ethtool: support FEC settings over netlink

Add FEC API to netlink.

This is not a 1-to-1 conversion.

FEC settings already depend on link modes to tell user which
modes are supported. Take this further an use link modes for
manual configuration. Old struct ethtool_fecparam is still
used to talk to the drivers, so we need to translate back
and forth. We can revisit the internal API if number of FEC
encodings starts to grow.

Enforce only one active FEC bit (by using a bit position
rather than another mask).

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 238 insertions, 0 deletions

diff --git a/net/ethtool/fec.c b/net/ethtool/fec.c
new file mode 100644
index 000000000000..31454b9188bd
--- /dev/null
+++ b/net/ethtool/fec.c
@@ -0,0 +1,238 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include "netlink.h"
+#include "common.h"
+#include "bitset.h"
+
+struct fec_req_info {
+	struct ethnl_req_info		base;
+};
+
+struct fec_reply_data {
+	struct ethnl_reply_data		base;
+	__ETHTOOL_DECLARE_LINK_MODE_MASK(fec_link_modes);
+	u32 active_fec;
+	u8 fec_auto;
+};
+
+#define FEC_REPDATA(__reply_base) \
+	container_of(__reply_base, struct fec_reply_data, base)
+
+#define ETHTOOL_FEC_MASK	((ETHTOOL_FEC_LLRS << 1) - 1)
+
+const struct nla_policy ethnl_fec_get_policy[ETHTOOL_A_FEC_HEADER + 1] = {
+	[ETHTOOL_A_FEC_HEADER]	= NLA_POLICY_NESTED(ethnl_header_policy),
+};
+
+static void
+ethtool_fec_to_link_modes(u32 fec, unsigned long *link_modes, u8 *fec_auto)
+{
+	if (fec_auto)
+		*fec_auto = !!(fec & ETHTOOL_FEC_AUTO);
+
+	if (fec & ETHTOOL_FEC_OFF)
+		__set_bit(ETHTOOL_LINK_MODE_FEC_NONE_BIT, link_modes);
+	if (fec & ETHTOOL_FEC_RS)
+		__set_bit(ETHTOOL_LINK_MODE_FEC_RS_BIT, link_modes);
+	if (fec & ETHTOOL_FEC_BASER)
+		__set_bit(ETHTOOL_LINK_MODE_FEC_BASER_BIT, link_modes);
+	if (fec & ETHTOOL_FEC_LLRS)
+		__set_bit(ETHTOOL_LINK_MODE_FEC_LLRS_BIT, link_modes);
+}
+
+static int
+ethtool_link_modes_to_fecparam(struct ethtool_fecparam *fec,
+			       unsigned long *link_modes, u8 fec_auto)
+{
+	memset(fec, 0, sizeof(*fec));
+
+	if (fec_auto)
+		fec->fec |= ETHTOOL_FEC_AUTO;
+
+	if (__test_and_clear_bit(ETHTOOL_LINK_MODE_FEC_NONE_BIT, link_modes))
+		fec->fec |= ETHTOOL_FEC_OFF;
+	if (__test_and_clear_bit(ETHTOOL_LINK_MODE_FEC_RS_BIT, link_modes))
+		fec->fec |= ETHTOOL_FEC_RS;
+	if (__test_and_clear_bit(ETHTOOL_LINK_MODE_FEC_BASER_BIT, link_modes))
+		fec->fec |= ETHTOOL_FEC_BASER;
+	if (__test_and_clear_bit(ETHTOOL_LINK_MODE_FEC_LLRS_BIT, link_modes))
+		fec->fec |= ETHTOOL_FEC_LLRS;
+
+	if (!bitmap_empty(link_modes, __ETHTOOL_LINK_MODE_MASK_NBITS))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int fec_prepare_data(const struct ethnl_req_info *req_base,
+			    struct ethnl_reply_data *reply_base,
+			    struct genl_info *info)
+{
+	__ETHTOOL_DECLARE_LINK_MODE_MASK(active_fec_modes) = {};
+	struct fec_reply_data *data = FEC_REPDATA(reply_base);
+	struct net_device *dev = reply_base->dev;
+	struct ethtool_fecparam fec = {};
+	int ret;
+
+	if (!dev->ethtool_ops->get_fecparam)
+		return -EOPNOTSUPP;
+	ret = ethnl_ops_begin(dev);
+	if (ret < 0)
+		return ret;
+	ret = dev->ethtool_ops->get_fecparam(dev, &fec);
+	ethnl_ops_complete(dev);
+	if (ret)
+		return ret;
+
+	WARN_ON_ONCE(fec.reserved);
+
+	ethtool_fec_to_link_modes(fec.fec, data->fec_link_modes,
+				  &data->fec_auto);
+
+	ethtool_fec_to_link_modes(fec.active_fec, active_fec_modes, NULL);
+	data->active_fec = find_first_bit(active_fec_modes,
+					  __ETHTOOL_LINK_MODE_MASK_NBITS);
+	/* Don't report attr if no FEC mode set. Note that
+	 * ethtool_fecparam_to_link_modes() ignores NONE and AUTO.
+	 */
+	if (data->active_fec == __ETHTOOL_LINK_MODE_MASK_NBITS)
+		data->active_fec = 0;
+
+	return 0;
+}
+
+static int fec_reply_size(const struct ethnl_req_info *req_base,
+			  const struct ethnl_reply_data *reply_base)
+{
+	bool compact = req_base->flags & ETHTOOL_FLAG_COMPACT_BITSETS;
+	const struct fec_reply_data *data = FEC_REPDATA(reply_base);
+	int len = 0;
+	int ret;
+
+	ret = ethnl_bitset_size(data->fec_link_modes, NULL,
+				__ETHTOOL_LINK_MODE_MASK_NBITS,
+				link_mode_names, compact);
+	if (ret < 0)
+		return ret;
+	len += ret;
+
+	len += nla_total_size(sizeof(u8)) +	/* _FEC_AUTO */
+	       nla_total_size(sizeof(u32));	/* _FEC_ACTIVE */
+
+	return len;
+}
+
+static int fec_fill_reply(struct sk_buff *skb,
+			  const struct ethnl_req_info *req_base,
+			  const struct ethnl_reply_data *reply_base)
+{
+	bool compact = req_base->flags & ETHTOOL_FLAG_COMPACT_BITSETS;
+	const struct fec_reply_data *data = FEC_REPDATA(reply_base);
+	int ret;
+
+	ret = ethnl_put_bitset(skb, ETHTOOL_A_FEC_MODES,
+			       data->fec_link_modes, NULL,
+			       __ETHTOOL_LINK_MODE_MASK_NBITS,
+			       link_mode_names, compact);
+	if (ret < 0)
+		return ret;
+
+	if (nla_put_u8(skb, ETHTOOL_A_FEC_AUTO, data->fec_auto) ||
+	    (data->active_fec &&
+	     nla_put_u32(skb, ETHTOOL_A_FEC_ACTIVE, data->active_fec)))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+const struct ethnl_request_ops ethnl_fec_request_ops = {
+	.request_cmd		= ETHTOOL_MSG_FEC_GET,
+	.reply_cmd		= ETHTOOL_MSG_FEC_GET_REPLY,
+	.hdr_attr		= ETHTOOL_A_FEC_HEADER,
+	.req_info_size		= sizeof(struct fec_req_info),
+	.reply_data_size	= sizeof(struct fec_reply_data),
+
+	.prepare_data		= fec_prepare_data,
+	.reply_size		= fec_reply_size,
+	.fill_reply		= fec_fill_reply,
+};
+
+/* FEC_SET */
+
+const struct nla_policy ethnl_fec_set_policy[ETHTOOL_A_FEC_AUTO + 1] = {
+	[ETHTOOL_A_FEC_HEADER]	= NLA_POLICY_NESTED(ethnl_header_policy),
+	[ETHTOOL_A_FEC_MODES]	= { .type = NLA_NESTED },
+	[ETHTOOL_A_FEC_AUTO]	= NLA_POLICY_MAX(NLA_U8, 1),
+};
+
+int ethnl_set_fec(struct sk_buff *skb, struct genl_info *info)
+{
+	__ETHTOOL_DECLARE_LINK_MODE_MASK(fec_link_modes) = {};
+	struct ethnl_req_info req_info = {};
+	struct nlattr **tb = info->attrs;
+	struct ethtool_fecparam fec = {};
+	const struct ethtool_ops *ops;
+	struct net_device *dev;
+	bool mod = false;
+	u8 fec_auto;
+	int ret;
+
+	ret = ethnl_parse_header_dev_get(&req_info, tb[ETHTOOL_A_FEC_HEADER],
+					 genl_info_net(info), info->extack,
+					 true);
+	if (ret < 0)
+		return ret;
+	dev = req_info.dev;
+	ops = dev->ethtool_ops;
+	ret = -EOPNOTSUPP;
+	if (!ops->get_fecparam || !ops->set_fecparam)
+		goto out_dev;
+
+	rtnl_lock();
+	ret = ethnl_ops_begin(dev);
+	if (ret < 0)
+		goto out_rtnl;
+	ret = ops->get_fecparam(dev, &fec);
+	if (ret < 0)
+		goto out_ops;
+
+	ethtool_fec_to_link_modes(fec.fec, fec_link_modes, &fec_auto);
+
+	ret = ethnl_update_bitset(fec_link_modes,
+				  __ETHTOOL_LINK_MODE_MASK_NBITS,
+				  tb[ETHTOOL_A_FEC_MODES],
+				  link_mode_names, info->extack, &mod);
+	if (ret < 0)
+		goto out_ops;
+	ethnl_update_u8(&fec_auto, tb[ETHTOOL_A_FEC_AUTO], &mod);
+
+	ret = 0;
+	if (!mod)
+		goto out_ops;
+
+	ret = ethtool_link_modes_to_fecparam(&fec, fec_link_modes, fec_auto);
+	if (ret) {
+		NL_SET_ERR_MSG_ATTR(info->extack, tb[ETHTOOL_A_FEC_MODES],
+				    "invalid FEC modes requested");
+		goto out_ops;
+	}
+	if (!fec.fec) {
+		ret = -EINVAL;
+		NL_SET_ERR_MSG_ATTR(info->extack, tb[ETHTOOL_A_FEC_MODES],
+				    "no FEC modes set");
+		goto out_ops;
+	}
+
+	ret = dev->ethtool_ops->set_fecparam(dev, &fec);
+	if (ret < 0)
+		goto out_ops;
+	ethtool_notify(dev, ETHTOOL_MSG_FEC_NTF, NULL);
+
+out_ops:
+	ethnl_ops_complete(dev);
+out_rtnl:
+	rtnl_unlock();
+out_dev:
+	dev_put(dev);
+	return ret;
+}