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

On Thursday 22 May 2014, Corentin LABBE wrote:

Le 22/05/2014 17:28, Arnd Bergmann a ?crit :

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On Thursday 22 May 2014 17:09:56 LABBE Corentin wrote:

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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.

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+	/* 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.

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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