[PATCH v5 2/3] misc: fastrpc: move ADSP duplicate session creation to the driver

[Vinayak Katoch <vinayak.katoch@oss.qualcomm.com>]

For ADSP, only a limited number of FastRPC context banks (CBs) are
available. Each CB supports a single session, which means only a few
processes can run on ADSP simultaneously. If all sessions are consumed
by fastrpc daemons, no session remains available when a user application
starts, causing the application to fail.

To work around this, qcom,nsessions = <5> was set in DT to duplicate
sessions inline during fastrpc_cb_init(). This policy does not belong
in DT and should be handled at the driver level instead.

Remove the qcom,nsessions DT property read and the per-CB duplication
logic from fastrpc_cb_init(). After all context banks have been
initialised in fastrpc_rpmsg_probe(), append FASTRPC_DUP_SESSIONS (4)
copies of the last session for the ADSP domain.

Signed-off-by: Vinayak Katoch <vinayak.katoch@oss.qualcomm.com>
---
 drivers/misc/fastrpc.c | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index f20d3e5ecc81..b29c1fd00de2 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -34,6 +34,7 @@
 #define CDSP_DOMAIN_ID (3)
 #define GDSP_DOMAIN_ID (4)
 #define FASTRPC_MAX_SESSIONS	14
+#define FASTRPC_DUP_SESSIONS	4
 #define FASTRPC_MAX_VMIDS	16
 #define FASTRPC_ALIGN		128
 #define FASTRPC_MAX_FDLIST	16
@@ -2338,7 +2339,6 @@ static int fastrpc_cb_init(struct platform_device *pdev)
 	struct fastrpc_channel_ctx *cctx;
 	struct fastrpc_session_ctx *sess;
 	struct device *dev = &pdev->dev;
-	int i, sessions = 0;
 	unsigned long flags;
 	u32 dma_bits;
 	u32 sid = 0;
@@ -2348,7 +2348,6 @@ static int fastrpc_cb_init(struct platform_device *pdev)
 	if (!cctx)
 		return -EINVAL;
 
-	of_property_read_u32(dev->of_node, "qcom,nsessions", &sessions);
 	if (of_property_read_u32(dev->of_node, "reg", &sid))
 		dev_info(dev, "FastRPC Session ID not specified in DT\n");
 
@@ -2369,16 +2368,6 @@ static int fastrpc_cb_init(struct platform_device *pdev)
 	if (cctx->domain_id == CDSP_DOMAIN_ID)
 		dma_bits = cctx->soc_data->dma_addr_bits_cdsp;
 
-	if (sessions > 0) {
-		struct fastrpc_session_ctx *dup_sess;
-
-		for (i = 1; i < sessions; i++) {
-			if (cctx->sesscount >= FASTRPC_MAX_SESSIONS)
-				break;
-			dup_sess = &cctx->session[cctx->sesscount++];
-			memcpy(dup_sess, sess, sizeof(*dup_sess));
-		}
-	}
 	spin_unlock_irqrestore(&cctx->lock, flags);
 	rc = dma_set_mask(dev, DMA_BIT_MASK(dma_bits));
 	if (rc) {
@@ -2669,6 +2658,22 @@ static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
 	if (err)
 		goto err_deregister_fdev;
 
+	if (data->domain_id == ADSP_DOMAIN_ID && data->sesscount > 0) {
+		struct fastrpc_session_ctx *last_sess;
+		struct fastrpc_session_ctx *dup_sess;
+		unsigned long flags;
+
+		spin_lock_irqsave(&data->lock, flags);
+		last_sess = &data->session[data->sesscount - 1];
+		for (i = 0; i < FASTRPC_DUP_SESSIONS; i++) {
+			if (data->sesscount >= FASTRPC_MAX_SESSIONS)
+				break;
+			dup_sess = &data->session[data->sesscount++];
+			memcpy(dup_sess, last_sess, sizeof(*dup_sess));
+		}
+		spin_unlock_irqrestore(&data->lock, flags);
+	}
+
 	return 0;
 
 err_deregister_fdev:

-- 
2.34.1