From:   =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <zajec5@gmail.com>
To:     Florian Fainelli <f.fainelli@gmail.com>,
        bcm-kernel-feedback-list@broadcom.com
Cc:     "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <zajec5@gmail.com>,
        =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Subject: [PATCH RFC Vb] bgmac: fix *initial* chip reset to support BCM5358
Date:   Fri, 24 Feb 2023 14:48:51 +0100
Message-Id: <20230224134851.18028-1-zajec5@gmail.com>
MIME-Version: 1.0
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Precedence: bulk

While bringing hardware up we should perform a full reset including the
switch bit (BGMAC_BCMA_IOCTL_SW_RESET aka SICF_SWRST). It's what
specification says and what reference driver does.

This seems to be critical for the BCM5358. Without this hardware doesn't
get initialized properly and doesn't seem to transmit or receive any
packets.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
RFC: This is alternative solutionto the
[PATCH RFC] bgmac: fix *initial* chip reset to support BCM5358
https://lore.kernel.org/lkml/20230207225327.27534-1-zajec5@gmail.com/T/

Any comments on the prefered solution? Parameter vs. flag?
---
 drivers/net/ethernet/broadcom/bgmac.c | 8 ++++++--
 drivers/net/ethernet/broadcom/bgmac.h | 2 ++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c
index 3038386a5afd..1761df8fb7f9 100644
--- a/drivers/net/ethernet/broadcom/bgmac.c
+++ b/drivers/net/ethernet/broadcom/bgmac.c
@@ -890,13 +890,13 @@ static void bgmac_chip_reset_idm_config(struct bgmac *bgmac)
 
 		if (iost & BGMAC_BCMA_IOST_ATTACHED) {
 			flags = BGMAC_BCMA_IOCTL_SW_CLKEN;
-			if (!bgmac->has_robosw)
+			if (bgmac->in_init || !bgmac->has_robosw)
 				flags |= BGMAC_BCMA_IOCTL_SW_RESET;
 		}
 		bgmac_clk_enable(bgmac, flags);
 	}
 
-	if (iost & BGMAC_BCMA_IOST_ATTACHED && !bgmac->has_robosw)
+	if (iost & BGMAC_BCMA_IOST_ATTACHED && (bgmac->in_init || !bgmac->has_robosw))
 		bgmac_idm_write(bgmac, BCMA_IOCTL,
 				bgmac_idm_read(bgmac, BCMA_IOCTL) &
 				~BGMAC_BCMA_IOCTL_SW_RESET);
@@ -1490,6 +1490,8 @@ int bgmac_enet_probe(struct bgmac *bgmac)
 	struct net_device *net_dev = bgmac->net_dev;
 	int err;
 
+	bgmac->in_init = true;
+
 	bgmac_chip_intrs_off(bgmac);
 
 	net_dev->irq = bgmac->irq;
@@ -1542,6 +1544,8 @@ int bgmac_enet_probe(struct bgmac *bgmac)
 	/* Omit FCS from max MTU size */
 	net_dev->max_mtu = BGMAC_RX_MAX_FRAME_SIZE - ETH_FCS_LEN;
 
+	bgmac->in_init = false;
+
 	err = register_netdev(bgmac->net_dev);
 	if (err) {
 		dev_err(bgmac->dev, "Cannot register net device\n");
diff --git a/drivers/net/ethernet/broadcom/bgmac.h b/drivers/net/ethernet/broadcom/bgmac.h
index e05ac92c0650..d73ef262991d 100644
--- a/drivers/net/ethernet/broadcom/bgmac.h
+++ b/drivers/net/ethernet/broadcom/bgmac.h
@@ -472,6 +472,8 @@ struct bgmac {
 	int irq;
 	u32 int_mask;
 
+	bool in_init;
+
 	/* Current MAC state */
 	int mac_speed;
 	int mac_duplex;
-- 
2.34.1