Commit c2b93d6b authored by Lee Trager's avatar Lee Trager Committed by Jakub Kicinski
Browse files

eth: fbnic: Create ring buffer for firmware logs 



When enabled, firmware may send logs messages which are specific to the
device and not the host. Create a ring buffer to store these messages
which are read by a user through DebugFS. Buffer access is protected by
a spinlock.

Signed-off-by: default avatarLee Trager <lee@trager.us>
Reviewed-by: default avatarJacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20250702192207.697368-4-lee@trager.us


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent e48f6620

drivers/net/ethernet/meta/fbnic/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ fbnic-y := fbnic_csr.o \ 
	   fbnic_devlink.o \

	   fbnic_ethtool.o \

	   fbnic_fw.o \

	   fbnic_fw_log.o \

	   fbnic_hw_stats.o \

	   fbnic_hwmon.o \

	   fbnic_irq.o \

drivers/net/ethernet/meta/fbnic/fbnic.h

+3 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 


#include "fbnic_csr.h"

#include "fbnic_fw.h"

#include "fbnic_fw_log.h"

#include "fbnic_hw_stats.h"

#include "fbnic_mac.h"

#include "fbnic_rpc.h"
@@ -85,6 +86,8 @@ struct fbnic_dev { 


	/* Lock protecting access to hw_stats */

	spinlock_t hw_stats_lock;



	struct fbnic_fw_log fw_log;

};



/* Reserve entry 0 in the MSI-X "others" array until we have filled all

drivers/net/ethernet/meta/fbnic/fbnic_fw_log.c

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+95 −0
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// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) Meta Platforms, Inc. and affiliates. */



#include <linux/spinlock.h>

#include <linux/vmalloc.h>



#include "fbnic.h"

#include "fbnic_fw.h"

#include "fbnic_fw_log.h"



int fbnic_fw_log_init(struct fbnic_dev *fbd)

{

	struct fbnic_fw_log *log = &fbd->fw_log;

	void *data;



	if (WARN_ON_ONCE(fbnic_fw_log_ready(fbd)))

		return -EEXIST;



	data = vmalloc(FBNIC_FW_LOG_SIZE);

	if (!data)

		return -ENOMEM;



	spin_lock_init(&fbd->fw_log.lock);

	INIT_LIST_HEAD(&log->entries);

	log->size = FBNIC_FW_LOG_SIZE;

	log->data_start = data;

	log->data_end = data + FBNIC_FW_LOG_SIZE;



	return 0;

}



void fbnic_fw_log_free(struct fbnic_dev *fbd)

{

	struct fbnic_fw_log *log = &fbd->fw_log;



	if (!fbnic_fw_log_ready(fbd))

		return;



	INIT_LIST_HEAD(&log->entries);

	log->size = 0;

	vfree(log->data_start);

	log->data_start = NULL;

	log->data_end = NULL;

}



int fbnic_fw_log_write(struct fbnic_dev *fbd, u64 index, u32 timestamp,

		       char *msg)

{

	struct fbnic_fw_log_entry *entry, *head, *tail, *next;

	struct fbnic_fw_log *log = &fbd->fw_log;

	size_t msg_len = strlen(msg) + 1;

	unsigned long flags;

	void *entry_end;



	if (!fbnic_fw_log_ready(fbd)) {

		dev_err(fbd->dev, "Firmware sent log entry without being requested!\n");

		return -ENOSPC;

	}



	spin_lock_irqsave(&log->lock, flags);



	if (list_empty(&log->entries)) {

		entry = log->data_start;

	} else {

		head = list_first_entry(&log->entries, typeof(*head), list);

		entry = (struct fbnic_fw_log_entry *)&head->msg[head->len + 1];

		entry = PTR_ALIGN(entry, 8);

	}



	entry_end = &entry->msg[msg_len + 1];



	/* We've reached the end of the buffer, wrap around */

	if (entry_end > log->data_end) {

		entry = log->data_start;

		entry_end = &entry->msg[msg_len + 1];

	}



	/* Make room for entry by removing from tail. */

	list_for_each_entry_safe_reverse(tail, next, &log->entries, list) {

		if (entry <= tail && entry_end > (void *)tail)

			list_del(&tail->list);

		else

			break;

	}



	entry->index = index;

	entry->timestamp = timestamp;

	entry->len = msg_len;

	strscpy(entry->msg, msg, entry->len);

	list_add(&entry->list, &log->entries);



	spin_unlock_irqrestore(&log->lock, flags);



	return 0;

}

drivers/net/ethernet/meta/fbnic/fbnic_fw_log.h

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Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

/* Copyright (c) Meta Platforms, Inc. and affiliates. */



#ifndef _FBNIC_FW_LOG_H_

#define _FBNIC_FW_LOG_H_



#include <linux/spinlock.h>

#include <linux/types.h>



/* A 512K log buffer was chosen fairly arbitrarily */

#define FBNIC_FW_LOG_SIZE	(512 * 1024) /* bytes */



/* Firmware log output is prepended with log index followed by a timestamp.

 * The timestamp is similar to Zephyr's format DD:HH:MM:SS.MMM

 */

#define FBNIC_FW_LOG_FMT	"[%5lld] [%02ld:%02ld:%02ld:%02ld.%03ld] %s\n"



struct fbnic_dev;



struct fbnic_fw_log_entry {

	struct list_head	list;

	u64			index;

	u32			timestamp;

	u16			len;

	char			msg[] __counted_by(len);

};



struct fbnic_fw_log {

	void			*data_start;

	void			*data_end;

	size_t			size;

	struct list_head	entries;

	/* Spin lock for accessing or modifying entries */

	spinlock_t		lock;

};



#define fbnic_fw_log_ready(_fbd)	(!!(_fbd)->fw_log.data_start)



int fbnic_fw_log_init(struct fbnic_dev *fbd);

void fbnic_fw_log_free(struct fbnic_dev *fbd);

int fbnic_fw_log_write(struct fbnic_dev *fbd, u64 index, u32 timestamp,

		       char *msg);

#endif /* _FBNIC_FW_LOG_H_ */