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Commit e24f7c9e authored by Yuan Kang's avatar Yuan Kang Committed by Herbert Xu
Browse files

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: default avatarYuan Kang <Yuan.Kang@freescale.com>
Signed-off-by: default avatarKim Phillips <kim.phillips@freescale.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 643b39b0

drivers/crypto/caam/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -82,3 +82,16 @@ config CRYPTO_DEV_FSL_CAAM_AHASH_API 


	  To compile this as a module, choose M here: the module

	  will be called caamhash.



config CRYPTO_DEV_FSL_CAAM_RNG_API

	tristate "Register caam device for hwrng API"

	depends on CRYPTO_DEV_FSL_CAAM

	default y

	select CRYPTO_RNG

	select HW_RANDOM

	help

	  Selecting this will register the SEC4 hardware rng to

	  the hw_random API for suppying the kernel entropy pool.



	  To compile this as a module, choose M here: the module

	  will be called caamrng.

drivers/crypto/caam/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -5,5 +5,6 @@ 
obj-$(CONFIG_CRYPTO_DEV_FSL_CAAM) += caam.o

obj-$(CONFIG_CRYPTO_DEV_FSL_CAAM_CRYPTO_API) += caamalg.o

obj-$(CONFIG_CRYPTO_DEV_FSL_CAAM_AHASH_API) += caamhash.o

obj-$(CONFIG_CRYPTO_DEV_FSL_CAAM_RNG_API) += caamrng.o



caam-objs := ctrl.o jr.o error.o key_gen.o

drivers/crypto/caam/caamrng.c

0 → 100644
+309 −0
Original line number Diff line number Diff line 
/*

 * 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			(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_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_WAIT);



	/* 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);

#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);

}



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,

};



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;

	struct device *ctrldev;

	struct caam_drv_private *priv;



	dev_node = of_find_compatible_node(NULL, NULL, "fsl,sec-v4.0");

	if (!dev_node)

		return -ENODEV;



	pdev = of_find_device_by_node(dev_node);

	if (!pdev)

		return -ENODEV;



	ctrldev = &pdev->dev;

	priv = dev_get_drvdata(ctrldev);

	of_node_put(dev_node);



	caam_init_rng(&rng_ctx, priv->jrdev[0]);



	dev_info(priv->jrdev[0], "registering rng-caam\n");

	return hwrng_register(&caam_rng);

}



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");