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rapidio/tsi721_dma: rework scatter-gather list handling

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Rework Tsi721 RapidIO DMA engine support to allow handling data
scatter/gather lists longer than number of hardware buffer descriptors in
the DMA channel's descriptor list.

The current implementation of Tsi721 DMA transfers requires that number of
entries in a scatter/gather list provided by a caller of
dmaengine_prep_rio_sg() should not exceed number of allocated hardware
buffer descriptors.

This patch removes the limitation by processing long scatter/gather lists
by sections that can be transferred using hardware descriptor ring of
configured size.  It also introduces a module parameter
"dma_desc_per_channel" to allow run-time configuration of Tsi721 hardware
buffer descriptor rings.

Signed-off-by: Alexandre Bounine <[email protected]>
Cc: Matt Porter <[email protected]>
Cc: Andre van Herk <[email protected]>
Cc: Stef van Os <[email protected]>
Cc: Vinod Koul <[email protected]>
Cc: Dan Williams <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Alexandre Bounine 2014-08-08 14:22:12 -07:00 • committed by Linus Torvalds
commit 50835e977b
3 changed files with 394 additions and 355 deletions
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12
drivers/rapidio/devices/tsi721.h
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@ -644,27 +644,26 @@ enum tsi721_smsg_int_flag {
#ifdef CONFIG_RAPIDIO_DMA_ENGINE
#define TSI721_BDMA_BD_RING_SZ 128
#define TSI721_BDMA_MAX_BCOUNT (TSI721_DMAD_BCOUNT1 + 1)
struct tsi721_tx_desc {
struct dma_async_tx_descriptor txd;
struct tsi721_dma_desc *hw_desc;
u16 destid;
/* low 64-bits of 66-bit RIO address */
u64 rio_addr;
/* upper 2-bits of 66-bit RIO address */
u8 rio_addr_u;
u32 bcount;
bool interrupt;
enum dma_rtype rtype;
struct list_head desc_node;
struct list_head tx_list;
struct scatterlist *sg;
unsigned int sg_len;
enum dma_status status;
};
struct tsi721_bdma_chan {
int id;
void __iomem *regs;
int bd_num; /* number of buffer descriptors */
int bd_num; /* number of HW buffer descriptors */
void *bd_base; /* start of DMA descriptors */
dma_addr_t bd_phys;
void *sts_base; /* start of DMA BD status FIFO */
@ -680,7 +679,6 @@ struct tsi721_bdma_chan {
struct list_head active_list;
struct list_head queue;
struct list_head free_list;
dma_cookie_t completed_cookie;
struct tasklet_struct tasklet;
bool active;
};

722
drivers/rapidio/devices/tsi721_dma.c
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