[PATCH] Revert "crypto: caam - optimize RNG sample size"

From: meenakshi . aggarwal
Date: Mon Aug 14 2023 - 01:33:56 EST


From: Meenakshi Aggarwal <meenakshi.aggarwal@xxxxxxx>

This reverts commit 1abc89661ad3cd18d8c6af5c2584bcc63df43bf2.

Reverting the commit because of RNG instantiation failure
observed on imx8mm board.

Signed-off-by: Meenakshi Aggarwal <meenakshi.aggarwal@xxxxxxx>
---
drivers/crypto/caam/ctrl.c | 52 +++++++++++++++-----------------------
drivers/crypto/caam/regs.h | 14 ++--------
2 files changed, 22 insertions(+), 44 deletions(-)

diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c
index ff9ddbbca377..ee6478eea933 100644
--- a/drivers/crypto/caam/ctrl.c
+++ b/drivers/crypto/caam/ctrl.c
@@ -358,7 +358,7 @@ static void kick_trng(struct device *dev, int ent_delay)
struct caam_drv_private *ctrlpriv = dev_get_drvdata(dev);
struct caam_ctrl __iomem *ctrl;
struct rng4tst __iomem *r4tst;
- u32 val, rtsdctl;
+ u32 val;

ctrl = (struct caam_ctrl __iomem *)ctrlpriv->ctrl;
r4tst = &ctrl->r4tst[0];
@@ -374,38 +374,26 @@ static void kick_trng(struct device *dev, int ent_delay)
* 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).
+ * were instantiated properly. Thus, instead of wasting
+ * time trying to set the values controlling the sample
+ * frequency, the function simply returns.
*/
- rtsdctl = rd_reg32(&r4tst->rtsdctl);
- val = (rtsdctl & RTSDCTL_ENT_DLY_MASK) >> RTSDCTL_ENT_DLY_SHIFT;
- if (ent_delay > val) {
- val = ent_delay;
- /* min. freq. count, equal to 1/4 of the entropy sample length */
- wr_reg32(&r4tst->rtfrqmin, val >> 2);
- /* max. freq. count, equal to 16 times the entropy sample length */
- wr_reg32(&r4tst->rtfrqmax, val << 4);
- }
-
- wr_reg32(&r4tst->rtsdctl, (val << RTSDCTL_ENT_DLY_SHIFT) |
- RTSDCTL_SAMP_SIZE_VAL);
-
- /*
- * To avoid reprogramming the self-test parameters over and over again,
- * use RTSDCTL[SAMP_SIZE] as an indicator.
- */
- if ((rtsdctl & RTSDCTL_SAMP_SIZE_MASK) != RTSDCTL_SAMP_SIZE_VAL) {
- wr_reg32(&r4tst->rtscmisc, (2 << 16) | 32);
- wr_reg32(&r4tst->rtpkrrng, 570);
- wr_reg32(&r4tst->rtpkrmax, 1600);
- wr_reg32(&r4tst->rtscml, (122 << 16) | 317);
- wr_reg32(&r4tst->rtscrl[0], (80 << 16) | 107);
- wr_reg32(&r4tst->rtscrl[1], (57 << 16) | 62);
- wr_reg32(&r4tst->rtscrl[2], (39 << 16) | 39);
- wr_reg32(&r4tst->rtscrl[3], (27 << 16) | 26);
- wr_reg32(&r4tst->rtscrl[4], (19 << 16) | 18);
- wr_reg32(&r4tst->rtscrl[5], (18 << 16) | 17);
- }
-
+ val = (rd_reg32(&r4tst->rtsdctl) & RTSDCTL_ENT_DLY_MASK)
+ >> RTSDCTL_ENT_DLY_SHIFT;
+ if (ent_delay <= val)
+ goto start_rng;
+
+ val = rd_reg32(&r4tst->rtsdctl);
+ val = (val & ~RTSDCTL_ENT_DLY_MASK) |
+ (ent_delay << RTSDCTL_ENT_DLY_SHIFT);
+ wr_reg32(&r4tst->rtsdctl, val);
+ /* min. freq. count, equal to 1/4 of the entropy sample length */
+ wr_reg32(&r4tst->rtfrqmin, ent_delay >> 2);
+ /* max. freq. count, equal to 16 times the entropy sample length */
+ wr_reg32(&r4tst->rtfrqmax, ent_delay << 4);
+ /* read the control register */
+ val = rd_reg32(&r4tst->rtmctl);
+start_rng:
/*
* select raw sampling in both entropy shifter
* and statistical checker; ; put RNG4 into run mode
diff --git a/drivers/crypto/caam/regs.h b/drivers/crypto/caam/regs.h
index 189e74c21f0c..66928f8a0c4b 100644
--- a/drivers/crypto/caam/regs.h
+++ b/drivers/crypto/caam/regs.h
@@ -3,7 +3,7 @@
* CAAM hardware register-level view
*
* Copyright 2008-2011 Freescale Semiconductor, Inc.
- * Copyright 2018, 2023 NXP
+ * Copyright 2018 NXP
*/

#ifndef REGS_H
@@ -523,8 +523,6 @@ struct rng4tst {
#define RTSDCTL_ENT_DLY_MASK (0xffff << RTSDCTL_ENT_DLY_SHIFT)
#define RTSDCTL_ENT_DLY_MIN 3200
#define RTSDCTL_ENT_DLY_MAX 12800
-#define RTSDCTL_SAMP_SIZE_MASK 0xffff
-#define RTSDCTL_SAMP_SIZE_VAL 512
u32 rtsdctl; /* seed control register */
union {
u32 rtsblim; /* PRGM=1: sparse bit limit register */
@@ -536,15 +534,7 @@ struct rng4tst {
u32 rtfrqmax; /* PRGM=1: freq. count max. limit register */
u32 rtfrqcnt; /* PRGM=0: freq. count register */
};
- union {
- u32 rtscmc; /* statistical check run monobit count */
- u32 rtscml; /* statistical check run monobit limit */
- };
- union {
- u32 rtscrc[6]; /* statistical check run length count */
- u32 rtscrl[6]; /* statistical check run length limit */
- };
- u32 rsvd1[33];
+ u32 rsvd1[40];
#define RDSTA_SKVT 0x80000000
#define RDSTA_SKVN 0x40000000
#define RDSTA_PR0 BIT(4)
--
2.25.1