@@ -5,6 +5,7 @@
*
* Copyright (C) M'boumba Cedric Madianga 2015
* Author: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
+ * Pierre-Yves Mordret <pierre-yves.mordret@st.com>
*
* License terms: GNU General Public License (GPL), version 2
*/
@@ -114,6 +115,8 @@
#define STM32_DMA_MAX_CHANNELS 0x08
#define STM32_DMA_MAX_REQUEST_ID 0x08
#define STM32_DMA_MAX_DATA_PARAM 0x03
+#define STM32_DMA_FIFO_SIZE 16 /* FIFO is 16 bytes */
+#define STM32_DMA_MIN_BURST 4
#define STM32_DMA_MAX_BURST 16
/* DMA Features */
@@ -183,6 +186,8 @@ struct stm32_dma_chan {
struct dma_slave_config dma_sconfig;
struct stm32_dma_chan_reg chan_reg;
u32 threshold;
+ u32 mem_burst;
+ u32 mem_width;
};
struct stm32_dma_device {
@@ -247,6 +252,85 @@ static int stm32_dma_get_width(struct stm32_dma_chan *chan,
}
}
+static enum dma_slave_buswidth stm32_dma_get_max_width(u32 buf_len,
+ u32 threshold)
+{
+ enum dma_slave_buswidth max_width;
+
+ if (threshold == STM32_DMA_FIFO_THRESHOLD_FULL)
+ max_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ else
+ max_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
+
+ while ((buf_len < max_width || buf_len % max_width) &&
+ max_width > DMA_SLAVE_BUSWIDTH_1_BYTE)
+ max_width = max_width >> 1;
+
+ return max_width;
+}
+
+static bool stm32_dma_fifo_threshold_is_allowed(u32 burst, u32 threshold,
+ enum dma_slave_buswidth width)
+{
+ u32 remaining;
+
+ if (width != DMA_SLAVE_BUSWIDTH_UNDEFINED) {
+ if (burst != 0) {
+ /*
+ * If number of beats fit in several whole bursts
+ * this configuration is allowed.
+ */
+ remaining = ((STM32_DMA_FIFO_SIZE / width) *
+ (threshold + 1) / 4) % burst;
+
+ if (remaining == 0)
+ return true;
+ } else {
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static bool stm32_dma_is_burst_possible(u32 buf_len, u32 threshold)
+{
+ switch (threshold) {
+ case STM32_DMA_FIFO_THRESHOLD_FULL:
+ if (buf_len >= STM32_DMA_MAX_BURST)
+ return true;
+ else
+ return false;
+ case STM32_DMA_FIFO_THRESHOLD_HALFFULL:
+ if (buf_len >= STM32_DMA_MAX_BURST / 2)
+ return true;
+ else
+ return false;
+ default:
+ return false;
+ }
+}
+
+static u32 stm32_dma_get_best_burst(u32 buf_len, u32 max_burst, u32 threshold,
+ enum dma_slave_buswidth width)
+{
+ u32 best_burst = max_burst;
+
+ if (best_burst == 1 || !stm32_dma_is_burst_possible(buf_len, threshold))
+ return 0;
+
+ while ((buf_len < best_burst * width && best_burst > 1) ||
+ !stm32_dma_fifo_threshold_is_allowed(best_burst, threshold,
+ width)) {
+ if (best_burst > STM32_DMA_MIN_BURST)
+ best_burst = best_burst >> 1;
+ else
+ best_burst = 0;
+ }
+
+ return best_burst;
+}
+
static int stm32_dma_get_burst(struct stm32_dma_chan *chan, u32 maxburst)
{
switch (maxburst) {
@@ -266,12 +350,12 @@ static int stm32_dma_get_burst(struct stm32_dma_chan *chan, u32 maxburst)
}
static void stm32_dma_set_fifo_config(struct stm32_dma_chan *chan,
- u32 src_maxburst, u32 dst_maxburst)
+ u32 src_burst, u32 dst_burst)
{
chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_MASK;
chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_DMEIE;
- if ((!src_maxburst) && (!dst_maxburst)) {
+ if (!src_burst && !dst_burst) {
/* Using direct mode */
chan->chan_reg.dma_scr |= STM32_DMA_SCR_DMEIE;
} else {
@@ -584,37 +668,52 @@ static void stm32_dma_issue_pending(struct dma_chan *c)
static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan,
enum dma_transfer_direction direction,
- enum dma_slave_buswidth *buswidth)
+ enum dma_slave_buswidth *buswidth,
+ u32 buf_len)
{
enum dma_slave_buswidth src_addr_width, dst_addr_width;
int src_bus_width, dst_bus_width;
int src_burst_size, dst_burst_size;
- u32 src_maxburst, dst_maxburst;
- u32 dma_scr = 0;
+ u32 src_maxburst, dst_maxburst, src_best_burst, dst_best_burst;
+ u32 dma_scr, threshold;
src_addr_width = chan->dma_sconfig.src_addr_width;
dst_addr_width = chan->dma_sconfig.dst_addr_width;
src_maxburst = chan->dma_sconfig.src_maxburst;
dst_maxburst = chan->dma_sconfig.dst_maxburst;
+ threshold = chan->threshold;
switch (direction) {
case DMA_MEM_TO_DEV:
+ /* Set device data size */
dst_bus_width = stm32_dma_get_width(chan, dst_addr_width);
if (dst_bus_width < 0)
return dst_bus_width;
- dst_burst_size = stm32_dma_get_burst(chan, dst_maxburst);
+ /* Set device burst size */
+ dst_best_burst = stm32_dma_get_best_burst(buf_len,
+ dst_maxburst,
+ threshold,
+ dst_addr_width);
+
+ dst_burst_size = stm32_dma_get_burst(chan, dst_best_burst);
if (dst_burst_size < 0)
return dst_burst_size;
- if (!src_addr_width)
- src_addr_width = dst_addr_width;
-
+ /* Set memory data size */
+ src_addr_width = stm32_dma_get_max_width(buf_len, threshold);
+ chan->mem_width = src_addr_width;
src_bus_width = stm32_dma_get_width(chan, src_addr_width);
if (src_bus_width < 0)
return src_bus_width;
- src_burst_size = stm32_dma_get_burst(chan, src_maxburst);
+ /* Set memory burst size */
+ src_maxburst = STM32_DMA_MAX_BURST;
+ src_best_burst = stm32_dma_get_best_burst(buf_len,
+ src_maxburst,
+ threshold,
+ src_addr_width);
+ src_burst_size = stm32_dma_get_burst(chan, src_best_burst);
if (src_burst_size < 0)
return src_burst_size;
@@ -624,27 +723,46 @@ static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan,
STM32_DMA_SCR_PBURST(dst_burst_size) |
STM32_DMA_SCR_MBURST(src_burst_size);
+ /* Set FIFO threshold */
+ chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_FTH_MASK;
+ chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_FTH(threshold);
+
+ /* Set peripheral address */
chan->chan_reg.dma_spar = chan->dma_sconfig.dst_addr;
*buswidth = dst_addr_width;
break;
case DMA_DEV_TO_MEM:
+ /* Set device data size */
src_bus_width = stm32_dma_get_width(chan, src_addr_width);
if (src_bus_width < 0)
return src_bus_width;
- src_burst_size = stm32_dma_get_burst(chan, src_maxburst);
+ /* Set device burst size */
+ src_best_burst = stm32_dma_get_best_burst(buf_len,
+ src_maxburst,
+ threshold,
+ src_addr_width);
+ chan->mem_burst = src_best_burst;
+ src_burst_size = stm32_dma_get_burst(chan, src_best_burst);
if (src_burst_size < 0)
return src_burst_size;
- if (!dst_addr_width)
- dst_addr_width = src_addr_width;
-
+ /* Set memory data size */
+ dst_addr_width = stm32_dma_get_max_width(buf_len, threshold);
+ chan->mem_width = dst_addr_width;
dst_bus_width = stm32_dma_get_width(chan, dst_addr_width);
if (dst_bus_width < 0)
return dst_bus_width;
- dst_burst_size = stm32_dma_get_burst(chan, dst_maxburst);
+ /* Set memory burst size */
+ dst_maxburst = STM32_DMA_MAX_BURST;
+ dst_best_burst = stm32_dma_get_best_burst(buf_len,
+ dst_maxburst,
+ threshold,
+ dst_addr_width);
+ chan->mem_burst = dst_best_burst;
+ dst_burst_size = stm32_dma_get_burst(chan, dst_best_burst);
if (dst_burst_size < 0)
return dst_burst_size;
@@ -654,6 +772,11 @@ static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan,
STM32_DMA_SCR_PBURST(src_burst_size) |
STM32_DMA_SCR_MBURST(dst_burst_size);
+ /* Set FIFO threshold */
+ chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_FTH_MASK;
+ chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_FTH(threshold);
+
+ /* Set peripheral address */
chan->chan_reg.dma_spar = chan->dma_sconfig.src_addr;
*buswidth = chan->dma_sconfig.src_addr_width;
break;
@@ -663,8 +786,9 @@ static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan,
return -EINVAL;
}
- stm32_dma_set_fifo_config(chan, src_maxburst, dst_maxburst);
+ stm32_dma_set_fifo_config(chan, src_best_burst, dst_best_burst);
+ /* Set DMA control register */
chan->chan_reg.dma_scr &= ~(STM32_DMA_SCR_DIR_MASK |
STM32_DMA_SCR_PSIZE_MASK | STM32_DMA_SCR_MSIZE_MASK |
STM32_DMA_SCR_PBURST_MASK | STM32_DMA_SCR_MBURST_MASK);
@@ -704,10 +828,6 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_slave_sg(
if (!desc)
return NULL;
- ret = stm32_dma_set_xfer_param(chan, direction, &buswidth);
- if (ret < 0)
- goto err;
-
/* Set peripheral flow controller */
if (chan->dma_sconfig.device_fc)
chan->chan_reg.dma_scr |= STM32_DMA_SCR_PFCTRL;
@@ -715,6 +835,11 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_slave_sg(
chan->chan_reg.dma_scr &= ~STM32_DMA_SCR_PFCTRL;
for_each_sg(sgl, sg, sg_len, i) {
+ ret = stm32_dma_set_xfer_param(chan, direction, &buswidth,
+ sg_dma_len(sg));
+ if (ret < 0)
+ goto err;
+
desc->sg_req[i].len = sg_dma_len(sg);
nb_data_items = desc->sg_req[i].len / buswidth;
@@ -779,7 +904,7 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_dma_cyclic(
return NULL;
}
- ret = stm32_dma_set_xfer_param(chan, direction, &buswidth);
+ ret = stm32_dma_set_xfer_param(chan, direction, &buswidth, period_len);
if (ret < 0)
return NULL;
@@ -828,9 +953,10 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_dma_memcpy(
dma_addr_t src, size_t len, unsigned long flags)
{
struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
- u32 num_sgs;
+ enum dma_slave_buswidth max_width;
struct stm32_dma_desc *desc;
size_t xfer_count, offset;
+ u32 num_sgs, best_burst, dma_burst, threshold;
int i;
num_sgs = DIV_ROUND_UP(len, STM32_DMA_MAX_DATA_ITEMS);
@@ -838,25 +964,34 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_dma_memcpy(
if (!desc)
return NULL;
+ threshold = chan->threshold;
+
for (offset = 0, i = 0; offset < len; offset += xfer_count, i++) {
xfer_count = min_t(size_t, len - offset,
STM32_DMA_MAX_DATA_ITEMS);
- desc->sg_req[i].len = xfer_count;
+ /* Compute best burst size */
+ max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ best_burst = stm32_dma_get_best_burst(len, STM32_DMA_MAX_BURST,
+ threshold, max_width);
+ dma_burst = stm32_dma_get_burst(chan, best_burst);
stm32_dma_clear_reg(&desc->sg_req[i].chan_reg);
desc->sg_req[i].chan_reg.dma_scr =
STM32_DMA_SCR_DIR(STM32_DMA_MEM_TO_MEM) |
+ STM32_DMA_SCR_PBURST(dma_burst) |
+ STM32_DMA_SCR_MBURST(dma_burst) |
STM32_DMA_SCR_MINC |
STM32_DMA_SCR_PINC |
STM32_DMA_SCR_TCIE |
STM32_DMA_SCR_TEIE;
- desc->sg_req[i].chan_reg.dma_sfcr = STM32_DMA_SFCR_DMDIS |
- STM32_DMA_SFCR_FTH(STM32_DMA_FIFO_THRESHOLD_FULL) |
- STM32_DMA_SFCR_FEIE;
+ desc->sg_req[i].chan_reg.dma_sfcr |= STM32_DMA_SFCR_MASK;
+ desc->sg_req[i].chan_reg.dma_sfcr |=
+ STM32_DMA_SFCR_FTH(threshold);
desc->sg_req[i].chan_reg.dma_spar = src + offset;
desc->sg_req[i].chan_reg.dma_sm0ar = dest + offset;
desc->sg_req[i].chan_reg.dma_sndtr = xfer_count;
+ desc->sg_req[i].len = xfer_count;
}
desc->num_sgs = num_sgs;
@@ -881,6 +1016,7 @@ static size_t stm32_dma_desc_residue(struct stm32_dma_chan *chan,
struct stm32_dma_desc *desc,
u32 next_sg)
{
+ u32 modulo, burst_size;
u32 residue = 0;
int i;
@@ -888,8 +1024,10 @@ static size_t stm32_dma_desc_residue(struct stm32_dma_chan *chan,
* In cyclic mode, for the last period, residue = remaining bytes from
* NDTR
*/
- if (chan->desc->cyclic && next_sg == 0)
- return stm32_dma_get_remaining_bytes(chan);
+ if (chan->desc->cyclic && next_sg == 0) {
+ residue = stm32_dma_get_remaining_bytes(chan);
+ goto end;
+ }
/*
* For all other periods in cyclic mode, and in sg mode,
@@ -900,6 +1038,15 @@ static size_t stm32_dma_desc_residue(struct stm32_dma_chan *chan,
residue += desc->sg_req[i].len;
residue += stm32_dma_get_remaining_bytes(chan);
+end:
+ if (!chan->mem_burst)
+ return residue;
+
+ burst_size = chan->mem_burst * chan->mem_width;
+ modulo = residue % burst_size;
+ if (modulo)
+ residue = residue - modulo + burst_size;
+
return residue;
}
@@ -989,7 +1136,6 @@ static void stm32_dma_set_config(struct stm32_dma_chan *chan,
chan->chan_reg.dma_scr |= STM32_DMA_SCR_TEIE | STM32_DMA_SCR_TCIE;
chan->threshold = STM32_DMA_THRESHOLD_FTR_GET(cfg->features);
- chan->chan_reg.dma_sfcr = STM32_DMA_SFCR_FTH(chan->threshold);
}
static struct dma_chan *stm32_dma_of_xlate(struct of_phandle_args *dma_spec,