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dmaengine: edma: Make reading the position of active channels work 

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@linutronix.de>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Joel Fernandes <joelf@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Thomas Gleixner 2014-04-28 10:49:43 +00:00 committed by Vinod Koul
parent c2da2340e5
commit cdae05a0f0
2 changed files with 10 additions and 16 deletions
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24
arch/arm/common/edma.c
View File

@ -994,29 +994,23 @@ void edma_set_dest(unsigned slot, dma_addr_t dest_port,
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

2
include/linux/platform_data/edma.h
View File

@ -130,7 +130,7 @@ void edma_set_src(unsigned slot, dma_addr_t src_port,
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,