diff options
Diffstat (limited to 'drivers/crypto/caam/caamrng.c')
| -rw-r--r-- | drivers/crypto/caam/caamrng.c | 381 |
1 files changed, 381 insertions, 0 deletions
diff --git a/drivers/crypto/caam/caamrng.c b/drivers/crypto/caam/caamrng.c new file mode 100644 index 000000000000..a4b4a3871bdf --- /dev/null +++ b/drivers/crypto/caam/caamrng.c @@ -0,0 +1,381 @@ +/* + * caam - Freescale FSL CAAM support for hw_random + * + * Copyright (C) 2011-2012 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 (10 * CAAM_CMD_SZ) + +/* Buffer, its dma address and lock */ +struct buf_data { + u8 buf[RN_BUF_SIZE]; + 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_sync_single_for_cpu(jrdev, bd->addr, RN_BUF_SIZE, + DMA_FROM_DEVICE); + 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_RNG_LEN, + 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 = (struct buf_data *)((char *)desc - + offsetof(struct buf_data, hw_desc)); + + if (err) { + char tmp[CAAM_ERROR_STR_MAX]; + + dev_err(jrdev, "%08x: %s\n", err, caam_jr_strstatus(tmp, err)); + } + + atomic_set(&bd->empty, BUF_NOT_EMPTY); + complete(&bd->filled); +#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 void 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); + + /* Propagate errors from shared to job descriptor */ + append_cmd(desc, SET_OK_NO_PROP_ERRORS | CMD_LOAD); + + /* 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); + dma_sync_single_for_cpu(jrdev, ctx->sh_desc_dma, desc_bytes(desc), + DMA_TO_DEVICE); +#ifdef DEBUG + print_hex_dump(KERN_ERR, "rng shdesc@: ", DUMP_PREFIX_ADDRESS, 16, 4, + desc, desc_bytes(desc), 1); +#endif +} + +static inline void 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); + + 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 +} + +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); +} + +#ifdef CONFIG_CRYPTO_DEV_FSL_CAAM_RNG_TEST +static inline void test_len(struct hwrng *rng, size_t len, bool wait) +{ + u8 *buf; + int real_len; + + buf = kzalloc(sizeof(u8) * len, GFP_KERNEL); + real_len = rng->read(rng, buf, len, wait); + if (real_len == 0 && wait) + pr_err("WAITING FAILED\n"); + pr_info("wanted %d bytes, got %d\n", len, real_len); + print_hex_dump(KERN_INFO, "random bytes@: ", DUMP_PREFIX_ADDRESS, + 16, 4, buf, real_len, 1); + kfree(buf); +} + +static inline void test_mode_once(struct hwrng *rng, bool wait) +{ +#define TEST_CHUNK (RN_BUF_SIZE / 4) + + test_len(rng, TEST_CHUNK, wait); + test_len(rng, RN_BUF_SIZE * 2, wait); + test_len(rng, RN_BUF_SIZE * 2 - TEST_CHUNK, wait); +} + +static inline void test_mode(struct hwrng *rng, bool wait) +{ +#define TEST_PASS 1 + int i; + + for (i = 0; i < TEST_PASS; i++) + test_mode_once(rng, wait); +} + +static void self_test(struct hwrng *rng) +{ + pr_info("testing without waiting\n"); + test_mode(rng, false); + pr_info("testing with waiting\n"); + test_mode(rng, true); +} +#endif + +static void caam_init_buf(struct caam_rng_ctx *ctx, int buf_id) +{ + struct buf_data *bd = &ctx->bufs[buf_id]; + + rng_create_job_desc(ctx, buf_id); + atomic_set(&bd->empty, BUF_EMPTY); + submit_job(ctx, buf_id == ctx->current_buf); + wait_for_completion(&bd->filled); +} + +static void caam_init_rng(struct caam_rng_ctx *ctx, struct device *jrdev) +{ + ctx->jrdev = jrdev; + rng_create_sh_desc(ctx); + ctx->current_buf = 0; + ctx->cur_buf_idx = 0; + caam_init_buf(ctx, 0); + caam_init_buf(ctx, 1); +} + +static struct hwrng caam_rng = { + .name = "rng-caam", + .cleanup = caam_cleanup, + .read = caam_read, +}; + +int caam_rng_startup(struct platform_device *pdev) +{ + struct device *ctrldev; + struct caam_drv_private *priv; + + ctrldev = &pdev->dev; + priv = dev_get_drvdata(ctrldev); + + /* Check RNG present in hardware before registration */ + if (!(rd_reg64(&priv->ctrl->perfmon.cha_num) & CHA_ID_RNG_MASK)) + return -ENODEV; + + caam_init_rng(&rng_ctx, priv->jrdev[0]); + +#ifdef CONFIG_CRYPTO_DEV_FSL_CAAM_RNG_TEST + self_test(&caam_rng); +#endif + + dev_info(priv->jrdev[0], "registering rng-caam\n"); + return hwrng_register(&caam_rng); +} + +void caam_rng_shutdown(void) +{ + hwrng_unregister(&caam_rng); +} + +#ifdef CONFIG_OF +static void __exit caam_rng_exit(void) +{ + hwrng_unregister(&caam_rng); +} + +static int __init caam_rng_init(void) +{ + struct device_node *dev_node; + struct platform_device *pdev; + + 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) + return -ENODEV; + + of_node_put(dev_node); + +} + +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"); +#endif |