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[PATCH v2 0/3] dmaengine: ti-dma-crossbar: channel reserving and edma3-tpcc support

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  [PATCH v2 0/3] dmaengine: ti-dma-crossbar: channel reserving and edma3-tpcc support Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-30 09:10 +0100
    [PATCH v2 1/3] dmaengine: ti-dma-crossbar: dra7: Use bitops instead of idr Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-10-30 09:10 +0100

#1259293 — [PATCH v2 0/3] dmaengine: ti-dma-crossbar: channel reserving and edma3-tpcc support

Hi,

Changes since v1:
- Fixed issue introduced by the bitops patch: wrong error check, also switch to
  use find_first_zero_bit() instead of find_next_zero_bit()

Cover letter:

This series depends on the eDMA work I have done, which has been now applied:
https://lkml.org/lkml/2015/10/16/64

DRA7 family of chips have both sDMA and eDMA. Currently only sDMA can be used
becasue the old driver stack for eDMA did not allowed integration w/o hacks.

Due to the nature of eDMA the crossbar needs to know which eDMA events it can
use to map incoming events towards the eDMA. In eDMA a channel is wired to be
used with one specific event. For example eDMA event 14 can only be handled by
eDMA channel 14.
The eDMA itself can be shared by different processors in the system (ARM, DSP,
etc) and since ARM/Linux is the master we need to know which channels are used
by other cores. Also we need to mask out channels used for memcpy from the
events we use for HW triggers.

Regards,
Peter
---
Peter Ujfalusi (3):
  dmaengine: ti-dma-crossbar: dra7: Use bitops instead of idr
  dmaengine: ti-dma-crossbar: dra7: Support for reserving DMA event
    ranges
  dmaengine: ti-dma-crossbar: dra7: Support for eDMA with new bindings

 .../devicetree/bindings/dma/ti-dma-crossbar.txt    |  6 ++
 drivers/dma/ti-dma-crossbar.c                      | 81 +++++++++++++++++++---
 2 files changed, 76 insertions(+), 11 deletions(-)

-- 
2.6.1

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#1259294 — [PATCH v2 1/3] dmaengine: ti-dma-crossbar: dra7: Use bitops instead of idr

The use of idr was nice, but it was a bit heavy and we did not need the
features it provides. Using simple bitmap to track allocated DMA channels
is adequate here and it will be easier to add support for reserving
channels later on.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
 drivers/dma/ti-dma-crossbar.c | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/drivers/dma/ti-dma-crossbar.c b/drivers/dma/ti-dma-crossbar.c
index a415edbe61b1..463ad6b18a32 100644
--- a/drivers/dma/ti-dma-crossbar.c
+++ b/drivers/dma/ti-dma-crossbar.c
@@ -12,7 +12,6 @@
 #include <linux/init.h>
 #include <linux/list.h>
 #include <linux/io.h>
-#include <linux/idr.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
 #include <linux/of_dma.h>
@@ -198,7 +197,8 @@ struct ti_dra7_xbar_data {
 	void __iomem *iomem;
 
 	struct dma_router dmarouter;
-	struct idr map_idr;
+	struct mutex mutex;
+	unsigned long *dma_inuse;
 
 	u16 safe_val; /* Value to rest the crossbar lines */
 	u32 xbar_requests; /* number of DMA requests connected to XBAR */
@@ -225,7 +225,9 @@ static void ti_dra7_xbar_free(struct device *dev, void *route_data)
 		map->xbar_in, map->xbar_out);
 
 	ti_dra7_xbar_write(xbar->iomem, map->xbar_out, xbar->safe_val);
-	idr_remove(&xbar->map_idr, map->xbar_out);
+	mutex_lock(&xbar->mutex);
+	clear_bit(map->xbar_out, xbar->dma_inuse);
+	mutex_unlock(&xbar->mutex);
 	kfree(map);
 }
 
@@ -255,8 +257,17 @@ static void *ti_dra7_xbar_route_allocate(struct of_phandle_args *dma_spec,
 		return ERR_PTR(-ENOMEM);
 	}
 
-	map->xbar_out = idr_alloc(&xbar->map_idr, NULL, 0, xbar->dma_requests,
-				  GFP_KERNEL);
+	mutex_lock(&xbar->mutex);
+	map->xbar_out = find_first_zero_bit(xbar->dma_inuse,
+					    xbar->dma_requests);
+	mutex_unlock(&xbar->mutex);
+	if (map->xbar_out == xbar->dma_requests) {
+		dev_err(&pdev->dev, "Run out of free DMA requests\n");
+		kfree(map);
+		return ERR_PTR(-ENOMEM);
+	}
+	set_bit(map->xbar_out, xbar->dma_inuse);
+
 	map->xbar_in = (u16)dma_spec->args[0];
 
 	dma_spec->args[0] = map->xbar_out + xbar->dma_offset;
@@ -299,8 +310,6 @@ static int ti_dra7_xbar_probe(struct platform_device *pdev)
 	if (!xbar)
 		return -ENOMEM;
 
-	idr_init(&xbar->map_idr);
-
 	dma_node = of_parse_phandle(node, "dma-masters", 0);
 	if (!dma_node) {
 		dev_err(&pdev->dev, "Can't get DMA master node\n");
@@ -322,6 +331,12 @@ static int ti_dra7_xbar_probe(struct platform_device *pdev)
 	}
 	of_node_put(dma_node);
 
+	xbar->dma_inuse = devm_kcalloc(&pdev->dev,
+				       BITS_TO_LONGS(xbar->dma_requests),
+				       sizeof(unsigned long), GFP_KERNEL);
+	if (!xbar->dma_inuse)
+		return -ENOMEM;
+
 	if (of_property_read_u32(node, "dma-requests", &xbar->xbar_requests)) {
 		dev_info(&pdev->dev,
 			 "Missing XBAR input information, using %u.\n",
@@ -343,6 +358,7 @@ static int ti_dra7_xbar_probe(struct platform_device *pdev)
 	xbar->dmarouter.route_free = ti_dra7_xbar_free;
 	xbar->dma_offset = (u32)match->data;
 
+	mutex_init(&xbar->mutex);
 	platform_set_drvdata(pdev, xbar);
 
 	/* Reset the crossbar */
-- 
2.6.1

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