nfp: add TLV capabilities to the BAR

NFP is entirely programmable, including the PCI data interface.
Using a fixed control BAR layout certainly makes implementations
easier, but require careful considerations when space is allocated.
Once BAR area is allocated to one feature nothing else can use it.
Allocating space statically also requires it to be sized upfront,
which leads to either unnecessary limitation or wastage.

We currently have a 32bit capability word defined which tells drivers
which application FW features are supported.   Most of the bits
are exhausted.  The same bits are also reused for enabling specific
features.  Bulk of capabilities don't have a need for an enable bit,
however, leading to confusion and wastage.

TLVs seems like a better fit for expressing capabilities of applications
running on programmable hardware.

This patch leaves the front of the BAR as is, and declares a TLV
capability start at offset 0x58.  Most of the space up to 0x0d90
is already allocated, but the used space can be wrapped with RESERVED
TLVs.  E.g.:

Address    Type         Length
 0x0058    RESERVED      0xe00  /* Wrap basic structures */
 0x0e5c    FEATURE_A     0x004
 0x0e64    FEATURE_B     0x004
 0x0e6c    RESERVED      0x990  /* Wrap qeueue stats */
 0x1800    FEATURE_C     0x100

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 113 insertions, 0 deletions

diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.c b/drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.c
new file mode 100644
index 000000000000..ff155242a665
--- /dev/null
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.c
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2018 Netronome Systems, Inc.
+ *
+ * This software is dual licensed under the GNU General License Version 2,
+ * June 1991 as shown in the file COPYING in the top-level directory of this
+ * source tree or the BSD 2-Clause License provided below.  You have the
+ * option to license this software under the complete terms of either license.
+ *
+ * The BSD 2-Clause License:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      1. Redistributions of source code must retain the above
+ *         copyright notice, this list of conditions and the following
+ *         disclaimer.
+ *
+ *      2. Redistributions in binary form must reproduce the above
+ *         copyright notice, this list of conditions and the following
+ *         disclaimer in the documentation and/or other materials
+ *         provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+#include "nfp_net_ctrl.h"
+#include "nfp_net.h"
+
+static void nfp_net_tlv_caps_reset(struct nfp_net_tlv_caps *caps)
+{
+	memset(caps, 0, sizeof(*caps));
+}
+
+int nfp_net_tlv_caps_parse(struct device *dev, u8 __iomem *ctrl_mem,
+			   struct nfp_net_tlv_caps *caps)
+{
+	u8 __iomem *data = ctrl_mem + NFP_NET_CFG_TLV_BASE;
+	u8 __iomem *end = ctrl_mem + NFP_NET_CFG_BAR_SZ;
+	u32 hdr;
+
+	nfp_net_tlv_caps_reset(caps);
+
+	hdr = readl(data);
+	if (!hdr)
+		return 0;
+
+	while (true) {
+		unsigned int length, offset;
+		u32 hdr = readl(data);
+
+		length = FIELD_GET(NFP_NET_CFG_TLV_HEADER_LENGTH, hdr);
+		offset = data - ctrl_mem + NFP_NET_CFG_TLV_BASE;
+
+		/* Advance past the header */
+		data += 4;
+
+		if (length % NFP_NET_CFG_TLV_LENGTH_INC) {
+			dev_err(dev, "TLV size not multiple of %u len:%u\n",
+				NFP_NET_CFG_TLV_LENGTH_INC, length);
+			return -EINVAL;
+		}
+		if (data + length > end) {
+			dev_err(dev, "oversized TLV offset:%u len:%u\n",
+				offset, length);
+			return -EINVAL;
+		}
+
+		switch (FIELD_GET(NFP_NET_CFG_TLV_HEADER_TYPE, hdr)) {
+		case NFP_NET_CFG_TLV_TYPE_UNKNOWN:
+			dev_err(dev, "NULL TLV at offset:%u\n", offset);
+			return -EINVAL;
+		case NFP_NET_CFG_TLV_TYPE_RESERVED:
+			break;
+		case NFP_NET_CFG_TLV_TYPE_END:
+			if (!length)
+				return 0;
+
+			dev_err(dev, "END TLV should be empty, has len:%d\n",
+				length);
+			return -EINVAL;
+		default:
+			if (!FIELD_GET(NFP_NET_CFG_TLV_HEADER_REQUIRED, hdr))
+				break;
+
+			dev_err(dev, "unknown TLV type:%u offset:%u len:%u\n",
+				FIELD_GET(NFP_NET_CFG_TLV_HEADER_TYPE, hdr),
+				offset, length);
+			return -EINVAL;
+		}
+
+		data += length;
+		if (data + 4 > end) {
+			dev_err(dev, "reached end of BAR without END TLV\n");
+			return -EINVAL;
+		}
+	}
+
+	/* Not reached */
+	return -EINVAL;
+}