diff options
Diffstat (limited to 'drivers/crypto/caam/ctrl.c')
| -rw-r--r-- | drivers/crypto/caam/ctrl.c | 63 |
1 files changed, 47 insertions, 16 deletions
diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c index 11c7f295857b..d5fe5f57108c 100644 --- a/drivers/crypto/caam/ctrl.c +++ b/drivers/crypto/caam/ctrl.c @@ -82,7 +82,7 @@ static int instantiate_rng(struct device *ctrldev) struct caam_drv_private *ctrlpriv = dev_get_drvdata(ctrldev); struct caam_full __iomem *topregs; unsigned int timeout = 100000; - u32 *desc; + u32 *desc, deco_dbg_reg; int i, ret = 0; desc = kmalloc(CAAM_CMD_SZ * 7, GFP_KERNEL | GFP_DMA); @@ -112,9 +112,17 @@ static int instantiate_rng(struct device *ctrldev) wr_reg32(&topregs->deco.jr_ctl_hi, DECO_JQCR_WHL | DECO_JQCR_FOUR); timeout = 10000000; - while ((rd_reg32(&topregs->deco.desc_dbg) & DECO_DBG_VALID) && - --timeout) + do { + deco_dbg_reg = rd_reg32(&topregs->deco.desc_dbg); + /* + * If an error occured in the descriptor, then + * the DECO status field will be set to 0x0D + */ + if ((deco_dbg_reg & DESC_DBG_DECO_STAT_MASK) == + DESC_DBG_DECO_STAT_HOST_ERR) + break; cpu_relax(); + } while ((deco_dbg_reg & DESC_DBG_DECO_STAT_VALID) && --timeout); if (!timeout) { dev_err(ctrldev, "failed to instantiate RNG\n"); @@ -128,10 +136,12 @@ out: } /* - * By default, the TRNG runs for 200 clocks per sample; - * 1600 clocks per sample generates better entropy. + * kick_trng - sets the various parameters for enabling the initialization + * of the RNG4 block in CAAM + * @pdev - pointer to the platform device + * @ent_delay - Defines the length (in system clocks) of each entropy sample. */ -static void kick_trng(struct platform_device *pdev) +static void kick_trng(struct platform_device *pdev, int ent_delay) { struct device *ctrldev = &pdev->dev; struct caam_drv_private *ctrlpriv = dev_get_drvdata(ctrldev); @@ -144,14 +154,31 @@ static void kick_trng(struct platform_device *pdev) /* put RNG4 into program mode */ setbits32(&r4tst->rtmctl, RTMCTL_PRGM); - /* 1600 clocks per sample */ + + /* + * Performance-wise, it does not make sense to + * set the delay to a value that is lower + * than the last one that worked (i.e. the state handles + * were instantiated properly. Thus, instead of wasting + * time trying to set the values controlling the sample + * frequency, the function simply returns. + */ + val = (rd_reg32(&r4tst->rtsdctl) & RTSDCTL_ENT_DLY_MASK) + >> RTSDCTL_ENT_DLY_SHIFT; + if (ent_delay <= val) { + /* put RNG4 into run mode */ + clrbits32(&r4tst->rtmctl, RTMCTL_PRGM); + return; + } + val = rd_reg32(&r4tst->rtsdctl); - val = (val & ~RTSDCTL_ENT_DLY_MASK) | (1600 << RTSDCTL_ENT_DLY_SHIFT); + val = (val & ~RTSDCTL_ENT_DLY_MASK) | + (ent_delay << RTSDCTL_ENT_DLY_SHIFT); wr_reg32(&r4tst->rtsdctl, val); - /* min. freq. count */ - wr_reg32(&r4tst->rtfrqmin, 400); - /* max. freq. count */ - wr_reg32(&r4tst->rtfrqmax, 6400); + /* min. freq. count, equal to 1/4 of the entropy sample length */ + wr_reg32(&r4tst->rtfrqmin, ent_delay >> 2); + /* max. freq. count, equal to 8 times the entropy sample length */ + wr_reg32(&r4tst->rtfrqmax, ent_delay << 3); /* put RNG4 into run mode */ clrbits32(&r4tst->rtmctl, RTMCTL_PRGM); } @@ -192,7 +219,7 @@ EXPORT_SYMBOL(caam_get_era); /* Probe routine for CAAM top (controller) level */ static int caam_probe(struct platform_device *pdev) { - int ret, ring, rspec; + int ret, ring, rspec, ent_delay = RTSDCTL_ENT_DLY_MIN; u64 caam_id; struct device *dev; struct device_node *nprop, *np; @@ -298,13 +325,17 @@ static int caam_probe(struct platform_device *pdev) /* * If SEC has RNG version >= 4 and RNG state handle has not been - * already instantiated ,do RNG instantiation + * already instantiated, do RNG instantiation */ if ((cha_vid & CHA_ID_RNG_MASK) >> CHA_ID_RNG_SHIFT >= 4 && !(rd_reg32(&topregs->ctrl.r4tst[0].rdsta) & RDSTA_IF0)) { - kick_trng(pdev); - ret = instantiate_rng(dev); + do { + kick_trng(pdev, ent_delay); + ret = instantiate_rng(dev); + ent_delay += 400; + } while ((ret == -EIO) && (ent_delay < RTSDCTL_ENT_DLY_MAX)); if (ret) { + dev_err(dev, "failed to instantiate RNG"); caam_remove(pdev); return ret; } |