nfp: add hwinfo support

Hwinfo is a simple key=value store of information which is read
from the flash and populated during chip power on.  Add code to
look up information in it.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/Makefile

@@ -4,6 +4,7 @@ nfp-objs := \
 	    nfpcore/nfp6000_pcie.o \
 	    nfpcore/nfp_cppcore.o \
 	    nfpcore/nfp_cpplib.o \
+	    nfpcore/nfp_hwinfo.o \
 	    nfpcore/nfp_resource.o \
 	    nfpcore/nfp_target.o \
 	    nfp_main.o \

drivers/net/ethernet/netronome/nfp/nfpcore/nfp.h

@@ -43,6 +43,10 @@
 
 #include "nfp_cpp.h"
 
+/* Implemented in nfp_hwinfo.c */
+
+const char *nfp_hwinfo_lookup(struct nfp_cpp *cpp, const char *lookup);
+
 /* Implemented in nfp_resource.c */
 
 #define NFP_RESOURCE_TBL_TARGET		NFP_CPP_TARGET_MU

drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cpp.h

@@ -219,6 +219,9 @@ u32 nfp_cpp_model(struct nfp_cpp *cpp);
 u16 nfp_cpp_interface(struct nfp_cpp *cpp);
 int nfp_cpp_serial(struct nfp_cpp *cpp, const u8 **serial);
 
+void *nfp_hwinfo_cache(struct nfp_cpp *cpp);
+void nfp_hwinfo_cache_set(struct nfp_cpp *cpp, void *val);
+
 struct nfp_cpp_area *nfp_cpp_area_alloc_with_name(struct nfp_cpp *cpp,
 						  u32 cpp_id,
 						  const char *name,

drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c

@@ -96,6 +96,9 @@ struct nfp_cpp {
 	/* Cached areas for cpp/xpb readl/writel speedups */
 	struct mutex area_cache_mutex;  /* Lock for the area cache */
 	struct list_head area_cache_list;
+
+	/* Cached information */
+	void *hwinfo;
 };
 
 /* Element of the area_cache_list */
@@ -237,6 +240,8 @@ void nfp_cpp_free(struct nfp_cpp *cpp)
 	if (cpp->op->free)
 		cpp->op->free(cpp);
 
+	kfree(cpp->hwinfo);
+
 	device_unregister(&cpp->dev);
 
 	kfree(cpp);
@@ -277,6 +282,16 @@ int nfp_cpp_serial(struct nfp_cpp *cpp, const u8 **serial)
 	return sizeof(cpp->serial);
 }
 
+void *nfp_hwinfo_cache(struct nfp_cpp *cpp)
+{
+	return cpp->hwinfo;
+}
+
+void nfp_hwinfo_cache_set(struct nfp_cpp *cpp, void *val)
+{
+	cpp->hwinfo = val;
+}
+
 /**
  * nfp_cpp_area_alloc_with_name() - allocate a new CPP area
  * @cpp:	CPP device handle

drivers/net/ethernet/netronome/nfp/nfpcore/nfp_hwinfo.c

+/*
+ * Copyright (C) 2015-2017 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.
+ */
+
+/* Parse the hwinfo table that the ARM firmware builds in the ARM scratch SRAM
+ * after chip reset.
+ *
+ * Examples of the fields:
+ *   me.count = 40
+ *   me.mask = 0x7f_ffff_ffff
+ *
+ *   me.count is the total number of MEs on the system.
+ *   me.mask is the bitmask of MEs that are available for application usage.
+ *
+ *   (ie, in this example, ME 39 has been reserved by boardconfig.)
+ */
+
+#include <asm/byteorder.h>
+#include <asm/unaligned.h>
+#include <linux/delay.h>
+#include <linux/log2.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#define NFP_SUBSYS "nfp_hwinfo"
+
+#include "crc32.h"
+#include "nfp.h"
+#include "nfp_cpp.h"
+#include "nfp6000/nfp6000.h"
+
+#define HWINFO_SIZE_MIN	0x100
+#define HWINFO_WAIT	20	/* seconds */
+
+/* The Hardware Info Table defines the properties of the system.
+ *
+ * HWInfo v1 Table (fixed size)
+ *
+ * 0x0000: u32 version	        Hardware Info Table version (1.0)
+ * 0x0004: u32 size	        Total size of the table, including
+ *			        the CRC32 (IEEE 802.3)
+ * 0x0008: u32 jumptab	        Offset of key/value table
+ * 0x000c: u32 keys	        Total number of keys in the key/value table
+ * NNNNNN:		        Key/value jump table and string data
+ * (size - 4): u32 crc32	CRC32 (same as IEEE 802.3, POSIX csum, etc)
+ *				CRC32("",0) = ~0, CRC32("a",1) = 0x48C279FE
+ *
+ * HWInfo v2 Table (variable size)
+ *
+ * 0x0000: u32 version	        Hardware Info Table version (2.0)
+ * 0x0004: u32 size	        Current size of the data area, excluding CRC32
+ * 0x0008: u32 limit	        Maximum size of the table
+ * 0x000c: u32 reserved	        Unused, set to zero
+ * NNNNNN:			Key/value data
+ * (size - 4): u32 crc32	CRC32 (same as IEEE 802.3, POSIX csum, etc)
+ *				CRC32("",0) = ~0, CRC32("a",1) = 0x48C279FE
+ *
+ * If the HWInfo table is in the process of being updated, the low bit
+ * of version will be set.
+ *
+ * HWInfo v1 Key/Value Table
+ * -------------------------
+ *
+ *  The key/value table is a set of offsets to ASCIIZ strings which have
+ *  been strcmp(3) sorted (yes, please use bsearch(3) on the table).
+ *
+ *  All keys are guaranteed to be unique.
+ *
+ * N+0:	u32 key_1		Offset to the first key
+ * N+4:	u32 val_1		Offset to the first value
+ * N+8: u32 key_2		Offset to the second key
+ * N+c: u32 val_2		Offset to the second value
+ * ...
+ *
+ * HWInfo v2 Key/Value Table
+ * -------------------------
+ *
+ * Packed UTF8Z strings, ie 'key1\000value1\000key2\000value2\000'
+ *
+ * Unsorted.
+ */
+
+#define NFP_HWINFO_VERSION_1 ('H' << 24 | 'I' << 16 | 1 << 8 | 0 << 1 | 0)
+#define NFP_HWINFO_VERSION_2 ('H' << 24 | 'I' << 16 | 2 << 8 | 0 << 1 | 0)
+#define NFP_HWINFO_VERSION_UPDATING	BIT(0)
+
+struct nfp_hwinfo {
+	u8 start[0];
+
+	__le32 version;
+	__le32 size;
+
+	/* v2 specific fields */
+	__le32 limit;
+	__le32 resv;
+
+	char data[];
+};
+
+static bool nfp_hwinfo_is_updating(struct nfp_hwinfo *hwinfo)
+{
+	return le32_to_cpu(hwinfo->version) & NFP_HWINFO_VERSION_UPDATING;
+}
+
+static int
+hwinfo_db_walk(struct nfp_cpp *cpp, struct nfp_hwinfo *hwinfo, u32 size)
+{
+	const char *key, *val, *end = hwinfo->data + size;
+
+	for (key = hwinfo->data; *key && key < end;
+	     key = val + strlen(val) + 1) {
+
+		val = key + strlen(key) + 1;
+		if (val >= end) {
+			nfp_warn(cpp, "Bad HWINFO - overflowing key\n");
+			return -EINVAL;
+		}
+
+		if (val + strlen(val) + 1 > end) {
+			nfp_warn(cpp, "Bad HWINFO - overflowing value\n");
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int
+hwinfo_db_validate(struct nfp_cpp *cpp, struct nfp_hwinfo *db, u32 len)
+{
+	u32 size, crc;
+
+	size = le32_to_cpu(db->size);
+	if (size > len) {
+		nfp_err(cpp, "Unsupported hwinfo size %u > %u\n", size, len);
+		return -EINVAL;
+	}
+
+	size -= sizeof(u32);
+	crc = crc32_posix(db, size);
+	if (crc != get_unaligned_le32(db->start + size)) {
+		nfp_err(cpp, "Corrupt hwinfo table (CRC mismatch), calculated 0x%x, expected 0x%x\n",
+			crc, get_unaligned_le32(db->start + size));
+
+		return -EINVAL;
+	}
+
+	return hwinfo_db_walk(cpp, db, size);
+}
+
+static int hwinfo_try_fetch(struct nfp_cpp *cpp, size_t *cpp_size)
+{
+	struct nfp_hwinfo *header;
+	struct nfp_resource *res;
+	u64 cpp_addr;
+	u32 cpp_id;
+	int err;
+	u8 *db;
+
+	res = nfp_resource_acquire(cpp, NFP_RESOURCE_NFP_HWINFO);
+	if (!IS_ERR(res)) {
+		cpp_id = nfp_resource_cpp_id(res);
+		cpp_addr = nfp_resource_address(res);
+		*cpp_size = nfp_resource_size(res);
+
+		nfp_resource_release(res);
+
+		if (*cpp_size < HWINFO_SIZE_MIN)
+			return -ENOENT;
+	} else if (PTR_ERR(res) == -ENOENT) {
+		/* Try getting the HWInfo table from the 'classic' location */
+		cpp_id = NFP_CPP_ISLAND_ID(NFP_CPP_TARGET_MU,
+					   NFP_CPP_ACTION_RW, 0, 1);
+		cpp_addr = 0x30000;
+		*cpp_size = 0x0e000;
+	} else {
+		return PTR_ERR(res);
+	}
+
+	db = kmalloc(*cpp_size + 1, GFP_KERNEL);
+	if (!db)
+		return -ENOMEM;
+
+	err = nfp_cpp_read(cpp, cpp_id, cpp_addr, db, *cpp_size);
+	if (err != *cpp_size) {
+		kfree(db);
+		return err < 0 ? err : -EIO;
+	}
+
+	header = (void *)db;
+	if (nfp_hwinfo_is_updating(header)) {
+		kfree(db);
+		return -EBUSY;
+	}
+
+	if (le32_to_cpu(header->version) != NFP_HWINFO_VERSION_2) {
+		nfp_err(cpp, "Unknown HWInfo version: 0x%08x\n",
+			le32_to_cpu(header->version));
+		kfree(db);
+		return -EINVAL;
+	}
+
+	/* NULL-terminate for safety */
+	db[*cpp_size] = '\0';
+
+	nfp_hwinfo_cache_set(cpp, db);
+
+	return 0;
+}
+
+static int hwinfo_fetch(struct nfp_cpp *cpp, size_t *hwdb_size)
+{
+	const unsigned long wait_until = jiffies + HWINFO_WAIT * HZ;
+	int err;
+
+	for (;;) {
+		const unsigned long start_time = jiffies;
+
+		err = hwinfo_try_fetch(cpp, hwdb_size);
+		if (!err)
+			return 0;
+
+		err = msleep_interruptible(100);
+		if (err || time_after(start_time, wait_until)) {
+			nfp_err(cpp, "NFP access error\n");
+			return -EIO;
+		}
+	}
+}
+
+static int nfp_hwinfo_load(struct nfp_cpp *cpp)
+{
+	struct nfp_hwinfo *db;
+	size_t hwdb_size = 0;
+	int err;
+
+	err = hwinfo_fetch(cpp, &hwdb_size);
+	if (err)
+		return err;
+
+	db = nfp_hwinfo_cache(cpp);
+	err = hwinfo_db_validate(cpp, db, hwdb_size);
+	if (err) {
+		kfree(db);
+		nfp_hwinfo_cache_set(cpp, NULL);
+		return err;
+	}
+
+	return 0;
+}
+
+/**
+ * nfp_hwinfo_lookup() - Find a value in the HWInfo table by name
+ * @cpp:	NFP CPP handle
+ * @lookup:	HWInfo name to search for
+ *
+ * Return: Value of the HWInfo name, or NULL
+ */
+const char *nfp_hwinfo_lookup(struct nfp_cpp *cpp, const char *lookup)
+{
+	const char *key, *val, *end;
+	struct nfp_hwinfo *hwinfo;
+	int err;
+
+	hwinfo = nfp_hwinfo_cache(cpp);
+	if (!hwinfo) {
+		err = nfp_hwinfo_load(cpp);
+		if (err)
+			return NULL;
+		hwinfo = nfp_hwinfo_cache(cpp);
+	}
+
+	if (!hwinfo || !lookup)
+		return NULL;
+
+	end = hwinfo->data + le32_to_cpu(hwinfo->size) - sizeof(u32);
+
+	for (key = hwinfo->data; *key && key < end;
+	     key = val + strlen(val) + 1) {
+
+		val = key + strlen(key) + 1;
+
+		if (strcmp(key, lookup) == 0)
+			return val;
+	}
+
+	return NULL;
+}