Dear Michal Simek,
In message 4E609682.8030701@monstr.eu you wrote:
> +static void sdma_out_be32(struct ll_priv *priv, u32 offset, u32 val) > +{ > + if (priv->mode & DCR_BIT) > + mtdcr_local(priv->ctrl + offset, val); > + else > + out_be32((u32 *)(priv->ctrl + offset * 4), val); > +}
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The first reg for DMA2 accessed trough DCR is at 0xB0, the second at 0xB1, etc..
This is indeed a good example, as it shows how terribly broken your code is.
See function sdma_out_be32() above. It is suppose to write a 32 bit value ("u32 val") as a 32 bit entity in big endian mode ("_be32") to some device register - but the register addresses are (1) not aligned to 32 bit boundaries and (2) not even 32 bits apart.
I think you misunderstand what there is written.
Maybe. Maybe even I want to misunderstand it. The problem is that the code does not prevent such misunderstanding.
There are many shortcomings of that code.
DCR is defined just for PPC right now because none wanted to do it for Microblaze.
Actually even this is incorrect - AFAIK Device Control Registers (DCR) exist not on all PPC systems, but only on 4xx (and even there only on some models). So your code works on a few systems, silently does not do anything on others, and crashes on yet others with an illegal instruction.
How do you call code that exposes such behaviour?
I don't want to have this in mainline.
Best regards,
Wolfgang Denk