[PATCH 5/5] dmaengine: ti: edma: Add support for handling reserved channels

[Peter Ujfalusi]

Like paRAM slots, channels could be used by other cores and in this case
we need to make sure that the driver do not alter these channels.

Move the reserved slot/channel query from DT to a separate function for
cleaner implementation.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
---
 drivers/dma/ti/edma.c | 161 +++++++++++++++++++++++++++---------------
 1 file changed, 106 insertions(+), 55 deletions(-)

diff --git a/drivers/dma/ti/edma.c b/drivers/dma/ti/edma.c
index ba7c4f07fcd6..5201aeebf5c1 100644
--- a/drivers/dma/ti/edma.c
+++ b/drivers/dma/ti/edma.c
@@ -260,6 +260,9 @@ struct edma_cc {
 	 */
 	unsigned long *slot_inuse;
 
+	/* for tracking reserved channels used by DSP */
+	unsigned long *reserved_chans;
+
 	struct dma_device		dma_slave;
 	struct dma_device		*dma_memcpy;
 	struct edma_chan		*slave_chans;
@@ -716,6 +719,12 @@ static int edma_alloc_channel(struct edma_chan *echan,
 	struct edma_cc *ecc = echan->ecc;
 	int channel = EDMA_CHAN_SLOT(echan->ch_num);
 
+	if (test_bit(echan->ch_num, ecc->reserved_chans)) {
+		dev_err(ecc->dev, "Channel%d is reserved, can not be used!\n",
+			echan->ch_num);
+		return -EINVAL;
+	}
+
 	/* ensure access through shadow region 0 */
 	edma_or_array2(ecc, EDMA_DRAE, 0, EDMA_REG_ARRAY_INDEX(channel),
 		       EDMA_CHANNEL_BIT(channel));
@@ -2096,6 +2105,76 @@ static int edma_xbar_event_map(struct device *dev, struct edma_soc_info *pdata,
 	return 0;
 }
 
+static struct edma_rsv_info *edma_get_reserved_ranges_dt(struct device *dev)
+{
+	static const char * const prop_names[] = {
+						"ti,edma-reserved-slot-ranges",
+						"ti,edma-reserved-chan-ranges"
+						};
+	struct edma_rsv_info *rsv_info = NULL;
+	struct property *props[2];
+	int sz[2], i, ret;
+
+	for (i = 0; i < 2; i++)
+		props[i] = of_find_property(dev->of_node, prop_names[i],
+					    &sz[i]);
+
+	if (!props[0] && !props[1])
+		return NULL;
+
+	rsv_info = devm_kzalloc(dev, sizeof(*rsv_info), GFP_KERNEL);
+	if (!rsv_info)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < 2; i++) {
+		u32 (*tmp)[2];
+		s16 (*reserved)[2];
+		size_t nelm;
+		int j;
+
+		if (!props[i])
+			continue;
+
+		nelm = sz[i] / sizeof(*tmp);
+		if (!nelm)
+			continue;
+
+		tmp = kcalloc(nelm, sizeof(*tmp), GFP_KERNEL);
+		if (!tmp)
+			return ERR_PTR(-ENOMEM);
+
+		reserved = devm_kcalloc(dev, nelm + 1, sizeof(*reserved),
+					GFP_KERNEL);
+		if (!reserved) {
+			kfree(tmp);
+			return ERR_PTR(-ENOMEM);
+		}
+
+		ret = of_property_read_u32_array(dev->of_node, prop_names[i],
+						 (u32 *)tmp, nelm * 2);
+		if (ret) {
+			kfree(tmp);
+			return ERR_PTR(ret);
+		}
+
+		for (j = 0; j < nelm; j++) {
+			reserved[j][0] = tmp[j][0];
+			reserved[j][1] = tmp[j][1];
+		}
+		reserved[nelm][0] = -1;
+		reserved[nelm][1] = -1;
+
+		if (i == 0)
+			rsv_info->rsv_slots = (const s16 (*)[2])reserved;
+		else if (i == 1)
+			rsv_info->rsv_chans = (const s16 (*)[2])reserved;
+
+		kfree(tmp);
+	}
+
+	return rsv_info;
+}
+
 static struct edma_soc_info *edma_setup_info_from_dt(struct device *dev,
 						     bool legacy_mode)
 {
@@ -2139,55 +2218,9 @@ static struct edma_soc_info *edma_setup_info_from_dt(struct device *dev,
 		info->memcpy_channels = memcpy_ch;
 	}
 
-	prop = of_find_property(dev->of_node, "ti,edma-reserved-slot-ranges",
-				&sz);
-	if (prop) {
-		const char pname[] = "ti,edma-reserved-slot-ranges";
-		u32 (*tmp)[2];
-		s16 (*rsv_slots)[2];
-		size_t nelm = sz / sizeof(*tmp);
-		struct edma_rsv_info *rsv_info;
-		int i;
-
-		if (!nelm)
-			return info;
-
-		tmp = kcalloc(nelm, sizeof(*tmp), GFP_KERNEL);
-		if (!tmp)
-			return ERR_PTR(-ENOMEM);
-
-		rsv_info = devm_kzalloc(dev, sizeof(*rsv_info), GFP_KERNEL);
-		if (!rsv_info) {
-			kfree(tmp);
-			return ERR_PTR(-ENOMEM);
-		}
-
-		rsv_slots = devm_kcalloc(dev, nelm + 1, sizeof(*rsv_slots),
-					 GFP_KERNEL);
-		if (!rsv_slots) {
-			kfree(tmp);
-			return ERR_PTR(-ENOMEM);
-		}
-
-		ret = of_property_read_u32_array(dev->of_node, pname,
-						 (u32 *)tmp, nelm * 2);
-		if (ret) {
-			kfree(tmp);
-			return ERR_PTR(ret);
-		}
-
-		for (i = 0; i < nelm; i++) {
-			rsv_slots[i][0] = tmp[i][0];
-			rsv_slots[i][1] = tmp[i][1];
-		}
-		rsv_slots[nelm][0] = -1;
-		rsv_slots[nelm][1] = -1;
-
-		info->rsv = rsv_info;
-		info->rsv->rsv_slots = (const s16 (*)[2])rsv_slots;
-
-		kfree(tmp);
-	}
+	info->rsv = edma_get_reserved_ranges_dt(dev);
+	if (IS_ERR(info->rsv))
+		return ERR_CAST(info->rsv);
 
 	return info;
 }
@@ -2250,7 +2283,7 @@ static int edma_probe(struct platform_device *pdev)
 	struct edma_soc_info	*info = pdev->dev.platform_data;
 	s8			(*queue_priority_mapping)[2];
 	int			i, off;
-	const s16		(*rsv_slots)[2];
+	const s16		(*reserved)[2];
 	const s16		(*xbar_chans)[2];
 	int			irq;
 	char			*irq_name;
@@ -2331,15 +2364,29 @@ static int edma_probe(struct platform_device *pdev)
 	if (!ecc->slot_inuse)
 		return -ENOMEM;
 
+	ecc->reserved_chans = devm_kcalloc(dev,
+					   BITS_TO_LONGS(ecc->num_channels),
+					   sizeof(unsigned long), GFP_KERNEL);
+	if (!ecc->reserved_chans)
+		return -ENOMEM;
+
 	ecc->default_queue = info->default_queue;
 
 	if (info->rsv) {
 		/* Set the reserved slots in inuse list */
-		rsv_slots = info->rsv->rsv_slots;
-		if (rsv_slots) {
-			for (i = 0; rsv_slots[i][0] != -1; i++)
-				bitmap_set(ecc->slot_inuse, rsv_slots[i][0],
-					   rsv_slots[i][1]);
+		reserved = info->rsv->rsv_slots;
+		if (reserved) {
+			for (i = 0; reserved[i][0] != -1; i++)
+				bitmap_set(ecc->slot_inuse, reserved[i][0],
+					   reserved[i][1]);
+		}
+
+		/* Mark reserved channels */
+		reserved = info->rsv->rsv_chans;
+		if (reserved) {
+			for (i = 0; reserved[i][0] != -1; i++)
+				bitmap_set(ecc->reserved_chans, reserved[i][0],
+					   reserved[i][1]);
 		}
 	}
 
@@ -2437,6 +2484,10 @@ static int edma_probe(struct platform_device *pdev)
 	edma_dma_init(ecc, legacy_mode);
 
 	for (i = 0; i < ecc->num_channels; i++) {
+		/* Do not touch reserved channels */
+		if (test_bit(i, ecc->reserved_chans))
+			continue;
+
 		/* Assign all channels to the default queue */
 		edma_assign_channel_eventq(&ecc->slave_chans[i],
 					   info->default_queue);
-- 
Peter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki