rapidio/tsi721_dma: add channel mask and queue size parameters

Add module parameters to allow load time configuration of DMA channels.

Depending on application, performance of DMA data transfers can benefit
from adjusted sizes of buffer descriptor ring and/or transaction
requests queue.

Having HW DMA channel selector mask allows to define which channels
(from seven available) are controlled by the mport device driver and
reserve some of them for direct use by other drivers.

Link: http://lkml.kernel.org/r/1469125134-16523-5-git-send-email-alexandre.bounine@idt.com
Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Tested-by: Barry Wood <barry.wood@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Andre van Herk <andre.van.herk@prodrive-technologies.com>
Cc: Barry Wood <barry.wood@idt.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 18 insertions, 10 deletions

diff --git a/drivers/rapidio/devices/tsi721.h b/drivers/rapidio/devices/tsi721.h
index 5456dbd..5941437 100644
--- a/drivers/rapidio/devices/tsi721.h
+++ b/drivers/rapidio/devices/tsi721.h
@@ -661,7 +661,7 @@ enum dma_rtype {
  */
 #define TSI721_DMA_CHNUM	TSI721_DMA_MAXCH
 
-#define TSI721_DMACH_MAINT	0	/* DMA channel for maint requests */
+#define TSI721_DMACH_MAINT	7	/* DMA channel for maint requests */
 #define TSI721_DMACH_MAINT_NBD	32	/* Number of BDs for maint requests */
 
 #define TSI721_DMACH_DMA	1	/* DMA channel for data transfers */
diff --git a/drivers/rapidio/devices/tsi721_dma.c b/drivers/rapidio/devices/tsi721_dma.c
index 155cae1e..13c669b 100644
--- a/drivers/rapidio/devices/tsi721_dma.c
+++ b/drivers/rapidio/devices/tsi721_dma.c
@@ -36,18 +36,26 @@
 
 #include "tsi721.h"
 
-#define TSI721_DMA_TX_QUEUE_SZ	16	/* number of transaction descriptors */
-
 #ifdef CONFIG_PCI_MSI
 static irqreturn_t tsi721_bdma_msix(int irq, void *ptr);
 #endif
 static int tsi721_submit_sg(struct tsi721_tx_desc *desc);
 
 static unsigned int dma_desc_per_channel = 128;
-module_param(dma_desc_per_channel, uint, S_IWUSR | S_IRUGO);
+module_param(dma_desc_per_channel, uint, S_IRUGO);
 MODULE_PARM_DESC(dma_desc_per_channel,
 		 "Number of DMA descriptors per channel (default: 128)");
 
+static unsigned int dma_txqueue_sz = 16;
+module_param(dma_txqueue_sz, uint, S_IRUGO);
+MODULE_PARM_DESC(dma_txqueue_sz,
+		 "DMA Transactions Queue Size (default: 16)");
+
+static u8 dma_sel = 0x7f;
+module_param(dma_sel, byte, S_IRUGO);
+MODULE_PARM_DESC(dma_sel,
+		 "DMA Channel Selection Mask (default: 0x7f = all)");
+
 static inline struct tsi721_bdma_chan *to_tsi721_chan(struct dma_chan *chan)
 {
 	return container_of(chan, struct tsi721_bdma_chan, dchan);
@@ -732,7 +740,7 @@ static int tsi721_alloc_chan_resources(struct dma_chan *dchan)
 	tsi_debug(DMA, &dchan->dev->device, "DMAC%d", bdma_chan->id);
 
 	if (bdma_chan->bd_base)
-		return TSI721_DMA_TX_QUEUE_SZ;
+		return dma_txqueue_sz;
 
 	/* Initialize BDMA channel */
 	if (tsi721_bdma_ch_init(bdma_chan, dma_desc_per_channel)) {
@@ -742,7 +750,7 @@ static int tsi721_alloc_chan_resources(struct dma_chan *dchan)
 	}
 
 	/* Allocate queue of transaction descriptors */
-	desc = kcalloc(TSI721_DMA_TX_QUEUE_SZ, sizeof(struct tsi721_tx_desc),
+	desc = kcalloc(dma_txqueue_sz, sizeof(struct tsi721_tx_desc),
 			GFP_ATOMIC);
 	if (!desc) {
 		tsi_err(&dchan->dev->device,
@@ -754,7 +762,7 @@ static int tsi721_alloc_chan_resources(struct dma_chan *dchan)
 
 	bdma_chan->tx_desc = desc;
 
-	for (i = 0; i < TSI721_DMA_TX_QUEUE_SZ; i++) {
+	for (i = 0; i < dma_txqueue_sz; i++) {
 		dma_async_tx_descriptor_init(&desc[i].txd, dchan);
 		desc[i].txd.tx_submit = tsi721_tx_submit;
 		desc[i].txd.flags = DMA_CTRL_ACK;
@@ -766,7 +774,7 @@ static int tsi721_alloc_chan_resources(struct dma_chan *dchan)
 	bdma_chan->active = true;
 	tsi721_bdma_interrupt_enable(bdma_chan, 1);
 
-	return TSI721_DMA_TX_QUEUE_SZ;
+	return dma_txqueue_sz;
 }
 
 static void tsi721_sync_dma_irq(struct tsi721_bdma_chan *bdma_chan)
@@ -962,7 +970,7 @@ void tsi721_dma_stop_all(struct tsi721_device *priv)
 	int i;
 
 	for (i = 0; i < TSI721_DMA_MAXCH; i++) {
-		if (i != TSI721_DMACH_MAINT)
+		if ((i != TSI721_DMACH_MAINT) && (dma_sel & (1 << i)))
 			tsi721_dma_stop(&priv->bdma[i]);
 	}
 }
@@ -979,7 +987,7 @@ int tsi721_register_dma(struct tsi721_device *priv)
 	for (i = 0; i < TSI721_DMA_MAXCH; i++) {
 		struct tsi721_bdma_chan *bdma_chan = &priv->bdma[i];
 
-		if (i == TSI721_DMACH_MAINT)
+		if ((i == TSI721_DMACH_MAINT) || (dma_sel & (1 << i)) == 0)
 			continue;
 
 		bdma_chan->regs = priv->regs + TSI721_DMAC_BASE(i);