1 // SPDX-License-Identifier: GPL-2.0+
3 * caam - Freescale FSL CAAM support for hw_random
5 * Copyright 2011 Freescale Semiconductor, Inc.
6 * Copyright 2018-2019 NXP
8 * Based on caamalg.c crypto API driver.
12 #include <linux/hw_random.h>
13 #include <linux/completion.h>
14 #include <linux/atomic.h>
15 #include <linux/kfifo.h>
21 #include "desc_constr.h"
25 #define CAAM_RNG_MAX_FIFO_STORE_SIZE 16
28 * Length of used descriptors, see caam_init_desc()
30 #define CAAM_RNG_DESC_LEN (CAAM_CMD_SZ + \
32 CAAM_CMD_SZ + CAAM_PTR_SZ_MAX)
34 /* rng per-device context */
38 struct device *ctrldev;
41 struct work_struct worker;
45 struct caam_rng_job_ctx {
46 struct completion *done;
50 static struct caam_rng_ctx *to_caam_rng_ctx(struct hwrng *r)
52 return (struct caam_rng_ctx *)r->priv;
55 static void caam_rng_done(struct device *jrdev, u32 *desc, u32 err,
58 struct caam_rng_job_ctx *jctx = context;
61 *jctx->err = caam_jr_strstatus(jrdev, err);
66 static u32 *caam_init_desc(u32 *desc, dma_addr_t dst_dma)
68 init_job_desc(desc, 0); /* + 1 cmd_sz */
69 /* Generate random bytes: + 1 cmd_sz */
70 append_operation(desc, OP_ALG_ALGSEL_RNG | OP_TYPE_CLASS1_ALG |
72 /* Store bytes: + 1 cmd_sz + caam_ptr_sz */
73 append_fifo_store(desc, dst_dma,
74 CAAM_RNG_MAX_FIFO_STORE_SIZE, FIFOST_TYPE_RNGSTORE);
76 print_hex_dump_debug("rng job desc@: ", DUMP_PREFIX_ADDRESS,
77 16, 4, desc, desc_bytes(desc), 1);
82 static int caam_rng_read_one(struct device *jrdev,
85 struct completion *done)
89 struct caam_rng_job_ctx jctx = {
94 len = CAAM_RNG_MAX_FIFO_STORE_SIZE;
96 dst_dma = dma_map_single(jrdev, dst, len, DMA_FROM_DEVICE);
97 if (dma_mapping_error(jrdev, dst_dma)) {
98 dev_err(jrdev, "unable to map destination memory\n");
102 init_completion(done);
103 err = caam_jr_enqueue(jrdev,
104 caam_init_desc(desc, dst_dma),
105 caam_rng_done, &jctx);
106 if (err == -EINPROGRESS) {
107 wait_for_completion(done);
111 dma_unmap_single(jrdev, dst_dma, len, DMA_FROM_DEVICE);
113 return err ?: (ret ?: len);
116 static void caam_rng_fill_async(struct caam_rng_ctx *ctx)
118 struct scatterlist sg[1];
119 struct completion done;
122 sg_init_table(sg, ARRAY_SIZE(sg));
123 nents = kfifo_dma_in_prepare(&ctx->fifo, sg, ARRAY_SIZE(sg),
124 CAAM_RNG_MAX_FIFO_STORE_SIZE);
128 len = caam_rng_read_one(ctx->jrdev, sg_virt(&sg[0]),
135 kfifo_dma_in_finish(&ctx->fifo, len);
138 static void caam_rng_worker(struct work_struct *work)
140 struct caam_rng_ctx *ctx = container_of(work, struct caam_rng_ctx,
142 caam_rng_fill_async(ctx);
145 static int caam_read(struct hwrng *rng, void *dst, size_t max, bool wait)
147 struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);
151 struct completion done;
153 return caam_rng_read_one(ctx->jrdev, dst, max,
154 ctx->desc_sync, &done);
157 out = kfifo_out(&ctx->fifo, dst, max);
158 if (kfifo_is_empty(&ctx->fifo))
159 schedule_work(&ctx->worker);
164 static void caam_cleanup(struct hwrng *rng)
166 struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);
168 flush_work(&ctx->worker);
169 caam_jr_free(ctx->jrdev);
170 kfifo_free(&ctx->fifo);
173 static int caam_init(struct hwrng *rng)
175 struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);
178 ctx->desc_sync = devm_kzalloc(ctx->ctrldev, CAAM_RNG_DESC_LEN,
179 GFP_DMA | GFP_KERNEL);
183 ctx->desc_async = devm_kzalloc(ctx->ctrldev, CAAM_RNG_DESC_LEN,
184 GFP_DMA | GFP_KERNEL);
185 if (!ctx->desc_async)
188 if (kfifo_alloc(&ctx->fifo, CAAM_RNG_MAX_FIFO_STORE_SIZE,
189 GFP_DMA | GFP_KERNEL))
192 INIT_WORK(&ctx->worker, caam_rng_worker);
194 ctx->jrdev = caam_jr_alloc();
195 err = PTR_ERR_OR_ZERO(ctx->jrdev);
197 kfifo_free(&ctx->fifo);
198 pr_err("Job Ring Device allocation for transform failed\n");
203 * Fill async buffer to have early randomness data for
206 caam_rng_fill_async(ctx);
211 int caam_rng_init(struct device *ctrldev);
213 void caam_rng_exit(struct device *ctrldev)
215 devres_release_group(ctrldev, caam_rng_init);
218 int caam_rng_init(struct device *ctrldev)
220 struct caam_rng_ctx *ctx;
222 struct caam_drv_private *priv = dev_get_drvdata(ctrldev);
225 /* Check for an instantiated RNG before registration */
227 rng_inst = (rd_reg32(&priv->ctrl->perfmon.cha_num_ls) &
228 CHA_ID_LS_RNG_MASK) >> CHA_ID_LS_RNG_SHIFT;
230 rng_inst = rd_reg32(&priv->ctrl->vreg.rng) & CHA_VER_NUM_MASK;
235 if (!devres_open_group(ctrldev, caam_rng_init, GFP_KERNEL))
238 ctx = devm_kzalloc(ctrldev, sizeof(*ctx), GFP_KERNEL);
242 ctx->ctrldev = ctrldev;
244 ctx->rng.name = "rng-caam";
245 ctx->rng.init = caam_init;
246 ctx->rng.cleanup = caam_cleanup;
247 ctx->rng.read = caam_read;
248 ctx->rng.priv = (unsigned long)ctx;
249 ctx->rng.quality = 1024;
251 dev_info(ctrldev, "registering rng-caam\n");
253 ret = devm_hwrng_register(ctrldev, &ctx->rng);
255 caam_rng_exit(ctrldev);
259 devres_close_group(ctrldev, caam_rng_init);