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crypto: omap-sham - error handling improved
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Introduces DMA error handling.

DMA error is returned as a result code of the hash request.
Clients needs to handle error codes and may repeat hash calculation attempt.

Also in the case of DMA error, SHAM module is set to be re-initialized again.
It significantly improves stability against possible HW failures.

Signed-off-by: Dmitry Kasatkin <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>
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@herbertx
Dmitry Kasatkin authored and herbertx committed Nov 27, 2010
1 parent c8eb540 commit 3e133c8
Showing 1 changed file with 44 additions and 23 deletions.
67 changes: 44 additions & 23 deletions drivers/crypto/omap-sham.c
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Original file line number Diff line number Diff line change
Expand Up @@ -83,6 +83,7 @@
#define FLAGS_INIT 0x0100
#define FLAGS_CPU 0x0200
#define FLAGS_HMAC 0x0400
#define FLAGS_ERROR 0x0800

/* 3rd byte */
#define FLAGS_BUSY 16
Expand Down Expand Up @@ -137,6 +138,7 @@ struct omap_sham_dev {
int irq;
struct clk *iclk;
spinlock_t lock;
int err;
int dma;
int dma_lch;
struct tasklet_struct done_task;
Expand Down Expand Up @@ -234,10 +236,12 @@ static int omap_sham_write_ctrl(struct omap_sham_dev *dd, size_t length,
SHA_REG_MASK_SOFTRESET, SHA_REG_MASK_SOFTRESET);

if (omap_sham_wait(dd, SHA_REG_SYSSTATUS,
SHA_REG_SYSSTATUS_RESETDONE))
SHA_REG_SYSSTATUS_RESETDONE)) {
clk_disable(dd->iclk);
return -ETIMEDOUT;

}
dd->flags |= FLAGS_INIT;
dd->err = 0;
}
} else {
omap_sham_write(dd, SHA_REG_DIGCNT, ctx->digcnt);
Expand Down Expand Up @@ -279,11 +283,12 @@ static int omap_sham_xmit_cpu(struct omap_sham_dev *dd, const u8 *buf,
if (err)
return err;

/* should be non-zero before next lines to disable clocks later */
ctx->digcnt += length;

if (omap_sham_wait(dd, SHA_REG_CTRL, SHA_REG_CTRL_INPUT_READY))
return -ETIMEDOUT;

ctx->digcnt += length;

if (final)
ctx->flags |= FLAGS_FINAL; /* catch last interrupt */

Expand All @@ -303,7 +308,6 @@ static int omap_sham_xmit_dma(struct omap_sham_dev *dd, dma_addr_t dma_addr,

dev_dbg(dd->dev, "xmit_dma: digcnt: %d, length: %d, final: %d\n",
ctx->digcnt, length, final);

/* flush cache entries related to our page */
if (dma_addr == ctx->dma_addr)
dma_sync_single_for_device(dd->dev, dma_addr, length,
Expand Down Expand Up @@ -411,6 +415,7 @@ static int omap_sham_update_dma_fast(struct omap_sham_dev *dd)
{
struct omap_sham_reqctx *ctx = ahash_request_ctx(dd->req);
unsigned int length;
int err;

ctx->flags |= FLAGS_FAST;

Expand All @@ -424,7 +429,11 @@ static int omap_sham_update_dma_fast(struct omap_sham_dev *dd)

ctx->total -= length;

return omap_sham_xmit_dma(dd, sg_dma_address(ctx->sg), length, 1);
err = omap_sham_xmit_dma(dd, sg_dma_address(ctx->sg), length, 1);
if (err != -EINPROGRESS)
dma_unmap_sg(dd->dev, ctx->sg, 1, DMA_TO_DEVICE);

return err;
}

static int omap_sham_update_cpu(struct omap_sham_dev *dd)
Expand Down Expand Up @@ -580,9 +589,6 @@ static int omap_sham_final_req(struct omap_sham_dev *dd)

ctx->bufcnt = 0;

if (err != -EINPROGRESS)
omap_sham_cleanup(req);

dev_dbg(dd->dev, "final_req: err: %d\n", err);

return err;
Expand Down Expand Up @@ -616,9 +622,11 @@ static void omap_sham_finish_req(struct ahash_request *req, int err)
omap_sham_copy_hash(ctx->dd->req, 1);
if (ctx->flags & FLAGS_HMAC)
err = omap_sham_finish_req_hmac(req);
} else {
ctx->flags |= FLAGS_ERROR;
}

if (ctx->flags & FLAGS_FINAL)
if ((ctx->flags & FLAGS_FINAL) || err)
omap_sham_cleanup(req);

clear_bit(FLAGS_BUSY, &ctx->dd->flags);
Expand Down Expand Up @@ -776,12 +784,14 @@ static int omap_sham_final(struct ahash_request *req)

ctx->flags |= FLAGS_FINUP;

/* OMAP HW accel works only with buffers >= 9 */
/* HMAC is always >= 9 because of ipad */
if ((ctx->digcnt + ctx->bufcnt) < 9)
err = omap_sham_final_shash(req);
else if (ctx->bufcnt)
return omap_sham_enqueue(req, OP_FINAL);
if (!(ctx->flags & FLAGS_ERROR)) {
/* OMAP HW accel works only with buffers >= 9 */
/* HMAC is always >= 9 because of ipad */
if ((ctx->digcnt + ctx->bufcnt) < 9)
err = omap_sham_final_shash(req);
else if (ctx->bufcnt)
return omap_sham_enqueue(req, OP_FINAL);
}

omap_sham_cleanup(req);

Expand Down Expand Up @@ -851,6 +861,8 @@ static int omap_sham_cra_init_alg(struct crypto_tfm *tfm, const char *alg_base)
struct omap_sham_ctx *tctx = crypto_tfm_ctx(tfm);
const char *alg_name = crypto_tfm_alg_name(tfm);

pr_info("enter\n");

/* Allocate a fallback and abort if it failed. */
tctx->fallback = crypto_alloc_shash(alg_name, 0,
CRYPTO_ALG_NEED_FALLBACK);
Expand Down Expand Up @@ -1008,7 +1020,7 @@ static void omap_sham_done_task(unsigned long data)
struct omap_sham_dev *dd = (struct omap_sham_dev *)data;
struct ahash_request *req = dd->req;
struct omap_sham_reqctx *ctx = ahash_request_ctx(req);
int ready = 1;
int ready = 0, err = 0;

if (ctx->flags & FLAGS_OUTPUT_READY) {
ctx->flags &= ~FLAGS_OUTPUT_READY;
Expand All @@ -1018,13 +1030,16 @@ static void omap_sham_done_task(unsigned long data)
if (dd->flags & FLAGS_DMA_ACTIVE) {
dd->flags &= ~FLAGS_DMA_ACTIVE;
omap_sham_update_dma_stop(dd);
omap_sham_update_dma_slow(dd);
if (!dd->err)
err = omap_sham_update_dma_slow(dd);
}

if (ready && !(dd->flags & FLAGS_DMA_ACTIVE)) {
dev_dbg(dd->dev, "update done\n");
err = dd->err ? : err;

if (err != -EINPROGRESS && (ready || err)) {
dev_dbg(dd->dev, "update done: err: %d\n", err);
/* finish curent request */
omap_sham_finish_req(req, 0);
omap_sham_finish_req(req, err);
/* start new request */
omap_sham_handle_queue(dd);
}
Expand Down Expand Up @@ -1056,6 +1071,7 @@ static irqreturn_t omap_sham_irq(int irq, void *dev_id)
omap_sham_read(dd, SHA_REG_CTRL);

ctx->flags |= FLAGS_OUTPUT_READY;
dd->err = 0;
tasklet_schedule(&dd->done_task);

return IRQ_HANDLED;
Expand All @@ -1065,8 +1081,13 @@ static void omap_sham_dma_callback(int lch, u16 ch_status, void *data)
{
struct omap_sham_dev *dd = data;

if (likely(lch == dd->dma_lch))
tasklet_schedule(&dd->done_task);
if (ch_status != OMAP_DMA_BLOCK_IRQ) {
pr_err("omap-sham DMA error status: 0x%hx\n", ch_status);
dd->err = -EIO;
dd->flags &= ~FLAGS_INIT; /* request to re-initialize */
}

tasklet_schedule(&dd->done_task);
}

static int omap_sham_dma_init(struct omap_sham_dev *dd)
Expand Down

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