Hi Seungwon Jeon,
On Monday 20 August 2013, Prabu Thangamuthu wrote:
> Hi Seungwon Jeon,
>
> On Tue, August 20, 2013, Seungwon Jeon wrote:
> > On Tue, August 20, 2013, Prabu Thangamuthu wrote:
> > > 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.
> > Yes, 27th is reserved bit filed. If it's read in old version host, it
> > could be '0' by reset value.
> Correct. If the reset value of 27th bit in older version IP's are designed with '0',
> then no need to get the version.
> Let me verify with IP team and confirm the reset value.
The reset value of 27th bit in older IP's are designed with '0' only.
> > Then, we can decide that this host supports only 32-bit address anyway?
Yes, we can use only HCON 27th bit value to decide 32 or 64-bit address mode.
Thanks & regards,
Prabu Thangamuthu.
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