[rtems-libbsd commit] busdma: Option to round to cache lines on sync
Christian Mauderer
christianm at rtems.org
Fri Jul 31 06:32:44 UTC 2020
Module: rtems-libbsd
Branch: master
Commit: 4820ccecc92f850333dbf01cc2dedfa31329e474
Changeset: http://git.rtems.org/rtems-libbsd/commit/?id=4820ccecc92f850333dbf01cc2dedfa31329e474
Author: Christian Mauderer <christian.mauderer at embedded-brains.de>
Date: Thu Apr 2 16:42:43 2020 +0200
busdma: Option to round to cache lines on sync
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.
---
freebsd/sys/dev/usb/usb_busdma.c | 31 ++++++++++++++++++++++++++++
freebsd/sys/dev/usb/usb_busdma.h | 5 +++++
freebsd/sys/dev/usb/usb_transfer.c | 20 ++++++++++++++++++
freebsd/sys/dev/usb/usbdi.h | 4 ++++
freebsd/sys/sys/bus_dma.h | 6 ++++++
rtemsbsd/include/machine/rtems-bsd-bus-dma.h | 3 +++
rtemsbsd/rtems/rtems-kernel-bus-dma-mbuf.c | 3 +++
rtemsbsd/rtems/rtems-kernel-bus-dma.c | 9 ++++++++
8 files changed, 81 insertions(+)
diff --git a/freebsd/sys/dev/usb/usb_busdma.c b/freebsd/sys/dev/usb/usb_busdma.c
index dc52fe1..b74f082 100644
--- a/freebsd/sys/dev/usb/usb_busdma.c
+++ b/freebsd/sys/dev/usb/usb_busdma.c
@@ -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 {
diff --git a/freebsd/sys/dev/usb/usb_busdma.h b/freebsd/sys/dev/usb/usb_busdma.h
index d75e67e..03eca30 100644
--- a/freebsd/sys/dev/usb/usb_busdma.h
+++ b/freebsd/sys/dev/usb/usb_busdma.h
@@ -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
};
diff --git a/freebsd/sys/dev/usb/usb_transfer.c b/freebsd/sys/dev/usb/usb_transfer.c
index 3b67c20..ee1e4c2 100644
--- a/freebsd/sys/dev/usb/usb_transfer.c
+++ b/freebsd/sys/dev/usb/usb_transfer.c
@@ -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
*
diff --git a/freebsd/sys/dev/usb/usbdi.h b/freebsd/sys/dev/usb/usbdi.h
index 0a39384..834810a 100644
--- a/freebsd/sys/dev/usb/usbdi.h
+++ b/freebsd/sys/dev/usb/usbdi.h
@@ -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);
diff --git a/freebsd/sys/sys/bus_dma.h b/freebsd/sys/sys/bus_dma.h
index e99d8ec..d5a08be 100644
--- a/freebsd/sys/sys/bus_dma.h
+++ b/freebsd/sys/sys/bus_dma.h
@@ -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;
diff --git a/rtemsbsd/include/machine/rtems-bsd-bus-dma.h b/rtemsbsd/include/machine/rtems-bsd-bus-dma.h
index ac97053..e956688 100644
--- a/rtemsbsd/include/machine/rtems-bsd-bus-dma.h
+++ b/rtemsbsd/include/machine/rtems-bsd-bus-dma.h
@@ -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
diff --git a/rtemsbsd/rtems/rtems-kernel-bus-dma-mbuf.c b/rtemsbsd/rtems/rtems-kernel-bus-dma-mbuf.c
index c435fd7..56ead4e 100644
--- a/rtemsbsd/rtems/rtems-kernel-bus-dma-mbuf.c
+++ b/rtemsbsd/rtems/rtems-kernel-bus-dma-mbuf.c
@@ -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) {
diff --git a/rtemsbsd/rtems/rtems-kernel-bus-dma.c b/rtemsbsd/rtems/rtems-kernel-bus-dma.c
index 8c15e92..4dc634f 100644
--- a/rtemsbsd/rtems/rtems-kernel-bus-dma.c
+++ b/rtemsbsd/rtems/rtems-kernel-bus-dma.c
@@ -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);
}
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