Re: [PATCH 3/8 v3] crypto:s5p-sss: Add support for SSS module on Exynos

From: Tomasz Figa <t.figa@samsung.com>
To: Naveen Krishna Chatradhi <ch.naveen@samsung.com>,
	linux-crypto@vger.kernel.org, linux-samsung-soc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, vzapolskiy@gmail.com,
	herbert@gondor.apana.org.au, naveenkrishna.ch@gmail.com,
	cpgs@samsung.com, tomasz.figa@gmail.com,
	"David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH 3/8 v3] crypto:s5p-sss: Add support for SSS module on Exynos
Date: Fri, 10 Jan 2014 16:44:50 +0100	[thread overview]
Message-ID: <52D01572.5010509@samsung.com> (raw)
In-Reply-To: <1389354171-31816-1-git-send-email-ch.naveen@samsung.com>

Hi Naveen,

Please see my comments inline.

On 10.01.2014 12:42, Naveen Krishna Chatradhi wrote:
> This patch adds new compatible and variant struct to support the SSS
> module on Exynos4 (Exynos4210), Exynos5 (Exynos5420 and Exynos5250)
> for which
> 1. AES register are at an offset of 0x200 and
> 2. hash interrupt is not available
>
> 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>
> ---
> Changes since v2:
> 1. Added variant struct to handle the differences in SSS modules
> 2. Changed the compatible strings to exynos4210-secss
> 3. Other changes suggested by Tomasz
>
>   .../devicetree/bindings/crypto/samsung-sss.txt     |   20 ++++
>   drivers/crypto/s5p-sss.c                           |  110 +++++++++++++++-----
>   2 files changed, 106 insertions(+), 24 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/crypto/samsung-sss.txt b/Documentation/devicetree/bindings/crypto/samsung-sss.txt
> index 2f9d7e4..fdc7d8b 100644
> --- a/Documentation/devicetree/bindings/crypto/samsung-sss.txt
> +++ b/Documentation/devicetree/bindings/crypto/samsung-sss.txt
> @@ -8,13 +8,33 @@ The SSS module in S5PV210 SoC supports the following:
>   -- SHA-1/SHA-256/MD5/HMAC (SHA-1/SHA-256/MD5)/PRNG
>   -- PRNG: Pseudo Random Number Generator
>
> +The SSS module in Exynos4 (Exynos4210) and
> +Exynos5 (Exynos5420 and Exynos5250) SoCs
> +supports the following also:
> +-- ARCFOUR (ARC4)
> +-- True Random Number Generator (TRNG)
> +-- Secure Key Manager
> +
>   Required properties:
>
>   - compatible : Should contain entries for this and backward compatible
>     SSS versions:
>     - "samsung,s5pv210-secss" for S5PV210 SoC.
> +  - "samsung,exynos4210-secss" for Exynos4210, Exynos5250 and Exynos5420 SoCs.

You can also add Exynos4212/4412 to the list.

>   - reg : Offset and length of the register set for the module
>   - interrupts : the interrupt-specifier for the SSS module.
>   		Two interrupts "feed control and hash" in case of S5PV210
> +		One interrupts "feed control" in case of Exynos4210,
> +			Exynos5250 and Exynos5420 SoCs.

You can refer to compatible string here instead of listing all the SoCs.

>   - clocks : the required gating clock for the SSS module.
>   - clock-names : the gating clock name to be requested in the SSS driver.

Again, please specify name of the clock in property description. The 
proper description for both clock properties should be:

- clock-names : list of device clock input names; should contain one 
entry - "secss".
- clocks : list of clock phandle and specifier pairs for all clocks 
listed in clock-names property.

> +
> +Example:
> +	/* SSS_VER_5 */
> +	sss@10830000 {
> +		compatible = "samsung,exynos4210-secss";
> +		reg = <0x10830000 0x10000>;
> +		interrupts = <0 112 0>;
> +		clocks = <&clock 471>;
> +		clock-names = "secss";
> +	};
> diff --git a/drivers/crypto/s5p-sss.c b/drivers/crypto/s5p-sss.c
> index 2da5617..f274f5f 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		0x00
>   #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		0x04
>   #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(off, s)	((off + 0x10) + (s << 2))
> +#define SSS_REG_AES_OUT_DATA(off, s)	((off + 0x20) + (s << 2))
> +#define SSS_REG_AES_IV_DATA(off, s)	((off + 0x30) + (s << 2))
> +#define SSS_REG_AES_CNT_DATA(off, s)	((off + 0x40) + (s << 2))
> +#define SSS_REG_AES_KEY_DATA(off, s)	((off + 0x80) + (s << 2))

I still somehow don't like this. Such macros are only hiding operations 
performed by the driver. See my comment below, in the code that 
references them, to see my proposal.

>
>   #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->variant->aes_offset)
> +#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)
> @@ -146,6 +151,20 @@
>   #define AES_KEY_LEN         16
>   #define CRYPTO_QUEUE_LEN    1
>
> +/**
> + * struct samsung_aes_variant - platform specific SSS driver data
> + * @has_hash_irq: true if SSS module uses hash interrupt, false otherwise
> + * @aes_offset: AES register offset from SSS module's base.
> + *
> + * Specifies platform specific configuration of SSS module.
> + * Note: A structure for driver specific platform data is used for future
> + * expansion of its usage.
> + */
> +struct samsung_aes_variant {
> +	bool			    has_hash_irq;
> +	unsigned int		    aes_offset;
> +};
> +
>   struct s5p_aes_reqctx {
>   	unsigned long mode;
>   };
> @@ -174,16 +193,48 @@ struct s5p_aes_dev {
>   	struct crypto_queue         queue;
>   	bool                        busy;
>   	spinlock_t                  lock;
> +
> +	struct samsung_aes_variant *variant;
>   };
>
>   static struct s5p_aes_dev *s5p_dev;
>
> +static const struct samsung_aes_variant s5p_aes_data = {
> +	.has_hash_irq	= true,
> +	.aes_offset	= 0x4000,
> +};
> +
> +static const struct samsung_aes_variant exynos_aes_data = {
> +	.has_hash_irq	= false,
> +	.aes_offset	= 0x200,
> +};
> +
>   static const struct of_device_id s5p_sss_dt_match[] = {
> -	{ .compatible = "samsung,s5pv210-secss", },
> +	{
> +		.compatible = "samsung,s5pv210-secss",
> +		.data = &s5p_aes_data,
> +	},
> +	{
> +		.compatible = "samsung,exynos4210-secss",
> +		.data = &exynos_aes_data,
> +	},
>   	{ },
>   };
>   MODULE_DEVICE_TABLE(of, s5p_sss_dt_match);
>
> +static inline struct samsung_aes_variant *find_s5p_sss_version
> +				   (struct platform_device *pdev)
> +{
> +	if (IS_ENABLED(CONFIG_OF) && (pdev->dev.of_node)) {
> +		const struct of_device_id *match;
> +		match = of_match_node(s5p_sss_dt_match,
> +					pdev->dev.of_node);
> +		return (struct samsung_aes_variant *)match->data;
> +	}
> +	return (struct samsung_aes_variant *)
> +			platform_get_device_id(pdev)->driver_data;
> +}
> +
>   static void s5p_set_dma_indata(struct s5p_aes_dev *dev, struct scatterlist *sg)
>   {
>   	SSS_WRITE(dev, FCBRDMAS, sg_dma_address(sg));
> @@ -327,16 +378,21 @@ static irqreturn_t s5p_aes_interrupt(int irq, void *dev_id)
>   static void s5p_set_aes(struct s5p_aes_dev *dev,
>   			uint8_t *key, uint8_t *iv, unsigned int keylen)
>   {
> +	struct samsung_aes_variant *var = dev->variant;
>   	void __iomem *keystart;
>
> -	memcpy(dev->ioaddr + SSS_REG_AES_IV_DATA(0), iv, 0x10);
> +	memcpy(dev->ioaddr + SSS_REG_AES_IV_DATA
> +				(var->aes_offset, 0), iv, 0x10);

What about adding aes_ioaddr to s5p_aes_dev struct? Then you could 
access the registers as follows:

	memcpy(dev->aes_ioaddr + SSS_REG_AES_IV_DATA(0), iv, 0x10);

The registers would be defined as offsets of AES base, e.g:

#define SSS_REG_AES_IV_DATA(s)		(0x10 + (s << 2))

>
>   	if (keylen == AES_KEYSIZE_256)
> -		keystart = dev->ioaddr + SSS_REG_AES_KEY_DATA(0);
> +		keystart = dev->ioaddr +
> +				SSS_REG_AES_KEY_DATA(var->aes_offset, 0);
>   	else if (keylen == AES_KEYSIZE_192)
> -		keystart = dev->ioaddr + SSS_REG_AES_KEY_DATA(2);
> +		keystart = dev->ioaddr +
> +				SSS_REG_AES_KEY_DATA(var->aes_offset, 2);
>   	else
> -		keystart = dev->ioaddr + SSS_REG_AES_KEY_DATA(4);
> +		keystart = dev->ioaddr +
> +				SSS_REG_AES_KEY_DATA(var->aes_offset, 4);
>
>   	memcpy(keystart, key, keylen);
>   }
> @@ -386,7 +442,7 @@ 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);

SSS_AES_WRITE would be define using dev->aes_ioaddr instead of dev->ioaddr.

Otherwise the patch looks fine.

Best regards,
Tomasz