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crypto: caam - hwrng support
caam_read copies random bytes from two buffers into output. caam rng can fill empty buffer 0xffff bytes at a time, but the buffer sizes are rounded down to multiple of cacheline size. Signed-off-by: Yuan Kang <Yuan.Kang@freescale.com> Signed-off-by: Kim Phillips <kim.phillips@freescale.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Yuan Kang
Herbert Xu
parent
643b39b031
commit
e24f7c9e87
@ -82,3 +82,16 @@ config CRYPTO_DEV_FSL_CAAM_AHASH_API
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To compile this as a module, choose M here: the module
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will be called caamhash.
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config CRYPTO_DEV_FSL_CAAM_RNG_API
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tristate "Register caam device for hwrng API"
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depends on CRYPTO_DEV_FSL_CAAM
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default y
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select CRYPTO_RNG
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select HW_RANDOM
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help
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Selecting this will register the SEC4 hardware rng to
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the hw_random API for suppying the kernel entropy pool.
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To compile this as a module, choose M here: the module
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will be called caamrng.
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@ -5,5 +5,6 @@
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obj-$(CONFIG_CRYPTO_DEV_FSL_CAAM) += caam.o
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obj-$(CONFIG_CRYPTO_DEV_FSL_CAAM_CRYPTO_API) += caamalg.o
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obj-$(CONFIG_CRYPTO_DEV_FSL_CAAM_AHASH_API) += caamhash.o
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obj-$(CONFIG_CRYPTO_DEV_FSL_CAAM_RNG_API) += caamrng.o
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caam-objs := ctrl.o jr.o error.o key_gen.o
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309
drivers/crypto/caam/caamrng.c
Normal file
309
drivers/crypto/caam/caamrng.c
Normal file
@ -0,0 +1,309 @@
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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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*
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* Based on caamalg.c crypto API driver.
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*
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* relationship between job descriptors to shared descriptors:
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*
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* --------------- --------------
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* | JobDesc #0 |-------------------->| ShareDesc |
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* | *(buffer 0) | |------------->| (generate) |
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* --------------- | | (move) |
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* | | (store) |
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* --------------- | --------------
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* | JobDesc #1 |------|
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* | *(buffer 1) |
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* ---------------
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*
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* A job desc looks like this:
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*
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* ---------------------
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* | Header |
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* | ShareDesc Pointer |
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* | SEQ_OUT_PTR |
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* | (output buffer) |
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* ---------------------
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*
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* The SharedDesc never changes, and each job descriptor points to one of two
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* buffers for each device, from which the data will be copied into the
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* requested destination
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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 "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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/*
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* Maximum buffer size: maximum number of random, cache-aligned bytes that
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* will be generated and moved to seq out ptr (extlen not allowed)
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*/
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#define RN_BUF_SIZE (0xffff / L1_CACHE_BYTES * \
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L1_CACHE_BYTES)
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/* length of descriptors */
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#define DESC_JOB_O_LEN (CAAM_CMD_SZ * 2 + CAAM_PTR_SZ * 2)
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#define DESC_RNG_LEN (10 * CAAM_CMD_SZ)
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/* Buffer, its dma address and lock */
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struct buf_data {
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u8 buf[RN_BUF_SIZE];
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dma_addr_t addr;
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struct completion filled;
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u32 hw_desc[DESC_JOB_O_LEN];
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#define BUF_NOT_EMPTY 0
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#define BUF_EMPTY 1
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#define BUF_PENDING 2 /* Empty, but with job pending --don't submit another */
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atomic_t empty;
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};
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/* rng per-device context */
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struct caam_rng_ctx {
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struct device *jrdev;
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dma_addr_t sh_desc_dma;
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u32 sh_desc[DESC_RNG_LEN];
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unsigned int cur_buf_idx;
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int current_buf;
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struct buf_data bufs[2];
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};
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static struct caam_rng_ctx rng_ctx;
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static inline void rng_unmap_buf(struct device *jrdev, struct buf_data *bd)
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{
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if (bd->addr)
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dma_unmap_single(jrdev, bd->addr, RN_BUF_SIZE,
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DMA_FROM_DEVICE);
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}
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static inline void rng_unmap_ctx(struct caam_rng_ctx *ctx)
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{
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struct device *jrdev = ctx->jrdev;
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if (ctx->sh_desc_dma)
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dma_unmap_single(jrdev, ctx->sh_desc_dma, DESC_RNG_LEN,
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DMA_TO_DEVICE);
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rng_unmap_buf(jrdev, &ctx->bufs[0]);
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rng_unmap_buf(jrdev, &ctx->bufs[1]);
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}
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static void rng_done(struct device *jrdev, u32 *desc, u32 err, void *context)
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{
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struct buf_data *bd;
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bd = (struct buf_data *)((char *)desc -
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offsetof(struct buf_data, hw_desc));
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if (err) {
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char tmp[CAAM_ERROR_STR_MAX];
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dev_err(jrdev, "%08x: %s\n", err, caam_jr_strstatus(tmp, err));
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}
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atomic_set(&bd->empty, BUF_NOT_EMPTY);
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complete(&bd->filled);
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#ifdef DEBUG
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print_hex_dump(KERN_ERR, "rng refreshed buf@: ",
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DUMP_PREFIX_ADDRESS, 16, 4, bd->buf, RN_BUF_SIZE, 1);
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#endif
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}
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static inline int submit_job(struct caam_rng_ctx *ctx, int to_current)
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{
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struct buf_data *bd = &ctx->bufs[!(to_current ^ ctx->current_buf)];
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struct device *jrdev = ctx->jrdev;
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u32 *desc = bd->hw_desc;
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int err;
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dev_dbg(jrdev, "submitting job %d\n", !(to_current ^ ctx->current_buf));
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init_completion(&bd->filled);
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err = caam_jr_enqueue(jrdev, desc, rng_done, ctx);
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if (err)
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complete(&bd->filled); /* don't wait on failed job*/
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else
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atomic_inc(&bd->empty); /* note if pending */
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return err;
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}
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static int caam_read(struct hwrng *rng, void *data, size_t max, bool wait)
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{
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struct caam_rng_ctx *ctx = &rng_ctx;
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struct buf_data *bd = &ctx->bufs[ctx->current_buf];
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int next_buf_idx, copied_idx;
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int err;
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if (atomic_read(&bd->empty)) {
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/* try to submit job if there wasn't one */
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if (atomic_read(&bd->empty) == BUF_EMPTY) {
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err = submit_job(ctx, 1);
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/* if can't submit job, can't even wait */
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if (err)
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return 0;
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}
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/* no immediate data, so exit if not waiting */
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if (!wait)
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return 0;
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/* waiting for pending job */
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if (atomic_read(&bd->empty))
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wait_for_completion(&bd->filled);
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}
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next_buf_idx = ctx->cur_buf_idx + max;
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dev_dbg(ctx->jrdev, "%s: start reading at buffer %d, idx %d\n",
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__func__, ctx->current_buf, ctx->cur_buf_idx);
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/* if enough data in current buffer */
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if (next_buf_idx < RN_BUF_SIZE) {
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memcpy(data, bd->buf + ctx->cur_buf_idx, max);
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ctx->cur_buf_idx = next_buf_idx;
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return max;
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}
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/* else, copy what's left... */
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copied_idx = RN_BUF_SIZE - ctx->cur_buf_idx;
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memcpy(data, bd->buf + ctx->cur_buf_idx, copied_idx);
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ctx->cur_buf_idx = 0;
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atomic_set(&bd->empty, BUF_EMPTY);
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/* ...refill... */
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submit_job(ctx, 1);
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/* and use next buffer */
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ctx->current_buf = !ctx->current_buf;
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dev_dbg(ctx->jrdev, "switched to buffer %d\n", ctx->current_buf);
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/* since there already is some data read, don't wait */
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return copied_idx + caam_read(rng, data + copied_idx,
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max - copied_idx, false);
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}
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static inline void rng_create_sh_desc(struct caam_rng_ctx *ctx)
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{
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struct device *jrdev = ctx->jrdev;
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u32 *desc = ctx->sh_desc;
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init_sh_desc(desc, HDR_SHARE_WAIT);
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/* Propagate errors from shared to job descriptor */
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append_cmd(desc, SET_OK_NO_PROP_ERRORS | CMD_LOAD);
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/* Generate random bytes */
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append_operation(desc, OP_ALG_ALGSEL_RNG | OP_TYPE_CLASS1_ALG);
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/* Store bytes */
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append_seq_fifo_store(desc, RN_BUF_SIZE, FIFOST_TYPE_RNGSTORE);
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ctx->sh_desc_dma = dma_map_single(jrdev, desc, desc_bytes(desc),
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DMA_TO_DEVICE);
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#ifdef DEBUG
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print_hex_dump(KERN_ERR, "rng shdesc@: ", DUMP_PREFIX_ADDRESS, 16, 4,
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desc, desc_bytes(desc), 1);
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#endif
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}
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static inline void rng_create_job_desc(struct caam_rng_ctx *ctx, int buf_id)
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{
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struct device *jrdev = ctx->jrdev;
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struct buf_data *bd = &ctx->bufs[buf_id];
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u32 *desc = bd->hw_desc;
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int sh_len = desc_len(ctx->sh_desc);
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init_job_desc_shared(desc, ctx->sh_desc_dma, sh_len, HDR_SHARE_DEFER |
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HDR_REVERSE);
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bd->addr = dma_map_single(jrdev, bd->buf, RN_BUF_SIZE, DMA_FROM_DEVICE);
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append_seq_out_ptr_intlen(desc, bd->addr, RN_BUF_SIZE, 0);
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#ifdef DEBUG
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print_hex_dump(KERN_ERR, "rng job desc@: ", DUMP_PREFIX_ADDRESS, 16, 4,
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desc, desc_bytes(desc), 1);
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#endif
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}
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static void caam_cleanup(struct hwrng *rng)
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{
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int i;
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struct buf_data *bd;
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for (i = 0; i < 2; i++) {
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bd = &rng_ctx.bufs[i];
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if (atomic_read(&bd->empty) == BUF_PENDING)
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wait_for_completion(&bd->filled);
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}
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rng_unmap_ctx(&rng_ctx);
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}
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static void caam_init_buf(struct caam_rng_ctx *ctx, int buf_id)
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{
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struct buf_data *bd = &ctx->bufs[buf_id];
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rng_create_job_desc(ctx, buf_id);
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atomic_set(&bd->empty, BUF_EMPTY);
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submit_job(ctx, buf_id == ctx->current_buf);
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wait_for_completion(&bd->filled);
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}
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static void caam_init_rng(struct caam_rng_ctx *ctx, struct device *jrdev)
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{
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ctx->jrdev = jrdev;
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rng_create_sh_desc(ctx);
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ctx->current_buf = 0;
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ctx->cur_buf_idx = 0;
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caam_init_buf(ctx, 0);
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caam_init_buf(ctx, 1);
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}
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static struct hwrng caam_rng = {
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.name = "rng-caam",
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.cleanup = caam_cleanup,
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.read = caam_read,
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};
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static void __exit caam_rng_exit(void)
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{
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hwrng_unregister(&caam_rng);
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}
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static int __init caam_rng_init(void)
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{
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struct device_node *dev_node;
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struct platform_device *pdev;
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struct device *ctrldev;
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struct caam_drv_private *priv;
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dev_node = of_find_compatible_node(NULL, NULL, "fsl,sec-v4.0");
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if (!dev_node)
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return -ENODEV;
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pdev = of_find_device_by_node(dev_node);
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if (!pdev)
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return -ENODEV;
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ctrldev = &pdev->dev;
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priv = dev_get_drvdata(ctrldev);
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of_node_put(dev_node);
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caam_init_rng(&rng_ctx, priv->jrdev[0]);
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dev_info(priv->jrdev[0], "registering rng-caam\n");
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return hwrng_register(&caam_rng);
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}
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module_init(caam_rng_init);
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module_exit(caam_rng_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("FSL CAAM support for hw_random API");
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MODULE_AUTHOR("Freescale Semiconductor - NMG");
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