diff mbox

[2/3] dma: pl08x: allocate OF slave channel data at probe time

Message ID 1444127243-689-1-git-send-email-linus.walleij@linaro.org (mailing list archive)
State Changes Requested
Headers show

Commit Message

Linus Walleij Oct. 6, 2015, 10:27 a.m. UTC
The current OF translation of channels can never work with
any DMA client using the DMA channels directly: the only way
to get the channels initialized properly is in the
dma_async_device_register() call, where chan->dev etc is
allocated and initialized.

Allocate and initialize all 32 possible DMA channels and
only augment a target channel with the periph_buses at
of_xlate(). Remove some const settings to make things work.

Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
Joachim: I think I need your teste-by on this to make sure
the LPC machine survives this patch set.
---
 drivers/dma/amba-pl08x.c   | 80 +++++++++++++++++++++++++++++-----------------
 include/linux/amba/pl08x.h |  2 +-
 2 files changed, 52 insertions(+), 30 deletions(-)

Comments

Joachim Eastwood Oct. 10, 2015, 9:52 p.m. UTC | #1
On 6 October 2015 at 12:27, Linus Walleij <linus.walleij@linaro.org> wrote:
> The current OF translation of channels can never work with
> any DMA client using the DMA channels directly: the only way
> to get the channels initialized properly is in the
> dma_async_device_register() call, where chan->dev etc is
> allocated and initialized.
>
> Allocate and initialize all 32 possible DMA channels and
> only augment a target channel with the periph_buses at
> of_xlate(). Remove some const settings to make things work.
>
> Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
> Cc: Joachim Eastwood <manabian@gmail.com>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> Joachim: I think I need your teste-by on this to make sure
> the LPC machine survives this patch set.
> ---
>  drivers/dma/amba-pl08x.c   | 80 +++++++++++++++++++++++++++++-----------------
>  include/linux/amba/pl08x.h |  2 +-
>  2 files changed, 52 insertions(+), 30 deletions(-)

This breaks dma on lpc18xx.

Seems like the slaves are unable to find the dma channel with this change.
Full boot log: http://slexy.org/raw/s20nJ4Gpyx

regards,
Joachim Eastwood
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diff mbox

Patch

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index dc864846f0a9..9420b9cdbf99 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -95,6 +95,13 @@ 
 
 #define DRIVER_NAME	"pl08xdmac"
 
+/*
+ * The PL08X IP blocks has up to 32 routable hardware signals. Sometimes a MUX
+ * will be mounted on top of the signals to further extend the available DMA
+ * routes.
+ */
+#define PL08X_DMA_SIGNALS 32
+
 #define PL80X_DMA_BUSWIDTHS \
 	BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) | \
 	BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
@@ -241,7 +248,7 @@  struct pl08x_dma_chan {
 	struct virt_dma_chan vc;
 	struct pl08x_phy_chan *phychan;
 	const char *name;
-	const struct pl08x_channel_data *cd;
+	struct pl08x_channel_data *cd;
 	struct dma_slave_config cfg;
 	struct pl08x_txd *at;
 	struct pl08x_driver_data *host;
@@ -2080,40 +2087,34 @@  static struct dma_chan *pl08x_of_xlate(struct of_phandle_args *dma_spec,
 				       struct of_dma *ofdma)
 {
 	struct pl08x_driver_data *pl08x = ofdma->of_dma_data;
-	struct pl08x_channel_data *data;
-	struct pl08x_dma_chan *chan;
 	struct dma_chan *dma_chan;
 
 	if (!pl08x)
 		return NULL;
 
-	if (dma_spec->args_count != 2)
+	if (dma_spec->args_count != 2) {
+		dev_err(&pl08x->adev->dev,
+			"DMA channel translation requires two cells\n");
 		return NULL;
+	}
 
+	/* Already allocated or coming from platform data */
 	dma_chan = pl08x_find_chan_id(pl08x, dma_spec->args[0]);
-	if (dma_chan)
-		return dma_get_slave_channel(dma_chan);
-
-	chan = devm_kzalloc(pl08x->slave.dev, sizeof(*chan) + sizeof(*data),
-			    GFP_KERNEL);
-	if (!chan)
-		return NULL;
-
-	data = (void *)&chan[1];
-	data->bus_id = "(none)";
-	data->periph_buses = dma_spec->args[1];
-
-	chan->cd = data;
-	chan->host = pl08x;
-	chan->slave = true;
-	chan->name = data->bus_id;
-	chan->state = PL08X_CHAN_IDLE;
-	chan->signal = dma_spec->args[0];
-	chan->vc.desc_free = pl08x_desc_free;
+	if (dma_chan) {
+		struct pl08x_dma_chan *plchan = to_pl08x_chan(dma_chan);
 
-	vchan_init(&chan->vc, &pl08x->slave);
+		dev_dbg(&pl08x->adev->dev,
+			"translated channel for signal %d\n",
+			dma_spec->args[0]);
+		/* Augment channel data for applicable AHB buses */
+		plchan->cd->periph_buses = dma_spec->args[1];
+		return dma_get_slave_channel(dma_chan);
+	}
 
-	return dma_get_slave_channel(&chan->vc.chan);
+	dev_err(&pl08x->adev->dev,
+		"can\'t find DMA slave channel for signal %d\n",
+		dma_spec->args[0]);
+	return NULL;
 }
 
 static int pl08x_of_probe(struct amba_device *adev,
@@ -2121,9 +2122,11 @@  static int pl08x_of_probe(struct amba_device *adev,
 			  struct device_node *np)
 {
 	struct pl08x_platform_data *pd;
+	struct pl08x_channel_data *chanp = NULL;
 	u32 cctl_memcpy = 0;
 	u32 val;
 	int ret;
+	int i;
 
 	pd = devm_kzalloc(&adev->dev, sizeof(*pd), GFP_KERNEL);
 	if (!pd)
@@ -2225,6 +2228,25 @@  static int pl08x_of_probe(struct amba_device *adev,
 	/* Use the buses that can access memory, obviously */
 	pd->memcpy_channel.periph_buses = pd->mem_buses;
 
+	/*
+	 * Allocate channel data for all possible slave channels (one for
+	 * each possible signal), channels will then be allocated for a
+	 * device and have it's AHB interfaces set up at translation time.
+	 */
+	chanp = devm_kzalloc(&adev->dev,
+			PL08X_DMA_SIGNALS *
+			sizeof(struct pl08x_channel_data),
+			GFP_KERNEL);
+	if (!chanp)
+		return -ENOMEM;
+	pd->slave_channels = chanp;
+	for (i = 0; i < PL08X_DMA_SIGNALS; i++) {
+		/* chanp->periph_buses will be assigned at translation */
+		chanp->bus_id = kasprintf(GFP_KERNEL, "slave%d", i);
+		chanp++;
+	}
+	pd->num_slave_channels = PL08X_DMA_SIGNALS;
+
 	pl08x->pd = pd;
 
 	return of_dma_controller_register(adev->dev.of_node, pl08x_of_xlate,
@@ -2264,6 +2286,10 @@  static int pl08x_probe(struct amba_device *adev, const struct amba_id *id)
 		goto out_no_pl08x;
 	}
 
+	/* Assign useful pointers to the driver state */
+	pl08x->adev = adev;
+	pl08x->vd = vd;
+
 	/* Initialize memcpy engine */
 	dma_cap_set(DMA_MEMCPY, pl08x->memcpy.cap_mask);
 	pl08x->memcpy.dev = &adev->dev;
@@ -2314,10 +2340,6 @@  static int pl08x_probe(struct amba_device *adev, const struct amba_id *id)
 		}
 	}
 
-	/* Assign useful pointers to the driver state */
-	pl08x->adev = adev;
-	pl08x->vd = vd;
-
 	/* By default, AHB1 only.  If dualmaster, from platform */
 	pl08x->lli_buses = PL08X_AHB1;
 	pl08x->mem_buses = PL08X_AHB1;
diff --git a/include/linux/amba/pl08x.h b/include/linux/amba/pl08x.h
index 10fe2a211c2e..27e9ec8778eb 100644
--- a/include/linux/amba/pl08x.h
+++ b/include/linux/amba/pl08x.h
@@ -86,7 +86,7 @@  struct pl08x_channel_data {
  * @mem_buses: buses which memory can be accessed from: PL08X_AHB1 | PL08X_AHB2
  */
 struct pl08x_platform_data {
-	const struct pl08x_channel_data *slave_channels;
+	struct pl08x_channel_data *slave_channels;
 	unsigned int num_slave_channels;
 	struct pl08x_channel_data memcpy_channel;
 	int (*get_xfer_signal)(const struct pl08x_channel_data *);