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dmaengine: dw_dmac: simplify master selection
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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@lists.infradead.org
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
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Arnd Bergmann authored and Vinod Koul committed Apr 15, 2013
1 parent bd2e6b6 commit f776076
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Showing 2 changed files with 33 additions and 48 deletions.
76 changes: 29 additions & 47 deletions drivers/dma/dw_dmac.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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 : \
Expand All @@ -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)); \
})

/*
Expand All @@ -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)
Expand Down Expand Up @@ -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.
Expand All @@ -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);
Expand Down Expand Up @@ -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;
Expand All @@ -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));
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -919,7 +901,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
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;
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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) {
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -1784,6 +1765,7 @@ 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) {
Expand Down
5 changes: 4 additions & 1 deletion drivers/dma/dw_dmac_regs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down

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