[PATCH v2 4/4] dmaengine: dw_dmac: simplify master selection

Andy Shevchenko
2013-03-26T14:53:57Z

From: Arnd Bergmann <arnd@arndb.de>

The patch to add the common DMA binding added a dummy dw_dma_slave
structure into the dw_dma_chan structure in order to configure the
masters correctly. It turns out that this can be simplified if we
pick the DMA masters in the dwc_alloc_chan_resources function instead
and save them in the dw_dma_chan structure directly.

This could be simplified further once all users that today use
dw_dma_slave for configuration get converted to device tree based
setup instead.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linux-arm-kernel at lists.infradead.org
---
drivers/dma/dw_dmac.c | 76 ++++++++++++++++++----------------------------
drivers/dma/dw_dmac_regs.h | 5 ++-
2 files changed, 33 insertions(+), 48 deletions(-)

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index c1f017b..5c9fec6 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -49,29 +49,22 @@ static inline unsigned int dwc_get_sms(struct dw_dma_slave *slave)
return slave ? slave->src_master : 1;
}

-#define SRC_MASTER 0
-#define DST_MASTER 1
-
-static inline unsigned int dwc_get_master(struct dma_chan *chan, int master)
+static inline void dwc_set_masters(struct dw_dma_chan *dwc)
{
- struct dw_dma *dw = to_dw_dma(chan->device);
- struct dw_dma_slave *dws = chan->private;
- unsigned int m;
-
- if (master == SRC_MASTER)
- m = dwc_get_sms(dws);
- else
- m = dwc_get_dms(dws);
+ struct dw_dma *dw = to_dw_dma(dwc->chan.device);
+ struct dw_dma_slave *dws = dwc->chan.private;
+ unsigned char mmax = dw->nr_masters - 1;

- return min_t(unsigned int, dw->nr_masters - 1, m);
+ if (dwc->request_line == ~0) {
+ dwc->src_master = min_t(unsigned char, mmax, dwc_get_sms(dws));
+ dwc->dst_master = min_t(unsigned char, mmax, dwc_get_dms(dws));
+ }
}

#define DWC_DEFAULT_CTLLO(_chan) ({ \
struct dw_dma_chan *_dwc = to_dw_dma_chan(_chan); \
struct dma_slave_config *_sconfig = &_dwc->dma_sconfig; \
bool _is_slave = is_slave_direction(_dwc->direction); \
- int _dms = dwc_get_master(_chan, DST_MASTER); \
- int _sms = dwc_get_master(_chan, SRC_MASTER); \
u8 _smsize = _is_slave ? _sconfig->src_maxburst : \
DW_DMA_MSIZE_16; \
u8 _dmsize = _is_slave ? _sconfig->dst_maxburst : \
@@ -81,8 +74,8 @@ static inline unsigned int dwc_get_master(struct dma_chan *chan, int master)
| DWC_CTLL_SRC_MSIZE(_smsize) \
| DWC_CTLL_LLP_D_EN \
| DWC_CTLL_LLP_S_EN \
- | DWC_CTLL_DMS(_dms) \
- | DWC_CTLL_SMS(_sms)); \
+ | DWC_CTLL_DMS(_dwc->dst_master) \
+ | DWC_CTLL_SMS(_dwc->src_master)); \
})

/*
@@ -92,13 +85,6 @@ static inline unsigned int dwc_get_master(struct dma_chan *chan, int master)
*/
#define NR_DESCS_PER_CHANNEL 64

-static inline unsigned int dwc_get_data_width(struct dma_chan *chan, int master)
-{
- struct dw_dma *dw = to_dw_dma(chan->device);
-
- return dw->data_width[dwc_get_master(chan, master)];
-}
-
/*----------------------------------------------------------------------*/

static struct device *chan2dev(struct dma_chan *chan)
@@ -172,13 +158,7 @@ static void dwc_initialize(struct dw_dma_chan *dwc)
if (dwc->initialized == true)
return;

- if (dws && dws->cfg_hi == ~0 && dws->cfg_lo == ~0) {
- /* Autoconfigure based on request line from DT */
- if (dwc->direction == DMA_MEM_TO_DEV)
- cfghi = DWC_CFGH_DST_PER(dwc->request_line);
- else if (dwc->direction == DMA_DEV_TO_MEM)
- cfghi = DWC_CFGH_SRC_PER(dwc->request_line);
- } else if (dws) {
+ if (dws) {
/*
* We need controller-specific data to set up slave
* transfers.
@@ -189,9 +169,9 @@ static void dwc_initialize(struct dw_dma_chan *dwc)
cfglo |= dws->cfg_lo & ~DWC_CFGL_CH_PRIOR_MASK;
} else {
if (dwc->direction == DMA_MEM_TO_DEV)
- cfghi = DWC_CFGH_DST_PER(dwc->dma_sconfig.slave_id);
+ cfghi = DWC_CFGH_DST_PER(dwc->request_line);
else if (dwc->direction == DMA_DEV_TO_MEM)
- cfghi = DWC_CFGH_SRC_PER(dwc->dma_sconfig.slave_id);
+ cfghi = DWC_CFGH_SRC_PER(dwc->request_line);
}

channel_writel(dwc, CFG_LO, cfglo);
@@ -745,6 +725,7 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
size_t len, unsigned long flags)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
+ struct dw_dma *dw = to_dw_dma(chan->device);
struct dw_desc *desc;
struct dw_desc *first;
struct dw_desc *prev;
@@ -767,8 +748,8 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,

dwc->direction = DMA_MEM_TO_MEM;

- data_width = min_t(unsigned int, dwc_get_data_width(chan, SRC_MASTER),
- dwc_get_data_width(chan, DST_MASTER));
+ data_width = min_t(unsigned int, dw->data_width[dwc->src_master],
+ dw->data_width[dwc->dst_master]);

src_width = dst_width = min_t(unsigned int, data_width,
dwc_fast_fls(src | dest | len));
@@ -826,6 +807,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
unsigned long flags, void *context)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
+ struct dw_dma *dw = to_dw_dma(chan->device);
struct dma_slave_config *sconfig = &dwc->dma_sconfig;
struct dw_desc *prev;
struct dw_desc *first;
@@ -859,7 +841,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
ctllo |= sconfig->device_fc ? DWC_CTLL_FC(DW_DMA_FC_P_M2P) :
DWC_CTLL_FC(DW_DMA_FC_D_M2P);

- data_width = dwc_get_data_width(chan, SRC_MASTER);
+ data_width = dw->data_width[dwc->src_master];

for_each_sg(sgl, sg, sg_len, i) {
struct dw_desc *desc;
@@ -919,7 +901,7 @@ slave_sg_todev_fill_desc:
ctllo |= sconfig->device_fc ? DWC_CTLL_FC(DW_DMA_FC_P_P2M) :
DWC_CTLL_FC(DW_DMA_FC_D_P2M);

- data_width = dwc_get_data_width(chan, DST_MASTER);
+ data_width = dw->data_width[dwc->dst_master];

for_each_sg(sgl, sg, sg_len, i) {
struct dw_desc *desc;
@@ -1020,6 +1002,10 @@ set_runtime_config(struct dma_chan *chan, struct dma_slave_config *sconfig)
memcpy(&dwc->dma_sconfig, sconfig, sizeof(*sconfig));
dwc->direction = sconfig->direction;

+ /* Take the request line from slave_id member */
+ if (dwc->request_line == ~0)
+ dwc->request_line = sconfig->slave_id;
+
convert_burst(&dwc->dma_sconfig.src_maxburst);
convert_burst(&dwc->dma_sconfig.dst_maxburst);
convert_slave_id(dwc);
@@ -1170,6 +1156,8 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
* doesn't mean what you think it means), and status writeback.
*/

+ dwc_set_masters(dwc);
+
spin_lock_irqsave(&dwc->lock, flags);
i = dwc->descs_allocated;
while (dwc->descs_allocated < NR_DESCS_PER_CHANNEL) {
@@ -1227,6 +1215,7 @@ static void dwc_free_chan_resources(struct dma_chan *chan)
list_splice_init(&dwc->free_list, &list);
dwc->descs_allocated = 0;
dwc->initialized = false;
+ dwc->request_line = ~0;

/* Disable interrupts */
channel_clear_bit(dw, MASK.XFER, dwc->mask);
@@ -1254,23 +1243,15 @@ struct dw_dma_of_filter_args {
static bool dw_dma_of_filter(struct dma_chan *chan, void *param)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
- struct dw_dma *dw = to_dw_dma(chan->device);
struct dw_dma_of_filter_args *fargs = param;
- struct dw_dma_slave *dws = &dwc->slave;

/* Ensure the device matches our channel */
if (chan->device != &fargs->dw->dma)
return false;

- dws->dma_dev = dw->dma.dev;
- dws->cfg_hi = ~0;
- dws->cfg_lo = ~0;
- dws->src_master = fargs->src;
- dws->dst_master = fargs->dst;
-
dwc->request_line = fargs->req;
-
- chan->private = dws;
+ dwc->src_master = fargs->src;
+ dwc->dst_master = fargs->dst;

return true;
}
@@ -1794,6 +1775,7 @@ static int dw_probe(struct platform_device *pdev)
channel_clear_bit(dw, CH_EN, dwc->mask);

dwc->direction = DMA_TRANS_NONE;
+ dwc->request_line = ~0;

/* Hardware configuration */
if (autocfg) {
diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
index 4d02c36..9b0e12e 100644
--- a/drivers/dma/dw_dmac_regs.h
+++ b/drivers/dma/dw_dmac_regs.h
@@ -212,8 +212,11 @@ struct dw_dma_chan {
/* hardware configuration */
unsigned int block_size;
bool nollp;
+
+ /* custom slave configuration */
unsigned int request_line;
- struct dw_dma_slave slave;
+ unsigned char src_master;
+ unsigned char dst_master;

/* configuration passed via DMA_SLAVE_CONFIG */
struct dma_slave_config dma_sconfig;
--
1.8.2.rc0.22.gb3600c3