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enhance tu fifo

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- rename wr/rd absolute to index, and rel to pointer.
- fix crash with _tu_fifo_remaining()
- change get_relative_pointer() to idx2ptr() and merge with _ff_mod()
This commit is contained in:
hathach 2022-12-08 16:39:24 +07:00
parent bae7fe5be7
commit 3e32fa36b8
2 changed files with 124 additions and 87 deletions
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205
src/common/tusb_fifo.c
View File

@ -34,6 +34,8 @@
#pragma diag_suppress = Pa082
#endif
#define TU_FIFO_DBG 0
// implement mutex lock and unlock
#if CFG_FIFO_MUTEX
@ -90,12 +92,9 @@ bool tu_fifo_config(tu_fifo_t *f, void* buffer, uint16_t depth, uint16_t item_si
return true;
}
// Static functions are intended to work on local variables
static inline uint16_t _ff_mod(uint16_t idx, uint16_t depth)
{
while ( idx >= depth) idx -= depth;
return idx;
}
//--------------------------------------------------------------------+
// Pull & Push
//--------------------------------------------------------------------+
// Intended to be used to read from hardware USB FIFO in e.g. STM32 where all data is read from a constant address
// Code adapted from dcd_synopsys.c
@ -179,7 +178,7 @@ static void _ff_push_n(tu_fifo_t* f, void const * app_buf, uint16_t n, uint16_t
// Write data to linear part of buffer
memcpy(ff_buf, app_buf, nLin_bytes);
// Write data wrapped around
TU_ASSERT(nWrap_bytes <= f->depth, );
memcpy(f->buffer, ((uint8_t const*) app_buf) + nLin_bytes, nWrap_bytes);
}
break;
@ -317,21 +316,24 @@ static void _ff_pull_n(tu_fifo_t* f, void* app_buf, uint16_t n, uint16_t rel, tu
}
}
//--------------------------------------------------------------------+
// Index (free-running and real buffer pointer)
//--------------------------------------------------------------------+
// Advance an absolute pointer
// "absolute" index is only in the range of [0..2*depth)
static uint16_t advance_pointer(tu_fifo_t* f, uint16_t p, uint16_t offset)
{
// We limit the index space of p such that a correct wrap around happens
// Check for a wrap around or if we are in unused index space - This has to be checked first!!
// We are exploiting the wrap around to the correct index
if ((p > (uint16_t)(p + offset)) || ((uint16_t)(p + offset) > f->max_pointer_idx))
uint16_t next_p = (uint16_t) (p + offset);
if ( (p > next_p) || (next_p > f->max_pointer_idx) )
{
p = (uint16_t) ((p + offset) + f->non_used_index_space);
next_p = (uint16_t) (next_p + f->non_used_index_space);
}
else
{
p += offset;
}
return p;
return next_p;
}
// Backward an absolute pointer
@ -340,30 +342,33 @@ static uint16_t backward_pointer(tu_fifo_t* f, uint16_t p, uint16_t offset)
// We limit the index space of p such that a correct wrap around happens
// Check for a wrap around or if we are in unused index space - This has to be checked first!!
// We are exploiting the wrap around to the correct index
if ((p < (uint16_t)(p - offset)) || ((uint16_t)(p - offset) > f->max_pointer_idx))
uint16_t new_p = (uint16_t) (p - offset);
if ( (p < new_p) || (new_p > f->max_pointer_idx) )
{
p = (uint16_t) ((p - offset) - f->non_used_index_space);
new_p = (uint16_t) (new_p - f->non_used_index_space);
}
else
{
p -= offset;
}
return p;
return new_p;
}
// get relative from absolute pointer
static uint16_t get_relative_pointer(tu_fifo_t* f, uint16_t p)
// index to pointer, simply an modulo with minus
static inline uint16_t idx2ptr(uint16_t idx, uint16_t depth)
{
return _ff_mod(p, f->depth);
while ( idx >= depth ) idx -= depth;
return idx;
}
// Works on local copies of w and r - return only the difference and as such can be used to determine an overflow
static inline uint16_t _tu_fifo_count(tu_fifo_t* f, uint16_t wAbs, uint16_t rAbs)
static inline uint16_t _tu_fifo_count(tu_fifo_t* f, uint16_t wr_idx, uint16_t rd_idx)
{
uint16_t cnt = wAbs-rAbs;
uint16_t cnt = (uint16_t) (wr_idx-rd_idx);
// In case we have non-power of two depth we need a further modification
if (rAbs > wAbs) cnt -= f->non_used_index_space;
if (rd_idx > wr_idx)
{
// 2*f->depth - (rd_idx - wr_idx);
cnt = (uint16_t) (cnt - f->non_used_index_space);
}
return cnt;
}
@ -400,39 +405,39 @@ static inline void _tu_fifo_correct_read_pointer(tu_fifo_t* f, uint16_t wAbs)
// Works on local copies of w and r
// Must be protected by mutexes since in case of an overflow read pointer gets modified
static bool _tu_fifo_peek(tu_fifo_t* f, void * p_buffer, uint16_t wAbs, uint16_t rAbs)
static bool _tu_fifo_peek(tu_fifo_t* f, void * p_buffer, uint16_t wr_idx, uint16_t rd_idx)
{
uint16_t cnt = _tu_fifo_count(f, wAbs, rAbs);
uint16_t cnt = _tu_fifo_count(f, wr_idx, rd_idx);
// Check overflow and correct if required
if (cnt > f->depth)
{
_tu_fifo_correct_read_pointer(f, wAbs);
_tu_fifo_correct_read_pointer(f, wr_idx);
cnt = f->depth;
}
// Skip beginning of buffer
if (cnt == 0) return false;
uint16_t rRel = get_relative_pointer(f, rAbs);
uint16_t rd_ptr = idx2ptr(rd_idx, f->depth);
// Peek data
_ff_pull(f, p_buffer, rRel);
_ff_pull(f, p_buffer, rd_ptr);
return true;
}
// Works on local copies of w and r
// Must be protected by mutexes since in case of an overflow read pointer gets modified
static uint16_t _tu_fifo_peek_n(tu_fifo_t* f, void * p_buffer, uint16_t n, uint16_t wAbs, uint16_t rAbs, tu_fifo_copy_mode_t copy_mode)
static uint16_t _tu_fifo_peek_n(tu_fifo_t* f, void * p_buffer, uint16_t n, uint16_t wr_idx, uint16_t rd_idx, tu_fifo_copy_mode_t copy_mode)
{
uint16_t cnt = _tu_fifo_count(f, wAbs, rAbs);
uint16_t cnt = _tu_fifo_count(f, wr_idx, rd_idx);
// Check overflow and correct if required
if (cnt > f->depth)
{
_tu_fifo_correct_read_pointer(f, wAbs);
rAbs = f->rd_idx;
_tu_fifo_correct_read_pointer(f, wr_idx);
rd_idx = f->rd_idx;
cnt = f->depth;
}
@ -442,53 +447,80 @@ static uint16_t _tu_fifo_peek_n(tu_fifo_t* f, void * p_buffer, uint16_t n, uint1
// Check if we can read something at and after offset - if too less is available we read what remains
if (cnt < n) n = cnt;
uint16_t rRel = get_relative_pointer(f, rAbs);
uint16_t rd_ptr = idx2ptr(rd_idx, f->depth);
// Peek data
_ff_pull_n(f, p_buffer, n, rRel, copy_mode);
_ff_pull_n(f, p_buffer, n, rd_ptr, copy_mode);
return n;
}
// Works on local copies of w and r
static inline uint16_t _tu_fifo_remaining(tu_fifo_t* f, uint16_t wAbs, uint16_t rAbs)
static inline uint16_t _tu_fifo_remaining(tu_fifo_t* f, uint16_t wr_idx, uint16_t rd_idx)
{
return f->depth - _tu_fifo_count(f, wAbs, rAbs);
uint16_t const count = _tu_fifo_count(f, wr_idx, rd_idx);
return (f->depth > count) ? (f->depth - count) : 0;
}
static uint16_t _tu_fifo_write_n(tu_fifo_t* f, const void * data, uint16_t n, tu_fifo_copy_mode_t copy_mode)
{
if ( n == 0 ) return 0;
TU_LOG(TU_FIFO_DBG, "rd = %u, wr = %02u, n = %u: ", f->rd_idx, f->wr_idx, n);
_ff_lock(f->mutex_wr);
uint16_t w = f->wr_idx, r = f->rd_idx;
uint16_t wr_idx = f->wr_idx;
uint16_t rd_idx = f->rd_idx;
uint8_t const* buf8 = (uint8_t const*) data;
uint16_t const remain = _tu_fifo_remaining(f, wr_idx, rd_idx);
if (!f->overwritable)
if ( n > remain)
{
// Not overwritable limit up to full
n = tu_min16(n, _tu_fifo_remaining(f, w, r));
}
else if (n >= f->depth)
{
// Only copy last part
buf8 = buf8 + (n - f->depth) * f->item_size;
n = f->depth;
if ( !f->overwritable )
{
// limit up to full
n = remain;
}
else
{
// oldest data in fifo i.e read pointer data will be overwritten
// Note: we modify read data but we do not want to modify the read pointer within a write function!
// since it would end up in a race condition with read functions!
// Note2: race condition could still occur if tu_fifo_read() is called while we modify its buffer (corrupted data)
// We start writing at the read pointer's position since we fill the complete
// buffer and we do not want to modify the read pointer within a write function!
// This would end up in a race condition with read functions!
w = r;
if ( n >= f->depth )
{
// Only copy last part
buf8 = buf8 + (n - f->depth) * f->item_size;
n = f->depth;
// We start writing at the read pointer's position since we fill the complete
// buffer and we do not want to modify the read pointer within a write function!
// This would end up in a race condition with read functions!
wr_idx = rd_idx;
}else
{
// TODO shift out oldest data from read pointer !!!
}
}
}
uint16_t wRel = get_relative_pointer(f, w);
if (n)
{
uint16_t wr_ptr = idx2ptr(wr_idx, f->depth);
// Write data
_ff_push_n(f, buf8, n, wRel, copy_mode);
TU_LOG(TU_FIFO_DBG, "actual_n = %u, wr_rel = %u", n, wr_ptr);
// Advance pointer
f->wr_idx = advance_pointer(f, w, n);
// Write data
_ff_push_n(f, buf8, n, wr_ptr, copy_mode);
// Advance pointer
f->wr_idx = advance_pointer(f, wr_idx, n);
TU_LOG(TU_FIFO_DBG, "\tnew_wr = %u\n", f->wr_idx);
}
_ff_unlock(f->mutex_wr);
@ -742,20 +774,20 @@ bool tu_fifo_write(tu_fifo_t* f, const void * data)
_ff_lock(f->mutex_wr);
bool ret;
uint16_t const w = f->wr_idx;
uint16_t const wr_idx = f->wr_idx;
if ( _tu_fifo_full(f, w, f->rd_idx) && !f->overwritable )
if ( _tu_fifo_full(f, wr_idx, f->rd_idx) && !f->overwritable )
{
ret = false;
}else
{
uint16_t wRel = get_relative_pointer(f, w);
uint16_t wr_ptr = idx2ptr(wr_idx, f->depth);
// Write data
_ff_push(f, data, wRel);
_ff_push(f, data, wr_ptr);
// Advance pointer
f->wr_idx = advance_pointer(f, w, 1);
f->wr_idx = advance_pointer(f, wr_idx, 1);
ret = true;
}
@ -909,17 +941,19 @@ void tu_fifo_advance_read_pointer(tu_fifo_t *f, uint16_t n)
void tu_fifo_get_read_info(tu_fifo_t *f, tu_fifo_buffer_info_t *info)
{
// Operate on temporary values in case they change in between
uint16_t w = f->wr_idx, r = f->rd_idx;
uint16_t wr_idx = f->wr_idx;
uint16_t rd_idx = f->rd_idx;
uint16_t cnt = _tu_fifo_count(f, w, r);
uint16_t cnt = _tu_fifo_count(f, wr_idx, rd_idx);
// Check overflow and correct if required - may happen in case a DMA wrote too fast
if (cnt > f->depth)
{
_ff_lock(f->mutex_rd);
_tu_fifo_correct_read_pointer(f, w);
_tu_fifo_correct_read_pointer(f, wr_idx);
_ff_unlock(f->mutex_rd);
r = f->rd_idx;
rd_idx = f->rd_idx;
cnt = f->depth;
}
@ -934,22 +968,24 @@ void tu_fifo_get_read_info(tu_fifo_t *f, tu_fifo_buffer_info_t *info)
}
// Get relative pointers
w = get_relative_pointer(f, w);
r = get_relative_pointer(f, r);
uint16_t wr_ptr = idx2ptr(wr_idx, f->depth);
uint16_t rd_ptr = idx2ptr(rd_idx, f->depth);
// Copy pointer to buffer to start reading from
info->ptr_lin = &f->buffer[r];
info->ptr_lin = &f->buffer[rd_ptr];
// Check if there is a wrap around necessary
if (w > r) {
if (wr_ptr > rd_ptr) {
// Non wrapping case
info->len_lin = cnt;
info->len_wrap = 0;
info->ptr_wrap = NULL;
}
else
{
info->len_lin = f->depth - r; // Also the case if FIFO was full
info->len_lin = f->depth - rd_ptr; // Also the case if FIFO was full
info->len_wrap = cnt - info->len_lin;
info->ptr_wrap = f->buffer;
}
@ -972,10 +1008,11 @@ void tu_fifo_get_read_info(tu_fifo_t *f, tu_fifo_buffer_info_t *info)
/******************************************************************************/
void tu_fifo_get_write_info(tu_fifo_t *f, tu_fifo_buffer_info_t *info)
{
uint16_t w = f->wr_idx, r = f->rd_idx;
uint16_t free = _tu_fifo_remaining(f, w, r);
uint16_t wr_idx = f->wr_idx;
uint16_t rd_idx = f->rd_idx;
uint16_t remain = _tu_fifo_remaining(f, wr_idx, rd_idx);
if (free == 0)
if (remain == 0)
{
info->len_lin = 0;
info->len_wrap = 0;
@ -985,23 +1022,23 @@ void tu_fifo_get_write_info(tu_fifo_t *f, tu_fifo_buffer_info_t *info)
}
// Get relative pointers
w = get_relative_pointer(f, w);
r = get_relative_pointer(f, r);
uint16_t wr_ptr = idx2ptr(wr_idx, f->depth);
uint16_t rd_ptr = idx2ptr(rd_idx, f->depth);
// Copy pointer to buffer to start writing to
info->ptr_lin = &f->buffer[w];
info->ptr_lin = &f->buffer[wr_ptr];
if (w < r)
if (wr_ptr < rd_ptr)
{
// Non wrapping case
info->len_lin = r-w;
info->len_lin = rd_ptr-wr_ptr;
info->len_wrap = 0;
info->ptr_wrap = NULL;
}
else
{
info->len_lin = f->depth - w;
info->len_wrap = free - info->len_lin; // Remaining length - n already was limited to free or FIFO depth
info->ptr_wrap = f->buffer; // Always start of buffer
info->len_lin = f->depth - wr_ptr;
info->len_wrap = remain - info->len_lin; // Remaining length - n already was limited to remain or FIFO depth
info->ptr_wrap = f->buffer; // Always start of buffer
}
}

6
src/common/tusb_fifo.h
View File

@ -101,10 +101,10 @@ bool tu_fifo_config(tu_fifo_t *f, void* buffer, uint16_t depth, uint16_t item_si
#if CFG_FIFO_MUTEX
TU_ATTR_ALWAYS_INLINE static inline
void tu_fifo_config_mutex(tu_fifo_t *f, tu_fifo_mutex_t write_mutex_hdl, tu_fifo_mutex_t read_mutex_hdl)
void tu_fifo_config_mutex(tu_fifo_t *f, tu_fifo_mutex_t wr_mutex, tu_fifo_mutex_t rd_mutex)
{
f->mutex_wr = write_mutex_hdl;
f->mutex_rd = read_mutex_hdl;
f->mutex_wr = wr_mutex;
f->mutex_rd = rd_mutex;
}
#endif