As Joel pointed out, edma_read_position() uses memcpy_fromio() to read
the parameter ram. That's not synchronized with the internal update as
it does a byte by byte copy. We need to do a 32bit read to get a
consistent value.
Further reading destination and source is pointless. In DEV_TO_MEM
transfers we are only interested in the destination, in MEM_TO_DEV we
care about the source. In MEM_TO_MEM it really does not matter which
one you read.
Simple solution: Remove the pointers, select dest/source via a bool
and return the read value.
Remove the export of this function while at it. The only potential
user is the dmaengine and that's always builtin.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/arm/common/edma.c | 24 +++++++++---------------
include/linux/platform_data/edma.h | 2 +-
2 files changed, 10 insertions(+), 16 deletions(-)
Index: linux-2.6/arch/arm/common/edma.c
===================================================================
--- linux-2.6.orig/arch/arm/common/edma.c
+++ linux-2.6/arch/arm/common/edma.c
@@ -994,29 +994,23 @@ void edma_set_dest(unsigned slot, dma_ad
EXPORT_SYMBOL(edma_set_dest);
/**
- * edma_get_position - returns the current transfer points
+ * edma_get_position - returns the current transfer point
* @slot: parameter RAM slot being examined
- * @src: pointer to source port position
- * @dst: pointer to destination port position
+ * @dst: true selects the dest position, false the source
*
- * Returns current source and destination addresses for a particular
- * parameter RAM slot. Its channel should not be active when this is called.
+ * Returns the position of the current active slot
*/
-void edma_get_position(unsigned slot, dma_addr_t *src, dma_addr_t *dst)
+dma_addr_t edma_get_position(unsigned slot, bool dst)
{
- struct edmacc_param temp;
- unsigned ctlr;
+ u32 offs, ctlr = EDMA_CTLR(slot);
- ctlr = EDMA_CTLR(slot);
slot = EDMA_CHAN_SLOT(slot);
- edma_read_slot(EDMA_CTLR_CHAN(ctlr, slot), &temp);
- if (src != NULL)
- *src = temp.src;
- if (dst != NULL)
- *dst = temp.dst;
+ offs = PARM_OFFSET(slot);
+ offs += dst ? PARM_DST : PARM_SRC;
+
+ return edma_read(ctlr, offs);
}
-EXPORT_SYMBOL(edma_get_position);
/**
* edma_set_src_index - configure DMA source address indexing
Index: linux-2.6/include/linux/platform_data/edma.h
===================================================================
--- linux-2.6.orig/include/linux/platform_data/edma.h
+++ linux-2.6/include/linux/platform_data/edma.h
@@ -130,7 +130,7 @@ void edma_set_src(unsigned slot, dma_add
enum address_mode mode, enum fifo_width);
void edma_set_dest(unsigned slot, dma_addr_t dest_port,
enum address_mode mode, enum fifo_width);
-void edma_get_position(unsigned slot, dma_addr_t *src, dma_addr_t *dst);
+dma_addr_t edma_get_position(unsigned slot, bool dst);
void edma_set_src_index(unsigned slot, s16 src_bidx, s16 src_cidx);
void edma_set_dest_index(unsigned slot, s16 dest_bidx, s16 dest_cidx);
void edma_set_transfer_params(unsigned slot, u16 acnt, u16 bcnt, u16 ccnt,
--
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