linux-kernel - [PATCH v1] hw_random: npcm: modify readl to readb

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Date:   Thu, 24 Sep 2020 00:23:05 +0300
From:   Tomer Maimon <tmaimon77@...il.com>
To:     mpm@...enic.com, herbert@...dor.apana.org.au, arnd@...db.de,
        gregkh@...uxfoundation.org, avifishman70@...il.com,
        tali.perry1@...il.com, venture@...gle.com, yuenn@...gle.com,
        benjaminfair@...gle.com, joel@....id.au
Cc:     linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        openbmc@...ts.ozlabs.org, tmaimon77@...il.com
Subject: [PATCH v1] hw_random: npcm: modify readl to readb

Modify the read size to the correct HW random
registers size, 8bit.
The incorrect read size caused and faulty
HW random value.

Signed-off-by: Tomer Maimon <tmaimon77@...il.com>
---
 drivers/char/hw_random/npcm-rng.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/char/hw_random/npcm-rng.c b/drivers/char/hw_random/npcm-rng.c
index 5d0d13f891b7..1ec5f267a656 100644
--- a/drivers/char/hw_random/npcm-rng.c
+++ b/drivers/char/hw_random/npcm-rng.c
@@ -58,24 +58,24 @@ static int npcm_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
 
 	pm_runtime_get_sync((struct device *)priv->rng.priv);
 
-	while (max >= sizeof(u32)) {
+	while (max) {
 		if (wait) {
-			if (readl_poll_timeout(priv->base + NPCM_RNGCS_REG,
+			if (readb_poll_timeout(priv->base + NPCM_RNGCS_REG,
 					       ready,
 					       ready & NPCM_RNG_DATA_VALID,
 					       NPCM_RNG_POLL_USEC,
 					       NPCM_RNG_TIMEOUT_USEC))
 				break;
 		} else {
-			if ((readl(priv->base + NPCM_RNGCS_REG) &
+			if ((readb(priv->base + NPCM_RNGCS_REG) &
 			    NPCM_RNG_DATA_VALID) == 0)
 				break;
 		}
 
-		*(u32 *)buf = readl(priv->base + NPCM_RNGD_REG);
-		retval += sizeof(u32);
-		buf += sizeof(u32);
-		max -= sizeof(u32);
+		*(u8 *)buf = readb(priv->base + NPCM_RNGD_REG);
+		retval++;
+		buf++;
+		max--;
 	}
 
 	pm_runtime_mark_last_busy((struct device *)priv->rng.priv);
-- 
2.22.0