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261 lines
5.6 KiB
261 lines
5.6 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* caam - Freescale FSL CAAM support for hw_random |
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* |
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* Copyright 2011 Freescale Semiconductor, Inc. |
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* Copyright 2018-2019 NXP |
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* |
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* Based on caamalg.c crypto API driver. |
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* |
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*/ |
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#include <linux/hw_random.h> |
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#include <linux/completion.h> |
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#include <linux/atomic.h> |
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#include <linux/kfifo.h> |
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#include "compat.h" |
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#include "regs.h" |
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#include "intern.h" |
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#include "desc_constr.h" |
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#include "jr.h" |
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#include "error.h" |
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#define CAAM_RNG_MAX_FIFO_STORE_SIZE 16 |
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/* |
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* Length of used descriptors, see caam_init_desc() |
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*/ |
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#define CAAM_RNG_DESC_LEN (CAAM_CMD_SZ + \ |
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CAAM_CMD_SZ + \ |
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CAAM_CMD_SZ + CAAM_PTR_SZ_MAX) |
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/* rng per-device context */ |
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struct caam_rng_ctx { |
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struct hwrng rng; |
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struct device *jrdev; |
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struct device *ctrldev; |
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void *desc_async; |
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void *desc_sync; |
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struct work_struct worker; |
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struct kfifo fifo; |
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}; |
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struct caam_rng_job_ctx { |
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struct completion *done; |
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int *err; |
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}; |
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static struct caam_rng_ctx *to_caam_rng_ctx(struct hwrng *r) |
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{ |
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return (struct caam_rng_ctx *)r->priv; |
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} |
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static void caam_rng_done(struct device *jrdev, u32 *desc, u32 err, |
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void *context) |
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{ |
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struct caam_rng_job_ctx *jctx = context; |
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if (err) |
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*jctx->err = caam_jr_strstatus(jrdev, err); |
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complete(jctx->done); |
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} |
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static u32 *caam_init_desc(u32 *desc, dma_addr_t dst_dma) |
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{ |
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init_job_desc(desc, 0); /* + 1 cmd_sz */ |
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/* Generate random bytes: + 1 cmd_sz */ |
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append_operation(desc, OP_ALG_ALGSEL_RNG | OP_TYPE_CLASS1_ALG | |
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OP_ALG_PR_ON); |
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/* Store bytes: + 1 cmd_sz + caam_ptr_sz */ |
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append_fifo_store(desc, dst_dma, |
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CAAM_RNG_MAX_FIFO_STORE_SIZE, FIFOST_TYPE_RNGSTORE); |
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print_hex_dump_debug("rng job desc@: ", DUMP_PREFIX_ADDRESS, |
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16, 4, desc, desc_bytes(desc), 1); |
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return desc; |
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} |
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static int caam_rng_read_one(struct device *jrdev, |
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void *dst, int len, |
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void *desc, |
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struct completion *done) |
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{ |
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dma_addr_t dst_dma; |
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int err, ret = 0; |
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struct caam_rng_job_ctx jctx = { |
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.done = done, |
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.err = &ret, |
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}; |
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len = CAAM_RNG_MAX_FIFO_STORE_SIZE; |
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dst_dma = dma_map_single(jrdev, dst, len, DMA_FROM_DEVICE); |
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if (dma_mapping_error(jrdev, dst_dma)) { |
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dev_err(jrdev, "unable to map destination memory\n"); |
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return -ENOMEM; |
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} |
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init_completion(done); |
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err = caam_jr_enqueue(jrdev, |
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caam_init_desc(desc, dst_dma), |
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caam_rng_done, &jctx); |
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if (err == -EINPROGRESS) { |
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wait_for_completion(done); |
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err = 0; |
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} |
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dma_unmap_single(jrdev, dst_dma, len, DMA_FROM_DEVICE); |
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return err ?: (ret ?: len); |
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} |
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static void caam_rng_fill_async(struct caam_rng_ctx *ctx) |
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{ |
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struct scatterlist sg[1]; |
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struct completion done; |
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int len, nents; |
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sg_init_table(sg, ARRAY_SIZE(sg)); |
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nents = kfifo_dma_in_prepare(&ctx->fifo, sg, ARRAY_SIZE(sg), |
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CAAM_RNG_MAX_FIFO_STORE_SIZE); |
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if (!nents) |
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return; |
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len = caam_rng_read_one(ctx->jrdev, sg_virt(&sg[0]), |
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sg[0].length, |
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ctx->desc_async, |
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&done); |
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if (len < 0) |
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return; |
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kfifo_dma_in_finish(&ctx->fifo, len); |
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} |
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static void caam_rng_worker(struct work_struct *work) |
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{ |
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struct caam_rng_ctx *ctx = container_of(work, struct caam_rng_ctx, |
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worker); |
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caam_rng_fill_async(ctx); |
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} |
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static int caam_read(struct hwrng *rng, void *dst, size_t max, bool wait) |
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{ |
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struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng); |
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int out; |
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if (wait) { |
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struct completion done; |
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return caam_rng_read_one(ctx->jrdev, dst, max, |
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ctx->desc_sync, &done); |
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} |
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out = kfifo_out(&ctx->fifo, dst, max); |
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if (kfifo_is_empty(&ctx->fifo)) |
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schedule_work(&ctx->worker); |
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return out; |
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} |
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static void caam_cleanup(struct hwrng *rng) |
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{ |
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struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng); |
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flush_work(&ctx->worker); |
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caam_jr_free(ctx->jrdev); |
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kfifo_free(&ctx->fifo); |
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} |
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static int caam_init(struct hwrng *rng) |
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{ |
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struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng); |
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int err; |
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ctx->desc_sync = devm_kzalloc(ctx->ctrldev, CAAM_RNG_DESC_LEN, |
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GFP_DMA | GFP_KERNEL); |
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if (!ctx->desc_sync) |
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return -ENOMEM; |
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ctx->desc_async = devm_kzalloc(ctx->ctrldev, CAAM_RNG_DESC_LEN, |
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GFP_DMA | GFP_KERNEL); |
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if (!ctx->desc_async) |
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return -ENOMEM; |
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if (kfifo_alloc(&ctx->fifo, CAAM_RNG_MAX_FIFO_STORE_SIZE, |
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GFP_DMA | GFP_KERNEL)) |
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return -ENOMEM; |
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INIT_WORK(&ctx->worker, caam_rng_worker); |
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ctx->jrdev = caam_jr_alloc(); |
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err = PTR_ERR_OR_ZERO(ctx->jrdev); |
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if (err) { |
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kfifo_free(&ctx->fifo); |
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pr_err("Job Ring Device allocation for transform failed\n"); |
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return err; |
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} |
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/* |
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* Fill async buffer to have early randomness data for |
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* hw_random |
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*/ |
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caam_rng_fill_async(ctx); |
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return 0; |
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} |
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int caam_rng_init(struct device *ctrldev); |
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void caam_rng_exit(struct device *ctrldev) |
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{ |
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devres_release_group(ctrldev, caam_rng_init); |
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} |
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int caam_rng_init(struct device *ctrldev) |
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{ |
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struct caam_rng_ctx *ctx; |
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u32 rng_inst; |
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struct caam_drv_private *priv = dev_get_drvdata(ctrldev); |
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int ret; |
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/* Check for an instantiated RNG before registration */ |
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if (priv->era < 10) |
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rng_inst = (rd_reg32(&priv->ctrl->perfmon.cha_num_ls) & |
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CHA_ID_LS_RNG_MASK) >> CHA_ID_LS_RNG_SHIFT; |
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else |
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rng_inst = rd_reg32(&priv->ctrl->vreg.rng) & CHA_VER_NUM_MASK; |
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if (!rng_inst) |
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return 0; |
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if (!devres_open_group(ctrldev, caam_rng_init, GFP_KERNEL)) |
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return -ENOMEM; |
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ctx = devm_kzalloc(ctrldev, sizeof(*ctx), GFP_KERNEL); |
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if (!ctx) |
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return -ENOMEM; |
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ctx->ctrldev = ctrldev; |
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ctx->rng.name = "rng-caam"; |
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ctx->rng.init = caam_init; |
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ctx->rng.cleanup = caam_cleanup; |
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ctx->rng.read = caam_read; |
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ctx->rng.priv = (unsigned long)ctx; |
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ctx->rng.quality = 1024; |
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dev_info(ctrldev, "registering rng-caam\n"); |
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ret = devm_hwrng_register(ctrldev, &ctx->rng); |
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if (ret) { |
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caam_rng_exit(ctrldev); |
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return ret; |
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} |
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devres_close_group(ctrldev, caam_rng_init); |
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return 0; |
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}
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