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/*
* Copyright (c) 2013-2014 NVIDIA Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/list.h>
#include <linux/completion.h>
#include <linux/workqueue.h>
#include <linux/bitops.h>
#include <linux/uaccess.h>
#include <asm/page.h>
#include <linux/dma-mapping.h>
#include <linux/string.h>
#include "ote_protocol.h"
#define LOGBUF_SIZE 8192
struct circular_buffer {
uint32_t size; /* Indicates the total size of the buffer */
uint32_t start; /* Starting point of valid data in buffer */
uint32_t end; /* First character which is empty (can be written to) */
uint32_t overflow; /* Indicator whether buffer has overwritten itself */
char *buf;
};
#if defined(CONFIG_OTE_ENABLE_LOGGER)
static int ote_logging_enabled;
struct circular_buffer *cb;
/*
* Initialize the shared buffer for TLK logging.
* The shared buffer is allocated in DMA memory to get uncached memory
* since TLK directly writes to the physical address of the shared buffer.
* The structure is declared in DMA memory too since it's members will
* also be updated by the TLK directly to their physical addresses.
*/
static int circ_buf_init(struct circular_buffer **cbptr)
{
dma_addr_t tp;
*cbptr = (struct circular_buffer *) dma_alloc_coherent(NULL,
sizeof(struct circular_buffer), &tp, GFP_KERNEL);
if (!*cbptr) {
pr_err("%s: no memory avaiable for circular buffer struct\n",
__func__);
return -ENOMEM;
}
memset(*cbptr, 0, sizeof(struct circular_buffer));
(*cbptr)->start = 0;
(*cbptr)->end = 0;
(*cbptr)->size = LOGBUF_SIZE;
(*cbptr)->buf = (char *) dma_alloc_coherent(NULL, LOGBUF_SIZE,
&tp, GFP_KERNEL);
if (!(*cbptr)->buf) {
pr_err("%s: no memory avaiable for shared buffer\n",
__func__);
/* Frees the memory allocated using dma_alloc_coherent */
dma_free_coherent(NULL,
sizeof(struct circular_buffer), cbptr, tp);
return -ENOMEM;
}
memset((*cbptr)->buf, 0, LOGBUF_SIZE);
(*cbptr)->overflow = 0;
return 0;
}
/*
* Copy the contents of the circular buffer into a char buffer in order.
* This helps to treat the buffer like a string and use it to tokenize it
* into lines, tag and display it.
*/
static int circ_buf_copy(struct circular_buffer *cb, char *text)
{
if (cb->end == cb->start)
return 0;
if (cb->end > cb->start) {
if (abs(cb->end - cb->start) > LOGBUF_SIZE) {
pr_err("%s: cbuf pointers corrupted\n", __func__);
return -EINVAL;
}
memcpy(text, cb->buf + cb->start, cb->end - cb->start);
} else if (cb->start > cb->end) {
if (abs(cb->end - cb->start) > LOGBUF_SIZE) {
pr_err("%s: cbuf pointers corrupted\n", __func__);
return -EINVAL;
}
memcpy(text, cb->buf + cb->start, cb->size - cb->start);
memcpy(text + cb->size - cb->start, cb->buf, cb->end);
}
return 0;
}
/*
* Function which prints TLK logs.
* Tokenizes the TLK logs into lines, tags each line
* and prints it out to kmsg file.
*/
void ote_print_logs(void)
{
char *text = NULL;
char *temp = NULL;
char *buffer = NULL;
if (!ote_logging_enabled)
return;
buffer = kzalloc(LOGBUF_SIZE, GFP_KERNEL);
BUG_ON(!buffer);
/* This detects if the buffer proved to be too small to hold the data.
* If buffer is not large enough, it overwrites it's oldest data,
* This warning serves to alert the user to possibly use a bigger buffer
*/
if (cb->overflow == 1) {
pr_info("\n[TLK] **WARNING** TLK buffer overwritten.\n\n");
cb->overflow = 0;
}
if (circ_buf_copy(cb, buffer) != 0) {
kfree(buffer);
return;
}
cb->buf[cb->end] = '\0';
/* In case no delimiter was found,
* the token is taken to be the entire string *stringp,
* and *stringp is made NULL.
*/
text = buffer;
temp = strsep(&text, "\n");
while (temp != NULL) {
if (strnlen(temp, LOGBUF_SIZE))
pr_info("[TLK] %s\n", temp);
temp = strsep(&text, "\n");
}
/* Indicate that buffer is empty */
cb->start = cb->end;
kfree(buffer);
}
#else
void ote_print_logs(void) {}
#endif
/*
* Call function to initialize circular buffer.
* An SMC is made to send the virtual address of the structure to
* the secure OS.
*/
static int __init ote_logger_init(void)
{
uintptr_t smc_args[MAX_EXT_SMC_ARGS];
#if defined(CONFIG_OTE_ENABLE_LOGGER)
if (circ_buf_init(&cb) != 0)
return -1;
smc_args[0] = TE_SMC_INIT_LOGGER;
smc_args[1] = (uintptr_t)cb;
/* enable logging only if secure firmware supports it */
if (!tlk_generic_smc(smc_args[0], smc_args[1], 0))
ote_logging_enabled = 1;
ote_print_logs();
#else
smc_args[0] = TE_SMC_INIT_LOGGER;
smc_args[1] = 0;
tlk_generic_smc(smc_args[0], smc_args[1], 0);
#endif
return 0;
}
arch_initcall(ote_logger_init);
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