Re: [PATCH V3 4/4] crypto: Add Xilinx AES driver

Corentin Labbe
2019-11-15T12:45:24Z

On Wed, Nov 06, 2019 at 05:10:35PM +0530, Kalyani Akula wrote:
> This patch adds AES driver support for the Xilinx ZynqMP SoC.
>
> Signed-off-by: Kalyani Akula <kalyani.akula@xilinx.com>
> ---
> drivers/crypto/Kconfig | 11 +
> drivers/crypto/Makefile | 2 +
> drivers/crypto/xilinx/Makefile | 3 +
> drivers/crypto/xilinx/zynqmp-aes-gcm.c | 457 +++++++++++++++++++++++++++++++++
> 4 files changed, 473 insertions(+)
> create mode 100644 drivers/crypto/xilinx/Makefile
> create mode 100644 drivers/crypto/xilinx/zynqmp-aes-gcm.c
>
> diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
> index 1fb622f..8e7d3a9 100644
> --- a/drivers/crypto/Kconfig
> +++ b/drivers/crypto/Kconfig
> @@ -696,6 +696,17 @@ config CRYPTO_DEV_ROCKCHIP
> help
> This driver interfaces with the hardware crypto accelerator.
> Supporting cbc/ecb chainmode, and aes/des/des3_ede cipher mode.
> +config CRYPTO_DEV_ZYNQMP_AES
> + tristate "Support for Xilinx ZynqMP AES hw accelerator"
> + depends on ARCH_ZYNQMP || COMPILE_TEST
> + select CRYPTO_AES
> + select CRYPTO_ENGINE
> + select CRYPTO_AEAD
> + help
> + Xilinx ZynqMP has AES-GCM engine used for symmetric key
> + encryption and decryption. This driver interfaces with AES hw
> + accelerator. Select this if you want to use the ZynqMP module
> + for AES algorithms.
>
> config CRYPTO_DEV_MEDIATEK
> tristate "MediaTek's EIP97 Cryptographic Engine driver"
> diff --git a/drivers/crypto/Makefile b/drivers/crypto/Makefile
> index afc4753..b6124b8 100644
> --- a/drivers/crypto/Makefile
> +++ b/drivers/crypto/Makefile
> @@ -47,4 +47,6 @@ obj-$(CONFIG_CRYPTO_DEV_VMX) += vmx/
> obj-$(CONFIG_CRYPTO_DEV_BCM_SPU) += bcm/
> obj-$(CONFIG_CRYPTO_DEV_SAFEXCEL) += inside-secure/
> obj-$(CONFIG_CRYPTO_DEV_ARTPEC6) += axis/
> +obj-$(CONFIG_CRYPTO_DEV_ZYNQMP_AES) += xilinx/
> +

Hello

you insert a useless newline

[...]
> +static int zynqmp_handle_aes_req(struct crypto_engine *engine,
> + void *req)
> +{
> + struct aead_request *areq =
> + container_of(req, struct aead_request, base);
> + struct crypto_aead *aead = crypto_aead_reqtfm(req);
> + struct zynqmp_aead_tfm_ctx *tfm_ctx = crypto_aead_ctx(aead);
> + struct zynqmp_aead_req_ctx *rq_ctx = aead_request_ctx(areq);
> + struct aead_request *subreq;
> + int need_fallback;
> + int err;
> +
> + need_fallback = zynqmp_fallback_check(tfm_ctx, areq);
> +
> + if (need_fallback) {
> + subreq = aead_request_alloc(tfm_ctx->fbk_cipher, GFP_KERNEL);
> + if (!subreq)
> + return -ENOMEM;
> +
> + aead_request_set_callback(subreq, areq->base.flags,
> + NULL, NULL);
> + aead_request_set_crypt(subreq, areq->src, areq->dst,
> + areq->cryptlen, areq->iv);
> + aead_request_set_ad(subreq, areq->assoclen);
> + if (rq_ctx->op == ZYNQMP_AES_ENCRYPT)
> + err = crypto_aead_encrypt(subreq);
> + else
> + err = crypto_aead_decrypt(subreq);
> + aead_request_free(subreq);

Every other crypto driver which use async fallback does not use aead_request_free() (and do not allocate a new request).
I am puzzled that you can free an async request without waiting for its completion.
Perhaps I am wrong, but since no other driver do like that...

[...]
> +static int zynqmp_aes_aead_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + int err = -1;
> +
> + if (!pdev->dev.of_node)
> + return -ENODEV;
> +
> + aes_drv_ctx.dev = dev;

You should test if dev is not already set.
And add a comment like "this driver support only one instance".

> + aes_drv_ctx.eemi_ops = zynqmp_pm_get_eemi_ops();
> + if (IS_ERR(aes_drv_ctx.eemi_ops)) {
> + dev_err(dev, "Failed to get ZynqMP EEMI interface\n");
> + return PTR_ERR(aes_drv_ctx.eemi_ops);
> + }
> +
> + err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(ZYNQMP_DMA_BIT_MASK));
> + if (err < 0) {
> + dev_err(dev, "No usable DMA configuration\n");
> + return err;
> + }
> +
> + aes_drv_ctx.engine = crypto_engine_alloc_init(dev, 1);
> + if (!aes_drv_ctx.engine) {
> + dev_err(dev, "Cannot alloc AES engine\n");
> + return err;
> + }
> +
> + err = crypto_engine_start(aes_drv_ctx.engine);
> + if (err) {
> + dev_err(dev, "Cannot start AES engine\n");
> + return err;
> + }
> +
> + err = crypto_register_aead(&aes_drv_ctx.alg.aead);
> + if (err < 0)
> + dev_err(dev, "Failed to register AEAD alg.\n");

In case of error you didnt crypto_engine_exit()

Regards