can't request region for resource [mem 0xc00086000-0xc0008601f]
> >> ocores-i2c: probe of ocores-i2c failed with error -16
> >> RedStone DMA 0002:05:00.0: BAR[0] 0x0000000c00000000-0x0000000c0007ffff flags 0x0014220c, length 524288
> >> RedStone DMA 0002:05:00.0: BAR[1] 0x0000000000000000-0x0000000000000000 flags 0x00000000, length 0
> >> RedStone DMA 0002:05:00.0: BAR[2] 0x0000000c00080000-0x0000000c00087fff flags 0x00040200, length 32768
> >> RedStone DMA 0002:05:00.0: BAR[3] 0x0000000000000000-0x0000000000000000 flags 0x00000000, length 0
> >> RedStone DMA 0002:05:00.0: BAR[4] 0x0000000000000000-0x0000000000000000 flags 0x00000000, length 0
> >> RedStone DMA 0002:05:00.0: BAR[5] 0x0000000000000000-0x0000000000000000 flags 0x00000000, length 0
> >> RedStone DMA 0002:05:00.0: Version 1.4, built on 4-16-15, id 0
> >> root@p1022ds:~# 
> > 
> > Can you shed some light on this?
> > 
> > Thanks.
> > 
> > York
> > 

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org â Open source software for ARM SoCs
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