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/*
* Copyright (c) 2010, 2013-2014 Wind River Systems, Inc.
*
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @file
* @brief Low-level debug output
*
* Low-level debugging output. Platform installs a character output routine at
* init time. If no routine is installed, a nop routine is called.
*/
#include <misc/printk.h>
#include <stdarg.h>
#include <toolchain.h>
#include <sections.h>
typedef int (*out_func_t)(int c, void *ctx);
static void _printk_dec_ulong(out_func_t out, void *ctx,
const unsigned long num, int pad_zero,
int min_width);
static void _printk_hex_ulong(out_func_t out, void *ctx,
const unsigned long num, int pad_zero,
int min_width);
/**
* @brief Default character output routine that does nothing
* @param c Character to swallow
*
* @return 0
*/
static int _nop_char_out(int c)
{
ARG_UNUSED(c);
/* do nothing */
return 0;
}
int (*_char_out)(int) = _nop_char_out;
/**
* @brief Install the character output routine for printk
*
* To be called by the platform's console driver at init time. Installs a
* routine that outputs one ASCII character at a time.
* @param fn putc routine to install
*
* @return N/A
*/
void __printk_hook_install(int (*fn)(int))
{
_char_out = fn;
}
/**
* @brief Get the current character output routine for printk
*
* To be called by any console driver that would like to save
* current hook - if any - for later re-installation.
*
* @return a function pointer or NULL if no hook is set
*/
void *__printk_get_hook(void)
{
return _char_out;
}
/**
* @brief Printk internals
*
* See printk() for description.
* @param fmt Format string
* @param ap Variable parameters
*
* @return N/A
*/
void _vprintk(out_func_t out, void *ctx, const char *fmt, va_list ap)
{
int might_format = 0; /* 1 if encountered a '%' */
int pad_zero = 0;
int min_width = -1;
/* fmt has already been adjusted if needed */
while (*fmt) {
if (!might_format) {
if (*fmt != '%') {
out((int)*fmt, ctx);
} else {
might_format = 1;
min_width = -1;
pad_zero = 0;
}
} else {
switch (*fmt) {
case '0':
if (min_width < 0 && pad_zero == 0) {
pad_zero = 1;
goto still_might_format;
}
/* Fall through */
case '1' ... '9':
if (min_width < 0) {
min_width = *fmt - '0';
} else {
min_width = 10 * min_width + *fmt - '0';
}
goto still_might_format;
case 'z':
case 'l':
case 'h':
/* FIXME: do nothing for these modifiers */
goto still_might_format;
case 'd':
case 'i': {
long d = va_arg(ap, long);
if (d < 0) {
out((int)'-', ctx);
d = -d;
min_width--;
}
_printk_dec_ulong(out, ctx, d, pad_zero,
min_width);
break;
}
case 'u': {
unsigned long u = va_arg(
ap, unsigned long);
_printk_dec_ulong(out, ctx, u, pad_zero,
min_width);
break;
}
case 'p':
out('0', ctx);
out('x', ctx);
/* left-pad pointers with zeros */
pad_zero = 1;
min_width = 8;
/* Fall through */
case 'x':
case 'X': {
unsigned long x = va_arg(
ap, unsigned long);
_printk_hex_ulong(out, ctx, x, pad_zero,
min_width);
break;
}
case 's': {
char *s = va_arg(ap, char *);
while (*s)
out((int)(*s++), ctx);
break;
}
case 'c': {
int c = va_arg(ap, int);
out(c, ctx);
break;
}
case '%': {
out((int)'%', ctx);
break;
}
default:
out((int)'%', ctx);
out((int)*fmt, ctx);
break;
}
might_format = 0;
}
still_might_format:
++fmt;
}
}
struct out_context {
int count;
};
static int char_out(int c, struct out_context *ctx)
{
ctx->count++;
return _char_out(c);
}
/**
* @brief Output a string
*
* Output a string on output installed by platform at init time. Some
* printf-like formatting is available.
*
* Available formatting:
* - %x/%X: outputs a 32-bit number in ABCDWXYZ format. All eight digits
* are printed: if less than 8 characters are needed, leading zeroes
* are displayed.
* - %s: output a null-terminated string
* - %p: pointer, same as %x
* - %d/%i/%u: outputs a 32-bit number in unsigned decimal format.
*
* @param fmt formatted string to output
*
* @return Number of characters printed
*/
int printk(const char *fmt, ...)
{
struct out_context ctx = { 0 };
va_list ap;
va_start(ap, fmt);
_vprintk((out_func_t)char_out, &ctx, fmt, ap);
va_end(ap);
return ctx.count;
}
/**
* @brief Output an unsigned long in hex format
*
* Output an unsigned long on output installed by platform at init time. Should
* be able to handle an unsigned long of any size, 32 or 64 bit.
* @param num Number to output
*
* @return N/A
*/
static void _printk_hex_ulong(out_func_t out, void *ctx,
const unsigned long num, int pad_zero,
int min_width)
{
int size = sizeof(num) * 2;
int found_largest_digit = 0;
int remaining = 8; /* 8 digits max */
for (; size; size--) {
char nibble = (num >> ((size - 1) << 2) & 0xf);
if (nibble || found_largest_digit || size == 1) {
found_largest_digit = 1;
nibble += nibble > 9 ? 87 : 48;
out((int)nibble, ctx);
continue;
}
if (remaining-- <= min_width) {
out((int)(pad_zero ? '0' : ' '), ctx);
}
}
}
/**
* @brief Output an unsigned long (32-bit) in decimal format
*
* Output an unsigned long on output installed by platform at init time. Only
* works with 32-bit values.
* @param num Number to output
*
* @return N/A
*/
static void _printk_dec_ulong(out_func_t out, void *ctx,
const unsigned long num, int pad_zero,
int min_width)
{
unsigned long pos = 999999999;
unsigned long remainder = num;
int found_largest_digit = 0;
int remaining = 10; /* 10 digits max */
/* make sure we don't skip if value is zero */
if (min_width <= 0) {
min_width = 1;
}
while (pos >= 9) {
if (found_largest_digit || remainder > pos) {
found_largest_digit = 1;
out((int)((remainder / (pos + 1)) + 48), ctx);
} else if (remaining <= min_width) {
out((int)(pad_zero ? '0' : ' '), ctx);
}
remaining--;
remainder %= (pos + 1);
pos /= 10;
}
out((int)(remainder + 48), ctx);
}
struct str_context {
char *str;
int max;
int count;
};
static int str_out(int c, struct str_context *ctx)
{
if (!ctx->str || ctx->count >= ctx->max) {
ctx->count++;
return c;
}
if (ctx->count == ctx->max - 1) {
ctx->str[ctx->count++] = '\0';
} else {
ctx->str[ctx->count++] = c;
}
return c;
}
int snprintk(char *str, size_t size, const char *fmt, ...)
{
struct str_context ctx = { str, size, 0 };
va_list ap;
va_start(ap, fmt);
_vprintk((out_func_t)str_out, &ctx, fmt, ap);
va_end(ap);
if (ctx.count < ctx.max) {
str[ctx.count] = '\0';
}
return ctx.count;
}
int vsnprintk(char *str, size_t size, const char *fmt, va_list ap)
{
struct str_context ctx = { str, size, 0 };
_vprintk((out_func_t)str_out, &ctx, fmt, ap);
if (ctx.count < ctx.max) {
str[ctx.count] = '\0';
}
return ctx.count;
}