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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2011 The ChromiumOS Authors. 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; version 2 of the License.
*
* 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.
*/
#include <console/cbmem_console.h>
#include <console/uart.h>
#include <cbmem.h>
#include <symbols.h>
/*
* Structure describing console buffer. It is overlaid on a flat memory area,
* with body covering the extent of the memory. Once the buffer is full,
* output will wrap back around to the start of the buffer. The high bit of the
* cursor field gets set to indicate that this happened. If the underlying
* storage allows this, the buffer will persist across multiple boots and append
* to the previous log.
*
* NOTE: These are known implementations accessing this console that need to be
* updated in case of structure/API changes:
*
* cbmem: [coreboot]/src/util/cbmem/cbmem.c
* libpayload: [coreboot]/payloads/libpayload/drivers/cbmem_console.c
* coreinfo: [coreboot]/payloads/coreinfo/bootlog_module.c
* Linux: drivers/firmware/google/memconsole-coreboot.c
* SeaBIOS: src/firmware/coreboot.c
* GRUB: grub-core/term/i386/coreboot/cbmemc.c
*/
struct cbmem_console {
u32 size;
u32 cursor;
u8 body[0];
} __packed;
#define MAX_SIZE (1 << 28) /* can't be changed without breaking readers! */
#define CURSOR_MASK (MAX_SIZE - 1) /* bits 31-28 are reserved for flags */
#define OVERFLOW (1UL << 31) /* set if in ring-buffer mode */
_Static_assert(CONFIG_CONSOLE_CBMEM_BUFFER_SIZE <= MAX_SIZE,
"cbmem_console format cannot support buffers larger than 256MB!");
static struct cbmem_console *cbmem_console_p;
/*
* While running from ROM, before DRAM is initialized, some area in cache as
* RAM space is used for the console buffer storage. The size and location of
* the area are defined by the linker script with _(e)preram_cbmem_console.
*
* When running from RAM, some console output is generated before CBMEM is
* reinitialized. This static buffer is used to store that output temporarily,
* to be concatenated with the CBMEM console buffer contents accumulated
* during the ROM stage, once CBMEM becomes available at RAM stage.
*/
#define STATIC_CONSOLE_SIZE 1024
static u8 static_console[STATIC_CONSOLE_SIZE];
static void current_console_set(struct cbmem_console *new_console_p)
{
cbmem_console_p = new_console_p;
}
static int buffer_valid(struct cbmem_console *cbm_cons_p, u32 total_space)
{
return (cbm_cons_p->cursor & CURSOR_MASK) < cbm_cons_p->size &&
cbm_cons_p->size <= MAX_SIZE &&
cbm_cons_p->size == total_space - sizeof(struct cbmem_console);
}
static void init_console_ptr(void *storage, u32 total_space)
{
struct cbmem_console *cbm_cons_p = storage;
if (!cbm_cons_p || total_space <= sizeof(struct cbmem_console)) {
current_console_set(NULL);
return;
}
if (!buffer_valid(cbm_cons_p, total_space)) {
cbm_cons_p->size = total_space - sizeof(struct cbmem_console);
cbm_cons_p->cursor = 0;
}
current_console_set(cbm_cons_p);
}
void cbmemc_init(void)
{
if (ENV_ROMSTAGE_OR_BEFORE) {
/* Pre-RAM environments use special buffer placed by linker script. */
init_console_ptr(_preram_cbmem_console, REGION_SIZE(preram_cbmem_console));
} else {
/* Post-RAM uses static (BSS) buffer before CBMEM is reinitialized. */
init_console_ptr(static_console, sizeof(static_console));
}
}
void cbmemc_tx_byte(unsigned char data)
{
if (!cbmem_console_p || !cbmem_console_p->size)
return;
u32 flags = cbmem_console_p->cursor & ~CURSOR_MASK;
u32 cursor = cbmem_console_p->cursor & CURSOR_MASK;
cbmem_console_p->body[cursor++] = data;
if (cursor >= cbmem_console_p->size) {
cursor = 0;
flags |= OVERFLOW;
}
cbmem_console_p->cursor = flags | cursor;
}
/*
* Copy the current console buffer (either from the cache as RAM area or from
* the static buffer, pointed at by src_cons_p) into the newly initialized CBMEM
* console. The use of cbmemc_tx_byte() ensures that all special cases for the
* target console (e.g. overflow) will be handled. If there had been an
* overflow in the source console, log a message to that effect.
*/
static void copy_console_buffer(struct cbmem_console *src_cons_p)
{
u32 c;
if (!src_cons_p)
return;
if (src_cons_p->cursor & OVERFLOW) {
const char overflow_warning[] = "\n*** Pre-CBMEM " ENV_STRING
" console overflowed, log truncated! ***\n";
for (c = 0; c < sizeof(overflow_warning) - 1; c++)
cbmemc_tx_byte(overflow_warning[c]);
for (c = src_cons_p->cursor & CURSOR_MASK;
c < src_cons_p->size; c++)
cbmemc_tx_byte(src_cons_p->body[c]);
}
for (c = 0; c < (src_cons_p->cursor & CURSOR_MASK); c++)
cbmemc_tx_byte(src_cons_p->body[c]);
/* Invalidate the source console, so it will be reinitialized on the
next reboot. Otherwise, we might copy the same bytes again. */
src_cons_p->size = 0;
}
static void cbmemc_reinit(int is_recovery)
{
const size_t size = CONFIG_CONSOLE_CBMEM_BUFFER_SIZE;
/* If CBMEM entry already existed, old contents are not altered. */
struct cbmem_console *cbmem_cons_p = cbmem_add(CBMEM_ID_CONSOLE, size);
struct cbmem_console *previous_cons_p = cbmem_console_p;
init_console_ptr(cbmem_cons_p, size);
copy_console_buffer(previous_cons_p);
}
ROMSTAGE_CBMEM_INIT_HOOK(cbmemc_reinit)
RAMSTAGE_CBMEM_INIT_HOOK(cbmemc_reinit)
POSTCAR_CBMEM_INIT_HOOK(cbmemc_reinit)
#if CONFIG(CONSOLE_CBMEM_DUMP_TO_UART)
void cbmem_dump_console(void)
{
u32 cursor;
if (!cbmem_console_p)
return;
uart_init(0);
if (cbmem_console_p->cursor & OVERFLOW)
for (cursor = cbmem_console_p->cursor & CURSOR_MASK;
cursor < cbmem_console_p->size; cursor++)
uart_tx_byte(0, cbmem_console_p->body[cursor]);
for (cursor = 0; cursor < (cbmem_console_p->cursor & CURSOR_MASK); cursor++)
uart_tx_byte(0, cbmem_console_p->body[cursor]);
}
#endif
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