Some implementations such as the Nomadik do not place a mux
in front of the DMA single/burst request signals into the
PL08x DMA controller, instead they lock a certain signal to
a certain device. This makes things simpler and the platform
does not need to implement a muxing function.
Implement this scheme and flag that the Nomadik uses this
method.
While we're at it, add a missing kerneldoc entry.
Cc: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
Cc: Joachim Eastwood <manabian@xxxxxxxxx>
Cc: Johannes Stezenbach <js@xxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
ChangeLog v1->v2:
- Also encode the number of outgoing request signals into
the vendor data. This will be used by the next patch to
allocate slave channels for the DT probe.
---
drivers/dma/amba-pl08x.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index 9b42c0588550..2ef80200d110 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -107,19 +107,27 @@ struct pl08x_driver_data;
/**
* struct vendor_data - vendor-specific config parameters for PL08x derivatives
* @channels: the number of channels available in this variant
+ * @signals: the number of request signals available from the hardware
* @dualmaster: whether this version supports dual AHB masters or not.
* @nomadik: whether the channels have Nomadik security extension bits
* that need to be checked for permission before use and some registers are
* missing
* @pl080s: whether this version is a PL080S, which has separate register and
* LLI word for transfer size.
+ * @fixed_signals: if the channel signal allocation on the PL08x is fixed,
+ * i.e. each device burst/single control signals are connected directly
+ * to the DMAC signal lines without any mux.
+ * @max_transfer_size: the maximum single element transfer size for this
+ * PL08x variant.
*/
struct vendor_data {
u8 config_offset;
u8 channels;
+ u8 signals;
bool dualmaster;
bool nomadik;
bool pl080s;
+ bool fixed_signals;
u32 max_transfer_size;
};
@@ -319,6 +327,15 @@ static int pl08x_request_mux(struct pl08x_dma_chan *plchan)
const struct pl08x_platform_data *pd = plchan->host->pd;
int ret;
+ /*
+ * For engines with fixed signal assignment for slave transfers,
+ * this signal is assigned during probe.
+ */
+ if (plchan->host->vd->fixed_signals) {
+ BUG_ON(plchan->signal < 0);
+ return 0;
+ }
+
if (plchan->mux_use++ == 0 && pd->get_xfer_signal) {
ret = pd->get_xfer_signal(plchan->cd);
if (ret < 0) {
@@ -335,6 +352,9 @@ static void pl08x_release_mux(struct pl08x_dma_chan *plchan)
{
const struct pl08x_platform_data *pd = plchan->host->pd;
+ if (plchan->host->vd->fixed_signals)
+ return;
+
if (plchan->signal >= 0) {
WARN_ON(plchan->mux_use == 0);
@@ -1909,6 +1929,18 @@ static int pl08x_dma_init_virtual_channels(struct pl08x_driver_data *pl08x,
if (slave) {
chan->cd = &pl08x->pd->slave_channels[i];
+ /*
+ * Some implementations have muxed signals, whereas some
+ * use a mux in front of the signals and need dynamic
+ * assignment of signals.
+ */
+ if (pl08x->vd->fixed_signals) {
+ chan->signal = i;
+ chan->name = chan->cd->bus_id;
+ dev_dbg(&pl08x->adev->dev,
+ "assign fixed signal %u to channel %s",
+ chan->signal, chan->name);
+ }
pl08x_dma_slave_init(chan);
} else {
chan->cd = &pl08x->pd->memcpy_channel;
@@ -2438,6 +2470,7 @@ out_no_pl08x:
static struct vendor_data vendor_pl080 = {
.config_offset = PL080_CH_CONFIG,
.channels = 8,
+ .signals = 16,
.dualmaster = true,
.max_transfer_size = PL080_CONTROL_TRANSFER_SIZE_MASK,
};
@@ -2445,14 +2478,17 @@ static struct vendor_data vendor_pl080 = {
static struct vendor_data vendor_nomadik = {
.config_offset = PL080_CH_CONFIG,
.channels = 8,
+ .signals = 32,
.dualmaster = true,
.nomadik = true,
+ .fixed_signals = true,
.max_transfer_size = PL080_CONTROL_TRANSFER_SIZE_MASK,
};
static struct vendor_data vendor_pl080s = {
.config_offset = PL080S_CH_CONFIG,
.channels = 8,
+ .signals = 32,
.pl080s = true,
.max_transfer_size = PL080S_CONTROL_TRANSFER_SIZE_MASK,
};
@@ -2460,6 +2496,7 @@ static struct vendor_data vendor_pl080s = {
static struct vendor_data vendor_pl081 = {
.config_offset = PL080_CH_CONFIG,
.channels = 2,
+ .signals = 16,
.dualmaster = false,
.max_transfer_size = PL080_CONTROL_TRANSFER_SIZE_MASK,
};
--
2.4.3
--
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