netdev - [PATCH 22/29] can: ti_hecc: keep MIM and MD set

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Date:   Thu, 10 Oct 2019 14:17:43 +0200
From:   Marc Kleine-Budde <mkl@...gutronix.de>
To:     netdev@...r.kernel.org, linux-can <linux-can@...r.kernel.org>
Cc:     davem@...emloft.net, kernel@...gutronix.de,
        jhofstee@...tronenergy.com,
        Martin Hundebøll <martin@...nix.com>,
        Kurt Van Dijck <dev.kurt@...dijck-laurijssen.be>,
        Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [PATCH 22/29] can: ti_hecc: keep MIM and MD set

From: Jeroen Hofstee <jhofstee@...tronenergy.com>

The HECC_CANMIM is set in the xmit path and cleared in the interrupt.
Since this is done with a read, modify, write action the register might
end up with some more MIM enabled then intended, since it is not
protected. That doesn't matter at all, since the tx interrupt disables
the mailbox with HECC_CANME (while holding a spinlock). So lets just
always keep MIM set.

While at it, since the mailbox direction never changes, don't set it
every time a message is send, ti_hecc_reset() already sets them to tx.

Signed-off-by: Jeroen Hofstee <jhofstee@...tronenergy.com>
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
 drivers/net/can/ti_hecc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/ti_hecc.c b/drivers/net/can/ti_hecc.c
index eb8151154083..d6a84f8ff863 100644
--- a/drivers/net/can/ti_hecc.c
+++ b/drivers/net/can/ti_hecc.c
@@ -382,6 +382,9 @@ static void ti_hecc_start(struct net_device *ndev)
 		hecc_set_bit(priv, HECC_CANMIM, mbx_mask);
 	}
 
+	/* Enable tx interrupts */
+	hecc_set_bit(priv, HECC_CANMIM, BIT(HECC_MAX_TX_MBOX) - 1);
+
 	/* Prevent message over-write & Enable interrupts */
 	hecc_write(priv, HECC_CANOPC, HECC_SET_REG);
 	if (priv->use_hecc1int) {
@@ -511,8 +514,6 @@ static netdev_tx_t ti_hecc_xmit(struct sk_buff *skb, struct net_device *ndev)
 	hecc_set_bit(priv, HECC_CANME, mbx_mask);
 	spin_unlock_irqrestore(&priv->mbx_lock, flags);
 
-	hecc_clear_bit(priv, HECC_CANMD, mbx_mask);
-	hecc_set_bit(priv, HECC_CANMIM, mbx_mask);
 	hecc_write(priv, HECC_CANTRS, mbx_mask);
 
 	return NETDEV_TX_OK;
@@ -676,7 +677,6 @@ static irqreturn_t ti_hecc_interrupt(int irq, void *dev_id)
 			mbx_mask = BIT(mbxno);
 			if (!(mbx_mask & hecc_read(priv, HECC_CANTA)))
 				break;
-			hecc_clear_bit(priv, HECC_CANMIM, mbx_mask);
 			hecc_write(priv, HECC_CANTA, mbx_mask);
 			spin_lock_irqsave(&priv->mbx_lock, flags);
 			hecc_clear_bit(priv, HECC_CANME, mbx_mask);
-- 
2.23.0