DSP currently supports 32-bit IOVA (32-bit PA + 4-bit SID) for
both Q6 and user DMA (uDMA) access. This is being upgraded to
34-bit PA + 4-bit SID due to a hardware revision in CDSP for
Kaanapali SoC, which expands the DMA addressable range.
Update DMA bits configuration in the driver to support CDSP on
Kaanapali SoC. Set the default `dma_bits` to 32-bit and update
it to 34-bit based on CDSP and OF matching on the fastrpc node.

Signed-off-by: Kumari Pallavi <kumari.pallavi@oss.qualcomm.com>
---
 drivers/misc/fastrpc.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index fcc80206b7c4..4f5a79c50f58 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -259,6 +259,8 @@ struct fastrpc_session_ctx {
 
 struct fastrpc_soc_data {
 	u32 sid_pos;
+	u32 dma_addr_bits_cdsp;
+	u32 dma_addr_bits_default;
 };
 
 struct fastrpc_channel_ctx {
@@ -2197,6 +2199,7 @@ static int fastrpc_cb_probe(struct platform_device *pdev)
 	int i, sessions = 0;
 	unsigned long flags;
 	int rc;
+	u32 dma_bits;
 
 	cctx = dev_get_drvdata(dev->parent);
 	if (!cctx)
@@ -2210,12 +2213,16 @@ static int fastrpc_cb_probe(struct platform_device *pdev)
 		spin_unlock_irqrestore(&cctx->lock, flags);
 		return -ENOSPC;
 	}
+	dma_bits = cctx->soc_data->dma_addr_bits_default;
 	sess = &cctx->session[cctx->sesscount++];
 	sess->used = false;
 	sess->valid = true;
 	sess->dev = dev;
 	dev_set_drvdata(dev, sess);
 
+	if (cctx->domain_id == CDSP_DOMAIN_ID)
+		dma_bits = cctx->soc_data->dma_addr_bits_cdsp;
+
 	if (of_property_read_u32(dev->of_node, "reg", &sess->sid))
 		dev_info(dev, "FastRPC Session ID not specified in DT\n");
 
@@ -2230,9 +2237,9 @@ static int fastrpc_cb_probe(struct platform_device *pdev)
 		}
 	}
 	spin_unlock_irqrestore(&cctx->lock, flags);
-	rc = dma_set_mask(dev, DMA_BIT_MASK(32));
+	rc = dma_set_mask(dev, DMA_BIT_MASK(dma_bits));
 	if (rc) {
-		dev_err(dev, "32-bit DMA enable failed\n");
+		dev_err(dev, "%u-bit DMA enable failed\n", dma_bits);
 		return rc;
 	}
 
@@ -2319,10 +2326,14 @@ static int fastrpc_get_domain_id(const char *domain)
 
 static const struct fastrpc_soc_data kaanapali_soc_data = {
 	.sid_pos = 56,
+	.dma_addr_bits_cdsp = 34,
+	.dma_addr_bits_default = 32,
 };
 
 static const struct fastrpc_soc_data default_soc_data = {
 	.sid_pos = 32,
+	.dma_addr_bits_cdsp = 32,
+	.dma_addr_bits_default = 32,
 };
 
 static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
-- 
2.34.1

On Fri, Dec 26, 2025 at 12:35:34PM +0530, Kumari Pallavi wrote:
> DSP currently supports 32-bit IOVA (32-bit PA + 4-bit SID) for
> both Q6 and user DMA (uDMA) access. This is being upgraded to
> 34-bit PA + 4-bit SID due to a hardware revision in CDSP for
> Kaanapali SoC, which expands the DMA addressable range.
> Update DMA bits configuration in the driver to support CDSP on
> Kaanapali SoC. Set the default `dma_bits` to 32-bit and update
> it to 34-bit based on CDSP and OF matching on the fastrpc node.
> 
> Signed-off-by: Kumari Pallavi <kumari.pallavi@oss.qualcomm.com>
> ---
>  drivers/misc/fastrpc.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

-- 
With best wishes
Dmitry