bgmac: fix *initial* chip reset to support BCM5358

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.

Originally bgmac was calling bgmac_chip_reset() before setting
"has_robosw" property which resulted in expected behaviour. That has
changed as a side effect of adding platform device support which
regressed BCM5358 support.

Fixes: f6a95a2 ("net: ethernet: bgmac: Add platform device support")
Cc: Jon Mason <[email protected]>
Signed-off-by: Rafał Miłecki <[email protected]>
Reviewed-by: Leon Romanovsky <[email protected]>
Reviewed-by: Florian Fainelli <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>

Author: Rafał Miłecki

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");

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;