312 lines · c
1// SPDX-License-Identifier: GPL-2.0+2/*3 * caam - Freescale FSL CAAM support for hw_random4 *5 * Copyright 2011 Freescale Semiconductor, Inc.6 * Copyright 2018-2019, 2023 NXP7 *8 * Based on caamalg.c crypto API driver.9 *10 */11 12#include <linux/hw_random.h>13#include <linux/completion.h>14#include <linux/atomic.h>15#include <linux/dma-mapping.h>16#include <linux/kernel.h>17#include <linux/kfifo.h>18 19#include "compat.h"20 21#include "regs.h"22#include "intern.h"23#include "desc_constr.h"24#include "jr.h"25#include "error.h"26 27#define CAAM_RNG_MAX_FIFO_STORE_SIZE 1628 29/*30 * Length of used descriptors, see caam_init_desc()31 */32#define CAAM_RNG_DESC_LEN (CAAM_CMD_SZ + \33 CAAM_CMD_SZ + \34 CAAM_CMD_SZ + CAAM_PTR_SZ_MAX)35 36/* rng per-device context */37struct caam_rng_ctx {38 struct hwrng rng;39 struct device *jrdev;40 struct device *ctrldev;41 void *desc_async;42 void *desc_sync;43 struct work_struct worker;44 struct kfifo fifo;45};46 47struct caam_rng_job_ctx {48 struct completion *done;49 int *err;50};51 52static struct caam_rng_ctx *to_caam_rng_ctx(struct hwrng *r)53{54 return (struct caam_rng_ctx *)r->priv;55}56 57static void caam_rng_done(struct device *jrdev, u32 *desc, u32 err,58 void *context)59{60 struct caam_rng_job_ctx *jctx = context;61 62 if (err)63 *jctx->err = caam_jr_strstatus(jrdev, err);64 65 complete(jctx->done);66}67 68static u32 *caam_init_desc(u32 *desc, dma_addr_t dst_dma)69{70 init_job_desc(desc, 0); /* + 1 cmd_sz */71 /* Generate random bytes: + 1 cmd_sz */72 append_operation(desc, OP_ALG_ALGSEL_RNG | OP_TYPE_CLASS1_ALG |73 OP_ALG_PR_ON);74 /* Store bytes: + 1 cmd_sz + caam_ptr_sz */75 append_fifo_store(desc, dst_dma,76 CAAM_RNG_MAX_FIFO_STORE_SIZE, FIFOST_TYPE_RNGSTORE);77 78 print_hex_dump_debug("rng job desc@: ", DUMP_PREFIX_ADDRESS,79 16, 4, desc, desc_bytes(desc), 1);80 81 return desc;82}83 84static int caam_rng_read_one(struct device *jrdev,85 void *dst, int len,86 void *desc,87 struct completion *done)88{89 dma_addr_t dst_dma;90 int err, ret = 0;91 struct caam_rng_job_ctx jctx = {92 .done = done,93 .err = &ret,94 };95 96 len = CAAM_RNG_MAX_FIFO_STORE_SIZE;97 98 dst_dma = dma_map_single(jrdev, dst, len, DMA_FROM_DEVICE);99 if (dma_mapping_error(jrdev, dst_dma)) {100 dev_err(jrdev, "unable to map destination memory\n");101 return -ENOMEM;102 }103 104 init_completion(done);105 err = caam_jr_enqueue(jrdev,106 caam_init_desc(desc, dst_dma),107 caam_rng_done, &jctx);108 if (err == -EINPROGRESS) {109 wait_for_completion(done);110 err = 0;111 }112 113 dma_unmap_single(jrdev, dst_dma, len, DMA_FROM_DEVICE);114 115 return err ?: (ret ?: len);116}117 118static void caam_rng_fill_async(struct caam_rng_ctx *ctx)119{120 struct scatterlist sg[1];121 struct completion done;122 int len, nents;123 124 sg_init_table(sg, ARRAY_SIZE(sg));125 nents = kfifo_dma_in_prepare(&ctx->fifo, sg, ARRAY_SIZE(sg),126 CAAM_RNG_MAX_FIFO_STORE_SIZE);127 if (!nents)128 return;129 130 len = caam_rng_read_one(ctx->jrdev, sg_virt(&sg[0]),131 sg[0].length,132 ctx->desc_async,133 &done);134 if (len < 0)135 return;136 137 kfifo_dma_in_finish(&ctx->fifo, len);138}139 140static void caam_rng_worker(struct work_struct *work)141{142 struct caam_rng_ctx *ctx = container_of(work, struct caam_rng_ctx,143 worker);144 caam_rng_fill_async(ctx);145}146 147static int caam_read(struct hwrng *rng, void *dst, size_t max, bool wait)148{149 struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);150 int out;151 152 if (wait) {153 struct completion done;154 155 return caam_rng_read_one(ctx->jrdev, dst, max,156 ctx->desc_sync, &done);157 }158 159 out = kfifo_out(&ctx->fifo, dst, max);160 if (kfifo_is_empty(&ctx->fifo))161 schedule_work(&ctx->worker);162 163 return out;164}165 166static void caam_cleanup(struct hwrng *rng)167{168 struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);169 170 flush_work(&ctx->worker);171 caam_jr_free(ctx->jrdev);172 kfifo_free(&ctx->fifo);173}174 175#ifdef CONFIG_CRYPTO_DEV_FSL_CAAM_RNG_TEST176static inline void test_len(struct hwrng *rng, size_t len, bool wait)177{178 u8 *buf;179 int read_len;180 struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);181 struct device *dev = ctx->ctrldev;182 183 buf = kcalloc(CAAM_RNG_MAX_FIFO_STORE_SIZE, sizeof(u8), GFP_KERNEL);184 185 while (len > 0) {186 read_len = rng->read(rng, buf, len, wait);187 188 if (read_len < 0 || (read_len == 0 && wait)) {189 dev_err(dev, "RNG Read FAILED received %d bytes\n",190 read_len);191 kfree(buf);192 return;193 }194 195 print_hex_dump_debug("random bytes@: ",196 DUMP_PREFIX_ADDRESS, 16, 4,197 buf, read_len, 1);198 199 len = len - read_len;200 }201 202 kfree(buf);203}204 205static inline void test_mode_once(struct hwrng *rng, bool wait)206{207 test_len(rng, 32, wait);208 test_len(rng, 64, wait);209 test_len(rng, 128, wait);210}211 212static void self_test(struct hwrng *rng)213{214 pr_info("Executing RNG SELF-TEST with wait\n");215 test_mode_once(rng, true);216}217#endif218 219static int caam_init(struct hwrng *rng)220{221 struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng);222 int err;223 224 ctx->desc_sync = devm_kzalloc(ctx->ctrldev, CAAM_RNG_DESC_LEN,225 GFP_KERNEL);226 if (!ctx->desc_sync)227 return -ENOMEM;228 229 ctx->desc_async = devm_kzalloc(ctx->ctrldev, CAAM_RNG_DESC_LEN,230 GFP_KERNEL);231 if (!ctx->desc_async)232 return -ENOMEM;233 234 if (kfifo_alloc(&ctx->fifo, ALIGN(CAAM_RNG_MAX_FIFO_STORE_SIZE,235 dma_get_cache_alignment()),236 GFP_KERNEL))237 return -ENOMEM;238 239 INIT_WORK(&ctx->worker, caam_rng_worker);240 241 ctx->jrdev = caam_jr_alloc();242 err = PTR_ERR_OR_ZERO(ctx->jrdev);243 if (err) {244 kfifo_free(&ctx->fifo);245 pr_err("Job Ring Device allocation for transform failed\n");246 return err;247 }248 249 /*250 * Fill async buffer to have early randomness data for251 * hw_random252 */253 caam_rng_fill_async(ctx);254 255 return 0;256}257 258int caam_rng_init(struct device *ctrldev);259 260void caam_rng_exit(struct device *ctrldev)261{262 devres_release_group(ctrldev, caam_rng_init);263}264 265int caam_rng_init(struct device *ctrldev)266{267 struct caam_rng_ctx *ctx;268 u32 rng_inst;269 struct caam_drv_private *priv = dev_get_drvdata(ctrldev);270 int ret;271 272 /* Check for an instantiated RNG before registration */273 if (priv->era < 10)274 rng_inst = (rd_reg32(&priv->jr[0]->perfmon.cha_num_ls) &275 CHA_ID_LS_RNG_MASK) >> CHA_ID_LS_RNG_SHIFT;276 else277 rng_inst = rd_reg32(&priv->jr[0]->vreg.rng) & CHA_VER_NUM_MASK;278 279 if (!rng_inst)280 return 0;281 282 if (!devres_open_group(ctrldev, caam_rng_init, GFP_KERNEL))283 return -ENOMEM;284 285 ctx = devm_kzalloc(ctrldev, sizeof(*ctx), GFP_KERNEL);286 if (!ctx)287 return -ENOMEM;288 289 ctx->ctrldev = ctrldev;290 291 ctx->rng.name = "rng-caam";292 ctx->rng.init = caam_init;293 ctx->rng.cleanup = caam_cleanup;294 ctx->rng.read = caam_read;295 ctx->rng.priv = (unsigned long)ctx;296 297 dev_info(ctrldev, "registering rng-caam\n");298 299 ret = devm_hwrng_register(ctrldev, &ctx->rng);300 if (ret) {301 caam_rng_exit(ctrldev);302 return ret;303 }304 305#ifdef CONFIG_CRYPTO_DEV_FSL_CAAM_RNG_TEST306 self_test(&ctx->rng);307#endif308 309 devres_close_group(ctrldev, caam_rng_init);310 return 0;311}312