DCP allows working with secure keys. These keys can reside in a
protected memory region of the crypto accelerator, burned in
eFuses or being an internal chip key. To use these keys a key
reference is transferred to the chip instead of a AES key.
For DCP these references can be:
0x00 to 0x03: Key slot number in the secure memory region
0xfe: Unique device key
0xff: OTP key (burned in eFuse)
To utilize this functionality we check for the
CRYPTO_TFM_REQ_REF_KEY flag, if it is set the key as provided
via mxs_dcp_aes_setkey() is used as reference.
Signed-off-by: Richard Weinberger <richard@xxxxxx>
---
drivers/crypto/mxs-dcp.c | 77 +++++++++++++++++++++++++++++++++++++++---------
1 file changed, 63 insertions(+), 14 deletions(-)
diff --git a/drivers/crypto/mxs-dcp.c b/drivers/crypto/mxs-dcp.c
index b4429891e368..22b048a3a91b 100644
--- a/drivers/crypto/mxs-dcp.c
+++ b/drivers/crypto/mxs-dcp.c
@@ -147,6 +147,10 @@ static struct dcp *global_sdcp;
#define MXS_DCP_CONTEXT 0x50
+#define MXS_DCP_KEY 0x60
+#define MXS_DCP_KEY_IDX(id, word) (((id) << 4) | (word))
+#define MXS_DCP_KEYDATA 0x70
+
#define MXS_DCP_CH_N_CMDPTR(n) (0x100 + ((n) * 0x40))
#define MXS_DCP_CH_N_SEMA(n) (0x110 + ((n) * 0x40))
@@ -158,6 +162,7 @@ static struct dcp *global_sdcp;
#define MXS_DCP_CONTROL0_HASH_TERM (1 << 13)
#define MXS_DCP_CONTROL0_HASH_INIT (1 << 12)
#define MXS_DCP_CONTROL0_PAYLOAD_KEY (1 << 11)
+#define MXS_DCP_CONTROL0_OTP_KEY (1 << 10)
#define MXS_DCP_CONTROL0_CIPHER_ENCRYPT (1 << 8)
#define MXS_DCP_CONTROL0_CIPHER_INIT (1 << 9)
#define MXS_DCP_CONTROL0_ENABLE_HASH (1 << 6)
@@ -222,15 +227,22 @@ static int mxs_dcp_run_aes(struct dcp_async_ctx *actx,
struct dcp *sdcp = global_sdcp;
struct dcp_dma_desc *desc = &sdcp->coh->desc[actx->chan];
struct dcp_aes_req_ctx *rctx = ablkcipher_request_ctx(req);
+ struct crypto_async_request *arq = &req->base;
+ bool key_referenced = !!(crypto_tfm_get_flags(arq->tfm) &
+ CRYPTO_TFM_REQ_REF_KEY);
+ dma_addr_t src_phys, dst_phys, key_phys = {0};
int ret;
- dma_addr_t key_phys = dma_map_single(sdcp->dev, sdcp->coh->aes_key,
- 2 * AES_KEYSIZE_128,
- DMA_TO_DEVICE);
- dma_addr_t src_phys = dma_map_single(sdcp->dev, sdcp->coh->aes_in_buf,
- DCP_BUF_SZ, DMA_TO_DEVICE);
- dma_addr_t dst_phys = dma_map_single(sdcp->dev, sdcp->coh->aes_out_buf,
- DCP_BUF_SZ, DMA_FROM_DEVICE);
+ if (!key_referenced) {
+ key_phys = dma_map_single(sdcp->dev, sdcp->coh->aes_key,
+ 2 * AES_KEYSIZE_128,
+ DMA_TO_DEVICE);
+ }
+
+ src_phys = dma_map_single(sdcp->dev, sdcp->coh->aes_in_buf,
+ DCP_BUF_SZ, DMA_TO_DEVICE);
+ dst_phys = dma_map_single(sdcp->dev, sdcp->coh->aes_out_buf,
+ DCP_BUF_SZ, DMA_FROM_DEVICE);
if (actx->fill % AES_BLOCK_SIZE) {
dev_err(sdcp->dev, "Invalid block size!\n");
@@ -243,8 +255,12 @@ static int mxs_dcp_run_aes(struct dcp_async_ctx *actx,
MXS_DCP_CONTROL0_INTERRUPT |
MXS_DCP_CONTROL0_ENABLE_CIPHER;
- /* Payload contains the key. */
- desc->control0 |= MXS_DCP_CONTROL0_PAYLOAD_KEY;
+ if (key_referenced) {
+ desc->control0 |= MXS_DCP_CONTROL0_OTP_KEY;
+ } else {
+ /* Payload contains the key. */
+ desc->control0 |= MXS_DCP_CONTROL0_PAYLOAD_KEY;
+ }
if (rctx->enc)
desc->control0 |= MXS_DCP_CONTROL0_CIPHER_ENCRYPT;
@@ -258,18 +274,26 @@ static int mxs_dcp_run_aes(struct dcp_async_ctx *actx,
else
desc->control1 |= MXS_DCP_CONTROL1_CIPHER_MODE_CBC;
+ if (key_referenced)
+ desc->control1 |= sdcp->coh->aes_key[0] << 8;
+
desc->next_cmd_addr = 0;
desc->source = src_phys;
desc->destination = dst_phys;
desc->size = actx->fill;
- desc->payload = key_phys;
+ if (key_referenced)
+ desc->payload = 0;
+ else
+ desc->payload = key_phys;
desc->status = 0;
ret = mxs_dcp_start_dma(actx);
aes_done_run:
- dma_unmap_single(sdcp->dev, key_phys, 2 * AES_KEYSIZE_128,
- DMA_TO_DEVICE);
+ if (!key_referenced) {
+ dma_unmap_single(sdcp->dev, key_phys, 2 * AES_KEYSIZE_128,
+ DMA_TO_DEVICE);
+ }
dma_unmap_single(sdcp->dev, src_phys, DCP_BUF_SZ, DMA_TO_DEVICE);
dma_unmap_single(sdcp->dev, dst_phys, DCP_BUF_SZ, DMA_FROM_DEVICE);
@@ -498,15 +522,40 @@ static int mxs_dcp_aes_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
unsigned int len)
{
struct dcp_async_ctx *actx = crypto_ablkcipher_ctx(tfm);
+ bool key_referenced = !!(crypto_ablkcipher_get_flags(tfm) &
+ CRYPTO_TFM_REQ_REF_KEY);
unsigned int ret;
/*
- * AES 128 is supposed by the hardware, store key into temporary
+ * AES 128 is supported by the hardware, store key into temporary
* buffer and exit. We must use the temporary buffer here, since
* there can still be an operation in progress.
*/
actx->key_len = len;
- if (len == AES_KEYSIZE_128) {
+
+ if (key_referenced) {
+ /*
+ * If a hardware key is used, no software fallback is possible.
+ */
+ if (len != AES_KEYSIZE_128)
+ return -EINVAL;
+
+ /*
+ * DCP supports the following key slots.
+ */
+ switch (key[0]) {
+ case 0x00:
+ case 0x01:
+ case 0x02:
+ case 0x03:
+ case 0xfe:
+ case 0xff:
+ memcpy(actx->key, key, len);
+ return 0;
+ default:
+ return -EINVAL;
+ }
+ } else if (len == AES_KEYSIZE_128) {
memcpy(actx->key, key, len);
return 0;
}
--
2.16.4
