linux/drivers/crypto/caam/caamrng.c
Kim Phillips 61bb86bba1 crypto: caam - set descriptor sharing type to SERIAL
SHARE_WAIT, whilst more optimal for association-less crypto,
has the ability to start thrashing the CCB descriptor/key
caches, given high levels of traffic across multiple security
associations (and thus keys).

Switch to using the SERIAL sharing type, which prefers
the last used CCB for the SA.  On a 2-DECO platform
such as the P3041, this can improve performance by
about 3.7%.

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2012-08-01 17:47:31 +08:00

313 lines
7.8 KiB
C

/*
* 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_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);
#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) {
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;
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");