crypto: ccp - Make some CCP DMA channels private

The CCP registers its queues as channels capable of handling
general DMA operations. The NTB driver will use DMA if
directed, but as public channels can be reserved for use in
asynchronous operations some channels should be held back
as private. Since the public/private determination is
handled at a device level, reserve the "other" (secondary)
CCP channels as private.

Add a module parameter that allows for override, to be
applied to all channels on all devices.

CC: <stable@vger.kernel.org> # 4.10.x-
Signed-off-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 41 insertions, 0 deletions

diff --git a/drivers/crypto/ccp/ccp-dmaengine.c b/drivers/crypto/ccp/ccp-dmaengine.c
index 8d0eeb46d4a2..e00be01fbf5a 100644
--- a/drivers/crypto/ccp/ccp-dmaengine.c
+++ b/drivers/crypto/ccp/ccp-dmaengine.c
@@ -10,6 +10,7 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/dmaengine.h>
 #include <linux/spinlock.h>
@@ -25,6 +26,37 @@
 	(mask == 0) ? 64 : fls64(mask);	\
 })
 
+/* The CCP as a DMA provider can be configured for public or private
+ * channels. Default is specified in the vdata for the device (PCI ID).
+ * This module parameter will override for all channels on all devices:
+ *   dma_chan_attr = 0x2 to force all channels public
+ *                 = 0x1 to force all channels private
+ *                 = 0x0 to defer to the vdata setting
+ *                 = any other value: warning, revert to 0x0
+ */
+static unsigned int dma_chan_attr = CCP_DMA_DFLT;
+module_param(dma_chan_attr, uint, 0444);
+MODULE_PARM_DESC(dma_chan_attr, "Set DMA channel visibility: 0 (default) = device defaults, 1 = make private, 2 = make public");
+
+unsigned int ccp_get_dma_chan_attr(struct ccp_device *ccp)
+{
+	switch (dma_chan_attr) {
+	case CCP_DMA_DFLT:
+		return ccp->vdata->dma_chan_attr;
+
+	case CCP_DMA_PRIV:
+		return DMA_PRIVATE;
+
+	case CCP_DMA_PUB:
+		return 0;
+
+	default:
+		dev_info_once(ccp->dev, "Invalid value for dma_chan_attr: %d\n",
+			      dma_chan_attr);
+		return ccp->vdata->dma_chan_attr;
+	}
+}
+
 static void ccp_free_cmd_resources(struct ccp_device *ccp,
 				   struct list_head *list)
 {
@@ -675,6 +707,15 @@ int ccp_dmaengine_register(struct ccp_device *ccp)
 	dma_cap_set(DMA_SG, dma_dev->cap_mask);
 	dma_cap_set(DMA_INTERRUPT, dma_dev->cap_mask);
 
+	/* The DMA channels for this device can be set to public or private,
+	 * and overridden by the module parameter dma_chan_attr.
+	 * Default: according to the value in vdata (dma_chan_attr=0)
+	 * dma_chan_attr=0x1: all channels private (override vdata)
+	 * dma_chan_attr=0x2: all channels public (override vdata)
+	 */
+	if (ccp_get_dma_chan_attr(ccp) == DMA_PRIVATE)
+		dma_cap_set(DMA_PRIVATE, dma_dev->cap_mask);
+
 	INIT_LIST_HEAD(&dma_dev->channels);
 	for (i = 0; i < ccp->cmd_q_count; i++) {
 		chan = ccp->ccp_dma_chan + i;