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busdma: Option to round to cache lines on sync

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Some targets support only flushing or invalidating complete cache lines.
In this cases misaligned buffers might lead to unexpected results. This
patch adds a flag that allows drivers to signal to the bus dma driver
that it is OK to round a buffer to the next full cache line. That's for
example necessary if a driver wants to send out 14 byte via a USB DMA.
Only the driver knows whether these 14 bytes are located in an otherwise
unused cache line aligned buffer.
This commit is contained in:
Christian Mauderer 2020-04-02 16:42:43 +02:00
parent 7e5d93bb6b
commit 4820ccecc9
8 changed files with 81 additions and 0 deletions
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31
freebsd/sys/dev/usb/usb_busdma.c
View File

@ -67,6 +67,9 @@
#include <dev/usb/usb_controller.h>
#include <dev/usb/usb_bus.h>
#endif /* USB_GLOBAL_INCLUDE_FILE */
#ifdef __rtems__
#include <machine/rtems-bsd-cache.h>
#endif /* __rtems__ */
#if USB_HAVE_BUSDMA
static void usb_dma_tag_create(struct usb_dma_tag *, usb_size_t, usb_size_t);
@ -543,6 +546,15 @@ usb_pc_alloc_mem(struct usb_page_cache *pc, struct usb_page *pg,
uptag = pc->tag_parent;
#if defined(__rtems__) && defined(CPU_DATA_CACHE_ALIGNMENT)
while (align % CPU_DATA_CACHE_ALIGNMENT != 0) {
align *= 2;
}
if (size % CPU_DATA_CACHE_ALIGNMENT != 0) {
size = (size + (CPU_DATA_CACHE_ALIGNMENT - 1)) &
~(CPU_DATA_CACHE_ALIGNMENT - 1);
}
#endif /* __rtems__ */
if (align != 1) {
/*
* The alignment must be greater or equal to the
@ -605,7 +617,12 @@ usb_pc_alloc_mem(struct usb_page_cache *pc, struct usb_page *pg,
/* load memory into DMA */
err = bus_dmamap_load(
utag->tag, map, ptr, size, &usb_pc_alloc_mem_cb,
#if defined(__rtems__) && CPU_DATA_CACHE_ALIGNMENT
pc, (BUS_DMA_WAITOK | BUS_DMA_COHERENT |
BUS_DMA_DO_CACHE_LINE_BLOW_UP));
#else /* __rtems__ */
pc, (BUS_DMA_WAITOK | BUS_DMA_COHERENT));
#endif /* __rtems__ */
if (err == EINPROGRESS) {
cv_wait(uptag->cv, uptag->mtx);
@ -662,6 +679,12 @@ usb_pc_free_mem(struct usb_page_cache *pc)
uint8_t
usb_pc_load_mem(struct usb_page_cache *pc, usb_size_t size, uint8_t sync)
{
#ifdef __rtems__
int flags;
flags = pc->dma_do_cache_line_blow_up ?
BUS_DMA_DO_CACHE_LINE_BLOW_UP : 0;
#endif /* __rtems__ */
/* setup page cache */
pc->page_offset_buf = 0;
pc->page_offset_end = size;
@ -687,7 +710,11 @@ usb_pc_load_mem(struct usb_page_cache *pc, usb_size_t size, uint8_t sync)
*/
err = bus_dmamap_load(
pc->tag, pc->map, pc->buffer, size,
#ifndef __rtems__
&usb_pc_alloc_mem_cb, pc, BUS_DMA_WAITOK);
#else /* __rtems__ */
&usb_pc_alloc_mem_cb, pc, BUS_DMA_WAITOK | flags);
#endif /* __rtems__ */
if (err == EINPROGRESS) {
cv_wait(uptag->cv, uptag->mtx);
err = 0;
@ -709,7 +736,11 @@ usb_pc_load_mem(struct usb_page_cache *pc, usb_size_t size, uint8_t sync)
*/
if (bus_dmamap_load(
pc->tag, pc->map, pc->buffer, size,
#ifndef __rtems__
&usb_pc_load_mem_cb, pc, BUS_DMA_WAITOK)) {
#else /* __rtems__ */
&usb_pc_load_mem_cb, pc, BUS_DMA_WAITOK | flags)) {
#endif /* __rtems__ */
}
}
} else {

5
freebsd/sys/dev/usb/usb_busdma.h
View File

@ -102,6 +102,11 @@ struct usb_page_cache {
* from the memory. Else write. */
uint8_t ismultiseg:1; /* set if we can have multiple
* segments */
#ifdef __rtems__
uint8_t dma_do_cache_line_blow_up:1;
/* set if it is OK to align the buffer
* start and end to next cache line */
#endif /* __rtems__ */
#endif
};

20
freebsd/sys/dev/usb/usb_transfer.c
View File

@ -2195,6 +2195,9 @@ usbd_xfer_set_frame_data(struct usb_xfer *xfer, usb_frcount_t frindex,
/* set virtual address to load and length */
xfer->frbuffers[frindex].buffer = ptr;
usbd_xfer_set_frame_len(xfer, frindex, len);
#ifdef __rtems__
xfer->frbuffers[frindex].dma_do_cache_line_blow_up = 0;
#endif /* __rtems__ */
}
void
@ -2209,6 +2212,23 @@ usbd_xfer_frame_data(struct usb_xfer *xfer, usb_frcount_t frindex,
*len = xfer->frlengths[frindex];
}
#ifdef __rtems__
/*------------------------------------------------------------------------*
* usbd_xfer_frame_allow_cache_line_blow_up
*
* Set a flag that the buffer start and end belonging to this frame can be
* aligned to the next cache line on sync and flush.
*------------------------------------------------------------------------*/
void
usbd_xfer_frame_allow_cache_line_blow_up(struct usb_xfer *xfer,
usb_frcount_t frindex)
{
KASSERT(frindex < xfer->max_frame_count, ("frame index overflow"));
xfer->frbuffers[frindex].dma_do_cache_line_blow_up = 1;
}
#endif /* __rtems__ */
/*------------------------------------------------------------------------*
* usbd_xfer_old_frame_length
*

4
freebsd/sys/dev/usb/usbdi.h
View File

@ -640,6 +640,10 @@ void usbd_xfer_set_frame_data(struct usb_xfer *xfer, usb_frcount_t frindex,
void *ptr, usb_frlength_t len);
void usbd_xfer_frame_data(struct usb_xfer *xfer, usb_frcount_t frindex,
void **ptr, int *len);
#ifdef __rtems__
void usbd_xfer_frame_allow_cache_line_blow_up(struct usb_xfer *xfer,
usb_frcount_t frindex);
#endif /* __rtems__ */
void usbd_xfer_set_frame_offset(struct usb_xfer *xfer, usb_frlength_t offset,
usb_frcount_t frindex);
usb_frlength_t usbd_xfer_max_len(struct usb_xfer *xfer);

6
freebsd/sys/sys/bus_dma.h
View File

@ -107,6 +107,12 @@
#define BUS_DMA_KEEP_PG_OFFSET 0x400
#define BUS_DMA_LOAD_MBUF 0x800
#ifdef __rtems__
/*
* Hint that the start address and size can be aligned to the next cache line.
*/
#define BUS_DMA_DO_CACHE_LINE_BLOW_UP 0x80000000
#endif /* __rtems__ */
/* Forwards needed by prototypes below. */
union ccb;

3
rtemsbsd/include/machine/rtems-bsd-bus-dma.h
View File

@ -75,6 +75,9 @@ struct bus_dma_tag {
struct bus_dmamap {
void *buffer_begin;
bus_size_t buffer_size;
int flags;
/* OK to flush / invalidate the complete cache line */
#define DMAMAP_CACHE_ALIGNED (1 << 0)
};
int

3
rtemsbsd/rtems/rtems-kernel-bus-dma-mbuf.c
View File

@ -69,6 +69,9 @@ bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
int first = 1;
bus_addr_t lastaddr = 0;
struct mbuf *m;
if ((flags & BUS_DMA_LOAD_MBUF) != 0) {
map->flags |= DMAMAP_CACHE_ALIGNED;
}
for (m = m0; m != NULL && error == 0; m = m->m_next) {
if (m->m_len > 0) {

9
rtemsbsd/rtems/rtems-kernel-bus-dma.c
View File

@ -365,9 +365,13 @@ bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
map->buffer_begin = buf;
map->buffer_size = buflen;
if ((flags & BUS_DMA_DO_CACHE_LINE_BLOW_UP) != 0) {
map->flags |= DMAMAP_CACHE_ALIGNED;
}
lastaddr = (vm_offset_t)0;
nsegs = 0;
error = bus_dmamap_load_buffer(dmat, dm_segments, buf, buflen,
NULL, flags, &lastaddr, &nsegs, 1);
@ -397,6 +401,11 @@ bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
uintptr_t begin = (uintptr_t) map->buffer_begin;
uintptr_t end = begin + size;
if ((map->flags & DMAMAP_CACHE_ALIGNED) != 0) {
begin &= ~CLMASK;
end = (end + CLMASK) & ~CLMASK;
size = end - begin;
}
if ((op & BUS_DMASYNC_PREWRITE) != 0 && (op & BUS_DMASYNC_PREREAD) == 0) {
rtems_cache_flush_multiple_data_lines((void *) begin, size);
}