Netdev Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Oleksij Rempel <o.rempel@pengutronix.de>
To: Andrew Lunn <andrew@lunn.ch>,
	Vivien Didelot <vivien.didelot@gmail.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Vladimir Oltean <olteanv@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Russell King <linux@armlinux.org.uk>
Cc: Oleksij Rempel <o.rempel@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mips@vger.kernel.org
Subject: [PATCH net-next v3 1/6] net: dsa: qca: ar9331: reorder MDIO write sequence
Date: Mon,  2 Aug 2021 15:10:32 +0200	[thread overview]
Message-ID: <20210802131037.32326-2-o.rempel@pengutronix.de> (raw)
In-Reply-To: <20210802131037.32326-1-o.rempel@pengutronix.de>

In case of this switch we work with 32bit registers on top of 16bit
bus. Some registers (for example access to forwarding database) have
trigger bit on the first 16bit half of request and the result +
configuration of request in the second half. Without this patch, we would
trigger database operation and overwrite result in one run.

To make it work properly, we should do the second part of transfer
before the first one is done.

So far, this rule seems to work for all registers on this switch.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
---
 drivers/net/dsa/qca/ar9331.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/net/dsa/qca/ar9331.c b/drivers/net/dsa/qca/ar9331.c
index ca2ad77b71f1..6686192e1883 100644
--- a/drivers/net/dsa/qca/ar9331.c
+++ b/drivers/net/dsa/qca/ar9331.c
@@ -837,16 +837,24 @@ static int ar9331_mdio_write(void *ctx, u32 reg, u32 val)
 		return 0;
 	}
 
-	ret = __ar9331_mdio_write(sbus, AR9331_SW_MDIO_PHY_MODE_REG, reg, val);
+	/* In case of this switch we work with 32bit registers on top of 16bit
+	 * bus. Some registers (for example access to forwarding database) have
+	 * trigger bit on the first 16bit half of request, the result and
+	 * configuration of request in the second half.
+	 * To make it work properly, we should do the second part of transfer
+	 * before the first one is done.
+	 */
+	ret = __ar9331_mdio_write(sbus, AR9331_SW_MDIO_PHY_MODE_REG, reg + 2,
+				  val >> 16);
 	if (ret < 0)
 		goto error;
 
-	ret = __ar9331_mdio_write(sbus, AR9331_SW_MDIO_PHY_MODE_REG, reg + 2,
-				  val >> 16);
+	ret = __ar9331_mdio_write(sbus, AR9331_SW_MDIO_PHY_MODE_REG, reg, val);
 	if (ret < 0)
 		goto error;
 
 	return 0;
+
 error:
 	dev_err_ratelimited(&sbus->dev, "Bus error. Failed to write register.\n");
 	return ret;
-- 
2.30.2


  reply	other threads:[~2021-08-02 13:11 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02 13:10 [PATCH net-next v3 0/6] ar9331: mainline some parts of switch functionality Oleksij Rempel
2021-08-02 13:10 ` Oleksij Rempel [this message]
2021-08-02 14:00   ` [PATCH net-next v3 1/6] net: dsa: qca: ar9331: reorder MDIO write sequence Vladimir Oltean
2021-08-02 13:10 ` [PATCH net-next v3 2/6] net: dsa: qca: ar9331: make proper initial port defaults Oleksij Rempel
2021-08-02 14:03   ` Vladimir Oltean
2021-08-02 19:45     ` Andrew Lunn
2021-08-03  6:36       ` Oleksij Rempel
2021-08-02 19:42   ` Andrew Lunn
2021-08-02 13:10 ` [PATCH net-next v3 3/6] net: dsa: qca: ar9331: add forwarding database support Oleksij Rempel
2021-08-02 15:37   ` Vladimir Oltean
2021-08-02 13:10 ` [PATCH net-next v3 4/6] net: dsa: qca: ar9331: add ageing time support Oleksij Rempel
2021-08-02 13:10 ` [PATCH net-next v3 5/6] net: dsa: qca: ar9331: add bridge support Oleksij Rempel
2021-08-02 14:55   ` Vladimir Oltean
2021-08-07 23:08   ` Vladimir Oltean
2021-08-09  5:04     ` Oleksij Rempel
2021-08-02 13:10 ` [PATCH net-next v3 6/6] net: dsa: qca: ar9331: add vlan support Oleksij Rempel
2021-08-02 14:50   ` Vladimir Oltean

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210802131037.32326-2-o.rempel@pengutronix.de \
    --to=o.rempel@pengutronix.de \
    --cc=andrew@lunn.ch \
    --cc=davem@davemloft.net \
    --cc=f.fainelli@gmail.com \
    --cc=kernel@pengutronix.de \
    --cc=kuba@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mips@vger.kernel.org \
    --cc=linux@armlinux.org.uk \
    --cc=netdev@vger.kernel.org \
    --cc=olteanv@gmail.com \
    --cc=vivien.didelot@gmail.com \
    --subject='Re: [PATCH net-next v3 1/6] net: dsa: qca: ar9331: reorder MDIO write sequence' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).