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

[Corentin LABBE <clabbe.montjoie@gmail.com>]

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>
>> ---
>>  drivers/crypto/Kconfig    |   49 ++
>>  drivers/crypto/Makefile   |    1 +
>>  drivers/crypto/sunxi-ss.c | 1476 +++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 1526 insertions(+)
>>  create mode 100644 drivers/crypto/sunxi-ss.c
>>
>> diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
>> index 03ccdb0..5ea0922 100644
>> --- a/drivers/crypto/Kconfig
>> +++ b/drivers/crypto/Kconfig
>> @@ -418,4 +418,53 @@ config CRYPTO_DEV_MXS_DCP
>>  	  To compile this driver as a module, choose M here: the module
>>  	  will be called mxs-dcp.
>>  
>> +config CRYPTO_DEV_SUNXI_SS
>> +        tristate "Support for Allwinner Security System cryptographic accelerator"
>> +        depends on ARCH_SUNXI
>> +        help
>> +          Some Allwinner processors have a crypto accelerator named
>> +          Security System. Select this if you want to use it.
>> +
>> +          To compile this driver as a module, choose M here: the module
>> +          will be called sunxi-ss.
>> +
>> +if CRYPTO_DEV_SUNXI_SS
>> +config CRYPTO_DEV_SUNXI_SS_PRNG
>> +	bool "Security System PRNG"
>> +	select CRYPTO_RNG2
>> +	help
>> +	  If you enable this option, the SS will provide a pseudo random
>> +	  number generator.
>> +config CRYPTO_DEV_SUNXI_SS_MD5
>> +	bool "Security System MD5"
>> +	select CRYPTO_MD5
>> +	help
>> +	  If you enable this option, the SS will provide MD5 hardware
>> +	  acceleration.
> 
> 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 ?

> 
>> +#ifdef CONFIG_CRYPTO_DEV_SUNXI_SS_MD5
>> +#include <crypto/md5.h>
>> +#define SUNXI_SS_HASH_COMMON
>> +#endif
>> +#ifdef CONFIG_CRYPTO_DEV_SUNXI_SS_SHA1
>> +#include <crypto/sha.h>
>> +#define SUNXI_SS_HASH_COMMON
>> +#endif
>> +#ifdef SUNXI_SS_HASH_COMMON
>> +#include <crypto/hash.h>
>> +#include <crypto/internal/hash.h>
>> +#endif
>> +#ifdef CONFIG_CRYPTO_DEV_SUNXI_SS_AES
>> +#include <crypto/aes.h>
>> +#endif
>> +
>> +#ifdef CONFIG_CRYPTO_DEV_SUNXI_SS_3DES
>> +#define SUNXI_SS_DES
>> +#endif
>> +#ifdef CONFIG_CRYPTO_DEV_SUNXI_SS_DES
>> +#define SUNXI_SS_DES
>> +#endif
>> +#ifdef SUNXI_SS_DES
>> +#include <crypto/des.h>
>> +#endif
>> +
>> +#ifdef CONFIG_CRYPTO_DEV_SUNXI_SS_PRNG
>> +#include <crypto/internal/rng.h>
> 
> That would cleanup this #ifdef chain either way.
> 
>> +/* General notes:
>> + * I cannot use a key/IV cache because each time one of these change ALL stuff
>> + * need to be re-writed.
>> + * And for example, with dm-crypt IV changes on each request.
>> + *
>> + * After each request the device must be disabled.
>> + *
>> + * For performance reason, we use writel_relaxed/read_relaxed for all
>> + * operations on RX and TX FIFO.
>> + * For all other registers, we use writel.
>> + * See http://permalink.gmane.org/gmane.linux.ports.arm.kernel/117644
>> + * and http://permalink.gmane.org/gmane.linux.ports.arm.kernel/117640
>> + * */
>> +
>> +static struct sunxi_ss_ctx {
>> +	void *base;
> 
> __iomem ?

ok

> 
>> +	int irq;
>> +	struct clk *busclk;
>> +	struct clk *ssclk;
>> +	struct device *dev;
>> +	struct resource *res;
>> +	void *buf_in; /* pointer to data to be uploaded to the device */
>> +	size_t buf_in_size; /* size of buf_in */
>> +	void *buf_out;
>> +	size_t buf_out_size;
>> +} _ss_ctx, *ss_ctx = &_ss_ctx;
>> +
>> +static DEFINE_MUTEX(lock);
>> +static DEFINE_MUTEX(bufout_lock);
>> +static DEFINE_MUTEX(bufin_lock);
> 
> I guess the mutexes should be part of sunxi_ss_ctx.
> 
> Are you sure you need the global _ss_ctx structure?
> Normally you should get a pointer from whoever calls you.

I will use platform_get_drvdata/platform_set_drvdata for cleaning all thoses global structures..

> 
>> +struct sunxi_req_ctx {
>> +	u8 key[AES_MAX_KEY_SIZE * 8];
>> +	u32 keylen;
>> +	u32 mode;
>> +	u64 byte_count; /* number of bytes "uploaded" to the device */
>> +	u32 waitbuf; /* a partial word waiting to be completed and
>> +			uploaded to the device */
>> +	/* number of bytes to be uploaded in the waitbuf word */
>> +	unsigned int nbwait;
>> +};
>> +
>> +#ifdef SUNXI_SS_HASH_COMMON
>> +/*============================================================================*/
>> +/*============================================================================*/
> 
> Please remove all the ======== lines.

ok

> 
>> +	/* 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.

> 
> How does the original driver do it?

There are no original driver, this driver is the first for the Security System.

> 
> 	Arnd
> 

Thanks for your review.