On 7/17/2019 6:25 PM, Andrey Smirnov wrote:
> In order to be able to unify 64 and 32 bit implementations of
> wr_reg64, let's convert it to use helpers from
> <linux/io-64-nonatomic-hi-lo.h> first. Here are the steps of the
> transformation:
> 
> 1. Inline wr_reg32 helpers:
> 
>       if (!caam_imx && caam_little_end) {
>               if (caam_little_end) {
>                       iowrite32(data >> 32, (u32 __iomem *)(reg) + 1);
>                       iowrite32(data, (u32 __iomem *)(reg));
>               } else {
>                       iowrite32be(data >> 32, (u32 __iomem *)(reg) + 1);
>                       iowrite32be(data, (u32 __iomem *)(reg));
>               }
>       } else {
>               if (caam_little_end) {
>                       iowrite32(data >> 32, (u32 __iomem *)(reg));
>                       iowrite32(data, (u32 __iomem *)(reg) + 1);
>               } else {
>                       iowrite32be(data >> 32, (u32 __iomem *)(reg));
>                       iowrite32be(data, (u32 __iomem *)(reg) + 1);
>               }
>       }
> 
> 2. Transfrom the conditionals such that the check for
> 'caam_little_end' is at the top level:
> 
>       if (caam_little_end) {
>               if (!caam_imx) {
>                       iowrite32(data >> 32, (u32 __iomem *)(reg) + 1);
>                       iowrite32(data, (u32 __iomem *)(reg));
>               } else {
>                       iowrite32(data >> 32, (u32 __iomem *)(reg));
>                       iowrite32(data, (u32 __iomem *)(reg) + 1);
>               }
>       } else {
>               iowrite32be(data >> 32, (u32 __iomem *)(reg));
>               iowrite32be(data, (u32 __iomem *)(reg) + 1);
>       }
> 
> 3. Invert the check for !caam_imx:
> 
>       if (caam_little_end) {
>               if (caam_imx) {
>                       iowrite32(data >> 32, (u32 __iomem *)(reg));
>                       iowrite32(data, (u32 __iomem *)(reg) + 1);
>               } else {
>                       iowrite32(data >> 32, (u32 __iomem *)(reg) + 1);
>                       iowrite32(data, (u32 __iomem *)(reg));
>               }
>       } else {
>               iowrite32be(data >> 32, (u32 __iomem *)(reg));
>               iowrite32be(data, (u32 __iomem *)(reg) + 1);
>       }
> 
> 4. Make use of iowrite64* helpers from <linux/io-64-nonatomic-hi-lo.h>
> 
>       if (caam_little_end) {
>               if (caam_imx) {
>                       iowrite32(data >> 32, (u32 __iomem *)(reg));
>                       iowrite32(data, (u32 __iomem *)(reg) + 1);
>               } else {
>                       iowrite64(data, reg);
>               }
>       } else {
>               iowrite64be(data, reg);
>       }
> 
> No functional change intended.
> 
> Signed-off-by: Andrey Smirnov <andrew.smir...@gmail.com>
Reviewed-by: Horia Geantă <horia.gea...@nxp.com>

Just to clarify one thing.

For a previous patch I mentioned:
> To be consistent with CAAM engine HW spec: in case of 64-bit registers,
> irrespective of device endianness, the lower address should be read from
> / written to first, followed by the upper address.
https://lore.kernel.org/linux-crypto/vi1pr0401mb259145c2dfdb5e4084ea5dfc98...@vi1pr0401mb2591.eurprd04.prod.outlook.com/

I've checked again and actually there is no limitation wrt. the order in which
the two 32-bit parts of 64-bit registers are read from / written to,
except for performance counters (only available on DN parts, not on i.MX).
However, performance counters do not user {rd,wr}_reg64 and should be fixed
separately.

In conclusion, it's ok to use either hi_lo or lo_hi semantics (which is _data_
semantics btw).
It makes more sense for this patch to include io-64-nonatomic-hi-lo.h since
that's what regs.h currently uses.

Horia

Reply via email to