crypto: caam - invalidate entropy register during RNG initialization

In order to make sure that we always use non-stale entropy data, change
the code to invalidate entropy register during RNG initialization.

Signed-off-by: Aymen Sghaier <aymen.sghaier@nxp.com>
Signed-off-by: Vipul Kumar <vipul_kumar@mentor.com>
[andrew.smirnov@gmail.com ported to upstream kernel, rewrote commit msg]
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Reviewed-by: Horia Geantă <horia.geanta@nxp.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Horia Geantă <horia.geanta@nxp.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Iuliana Prodan <iuliana.prodan@nxp.com>
Cc: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-imx@nxp.com
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c
index 7f7f2960b0cca6b1f9d88156cbf51665f2bffc11..b278471f4013b205fd49ddef0d1de18c55b04406 100644 (file)
--- a/drivers/crypto/caam/ctrl.c
+++ b/drivers/crypto/caam/ctrl.c
@@ -341,8 +341,12 @@ static void kick_trng(struct platform_device *pdev, int ent_delay)
        ctrl = (struct caam_ctrl __iomem *)ctrlpriv->ctrl;
        r4tst = &ctrl->r4tst[0];
 
-       /* put RNG4 into program mode */
-       clrsetbits_32(&r4tst->rtmctl, 0, RTMCTL_PRGM);
+       /*
+        * Setting both RTMCTL:PRGM and RTMCTL:TRNG_ACC causes TRNG to
+        * properly invalidate the entropy in the entropy register and
+        * force re-generation.
+        */
+       clrsetbits_32(&r4tst->rtmctl, 0, RTMCTL_PRGM | RTMCTL_ACC);
 
        /*
         * Performance-wise, it does not make sense to
@@ -372,7 +376,8 @@ start_rng:
         * select raw sampling in both entropy shifter
         * and statistical checker; ; put RNG4 into run mode
         */
-       clrsetbits_32(&r4tst->rtmctl, RTMCTL_PRGM, RTMCTL_SAMP_MODE_RAW_ES_SC);
+       clrsetbits_32(&r4tst->rtmctl, RTMCTL_PRGM | RTMCTL_ACC,
+                     RTMCTL_SAMP_MODE_RAW_ES_SC);
 }
 
 static int caam_get_era_from_hw(struct caam_ctrl __iomem *ctrl)

diff --git a/drivers/crypto/caam/regs.h b/drivers/crypto/caam/regs.h
index 05127b70527d7f372e5de0d37c6cba6cfb3b8fe5..c191e8fd0fa76ce513c6dbb9b2bc7154f1554486 100644 (file)
--- a/drivers/crypto/caam/regs.h
+++ b/drivers/crypto/caam/regs.h
@@ -487,7 +487,8 @@ struct rngtst {
 
 /* RNG4 TRNG test registers */
 struct rng4tst {
-#define RTMCTL_PRGM    0x00010000      /* 1 -> program mode, 0 -> run mode */
+#define RTMCTL_ACC  BIT(5)  /* TRNG access mode */
+#define RTMCTL_PRGM BIT(16) /* 1 -> program mode, 0 -> run mode */
 #define RTMCTL_SAMP_MODE_VON_NEUMANN_ES_SC     0 /* use von Neumann data in
                                                     both entropy shifter and
                                                     statistical checker */