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Improve tu_fifo capabilites
Added tu_fifo_get_linear_write_info(), tu_fifo_backward_write_pointer(), and tu_fifo_backward_read_pointer()
This commit is contained in:
Reinhard Panhuber
parent
a5d7b6266d
commit
c87357c025
@ -354,10 +354,7 @@ static uint16_t _tu_fifo_peek_at_n(tu_fifo_t* f, uint16_t offset, void * p_buffe
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// Check if we can read something at and after offset - if too less is available we read what remains
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cnt -= offset;
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if (cnt < n) {
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if (cnt == 0) return 0;
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n = cnt;
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}
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if (cnt < n) n = cnt;
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uint16_t rRel = get_relative_pointer(f, rAbs, offset);
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@ -664,10 +661,7 @@ uint16_t tu_fifo_peek_n_into_other_fifo (tu_fifo_t* f, tu_fifo_t* f_target, uint
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// Check if we can read something at and after offset - if too less is available we read what remains
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cnt -= offset;
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if (cnt < n) {
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if (cnt == 0) return 0;
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n = cnt;
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}
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if (cnt < n) n = cnt;
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tu_fifo_lock(f_target); // Lock both read and write pointers - in case of an overwritable FIFO both may be modified
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@ -881,3 +875,195 @@ void tu_fifo_advance_read_pointer(tu_fifo_t *f, uint16_t n)
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{
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f->rd_idx = advance_pointer(f, f->rd_idx, n);
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}
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/******************************************************************************/
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/*!
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@brief Move back write pointer - intended to be used in combination with DMA.
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It is possible to fill the FIFO by use of a DMA in circular mode. Within
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DMA ISRs you may update the write pointer to be able to read from the FIFO.
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As long as the DMA is the only process writing into the FIFO this is safe
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to use.
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USE WITH CARE - WE DO NOT CONDUCT SAFTY CHECKS HERE!
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@param[in] f
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Pointer to the FIFO buffer to manipulate
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@param[in] n
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Number of items the write pointer moves backward
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*/
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/******************************************************************************/
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void tu_fifo_backward_write_pointer(tu_fifo_t *f, uint16_t n)
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{
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f->wr_idx = backward_pointer(f, f->wr_idx, n);
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}
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/******************************************************************************/
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/*!
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@brief Move back read pointer - intended to be used in combination with DMA.
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It is possible to read from the FIFO by use of a DMA in linear mode. Within
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DMA ISRs you may update the read pointer to be able to again write into the
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FIFO. As long as the DMA is the only process reading from the FIFO this is
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safe to use.
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USE WITH CARE - WE DO NOT CONDUCT SAFTY CHECKS HERE!
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@param[in] f
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Pointer to the FIFO buffer to manipulate
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@param[in] n
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Number of items the read pointer moves backward
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*/
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/******************************************************************************/
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void tu_fifo_backward_read_pointer(tu_fifo_t *f, uint16_t n)
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{
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f->rd_idx = backward_pointer(f, f->rd_idx, n);
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}
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/******************************************************************************/
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/*!
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@brief Get linear read info
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Returns the length and pointer from which bytes can be read in a linear manner.
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This is of major interest for DMA transmissions. If returned length is zero the
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corresponding pointer is invalid. The returned length is limited to the number
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of BYTES n which the user wants to write into the buffer.
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The write pointer does NOT get advanced, use tu_fifo_advance_read_pointer() to
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do so! If the length returned is less than n i.e. len<n, then a wrap occurs
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and you need to execute this function a second time to get a pointer to the
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wrapped part!
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@param[in] f
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Pointer to FIFO
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@param[in] offset
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Number of BYTES to ignore before start writing
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@param[out] **ptr
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Pointer to start writing to
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@param[in] n
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Number of BYTES to read from buffer
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@return len
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Length of linear part IN BYTES, if zero corresponding pointer ptr is invalid
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*/
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/******************************************************************************/
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uint16_t tu_fifo_get_linear_read_info(tu_fifo_t *f, uint16_t offset, void **ptr, uint16_t n)
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{
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// Operate on temporary values in case they change in between
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uint16_t w = f->wr_idx, r = f->rd_idx;
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uint16_t cnt = _tu_fifo_count(f, w, r);
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// Check overflow and correct if required
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if (cnt > f->depth)
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{
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tu_fifo_lock(f);
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_tu_fifo_correct_read_pointer(f, w);
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tu_fifo_unlock(f);
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r = f->rd_idx;
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cnt = f->depth;
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}
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// Convert to bytes
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cnt = cnt * f->item_size;
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// Skip beginning of buffer
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if (cnt == 0 || offset >= cnt) return 0;
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// Check if we can read something at and after offset - if too less is available we read what remains
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cnt -= offset;
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if (cnt < n) n = cnt;
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// Get relative pointers
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w = get_relative_pointer(f, w, 0);
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r = get_relative_pointer(f, r, offset);
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// Check if there is a wrap around necessary
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uint16_t len;
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if (w >= r) {
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len = w - r;
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}
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else
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{
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len = f->depth - r;
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}
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len = len * f->item_size;
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// Limit to required length
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len = tu_min16(n, len);
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// Copy pointer to buffer to start reading from
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*ptr = &f->buffer[r];
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return len;
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}
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/******************************************************************************/
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/*!
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@brief Get linear write info
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Returns the length and pointer from which bytes can be written into buffer array in a linear manner.
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This is of major interest for DMA transmissions not using circular mode. If returned length is zero the
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corresponding pointer is invalid. The returned length is limited to the number of BYTES n which the user
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wants to write into the buffer.
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The write pointer does NOT get advanced, use tu_fifo_advance_write_pointer() to do so! If the length
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returned is less than n i.e. len<n, then a wrap occurs and you need to execute this function a second
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time to get a pointer to the wrapped part!
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@param[in] f
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Pointer to FIFO
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@param[in] offset
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Number of bytes to ignore before start writing
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@param[out] **ptr
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Pointer to start writing to
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@param[in] n
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Number of BYTES to write into buffer
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@return len
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Length of linear part IN BYTES, if zero corresponding pointer ptr is invalid
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*/
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/******************************************************************************/
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uint16_t tu_fifo_get_linear_write_info(tu_fifo_t *f, uint16_t offset, void **ptr, uint16_t n)
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{
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uint16_t w = f->wr_idx, r = f->rd_idx;
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uint16_t free = _tu_fifo_remaining(f, w, r) * f->item_size;
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if (!f->overwritable)
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{
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// Not overwritable limit up to full
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n = tu_min16(n, free);
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}
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else if (n >= f->depth * f->item_size)
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{
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// If overwrite is allowed it must be less than or equal to 2 x buffer length, otherwise the overflow can not be resolved by the read functions
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TU_VERIFY(n <= 2*f->depth * f->item_size);
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n = f->depth * f->item_size;
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// We start writing at the read pointer's position since we fill the complete
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// buffer and we do not want to modify the read pointer within a write function!
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// This would end up in a race condition with read functions!
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w = r;
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}
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// Check if there is room to write to
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if (free == 0 || offset >= free) return 0;
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// Get relative pointers
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w = get_relative_pointer(f, w, offset);
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r = get_relative_pointer(f, r, 0);
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uint16_t len;
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if (w < r)
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{
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len = r-w;
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}
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else
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{
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len = f->depth - w;
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}
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len = len * f->item_size;
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// Limit to required length
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len = tu_min16(n, len);
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// Copy pointer to buffer to start reading from
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*ptr = &f->buffer[w];
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return len;
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}
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@ -134,7 +134,16 @@ void tu_fifo_correct_read_pointer (tu_fifo_t* f);
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// Pointer modifications intended to be used in combinations with DMAs.
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// USE WITH CARE - NO SAFTY CHECKS CONDUCTED HERE! NOT MUTEX PROTECTED!
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void tu_fifo_advance_write_pointer (tu_fifo_t *f, uint16_t n);
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void tu_fifo_backward_write_pointer (tu_fifo_t *f, uint16_t n);
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void tu_fifo_advance_read_pointer (tu_fifo_t *f, uint16_t n);
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void tu_fifo_backward_read_pointer (tu_fifo_t *f, uint16_t n);
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// If you want to read/write from/to the FIFO by use of a DMA, you may need to conduct two copies to handle a possible wrapping part
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// This functions deliver a pointer to start reading/writing from/to and a valid linear length along which no wrap occurs.
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// In case not all of your data is available within one read/write, update the read/write pointer by
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// tu_fifo_advance_read_pointer()/tu_fifo_advance_write_pointer and conduct a second read/write operation
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uint16_t tu_fifo_get_linear_read_info (tu_fifo_t *f, uint16_t offset, void **ptr, uint16_t n);
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uint16_t tu_fifo_get_linear_write_info (tu_fifo_t *f, uint16_t offset, void **ptr, uint16_t n);
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static inline bool tu_fifo_peek(tu_fifo_t* f, void * p_buffer)
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{
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