Re: [PATCH v3 2/5] crypto : stm32 - Add STM32F4 CRC32 support

[Fabien DESSENNE]

Hi Cosar,

Thank you for the patch

On 22/05/17 16:34, Cosar Dindar wrote:
> This patch adds CRC (CRC32 Crypto) support for STM32F4 series.
>
> As an hardware limitation polynomial and key setting are not supported.
> They are fixed as 0x4C11DB7 (poly) and 0xFFFFFFFF (key).
> CRC32C Castagnoli algorithm is not used.
>
> Signed-off-by: Cosar Dindar <cosardindar@xxxxxxxxx>
> ---
>   drivers/crypto/stm32/stm32_crc32.c | 68 ++++++++++++++++++++++++++++++++------
>   1 file changed, 58 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/crypto/stm32/stm32_crc32.c b/drivers/crypto/stm32/stm32_crc32.c
> index ec83b1e..12fbd98 100644
> --- a/drivers/crypto/stm32/stm32_crc32.c
> +++ b/drivers/crypto/stm32/stm32_crc32.c
> @@ -7,6 +7,7 @@
>   #include <linux/bitrev.h>
>   #include <linux/clk.h>
>   #include <linux/module.h>
> +#include <linux/of.h>
>   #include <linux/platform_device.h>
>   
>   #include <crypto/internal/hash.h>
> @@ -39,6 +40,9 @@ struct stm32_crc {
>   	struct clk       *clk;
>   	u8               pending_data[sizeof(u32)];
>   	size_t           nb_pending_bytes;
> +	bool             key_support;
> +	bool             poly_support;
> +	bool             reverse_support;
>   };
>   
>   struct stm32_crc_list {
> @@ -106,13 +110,31 @@ static int stm32_crc_init(struct shash_desc *desc)
>   	}
>   	spin_unlock_bh(&crc_list.lock);
>   
> -	/* Reset, set key, poly and configure in bit reverse mode */
> -	writel(bitrev32(mctx->key), ctx->crc->regs + CRC_INIT);
> -	writel(bitrev32(mctx->poly), ctx->crc->regs + CRC_POL);
> -	writel(CRC_CR_RESET | CRC_CR_REVERSE, ctx->crc->regs + CRC_CR);
> +	/* set key */
> +	if (ctx->crc->key_support) {
> +		writel(bitrev32(mctx->key), ctx->crc->regs + CRC_INIT);
> +	} else if (mctx->key != CRC_INIT_DEFAULT) {
> +		dev_err(ctx->crc->dev, "Unsupported key value! Should be: 0x%x\n",
> +			CRC_INIT_DEFAULT);
> +		return -EINVAL;
> +	}
> +
> +	/* set poly */
> +	if (ctx->crc->poly_support)
> +		writel(bitrev32(mctx->poly), ctx->crc->regs + CRC_POL);
> +
> +	/* reset and configure in bit reverse mode if supported */
> +	if (ctx->crc->reverse_support)
> +		writel(CRC_CR_RESET | CRC_CR_REVERSE, ctx->crc->regs + CRC_CR);
> +	else
> +		writel(CRC_CR_RESET, ctx->crc->regs + CRC_CR);
> +
> +	/* store partial result */
> +	if (!ctx->crc->reverse_support)
> +		ctx->partial = bitrev32(readl(crc->regs + CRC_DR));
> +	else
> +		ctx->partial = readl(ctx->crc->regs + CRC_DR);
>   
> -	/* Store partial result */
> -	ctx->partial = readl(ctx->crc->regs + CRC_DR);
>   	ctx->crc->nb_pending_bytes = 0;
>   
>   	return 0;
> @@ -135,7 +157,12 @@ static int stm32_crc_update(struct shash_desc *desc, const u8 *d8,
>   
>   		if (crc->nb_pending_bytes == sizeof(u32)) {
>   			/* Process completed pending data */
> -			writel(*(u32 *)crc->pending_data, crc->regs + CRC_DR);
> +			if (!ctx->crc->reverse_support)
> +				writel(bitrev32(*(u32 *)crc->pending_data),
> +				       crc->regs + CRC_DR);
> +			else
> +				writel(*(u32 *)crc->pending_data,
> +				       crc->regs + CRC_DR);
>   			crc->nb_pending_bytes = 0;
>   		}
>   	}
> @@ -143,10 +170,16 @@ static int stm32_crc_update(struct shash_desc *desc, const u8 *d8,
>   	d32 = (u32 *)d8;
>   	for (i = 0; i < length >> 2; i++)
>   		/* Process 32 bits data */
> -		writel(*(d32++), crc->regs + CRC_DR);
> +		if (!ctx->crc->reverse_support)
> +			writel(bitrev32(*(d32++)), crc->regs + CRC_DR);
> +		else
> +			writel(*(d32++), crc->regs + CRC_DR);
>   
>   	/* Store partial result */
> -	ctx->partial = readl(crc->regs + CRC_DR);
> +	if (!ctx->crc->reverse_support)
> +		ctx->partial = bitrev32(readl(crc->regs + CRC_DR));
> +	else
> +		ctx->partial = readl(crc->regs + CRC_DR);
>   
>   	/* Check for pending data (non 32 bits) */
>   	length &= 3;
> @@ -243,6 +276,7 @@ static int stm32_crc_probe(struct platform_device *pdev)
>   	struct stm32_crc *crc;
>   	struct resource *res;
>   	int ret;
> +	int algs_size;
>   
>   	crc = devm_kzalloc(dev, sizeof(*crc), GFP_KERNEL);
>   	if (!crc)
> @@ -269,13 +303,26 @@ static int stm32_crc_probe(struct platform_device *pdev)
>   		return ret;
>   	}
>   
> +	/* set key, poly and reverse support if device is of F7 series */
> +	if (of_device_is_compatible(crc->dev->of_node, "st,stm32f7-crc")) {
> +		crc->key_support = true;
> +		crc->poly_support = true;
> +		crc->reverse_support = true;
> +	}
> +
>   	platform_set_drvdata(pdev, crc);
>   
>   	spin_lock(&crc_list.lock);
>   	list_add(&crc->list, &crc_list.dev_list);
>   	spin_unlock(&crc_list.lock);
>   
> -	ret = crypto_register_shashes(algs, ARRAY_SIZE(algs));
> +	/* For F4 series only CRC32 algorithm will be used */
> +	if (of_device_is_compatible(crc->dev->of_node, "st,stm32f4-crc"))
> +		algs_size = 1;
> +	else
> +		algs_size = ARRAY_SIZE(algs);
> +
> +	ret = crypto_register_shashes(algs, algs_size);
>   	if (ret) {
>   		dev_err(dev, "Failed to register\n");
>   		clk_disable_unprepare(crc->clk);
> @@ -304,6 +351,7 @@ static int stm32_crc_remove(struct platform_device *pdev)
>   
>   static const struct of_device_id stm32_dt_ids[] = {
>   	{ .compatible = "st,stm32f7-crc", },
> +	{ .compatible = "st,stm32f4-crc", },
>   	{},
>   };
>   MODULE_DEVICE_TABLE(of, stm32_dt_ids);
Reviewed-by: Fabien Dessenne <fabien.dessenne@xxxxxx>