[PATCH 4/4] dmaengine: dw: Simplify max-burst calculation procedure
From: Serge Semin
Date: Tue Apr 16 2024 - 12:30:30 EST
In order to have a more coherent DW AHB DMA slave configuration method
let's simplify the source and destination channel max-burst calculation
procedure:
1. Create the max-burst verification method as it has been just done for
the memory and peripheral address widths. Thus the DWC DMA slave config
method will turn to a set of the verification methods execution.
2. Since both the generic DW AHB DMA and Intel DMA32 engines support the
power-of-2 bursts only, then the specified by the client driver max-burst
values can be converted to being power-of-2 right in the max-burst
verification method.
3. Since max-burst encoded value is required on the CTL_LO fields
calculation stage, the encode_maxburst() callback can be easily dropped
from the dw_dma structure meanwhile the encoding procedure will be
executed right in the CTL_LO register value calculation.
Thus the update will provide the next positive effects: the internal
DMA-slave config structure will contain only the real DMA-transfer config
value, which will be encoded to the DMA-controller register fields only
when it's required on the buffer mapping; the redundant encode_maxburst()
callback will be dropped simplifying the internal HW-abstraction API;
DWC-config method will look more readable executing the verification
functions one-by-one.
Signed-off-by: Serge Semin <fancer.lancer@xxxxxxxxx>
---
drivers/dma/dw/core.c | 26 +++++++++++++++++---------
drivers/dma/dw/dw.c | 23 +++++++++++------------
drivers/dma/dw/idma32.c | 15 +++++++--------
drivers/dma/dw/regs.h | 1 -
4 files changed, 35 insertions(+), 30 deletions(-)
diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index 61e026310dd8..8b4ecd137ae2 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -779,6 +779,21 @@ bool dw_dma_filter(struct dma_chan *chan, void *param)
}
EXPORT_SYMBOL_GPL(dw_dma_filter);
+static void dwc_verify_maxburst(struct dma_chan *chan)
+{
+ struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
+
+ dwc->dma_sconfig.src_maxburst =
+ clamp(dwc->dma_sconfig.src_maxburst, 1U, dwc->max_burst);
+ dwc->dma_sconfig.dst_maxburst =
+ clamp(dwc->dma_sconfig.dst_maxburst, 1U, dwc->max_burst);
+
+ dwc->dma_sconfig.src_maxburst =
+ rounddown_pow_of_two(dwc->dma_sconfig.src_maxburst);
+ dwc->dma_sconfig.dst_maxburst =
+ rounddown_pow_of_two(dwc->dma_sconfig.dst_maxburst);
+}
+
static int dwc_verify_p_buswidth(struct dma_chan *chan)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
@@ -828,7 +843,7 @@ static int dwc_verify_m_buswidth(struct dma_chan *chan)
dwc->dma_sconfig.src_addr_width = mem_width;
} else if (dwc->dma_sconfig.direction == DMA_DEV_TO_MEM) {
reg_width = dwc->dma_sconfig.src_addr_width;
- reg_burst = rounddown_pow_of_two(dwc->dma_sconfig.src_maxburst);
+ reg_burst = dwc->dma_sconfig.src_maxburst;
dwc->dma_sconfig.dst_addr_width = min(mem_width, reg_width * reg_burst);
}
@@ -839,15 +854,11 @@ static int dwc_verify_m_buswidth(struct dma_chan *chan)
static int dwc_config(struct dma_chan *chan, struct dma_slave_config *sconfig)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
- struct dw_dma *dw = to_dw_dma(chan->device);
int err;
memcpy(&dwc->dma_sconfig, sconfig, sizeof(*sconfig));
- dwc->dma_sconfig.src_maxburst =
- clamp(dwc->dma_sconfig.src_maxburst, 1U, dwc->max_burst);
- dwc->dma_sconfig.dst_maxburst =
- clamp(dwc->dma_sconfig.dst_maxburst, 1U, dwc->max_burst);
+ dwc_verify_maxburst(chan);
err = dwc_verify_p_buswidth(chan);
if (err)
@@ -857,9 +868,6 @@ static int dwc_config(struct dma_chan *chan, struct dma_slave_config *sconfig)
if (err)
return err;
- dw->encode_maxburst(dwc, &dwc->dma_sconfig.src_maxburst);
- dw->encode_maxburst(dwc, &dwc->dma_sconfig.dst_maxburst);
-
return 0;
}
diff --git a/drivers/dma/dw/dw.c b/drivers/dma/dw/dw.c
index c65438d1f1ff..c52333646edd 100644
--- a/drivers/dma/dw/dw.c
+++ b/drivers/dma/dw/dw.c
@@ -64,6 +64,15 @@ static size_t dw_dma_block2bytes(struct dw_dma_chan *dwc, u32 block, u32 width)
return DWC_CTLH_BLOCK_TS(block) << width;
}
+static inline u8 dw_dma_encode_maxburst(u32 maxburst)
+{
+ /*
+ * Fix burst size according to dw_dmac. We need to convert them as:
+ * 1 -> 0, 4 -> 1, 8 -> 2, 16 -> 3.
+ */
+ return maxburst > 1 ? fls(maxburst) - 2 : 0;
+}
+
static u32 dw_dma_prepare_ctllo(struct dw_dma_chan *dwc)
{
struct dma_slave_config *sconfig = &dwc->dma_sconfig;
@@ -73,10 +82,10 @@ static u32 dw_dma_prepare_ctllo(struct dw_dma_chan *dwc)
sms = dwc->dws.m_master;
smsize = 0;
dms = dwc->dws.p_master;
- dmsize = sconfig->dst_maxburst;
+ dmsize = dw_dma_encode_maxburst(sconfig->dst_maxburst);
} else if (dwc->direction == DMA_DEV_TO_MEM) {
sms = dwc->dws.p_master;
- smsize = sconfig->src_maxburst;
+ smsize = dw_dma_encode_maxburst(sconfig->src_maxburst);
dms = dwc->dws.m_master;
dmsize = 0;
} else /* DMA_MEM_TO_MEM */ {
@@ -91,15 +100,6 @@ static u32 dw_dma_prepare_ctllo(struct dw_dma_chan *dwc)
DWC_CTLL_DMS(dms) | DWC_CTLL_SMS(sms);
}
-static void dw_dma_encode_maxburst(struct dw_dma_chan *dwc, u32 *maxburst)
-{
- /*
- * Fix burst size according to dw_dmac. We need to convert them as:
- * 1 -> 0, 4 -> 1, 8 -> 2, 16 -> 3.
- */
- *maxburst = *maxburst > 1 ? fls(*maxburst) - 2 : 0;
-}
-
static void dw_dma_set_device_name(struct dw_dma *dw, int id)
{
snprintf(dw->name, sizeof(dw->name), "dw:dmac%d", id);
@@ -128,7 +128,6 @@ int dw_dma_probe(struct dw_dma_chip *chip)
dw->suspend_chan = dw_dma_suspend_chan;
dw->resume_chan = dw_dma_resume_chan;
dw->prepare_ctllo = dw_dma_prepare_ctllo;
- dw->encode_maxburst = dw_dma_encode_maxburst;
dw->bytes2block = dw_dma_bytes2block;
dw->block2bytes = dw_dma_block2bytes;
diff --git a/drivers/dma/dw/idma32.c b/drivers/dma/dw/idma32.c
index 3a1b12517655..428aba9fc2db 100644
--- a/drivers/dma/dw/idma32.c
+++ b/drivers/dma/dw/idma32.c
@@ -199,6 +199,11 @@ static size_t idma32_block2bytes(struct dw_dma_chan *dwc, u32 block, u32 width)
return IDMA32C_CTLH_BLOCK_TS(block);
}
+static inline u32 idma32_encode_maxburst(u32 maxburst)
+{
+ return maxburst > 1 ? fls(maxburst) - 1 : 0;
+}
+
static u32 idma32_prepare_ctllo(struct dw_dma_chan *dwc)
{
struct dma_slave_config *sconfig = &dwc->dma_sconfig;
@@ -206,9 +211,9 @@ static u32 idma32_prepare_ctllo(struct dw_dma_chan *dwc)
if (dwc->direction == DMA_MEM_TO_DEV) {
smsize = 0;
- dmsize = sconfig->dst_maxburst;
+ dmsize = idma32_encode_maxburst(sconfig->dst_maxburst);
} else if (dwc->direction == DMA_DEV_TO_MEM) {
- smsize = sconfig->src_maxburst;
+ smsize = idma32_encode_maxburst(sconfig->src_maxburst);
dmsize = 0;
} else /* DMA_MEM_TO_MEM */ {
smsize = 0;
@@ -219,11 +224,6 @@ static u32 idma32_prepare_ctllo(struct dw_dma_chan *dwc)
DWC_CTLL_DST_MSIZE(dmsize) | DWC_CTLL_SRC_MSIZE(smsize);
}
-static void idma32_encode_maxburst(struct dw_dma_chan *dwc, u32 *maxburst)
-{
- *maxburst = *maxburst > 1 ? fls(*maxburst) - 1 : 0;
-}
-
static void idma32_set_device_name(struct dw_dma *dw, int id)
{
snprintf(dw->name, sizeof(dw->name), "idma32:dmac%d", id);
@@ -280,7 +280,6 @@ int idma32_dma_probe(struct dw_dma_chip *chip)
dw->suspend_chan = idma32_suspend_chan;
dw->resume_chan = idma32_resume_chan;
dw->prepare_ctllo = idma32_prepare_ctllo;
- dw->encode_maxburst = idma32_encode_maxburst;
dw->bytes2block = idma32_bytes2block;
dw->block2bytes = idma32_block2bytes;
diff --git a/drivers/dma/dw/regs.h b/drivers/dma/dw/regs.h
index 76654bd13c1a..5969d9cc8d7a 100644
--- a/drivers/dma/dw/regs.h
+++ b/drivers/dma/dw/regs.h
@@ -327,7 +327,6 @@ struct dw_dma {
void (*suspend_chan)(struct dw_dma_chan *dwc, bool drain);
void (*resume_chan)(struct dw_dma_chan *dwc, bool drain);
u32 (*prepare_ctllo)(struct dw_dma_chan *dwc);
- void (*encode_maxburst)(struct dw_dma_chan *dwc, u32 *maxburst);
u32 (*bytes2block)(struct dw_dma_chan *dwc, size_t bytes,
unsigned int width, size_t *len);
size_t (*block2bytes)(struct dw_dma_chan *dwc, u32 block, u32 width);
--
2.43.0