Re: [PATCH 3/5] crypto:s5p-sss: Add support for SSS module on Exynos5

Tomasz Figa
2014-01-08T00:29:16Z

Hi Naveen,

Please see my comments inline.

On Tuesday 07 of January 2014 17:21:47 Naveen Krishna Ch wrote:
> The differences between SSS modules on S5PV210 and Exynos5
> (AFA the driver supports)
> 1. AES register are at an offset of 0x200 on Exynos5
> 2. hash interrupt is no longer needed on Exynos5

What about Exynos 4 SoCs? Do they have S5PV210- or Exynos5-style security
block?

>
> This patch adds code needed to address the above changes.
>
> Signed-off-by: Naveen Krishna Ch <ch.naveen@samsung.com>
> CC: Herbert Xu <herbert@gondor.apana.org.au>
> CC: David S. Miller <davem@davemloft.net>
> CC: Vladimir Zapolskiy <vzapolskiy@gmail.com>
> TO: <linux-crypto@vger.kernel.org>
> CC: <linux-samsung-soc@vger.kernel.org>
> ---
> drivers/crypto/s5p-sss.c | 59 ++++++++++++++++++++++++++++++++--------------
> 1 file changed, 41 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/crypto/s5p-sss.c b/drivers/crypto/s5p-sss.c
> index dcb9fc1..a11cd0e 100644
> --- a/drivers/crypto/s5p-sss.c
> +++ b/drivers/crypto/s5p-sss.c
> @@ -106,7 +106,7 @@
> #define SSS_REG_FCPKDMAO 0x005C
>
> /* AES registers */
> -#define SSS_REG_AES_CONTROL 0x4000
> +#define SSS_REG_AES_CONTROL(dev) ((dev)->aes_offset + 0x00)

This is ugly. Please consider using a variant struct to store addresses
of registers that depend on IP version.

> #define SSS_AES_BYTESWAP_DI _BIT(11)
> #define SSS_AES_BYTESWAP_DO _BIT(10)
> #define SSS_AES_BYTESWAP_IV _BIT(9)
> @@ -122,21 +122,26 @@
> #define SSS_AES_CHAIN_MODE_CTR _SBF(1, 0x02)
> #define SSS_AES_MODE_DECRYPT _BIT(0)
>
> -#define SSS_REG_AES_STATUS 0x4004
> +#define SSS_REG_AES_STATUS(dev) ((dev)->aes_offset + 0x04)

Ditto.

> #define SSS_AES_BUSY _BIT(2)
> #define SSS_AES_INPUT_READY _BIT(1)
> #define SSS_AES_OUTPUT_READY _BIT(0)
>
> -#define SSS_REG_AES_IN_DATA(s) (0x4010 + (s << 2))
> -#define SSS_REG_AES_OUT_DATA(s) (0x4020 + (s << 2))
> -#define SSS_REG_AES_IV_DATA(s) (0x4030 + (s << 2))
> -#define SSS_REG_AES_CNT_DATA(s) (0x4040 + (s << 2))
> -#define SSS_REG_AES_KEY_DATA(s) (0x4080 + (s << 2))
> +#define SSS_REG_AES_IN_DATA(dev, s) ((dev)->aes_offset + 0x10 + (s << 2))
> +#define SSS_REG_AES_OUT_DATA(dev, s) ((dev)->aes_offset + 0x20 + (s << 2))
> +#define SSS_REG_AES_IV_DATA(dev, s) ((dev)->aes_offset + 0x30 + (s << 2))
> +#define SSS_REG_AES_CNT_DATA(dev, s) ((dev)->aes_offset + 0x40 + (s << 2))
> +#define SSS_REG_AES_KEY_DATA(dev, s) ((dev)->aes_offset + 0x80 + (s << 2))

Ditto.

>
> #define SSS_REG(dev, reg) ((dev)->ioaddr + (SSS_REG_##reg))
> #define SSS_READ(dev, reg) __raw_readl(SSS_REG(dev, reg))
> #define SSS_WRITE(dev, reg, val) __raw_writel((val), SSS_REG(dev, reg))
>
> +#define SSS_AES_REG(dev, reg) ((dev)->ioaddr + (SSS_REG_##reg(dev)))
> +#define SSS_AES_READ(dev, reg) __raw_readl(SSS_AES_REG(dev, reg))
> +#define SSS_AES_WRITE(dev, reg, val) __raw_writel((val), \
> + SSS_AES_REG(dev, reg))
> +
> /* HW engine modes */
> #define FLAGS_AES_DECRYPT _BIT(0)
> #define FLAGS_AES_MODE_MASK _SBF(1, 0x03)
> @@ -177,6 +182,13 @@ struct s5p_aes_dev {
>
> /* To support SSS versions across Samsung SoCs */
> unsigned int version;
> +
> + /*
> + * Register banks corresponding to various algorithms
> + * (Ex: AES, TDES, HASH, TRNG, PKA etc.)
> + * are at an offsets from the base (depending on SSS verion)
> + */
> + unsigned int aes_offset;

This is a candidate to be stored inside a variant struct.

> };
>
> static struct s5p_aes_dev *s5p_dev;
> @@ -358,14 +370,14 @@ static void s5p_set_aes(struct s5p_aes_dev *dev,
> {
> void __iomem *keystart;
>
> - memcpy(dev->ioaddr + SSS_REG_AES_IV_DATA(0), iv, 0x10);
> + memcpy(dev->ioaddr + SSS_REG_AES_IV_DATA(dev, 0), iv, 0x10);
>
> if (keylen == AES_KEYSIZE_256)
> - keystart = dev->ioaddr + SSS_REG_AES_KEY_DATA(0);
> + keystart = dev->ioaddr + SSS_REG_AES_KEY_DATA(dev, 0);
> else if (keylen == AES_KEYSIZE_192)
> - keystart = dev->ioaddr + SSS_REG_AES_KEY_DATA(2);
> + keystart = dev->ioaddr + SSS_REG_AES_KEY_DATA(dev, 2);
> else
> - keystart = dev->ioaddr + SSS_REG_AES_KEY_DATA(4);
> + keystart = dev->ioaddr + SSS_REG_AES_KEY_DATA(dev, 4);
>
> memcpy(keystart, key, keylen);
> }
> @@ -415,7 +427,7 @@ static void s5p_aes_crypt_start(struct s5p_aes_dev *dev, unsigned long mode)
> if (err)
> goto outdata_error;
>
> - SSS_WRITE(dev, AES_CONTROL, aes_control);
> + SSS_AES_WRITE(dev, AES_CONTROL, aes_control);
> s5p_set_aes(dev, dev->ctx->aes_key, req->info, dev->ctx->keylen);
>
> s5p_set_dma_indata(dev, req->src);
> @@ -618,6 +630,11 @@ static int s5p_aes_probe(struct platform_device *pdev)
>
> pdata->version = find_s5p_sss_version(pdev);
>
> + if (pdata->version == SSS_VER_5)
> + pdata->aes_offset = 0x200;
> + else
> + pdata->aes_offset = 0x4000;
> +

Using a variant struct if clauses like this would be eliminated.

> pdata->clk = devm_clk_get(dev, "secss");
> if (IS_ERR(pdata->clk)) {
> dev_err(dev, "failed to find secss clock source\n");
> @@ -643,17 +660,23 @@ static int s5p_aes_probe(struct platform_device *pdev)
> goto err_irq;
> }
>
> + /*
> + * SSS module present in Exynos5 Series SoCs
> + * does not use hash interrupt
> + */
> pdata->irq_hash = platform_get_irq(pdev, 1);
> - if (pdata->irq_hash < 0) {
> + if ((pdata->version == SSS_VER_4) && (pdata->irq_hash < 0)) {

A boolean field "has_hash_irq" in a variant struct could be used to tell
whether this interrupt is needed instead of relying on version.

Best regards,
Tomasz