[PATCH v4 2/2] crypto: stm32 - Support for STM32 CRYP crypto module
Fabien DESSENNE
fabien.dessenne at st.com
Thu Oct 19 06:01:56 PDT 2017
Hi Corentin
Thank you for your comments. I will fix according to them. See also me
answers/questions below
While we are at it, do you plan to deliver a new version of the
crypto_engine update? (I had to remove the AEAD part of this new driver
since it depends on that pending update)
BR
Fabien
On 19/10/17 12:34, Corentin Labbe wrote:
> Hello
>
> I have some minor comment below
>
> On Thu, Oct 19, 2017 at 11:03:59AM +0200, Fabien Dessenne wrote:
>> This module registers block cipher algorithms that make use of the
>> STMicroelectronics STM32 crypto "CRYP1" hardware.
>> The following algorithms are supported:
>> - aes: ecb, cbc, ctr
>> - des: ecb, cbc
>> - tdes: ecb, cbc
>>
>> Signed-off-by: Fabien Dessennie <fabien.dessenne at st.com>
>> ---
>> drivers/crypto/stm32/Kconfig | 9 +
>> drivers/crypto/stm32/Makefile | 3 +-
>> drivers/crypto/stm32/stm32-cryp.c | 1188 +++++++++++++++++++++++++++++++++++++
>> 3 files changed, 1199 insertions(+), 1 deletion(-)
>> create mode 100644 drivers/crypto/stm32/stm32-cryp.c
>>
>> diff --git a/drivers/crypto/stm32/Kconfig b/drivers/crypto/stm32/Kconfig
>> index 602332e..61ef00b 100644
>> --- a/drivers/crypto/stm32/Kconfig
>> +++ b/drivers/crypto/stm32/Kconfig
> [...]
>> +/* Bit [0] encrypt / decrypt */
>> +#define FLG_ENCRYPT BIT(0)
>> +/* Bit [8..1] algo & operation mode */
>> +#define FLG_AES BIT(1)
>> +#define FLG_DES BIT(2)
>> +#define FLG_TDES BIT(3)
>> +#define FLG_ECB BIT(4)
>> +#define FLG_CBC BIT(5)
>> +#define FLG_CTR BIT(6)
>> +/* Mode mask = bits [15..0] */
>> +#define FLG_MODE_MASK GENMASK(15, 0)
>> +
>> +/* Registers */
>> +#define CRYP_CR 0x00000000
>> +#define CRYP_SR 0x00000004
>> +#define CRYP_DIN 0x00000008
>> +#define CRYP_DOUT 0x0000000C
>> +#define CRYP_DMACR 0x00000010
>> +#define CRYP_IMSCR 0x00000014
>> +#define CRYP_RISR 0x00000018
>> +#define CRYP_MISR 0x0000001C
>> +#define CRYP_K0LR 0x00000020
>> +#define CRYP_K0RR 0x00000024
>> +#define CRYP_K1LR 0x00000028
>> +#define CRYP_K1RR 0x0000002C
>> +#define CRYP_K2LR 0x00000030
>> +#define CRYP_K2RR 0x00000034
>> +#define CRYP_K3LR 0x00000038
>> +#define CRYP_K3RR 0x0000003C
>> +#define CRYP_IV0LR 0x00000040
>> +#define CRYP_IV0RR 0x00000044
>> +#define CRYP_IV1LR 0x00000048
>> +#define CRYP_IV1RR 0x0000004C
>> +
>> +/* Registers values */
>> +#define CR_DEC_NOT_ENC 0x00000004
>> +#define CR_TDES_ECB 0x00000000
>> +#define CR_TDES_CBC 0x00000008
>> +#define CR_DES_ECB 0x00000010
>> +#define CR_DES_CBC 0x00000018
>> +#define CR_AES_ECB 0x00000020
>> +#define CR_AES_CBC 0x00000028
>> +#define CR_AES_CTR 0x00000030
>> +#define CR_AES_KP 0x00000038
>> +#define CR_AES_UNKNOWN 0xFFFFFFFF
>> +#define CR_ALGO_MASK 0x00080038
>> +#define CR_DATA32 0x00000000
>> +#define CR_DATA16 0x00000040
>> +#define CR_DATA8 0x00000080
>> +#define CR_DATA1 0x000000C0
>> +#define CR_KEY128 0x00000000
>> +#define CR_KEY192 0x00000100
>> +#define CR_KEY256 0x00000200
>> +#define CR_FFLUSH 0x00004000
>> +#define CR_CRYPEN 0x00008000
> Why not using BIT(x) ?
Some values are not only 1 bit (then we may use BIT and BITGEN but this
would be less readable), so I prefer to keep this values.
> Why not using also directly FLG_XX since CR_XX are arbitray values ? like using instead CR_AES_CBC = FLG_AES | FLG_CBC
The CR_ values are used to write in the registers. FLG_ are arbitraty
values, so we cannot mix them.
>
> [...]
>> +static inline void stm32_cryp_wait_enable(struct stm32_cryp *cryp)
>> +{
>> + while (stm32_cryp_read(cryp, CRYP_CR) & CR_CRYPEN)
>> + cpu_relax();
>> +}
> This function is not used, so you could remove it
>
>> +
>> +static inline void stm32_cryp_wait_busy(struct stm32_cryp *cryp)
>> +{
>> + while (stm32_cryp_read(cryp, CRYP_SR) & SR_BUSY)
>> + cpu_relax();
>> +}
> No timeout ?
>
>
>> +
>> +static inline void stm32_cryp_wait_output(struct stm32_cryp *cryp)
>> +{
>> + while (!(stm32_cryp_read(cryp, CRYP_SR) & SR_OFNE))
>> + cpu_relax();
>> +}
> This function is not used, so you could remove it
>
> [...]
>> +static int stm32_cryp_check_aligned(struct scatterlist *sg, size_t total,
>> + size_t align)
>> +{
>> + int len = 0;
>> +
>> + if (!total)
>> + return 0;
>> +
>> + if (!IS_ALIGNED(total, align))
>> + return -EINVAL;
>> +
>> + while (sg) {
>> + if (!IS_ALIGNED(sg->offset, sizeof(u32)))
>> + return -1;
> -1 is not a good return value, prefer any -Exxxx
>
>> +
>> + if (!IS_ALIGNED(sg->length, align))
>> + return -1;
>> +
>> + len += sg->length;
>> + sg = sg_next(sg);
>> + }
>> +
>> + if (len != total)
>> + return -1;
> [...]
>> +static int stm32_cryp_copy_sgs(struct stm32_cryp *cryp)
>> +{
>> + void *buf_in, *buf_out;
>> + int pages, total_in, total_out;
>> +
>> + if (!stm32_cryp_check_io_aligned(cryp)) {
>> + cryp->sgs_copied = 0;
>> + return 0;
>> + }
>> +
>> + total_in = ALIGN(cryp->total_in, cryp->hw_blocksize);
>> + pages = total_in ? get_order(total_in) : 1;
>> + buf_in = (void *)__get_free_pages(GFP_ATOMIC, pages);
>> +
>> + total_out = ALIGN(cryp->total_out, cryp->hw_blocksize);
>> + pages = total_out ? get_order(total_out) : 1;
>> + buf_out = (void *)__get_free_pages(GFP_ATOMIC, pages);
>> +
>> + if (!buf_in || !buf_out) {
>> + pr_err("Couldn't allocate pages for unaligned cases.\n");
> You must use dev_err() instead. without it, it will be hard to know which subsystem said that error message.
>
> [...]
>> +static int stm32_cryp_cra_init(struct crypto_tfm *tfm)
>> +{
>> + tfm->crt_ablkcipher.reqsize = sizeof(struct stm32_cryp_reqctx);
>> +
>> + return 0;
>> +}
> You could simply remove this function
I am not sure we can. Here we set reqsize.
Most of the other drivers do the same, but maybe this is wrong everywhere.
Could you give more details?
>
> [...]
>> +
>> +static void stm32_cryp_cra_exit(struct crypto_tfm *tfm)
>> +{
>> +}
>> +
>> +static int stm32_cryp_crypt(struct ablkcipher_request *req, unsigned long mode)
>> +{
>> + struct stm32_cryp_ctx *ctx = crypto_ablkcipher_ctx(
>> + crypto_ablkcipher_reqtfm(req));
>> + struct stm32_cryp_reqctx *rctx = ablkcipher_request_ctx(req);
>> + struct stm32_cryp *cryp = stm32_cryp_find_dev(ctx);
>> +
>> + if (!cryp)
>> + return -ENODEV;
>> +
>> + rctx->mode = mode;
>> +
>> + return crypto_transfer_cipher_request_to_engine(cryp->engine, req);
>> +}
>> +
>> +static int stm32_cryp_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
>> + unsigned int keylen)
>> +{
>> + struct stm32_cryp_ctx *ctx = crypto_ablkcipher_ctx(tfm);
>> +
>> + memcpy(ctx->key, key, keylen);
>> + ctx->keylen = keylen;
> You never zeroize the key after request.
>
> [...]
>> +static const struct of_device_id stm32_dt_ids[] = {
>> + { .compatible = "st,stm32f756-cryp", },
>> + {},
>> +};
>> +MODULE_DEVICE_TABLE(of, sti_dt_ids);
>> +
>> +static int stm32_cryp_probe(struct platform_device *pdev)
>> +{
>> + struct device *dev = &pdev->dev;
>> + struct stm32_cryp *cryp;
>> + struct resource *res;
>> + struct reset_control *rst;
>> + const struct of_device_id *match;
>> + int irq, ret;
>> +
>> + cryp = devm_kzalloc(dev, sizeof(*cryp), GFP_KERNEL);
>> + if (!cryp)
>> + return -ENOMEM;
>> +
>> + match = of_match_device(stm32_dt_ids, dev);
>> + if (!match)
>> + return -ENODEV;
> I think this test is unnecessary, at least it should be before the devm_kzalloc
>
> Regards
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