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crypto: caam/rng: Add support for PRNG
Add support for random number generation using PRNG mode of CAAM and expose the interface through crypto API. Signed-off-by: Meenakshi Aggarwal <meenakshi.aggarwal@nxp.com>
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// SPDX-License-Identifier: GPL-2.0+ | ||
/* | ||
* Driver to expose SEC4 PRNG via crypto RNG API | ||
* | ||
* Copyright 2022 NXP | ||
* | ||
*/ | ||
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#include <linux/completion.h> | ||
#include <crypto/internal/rng.h> | ||
#include "compat.h" | ||
#include "regs.h" | ||
#include "intern.h" | ||
#include "desc_constr.h" | ||
#include "jr.h" | ||
#include "error.h" | ||
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/* | ||
* Length of used descriptors, see caam_init_desc() | ||
*/ | ||
#define CAAM_PRNG_DESC_LEN (CAAM_CMD_SZ + \ | ||
CAAM_CMD_SZ + \ | ||
CAAM_CMD_SZ + CAAM_PTR_SZ_MAX) | ||
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/* prng per-device context */ | ||
struct caam_prng_ctx { | ||
struct device *jrdev; | ||
struct completion done; | ||
}; | ||
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struct caam_prng_alg { | ||
struct rng_alg rng; | ||
bool registered; | ||
}; | ||
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static void caam_prng_done(struct device *jrdev, u32 *desc, u32 err, | ||
void *context) | ||
{ | ||
struct caam_prng_ctx *jctx = context; | ||
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if (err) | ||
caam_jr_strstatus(jrdev, err); | ||
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complete(&jctx->done); | ||
} | ||
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static u32 *caam_init_reseed_desc(u32 *desc, dma_addr_t seed_dma, u32 len) | ||
{ | ||
init_job_desc(desc, 0); /* + 1 cmd_sz */ | ||
/* Generate random bytes: + 1 cmd_sz */ | ||
append_operation(desc, OP_TYPE_CLASS1_ALG | OP_ALG_ALGSEL_RNG | | ||
OP_ALG_AS_FINALIZE | OP_ALG_AI_ON); | ||
/* Store bytes: + 1 cmd_sz + caam_ptr_sz */ | ||
append_load(desc, seed_dma, len, CLASS_1 | LDST_SRCDST_BYTE_CONTEXT); | ||
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print_hex_dump_debug("prng reseed desc@: ", DUMP_PREFIX_ADDRESS, | ||
16, 4, desc, desc_bytes(desc), 1); | ||
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return desc; | ||
} | ||
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static u32 *caam_init_prng_desc(u32 *desc, dma_addr_t dst_dma, u32 len) | ||
{ | ||
init_job_desc(desc, 0); /* + 1 cmd_sz */ | ||
/* Generate random bytes: + 1 cmd_sz */ | ||
append_operation(desc, OP_ALG_ALGSEL_RNG | OP_TYPE_CLASS1_ALG); | ||
/* Store bytes: + 1 cmd_sz + caam_ptr_sz */ | ||
append_fifo_store(desc, dst_dma, | ||
len, FIFOST_TYPE_RNGSTORE); | ||
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print_hex_dump_debug("prng job desc@: ", DUMP_PREFIX_ADDRESS, | ||
16, 4, desc, desc_bytes(desc), 1); | ||
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return desc; | ||
} | ||
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static int caam_prng_generate(struct crypto_rng *tfm, | ||
const u8 *src, unsigned int slen, | ||
u8 *dst, unsigned int dlen) | ||
{ | ||
struct caam_prng_ctx ctx; | ||
dma_addr_t dst_dma; | ||
u32 *desc; | ||
int ret; | ||
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ctx.jrdev = caam_jr_alloc(); | ||
ret = PTR_ERR_OR_ZERO(ctx.jrdev); | ||
if (ret) { | ||
pr_err("Job Ring Device allocation failed\n"); | ||
return ret; | ||
} | ||
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desc = kzalloc(CAAM_PRNG_DESC_LEN, GFP_KERNEL | GFP_DMA); | ||
if (!desc) { | ||
caam_jr_free(ctx.jrdev); | ||
return -ENOMEM; | ||
} | ||
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dst_dma = dma_map_single(ctx.jrdev, dst, dlen, DMA_FROM_DEVICE); | ||
if (dma_mapping_error(ctx.jrdev, dst_dma)) { | ||
dev_err(ctx.jrdev, "Failed to map destination buffer memory\n"); | ||
ret = -ENOMEM; | ||
goto out; | ||
} | ||
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init_completion(&ctx.done); | ||
ret = caam_jr_enqueue(ctx.jrdev, | ||
caam_init_prng_desc(desc, dst_dma, dlen), | ||
caam_prng_done, &ctx); | ||
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if (ret == -EINPROGRESS) { | ||
wait_for_completion(&ctx.done); | ||
ret = 0; | ||
} | ||
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dma_unmap_single(ctx.jrdev, dst_dma, dlen, DMA_FROM_DEVICE); | ||
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out: | ||
kfree(desc); | ||
caam_jr_free(ctx.jrdev); | ||
return ret; | ||
} | ||
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static void caam_prng_exit(struct crypto_tfm *tfm) | ||
{ | ||
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return; | ||
} | ||
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static int caam_prng_init(struct crypto_tfm *tfm) | ||
{ | ||
return 0; | ||
} | ||
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static int caam_prng_seed(struct crypto_rng *tfm, | ||
const u8 *seed, unsigned int slen) | ||
{ | ||
struct caam_prng_ctx ctx; | ||
dma_addr_t seed_dma; | ||
u32 *desc; | ||
int ret; | ||
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ctx.jrdev = caam_jr_alloc(); | ||
ret = PTR_ERR_OR_ZERO(ctx.jrdev); | ||
if (ret) { | ||
pr_err("Job Ring Device allocation failed\n"); | ||
return ret; | ||
} | ||
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desc = kzalloc(CAAM_PRNG_DESC_LEN, GFP_KERNEL | GFP_DMA); | ||
if (!desc) { | ||
caam_jr_free(ctx.jrdev); | ||
return -ENOMEM; | ||
} | ||
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seed_dma = dma_map_single(ctx.jrdev, seed, slen, DMA_FROM_DEVICE); | ||
if (dma_mapping_error(ctx.jrdev, seed_dma)) { | ||
dev_err(ctx.jrdev, "Failed to map destination buffer memory\n"); | ||
ret = -ENOMEM; | ||
goto out; | ||
} | ||
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init_completion(&ctx.done); | ||
ret = caam_jr_enqueue(ctx.jrdev, | ||
caam_init_reseed_desc(desc, seed_dma, slen), | ||
caam_prng_done, &ctx); | ||
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if (ret == -EINPROGRESS) { | ||
wait_for_completion(&ctx.done); | ||
ret = 0; | ||
} | ||
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dma_unmap_single(ctx.jrdev, seed_dma, slen, DMA_FROM_DEVICE); | ||
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out: | ||
kfree(desc); | ||
caam_jr_free(ctx.jrdev); | ||
return ret; | ||
} | ||
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static struct caam_prng_alg caam_prng_alg = { | ||
.rng = { | ||
.generate = caam_prng_generate, | ||
.seed = caam_prng_seed, | ||
.seedsize = 32, | ||
.base = { | ||
.cra_name = "stdrng", | ||
.cra_driver_name = "prng-caam", | ||
.cra_priority = 500, | ||
.cra_ctxsize = sizeof(struct caam_prng_ctx), | ||
.cra_module = THIS_MODULE, | ||
.cra_init = caam_prng_init, | ||
.cra_exit = caam_prng_exit, | ||
}, | ||
} | ||
}; | ||
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void caam_prng_unregister(void *data) | ||
{ | ||
if (caam_prng_alg.registered) | ||
crypto_unregister_rng(&caam_prng_alg.rng); | ||
} | ||
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int caam_prng_register(struct device *ctrldev) | ||
{ | ||
struct caam_drv_private *priv = dev_get_drvdata(ctrldev); | ||
u32 rng_inst; | ||
int ret = 0; | ||
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/* Check for available RNG blocks before registration */ | ||
if (priv->era < 10) | ||
rng_inst = (rd_reg32(&priv->jr[0]->perfmon.cha_num_ls) & | ||
CHA_ID_LS_RNG_MASK) >> CHA_ID_LS_RNG_SHIFT; | ||
else | ||
rng_inst = rd_reg32(&priv->jr[0]->vreg.rng) & CHA_VER_NUM_MASK; | ||
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if (!rng_inst) { | ||
dev_dbg(ctrldev, "RNG block is not available..." | ||
"skipping registering rng algorithm\n"); | ||
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return ret; | ||
} | ||
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ret = crypto_register_rng(&caam_prng_alg.rng); | ||
if (ret) { | ||
dev_err(ctrldev, | ||
"couldn't register rng crypto alg: %d\n", | ||
ret); | ||
return ret; | ||
} | ||
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caam_prng_alg.registered = true; | ||
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dev_info(ctrldev, | ||
"rng crypto API alg registered %s\n", caam_prng_alg.rng.base.cra_name); | ||
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return 0; | ||
} |
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