Hi Arnd, Seungwon Jeon,
> On Tue, August 20, 2013, Seungwon Jeon wrote:
> Hi Prabu,
>
> On Tue, August 20, 2013, Arnd Bergmann wrote:
> > On Monday 19 August 2013, Prabu Thangamuthu wrote:
> > >
> > > +#ifdef CONFIG_MMC_DW_IDMAC_64BIT_ADDRESS
> > > + u32 des1; /* Reserved */
> > > +
> > > + u32 des2; /* Buffer sizes */
> > > +#define IDMAC_SET_BUFFER1_SIZE(d, s) \
> > > + ((d)->des2 = ((d)->des2 & 0x03ffe000) | ((s) & 0x1fff))
> > > +
> > > + u32 des3; /* Reserved */
> > > +
> > > + u32 des4; /* Lower 32-bits of Buffer Address Pointer 1*/
> > > + u32 des5; /* Upper 32-bits of Buffer Address Pointer 1*/
> > > + u32 des6; /* Lower 32-bits of Next Descriptor Address */
> > > + u32 des7; /* Upper 32-bits of Next Descriptor Address */
> > > +#else
> > > u32 des1; /* Buffer sizes */
> > > #define IDMAC_SET_BUFFER1_SIZE(d, s) \
> > > ((d)->des1 = ((d)->des1 & 0x03ffe000) | ((s) & 0x1fff)) @@
> > > -73,6 +86,7 @@ struct idmac_desc {
> > > u32 des2; /* buffer 1 physical address */
> > >
> > > u32 des3; /* buffer 2 physical address */
> > > +#endif /* CONFIG_MMC_DW_IDMAC_64BIT_ADDRESS */
> >
> > This is not a good idea: It means you cannot build the driver to
> > support both 32 and 64 bit at run-time. You have to remove all the
> > #ifdef here and replace it with runtime checks. You also need to
> > update the binding document to provide a way to detect which one is
> > present in a given system.
OK, I will modify the code to support both 32-bit and 64-bit at run-time based on
hardware capability.
> I guess HCON register can be used to identify 32 or 64 bit, right?
> You already used it.
> addr_config = (mci_readl(host, HCON) >> 27) & 0x01;
>
> Then, CONFIG_MMC_DW_IDMAC_64BIT_ADDRESS could be removed.
You are correct. HCON register 27th bit is used to decide 32-bit or 64-bit support.
But, this bit is reserved in older IP versions and it is valid from IP version 2.70a onwards only.
So, I will consider both IP version and HCON register 27th bit to provide run-time support.
Thank you Arnd and Seungwon Jeo for your valuable comments.
Regards,
Prabu Thangamuthu.
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