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dmaengine: at_hdmac: add slave config operation
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This patch introduces DMA_SLAVE_CONFIG to at_hdmac Atmel DMA driver.

It is needed to fix a regression in the use of atmel-mci.c driver on Atmel
AT91 platforms brouth by e2b35f3:
"dmaengine/dw_dmac: Fix dw_dmac user drivers to adapt to slave_config changes"

We remove some parts of the private structure "at_dma_slave" and use the
information provided by "struct dma_slave_config": source/destination
peripheral registers and access width.

AT_DMA_SLAVE_WIDTH_* values used previously are not needed anymore as we
now use the standard ones. Although some conversion functions are needed to
match register expected values.

Some AT91 sub-architecture specific files are slightly touched by this patch
but it cannot be split because it can break compilation.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
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Nicolas Ferre authored and Vinod Koul committed Mar 21, 2012
1 parent 185ecb5 commit beeaa10
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Showing 4 changed files with 75 additions and 29 deletions.
1 change: 0 additions & 1 deletion arch/arm/mach-at91/at91sam9g45_devices.c
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Original file line number Diff line number Diff line change
Expand Up @@ -431,7 +431,6 @@ void __init at91_add_device_mci(short mmc_id, struct mci_platform_data *data)

/* DMA slave channel configuration */
atslave->dma_dev = &at_hdmac_device.dev;
atslave->reg_width = AT_DMA_SLAVE_WIDTH_32BIT;
atslave->cfg = ATC_FIFOCFG_HALFFIFO
| ATC_SRC_H2SEL_HW | ATC_DST_H2SEL_HW;
atslave->ctrla = ATC_SCSIZE_16 | ATC_DCSIZE_16;
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15 changes: 0 additions & 15 deletions arch/arm/mach-at91/include/mach/at_hdmac.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,18 +23,6 @@ struct at_dma_platform_data {
dma_cap_mask_t cap_mask;
};

/**
* enum at_dma_slave_width - DMA slave register access width.
* @AT_DMA_SLAVE_WIDTH_8BIT: Do 8-bit slave register accesses
* @AT_DMA_SLAVE_WIDTH_16BIT: Do 16-bit slave register accesses
* @AT_DMA_SLAVE_WIDTH_32BIT: Do 32-bit slave register accesses
*/
enum at_dma_slave_width {
AT_DMA_SLAVE_WIDTH_8BIT = 0,
AT_DMA_SLAVE_WIDTH_16BIT,
AT_DMA_SLAVE_WIDTH_32BIT,
};

/**
* struct at_dma_slave - Controller-specific information about a slave
* @dma_dev: required DMA master device
Expand All @@ -48,9 +36,6 @@ enum at_dma_slave_width {
*/
struct at_dma_slave {
struct device *dma_dev;
dma_addr_t tx_reg;
dma_addr_t rx_reg;
enum at_dma_slave_width reg_width;
u32 cfg;
u32 ctrla;
};
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56 changes: 43 additions & 13 deletions drivers/dma/at_hdmac.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -648,6 +648,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
struct at_dma_slave *atslave = chan->private;
struct dma_slave_config *sconfig = &atchan->dma_sconfig;
struct at_desc *first = NULL;
struct at_desc *prev = NULL;
u32 ctrla;
Expand All @@ -669,19 +670,18 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
return NULL;
}

reg_width = atslave->reg_width;

ctrla = ATC_DEFAULT_CTRLA | atslave->ctrla;
ctrlb = ATC_IEN;

switch (direction) {
case DMA_MEM_TO_DEV:
reg_width = convert_buswidth(sconfig->dst_addr_width);
ctrla |= ATC_DST_WIDTH(reg_width);
ctrlb |= ATC_DST_ADDR_MODE_FIXED
| ATC_SRC_ADDR_MODE_INCR
| ATC_FC_MEM2PER
| ATC_SIF(AT_DMA_MEM_IF) | ATC_DIF(AT_DMA_PER_IF);
reg = atslave->tx_reg;
reg = sconfig->dst_addr;
for_each_sg(sgl, sg, sg_len, i) {
struct at_desc *desc;
u32 len;
Expand Down Expand Up @@ -709,13 +709,14 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
}
break;
case DMA_DEV_TO_MEM:
reg_width = convert_buswidth(sconfig->src_addr_width);
ctrla |= ATC_SRC_WIDTH(reg_width);
ctrlb |= ATC_DST_ADDR_MODE_INCR
| ATC_SRC_ADDR_MODE_FIXED
| ATC_FC_PER2MEM
| ATC_SIF(AT_DMA_PER_IF) | ATC_DIF(AT_DMA_MEM_IF);

reg = atslave->rx_reg;
reg = sconfig->src_addr;
for_each_sg(sgl, sg, sg_len, i) {
struct at_desc *desc;
u32 len;
Expand Down Expand Up @@ -791,12 +792,15 @@ atc_dma_cyclic_check_values(unsigned int reg_width, dma_addr_t buf_addr,
* atc_dma_cyclic_fill_desc - Fill one period decriptor
*/
static int
atc_dma_cyclic_fill_desc(struct at_dma_slave *atslave, struct at_desc *desc,
atc_dma_cyclic_fill_desc(struct dma_chan *chan, struct at_desc *desc,
unsigned int period_index, dma_addr_t buf_addr,
size_t period_len, enum dma_transfer_direction direction)
unsigned int reg_width, size_t period_len,
enum dma_transfer_direction direction)
{
u32 ctrla;
unsigned int reg_width = atslave->reg_width;
struct at_dma_chan *atchan = to_at_dma_chan(chan);
struct at_dma_slave *atslave = chan->private;
struct dma_slave_config *sconfig = &atchan->dma_sconfig;
u32 ctrla;

/* prepare common CRTLA value */
ctrla = ATC_DEFAULT_CTRLA | atslave->ctrla
Expand All @@ -807,7 +811,7 @@ atc_dma_cyclic_fill_desc(struct at_dma_slave *atslave, struct at_desc *desc,
switch (direction) {
case DMA_MEM_TO_DEV:
desc->lli.saddr = buf_addr + (period_len * period_index);
desc->lli.daddr = atslave->tx_reg;
desc->lli.daddr = sconfig->dst_addr;
desc->lli.ctrla = ctrla;
desc->lli.ctrlb = ATC_DST_ADDR_MODE_FIXED
| ATC_SRC_ADDR_MODE_INCR
Expand All @@ -817,7 +821,7 @@ atc_dma_cyclic_fill_desc(struct at_dma_slave *atslave, struct at_desc *desc,
break;

case DMA_DEV_TO_MEM:
desc->lli.saddr = atslave->rx_reg;
desc->lli.saddr = sconfig->src_addr;
desc->lli.daddr = buf_addr + (period_len * period_index);
desc->lli.ctrla = ctrla;
desc->lli.ctrlb = ATC_DST_ADDR_MODE_INCR
Expand Down Expand Up @@ -850,9 +854,11 @@ atc_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
struct at_dma_slave *atslave = chan->private;
struct dma_slave_config *sconfig = &atchan->dma_sconfig;
struct at_desc *first = NULL;
struct at_desc *prev = NULL;
unsigned long was_cyclic;
unsigned int reg_width;
unsigned int periods = buf_len / period_len;
unsigned int i;

Expand All @@ -872,8 +878,13 @@ atc_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
return NULL;
}

if (sconfig->direction == DMA_MEM_TO_DEV)
reg_width = convert_buswidth(sconfig->dst_addr_width);
else
reg_width = convert_buswidth(sconfig->src_addr_width);

/* Check for too big/unaligned periods and unaligned DMA buffer */
if (atc_dma_cyclic_check_values(atslave->reg_width, buf_addr,
if (atc_dma_cyclic_check_values(reg_width, buf_addr,
period_len, direction))
goto err_out;

Expand All @@ -885,8 +896,8 @@ atc_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
if (!desc)
goto err_desc_get;

if (atc_dma_cyclic_fill_desc(atslave, desc, i, buf_addr,
period_len, direction))
if (atc_dma_cyclic_fill_desc(chan, desc, i, buf_addr,
reg_width, period_len, direction))
goto err_desc_get;

atc_desc_chain(&first, &prev, desc);
Expand All @@ -909,6 +920,23 @@ atc_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
return NULL;
}

static int set_runtime_config(struct dma_chan *chan,
struct dma_slave_config *sconfig)
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);

/* Check if it is chan is configured for slave transfers */
if (!chan->private)
return -EINVAL;

memcpy(&atchan->dma_sconfig, sconfig, sizeof(*sconfig));

convert_burst(&atchan->dma_sconfig.src_maxburst);
convert_burst(&atchan->dma_sconfig.dst_maxburst);

return 0;
}


static int atc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
unsigned long arg)
Expand Down Expand Up @@ -969,6 +997,8 @@ static int atc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
clear_bit(ATC_IS_CYCLIC, &atchan->status);

spin_unlock_irqrestore(&atchan->lock, flags);
} else if (cmd == DMA_SLAVE_CONFIG) {
return set_runtime_config(chan, (struct dma_slave_config *)arg);
} else {
return -ENXIO;
}
Expand Down
32 changes: 32 additions & 0 deletions drivers/dma/at_hdmac_regs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -207,6 +207,7 @@ enum atc_status {
* @save_cfg: configuration register that is saved on suspend/resume cycle
* @save_dscr: for cyclic operations, preserve next descriptor address in
* the cyclic list on suspend/resume cycle
* @dma_sconfig: configuration for slave transfers, passed via DMA_SLAVE_CONFIG
* @lock: serializes enqueue/dequeue operations to descriptors lists
* @active_list: list of descriptors dmaengine is being running on
* @queue: list of descriptors ready to be submitted to engine
Expand All @@ -222,6 +223,7 @@ struct at_dma_chan {
struct tasklet_struct tasklet;
u32 save_cfg;
u32 save_dscr;
struct dma_slave_config dma_sconfig;

spinlock_t lock;

Expand All @@ -243,6 +245,36 @@ static inline struct at_dma_chan *to_at_dma_chan(struct dma_chan *dchan)
return container_of(dchan, struct at_dma_chan, chan_common);
}

/*
* Fix sconfig's burst size according to at_hdmac. We need to convert them as:
* 1 -> 0, 4 -> 1, 8 -> 2, 16 -> 3, 32 -> 4, 64 -> 5, 128 -> 6, 256 -> 7.
*
* This can be done by finding most significant bit set.
*/
static inline void convert_burst(u32 *maxburst)
{
if (*maxburst > 1)
*maxburst = fls(*maxburst) - 2;
else
*maxburst = 0;
}

/*
* Fix sconfig's bus width according to at_hdmac.
* 1 byte -> 0, 2 bytes -> 1, 4 bytes -> 2.
*/
static inline u8 convert_buswidth(enum dma_slave_buswidth addr_width)
{
switch (addr_width) {
case DMA_SLAVE_BUSWIDTH_2_BYTES:
return 1;
case DMA_SLAVE_BUSWIDTH_4_BYTES:
return 2;
default:
/* For 1 byte width or fallback */
return 0;
}
}

/*-- Controller ------------------------------------------------------*/

Expand Down

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