[PATCH net 0/2] net: stmmac: Fix multicast filter on IPQ806x

[PATCH net 0/2] net: stmmac: Fix multicast filter on IPQ806x

[Jonathan McDowell]

This pair of patches are the result of discovering a failure to
correctly receive IPv6 multicast packets on such a device (in particular
DHCPv6 requests and RA solicitations). Putting the device into
promiscuous mode, or allmulti, both resulted in such packets correctly
being received. Examination of the vendor driver (nss-gmac from the
qsdk) shows that it does not enable the multicast filter and instead
falls back to allmulti.

Extend the base dwmac1000 driver to fall back when there's no suitable
hardware filter, and update the ipq806x platform to request this.

Jonathan McDowell (2):
  net: stmmac: dwmac1000: provide multicast filter fallback
  net: ethernet: stmmac: Disable hardware multicast filter

 drivers/net/ethernet/stmicro/stmmac/dwmac-ipq806x.c  | 1 +
 drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c | 3 +++
 2 files changed, 4 insertions(+)

-- 
2.20.1

[PATCH net 1/2] net: stmmac: dwmac1000: provide multicast filter fallback

[Jonathan McDowell]

If we don't have a hardware multicast filter available then instead of
silently failing to listen for the requested ethernet broadcast
addresses fall back to receiving all multicast packets, in a similar
fashion to other drivers with no multicast filter.

Cc: stable@vger.kernel.org
Signed-off-by: Jonathan McDowell <noodles@earth.li>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c
index efc6ec1b8027..fc8759f146c7 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c
@@ -164,6 +164,9 @@ static void dwmac1000_set_filter(struct mac_device_info *hw,
 		value = GMAC_FRAME_FILTER_PR | GMAC_FRAME_FILTER_PCF;
 	} else if (dev->flags & IFF_ALLMULTI) {
 		value = GMAC_FRAME_FILTER_PM;	/* pass all multi */
+	} else if (!netdev_mc_empty(dev) && (mcbitslog2 == 0)) {
+		/* Fall back to all multicast if we've no filter */
+		value = GMAC_FRAME_FILTER_PM;
 	} else if (!netdev_mc_empty(dev)) {
 		struct netdev_hw_addr *ha;
 
-- 
2.20.1

[PATCH net 2/2] net: ethernet: stmmac: Disable hardware multicast filter

[Jonathan McDowell]

The IPQ806x does not appear to have a functional multicast ethernet
address filter. This was observed as a failure to correctly receive IPv6
packets on a LAN to the all stations address. Checking the vendor driver
shows that it does not attempt to enable the multicast filter and
instead falls back to receiving all multicast packets, internally
setting ALLMULTI.

Use the new fallback support in the dwmac1000 driver to correctly
achieve the same with the mainline IPQ806x driver. Confirmed to fix IPv6
functionality on an RB3011 router.

Cc: stable@vger.kernel.org
Signed-off-by: Jonathan McDowell <noodles@earth.li>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-ipq806x.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-ipq806x.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-ipq806x.c
index 02102c781a8c..bf3250e0e59c 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-ipq806x.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-ipq806x.c
@@ -351,6 +351,7 @@ static int ipq806x_gmac_probe(struct platform_device *pdev)
 	plat_dat->has_gmac = true;
 	plat_dat->bsp_priv = gmac;
 	plat_dat->fix_mac_speed = ipq806x_gmac_fix_mac_speed;
+	plat_dat->multicast_filter_bins = 0;
 
 	err = stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);
 	if (err)
-- 
2.20.1

Re: [PATCH net 0/2] net: stmmac: Fix multicast filter on IPQ806x

[David Miller]

From: Jonathan McDowell <noodles@earth.li>
Date: Wed, 12 Aug 2020 20:36:54 +0100

> This pair of patches are the result of discovering a failure to
> correctly receive IPv6 multicast packets on such a device (in particular
> DHCPv6 requests and RA solicitations). Putting the device into
> promiscuous mode, or allmulti, both resulted in such packets correctly
> being received. Examination of the vendor driver (nss-gmac from the
> qsdk) shows that it does not enable the multicast filter and instead
> falls back to allmulti.
> 
> Extend the base dwmac1000 driver to fall back when there's no suitable
> hardware filter, and update the ipq806x platform to request this.

Series applied, thank you.