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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
commit | 76cb841cb886eef6b3bee341a2266c76578724ad (patch) | |
tree | f5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /drivers/crypto/caam/caamrng.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | drivers/crypto/caam/caamrng.c | 373 |
1 files changed, 373 insertions, 0 deletions
diff --git a/drivers/crypto/caam/caamrng.c b/drivers/crypto/caam/caamrng.c new file mode 100644 index 000000000..ff6718a11 --- /dev/null +++ b/drivers/crypto/caam/caamrng.c @@ -0,0 +1,373 @@ +/* + * caam - Freescale FSL CAAM support for hw_random + * + * Copyright 2011 Freescale Semiconductor, Inc. + * + * Based on caamalg.c crypto API driver. + * + * relationship between job descriptors to shared descriptors: + * + * --------------- -------------- + * | JobDesc #0 |-------------------->| ShareDesc | + * | *(buffer 0) | |------------->| (generate) | + * --------------- | | (move) | + * | | (store) | + * --------------- | -------------- + * | JobDesc #1 |------| + * | *(buffer 1) | + * --------------- + * + * A job desc looks like this: + * + * --------------------- + * | Header | + * | ShareDesc Pointer | + * | SEQ_OUT_PTR | + * | (output buffer) | + * --------------------- + * + * The SharedDesc never changes, and each job descriptor points to one of two + * buffers for each device, from which the data will be copied into the + * requested destination + */ + +#include <linux/hw_random.h> +#include <linux/completion.h> +#include <linux/atomic.h> + +#include "compat.h" + +#include "regs.h" +#include "intern.h" +#include "desc_constr.h" +#include "jr.h" +#include "error.h" + +/* + * Maximum buffer size: maximum number of random, cache-aligned bytes that + * will be generated and moved to seq out ptr (extlen not allowed) + */ +#define RN_BUF_SIZE (0xffff / L1_CACHE_BYTES * \ + L1_CACHE_BYTES) + +/* length of descriptors */ +#define DESC_JOB_O_LEN (CAAM_CMD_SZ * 2 + CAAM_PTR_SZ * 2) +#define DESC_RNG_LEN (3 * CAAM_CMD_SZ) + +/* Buffer, its dma address and lock */ +struct buf_data { + u8 buf[RN_BUF_SIZE] ____cacheline_aligned; + dma_addr_t addr; + struct completion filled; + u32 hw_desc[DESC_JOB_O_LEN]; +#define BUF_NOT_EMPTY 0 +#define BUF_EMPTY 1 +#define BUF_PENDING 2 /* Empty, but with job pending --don't submit another */ + atomic_t empty; +}; + +/* rng per-device context */ +struct caam_rng_ctx { + struct device *jrdev; + dma_addr_t sh_desc_dma; + u32 sh_desc[DESC_RNG_LEN]; + unsigned int cur_buf_idx; + int current_buf; + struct buf_data bufs[2]; +}; + +static struct caam_rng_ctx *rng_ctx; + +static inline void rng_unmap_buf(struct device *jrdev, struct buf_data *bd) +{ + if (bd->addr) + dma_unmap_single(jrdev, bd->addr, RN_BUF_SIZE, + DMA_FROM_DEVICE); +} + +static inline void rng_unmap_ctx(struct caam_rng_ctx *ctx) +{ + struct device *jrdev = ctx->jrdev; + + if (ctx->sh_desc_dma) + dma_unmap_single(jrdev, ctx->sh_desc_dma, + desc_bytes(ctx->sh_desc), DMA_TO_DEVICE); + rng_unmap_buf(jrdev, &ctx->bufs[0]); + rng_unmap_buf(jrdev, &ctx->bufs[1]); +} + +static void rng_done(struct device *jrdev, u32 *desc, u32 err, void *context) +{ + struct buf_data *bd; + + bd = container_of(desc, struct buf_data, hw_desc[0]); + + if (err) + caam_jr_strstatus(jrdev, err); + + atomic_set(&bd->empty, BUF_NOT_EMPTY); + complete(&bd->filled); + + /* Buffer refilled, invalidate cache */ + dma_sync_single_for_cpu(jrdev, bd->addr, RN_BUF_SIZE, DMA_FROM_DEVICE); + +#ifdef DEBUG + print_hex_dump(KERN_ERR, "rng refreshed buf@: ", + DUMP_PREFIX_ADDRESS, 16, 4, bd->buf, RN_BUF_SIZE, 1); +#endif +} + +static inline int submit_job(struct caam_rng_ctx *ctx, int to_current) +{ + struct buf_data *bd = &ctx->bufs[!(to_current ^ ctx->current_buf)]; + struct device *jrdev = ctx->jrdev; + u32 *desc = bd->hw_desc; + int err; + + dev_dbg(jrdev, "submitting job %d\n", !(to_current ^ ctx->current_buf)); + init_completion(&bd->filled); + err = caam_jr_enqueue(jrdev, desc, rng_done, ctx); + if (err) + complete(&bd->filled); /* don't wait on failed job*/ + else + atomic_inc(&bd->empty); /* note if pending */ + + return err; +} + +static int caam_read(struct hwrng *rng, void *data, size_t max, bool wait) +{ + struct caam_rng_ctx *ctx = rng_ctx; + struct buf_data *bd = &ctx->bufs[ctx->current_buf]; + int next_buf_idx, copied_idx; + int err; + + if (atomic_read(&bd->empty)) { + /* try to submit job if there wasn't one */ + if (atomic_read(&bd->empty) == BUF_EMPTY) { + err = submit_job(ctx, 1); + /* if can't submit job, can't even wait */ + if (err) + return 0; + } + /* no immediate data, so exit if not waiting */ + if (!wait) + return 0; + + /* waiting for pending job */ + if (atomic_read(&bd->empty)) + wait_for_completion(&bd->filled); + } + + next_buf_idx = ctx->cur_buf_idx + max; + dev_dbg(ctx->jrdev, "%s: start reading at buffer %d, idx %d\n", + __func__, ctx->current_buf, ctx->cur_buf_idx); + + /* if enough data in current buffer */ + if (next_buf_idx < RN_BUF_SIZE) { + memcpy(data, bd->buf + ctx->cur_buf_idx, max); + ctx->cur_buf_idx = next_buf_idx; + return max; + } + + /* else, copy what's left... */ + copied_idx = RN_BUF_SIZE - ctx->cur_buf_idx; + memcpy(data, bd->buf + ctx->cur_buf_idx, copied_idx); + ctx->cur_buf_idx = 0; + atomic_set(&bd->empty, BUF_EMPTY); + + /* ...refill... */ + submit_job(ctx, 1); + + /* and use next buffer */ + ctx->current_buf = !ctx->current_buf; + dev_dbg(ctx->jrdev, "switched to buffer %d\n", ctx->current_buf); + + /* since there already is some data read, don't wait */ + return copied_idx + caam_read(rng, data + copied_idx, + max - copied_idx, false); +} + +static inline int rng_create_sh_desc(struct caam_rng_ctx *ctx) +{ + struct device *jrdev = ctx->jrdev; + u32 *desc = ctx->sh_desc; + + init_sh_desc(desc, HDR_SHARE_SERIAL); + + /* Generate random bytes */ + append_operation(desc, OP_ALG_ALGSEL_RNG | OP_TYPE_CLASS1_ALG); + + /* Store bytes */ + append_seq_fifo_store(desc, RN_BUF_SIZE, FIFOST_TYPE_RNGSTORE); + + ctx->sh_desc_dma = dma_map_single(jrdev, desc, desc_bytes(desc), + DMA_TO_DEVICE); + if (dma_mapping_error(jrdev, ctx->sh_desc_dma)) { + dev_err(jrdev, "unable to map shared descriptor\n"); + return -ENOMEM; + } +#ifdef DEBUG + print_hex_dump(KERN_ERR, "rng shdesc@: ", DUMP_PREFIX_ADDRESS, 16, 4, + desc, desc_bytes(desc), 1); +#endif + return 0; +} + +static inline int rng_create_job_desc(struct caam_rng_ctx *ctx, int buf_id) +{ + struct device *jrdev = ctx->jrdev; + struct buf_data *bd = &ctx->bufs[buf_id]; + u32 *desc = bd->hw_desc; + int sh_len = desc_len(ctx->sh_desc); + + init_job_desc_shared(desc, ctx->sh_desc_dma, sh_len, HDR_SHARE_DEFER | + HDR_REVERSE); + + bd->addr = dma_map_single(jrdev, bd->buf, RN_BUF_SIZE, DMA_FROM_DEVICE); + if (dma_mapping_error(jrdev, bd->addr)) { + dev_err(jrdev, "unable to map dst\n"); + return -ENOMEM; + } + + append_seq_out_ptr_intlen(desc, bd->addr, RN_BUF_SIZE, 0); +#ifdef DEBUG + print_hex_dump(KERN_ERR, "rng job desc@: ", DUMP_PREFIX_ADDRESS, 16, 4, + desc, desc_bytes(desc), 1); +#endif + return 0; +} + +static void caam_cleanup(struct hwrng *rng) +{ + int i; + struct buf_data *bd; + + for (i = 0; i < 2; i++) { + bd = &rng_ctx->bufs[i]; + if (atomic_read(&bd->empty) == BUF_PENDING) + wait_for_completion(&bd->filled); + } + + rng_unmap_ctx(rng_ctx); +} + +static int caam_init_buf(struct caam_rng_ctx *ctx, int buf_id) +{ + struct buf_data *bd = &ctx->bufs[buf_id]; + int err; + + err = rng_create_job_desc(ctx, buf_id); + if (err) + return err; + + atomic_set(&bd->empty, BUF_EMPTY); + submit_job(ctx, buf_id == ctx->current_buf); + wait_for_completion(&bd->filled); + + return 0; +} + +static int caam_init_rng(struct caam_rng_ctx *ctx, struct device *jrdev) +{ + int err; + + ctx->jrdev = jrdev; + + err = rng_create_sh_desc(ctx); + if (err) + return err; + + ctx->current_buf = 0; + ctx->cur_buf_idx = 0; + + err = caam_init_buf(ctx, 0); + if (err) + return err; + + return caam_init_buf(ctx, 1); +} + +static struct hwrng caam_rng = { + .name = "rng-caam", + .cleanup = caam_cleanup, + .read = caam_read, +}; + +static void __exit caam_rng_exit(void) +{ + caam_jr_free(rng_ctx->jrdev); + hwrng_unregister(&caam_rng); + kfree(rng_ctx); +} + +static int __init caam_rng_init(void) +{ + struct device *dev; + struct device_node *dev_node; + struct platform_device *pdev; + struct device *ctrldev; + struct caam_drv_private *priv; + int err; + + dev_node = of_find_compatible_node(NULL, NULL, "fsl,sec-v4.0"); + if (!dev_node) { + dev_node = of_find_compatible_node(NULL, NULL, "fsl,sec4.0"); + if (!dev_node) + return -ENODEV; + } + + pdev = of_find_device_by_node(dev_node); + if (!pdev) { + of_node_put(dev_node); + return -ENODEV; + } + + ctrldev = &pdev->dev; + priv = dev_get_drvdata(ctrldev); + of_node_put(dev_node); + + /* + * If priv is NULL, it's probably because the caam driver wasn't + * properly initialized (e.g. RNG4 init failed). Thus, bail out here. + */ + if (!priv) + return -ENODEV; + + /* Check for an instantiated RNG before registration */ + if (!(rd_reg32(&priv->ctrl->perfmon.cha_num_ls) & CHA_ID_LS_RNG_MASK)) + return -ENODEV; + + dev = caam_jr_alloc(); + if (IS_ERR(dev)) { + pr_err("Job Ring Device allocation for transform failed\n"); + return PTR_ERR(dev); + } + rng_ctx = kmalloc(sizeof(*rng_ctx), GFP_DMA | GFP_KERNEL); + if (!rng_ctx) { + err = -ENOMEM; + goto free_caam_alloc; + } + err = caam_init_rng(rng_ctx, dev); + if (err) + goto free_rng_ctx; + + dev_info(dev, "registering rng-caam\n"); + + err = hwrng_register(&caam_rng); + if (!err) + return err; + +free_rng_ctx: + kfree(rng_ctx); +free_caam_alloc: + caam_jr_free(dev); + return err; +} + +module_init(caam_rng_init); +module_exit(caam_rng_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("FSL CAAM support for hw_random API"); +MODULE_AUTHOR("Freescale Semiconductor - NMG"); |