Re: [PATCH 3/3] crypto: Add Allwinner Security System crypto accelerator

Arnd Bergmann
2014-05-23T10:46:58Z

On Thursday 22 May 2014, Corentin LABBE wrote:
> Le 22/05/2014 17:28, Arnd Bergmann a écrit :
> > On Thursday 22 May 2014 17:09:56 LABBE Corentin wrote:
> >> Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
> >
> > My feeling is that this should either be one driver that provides
> > all five algorithms unconditionally, or five drivers that are each
> > separate loadable modules and based on top of a common module
> > that only exports functions but has no active logic itself
>
> I agree for the split.
> It was my first intention but I feared to add too many files.
> So I propose to split in 6, sunxi-ss-hash.c, sunxi-ss-des.c, sunxi-ss-aes.c, sunxi-ss-rng.c, sunxi-ss-common.c and sunxi-ss.h
> Does can I add a sunxi-ss directory in drivers/crypto ?

Yes, I think a subdirectory would be best.

> >> + /* If we have more than one SG, we cannot use kmap_atomic since
> >> + * we hold the mapping too long*/
> >> + src_addr = kmap(sg_page(in_sg)) + in_sg->offset;
> >> + if (src_addr == NULL) {
> >> + dev_err(ss_ctx->dev, "KMAP error for src SG\n");
> >> + return -1;
> >> + }
> >> + dst_addr = kmap(sg_page(out_sg)) + out_sg->offset;
> >> + if (dst_addr == NULL) {
> >> + kunmap(src_addr);
> >> + dev_err(ss_ctx->dev, "KMAP error for dst SG\n");
> >> + return -1;
> >> + }
> >> + src32 = (u32 *)src_addr;
> >> + dst32 = (u32 *)dst_addr;
> >> + ileft = nbytes / 4;
> >> + oleft = nbytes / 4;
> >> + sgileft = in_sg->length / 4;
> >> + sgoleft = out_sg->length / 4;
> >> + do {
> >> + tmp = readl_relaxed(ss_ctx->base + SUNXI_SS_FCSR);
> >> + rx_cnt = SS_RXFIFO_SPACES(tmp);
> >> + tx_cnt = SS_TXFIFO_SPACES(tmp);
> >> + todo = min3(rx_cnt, ileft, sgileft);
> >> + if (todo > 0) {
> >> + ileft -= todo;
> >> + sgileft -= todo;
> >> + }
> >> + while (todo > 0) {
> >> + writel_relaxed(*src32++, ss_ctx->base + SS_RXFIFO);
> >> + todo--;
> >> + }
> >
> > I wonder if this is meant to be used in combination with a dma engine
> > rather than accessed with writel/readl.
>
> You could do both, but the dmaengine driver is under development.
> When it will be ready, I will add DMA support.
> But my intention is to keep both mode, since poll mode is better than DMA for small request.

Ok, I see.

> > How does the original driver do it?
>
> There are no original driver, this driver is the first for the Security System.

Ah, I thought there was one in the allwinner BSP kernel.

Arnd