linux-kernel - [PATCH RESEND] coresight: etr: Use noncontiguous api instead of noncoherent

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Message-ID: <20250508031851.2566235-1-quic_jinlmao@quicinc.com>
Date: Wed, 7 May 2025 20:18:51 -0700
From: Mao Jinlong <quic_jinlmao@...cinc.com>
To: Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach
	<mike.leach@...aro.org>,
        James Clark <james.clark@...aro.org>,
        "Alexander
 Shishkin" <alexander.shishkin@...ux.intel.com>
CC: Shilpa Suresh <quic_c_sbsure@...cinc.com>, <coresight@...ts.linaro.org>,
        <linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        "Mao
 Jinlong" <quic_jinlmao@...cinc.com>
Subject: [PATCH RESEND] coresight: etr: Use noncontiguous api instead of noncoherent

From: Shilpa Suresh <quic_c_sbsure@...cinc.com>

The iommu support for noncoherent is removed by commit(dma-mapping:
remove the {alloc,free}_noncoherent methods
81d88ce55092edf1a1f928efb373f289c6b90efd). Use alloc_noncontiguous
function for etr flat buffer allocation.

Signed-off-by: Shilpa Suresh <quic_c_sbsure@...cinc.com>
Signed-off-by: Mao Jinlong <quic_jinlmao@...cinc.com>
---
 .../hwtracing/coresight/coresight-tmc-etr.c   | 47 ++++++++++++++-----
 1 file changed, 34 insertions(+), 13 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 76a8cb29b68a..3b204f3bd45b 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -24,6 +24,7 @@ struct etr_flat_buf {
 	dma_addr_t	daddr;
 	void		*vaddr;
 	size_t		size;
+	struct sg_table	*sgt;
 };
 
 struct etr_buf_hw {
@@ -616,15 +617,24 @@ static int tmc_etr_alloc_flat_buf(struct tmc_drvdata *drvdata,
 	if (!flat_buf)
 		return -ENOMEM;
 
-	flat_buf->vaddr = dma_alloc_noncoherent(real_dev, etr_buf->size,
-						&flat_buf->daddr,
-						DMA_FROM_DEVICE,
-						GFP_KERNEL | __GFP_NOWARN);
-	if (!flat_buf->vaddr) {
+	flat_buf->sgt = dma_alloc_noncontiguous(real_dev, etr_buf->size,
+						DMA_FROM_DEVICE, GFP_KERNEL, 0);
+	if (!flat_buf->sgt) {
 		kfree(flat_buf);
 		return -ENOMEM;
 	}
 
+	flat_buf->daddr = sg_dma_address(flat_buf->sgt->sgl);
+	flat_buf->vaddr = dma_vmap_noncontiguous(real_dev, etr_buf->size,
+						flat_buf->sgt);
+	if (!flat_buf->vaddr) {
+		dma_free_noncontiguous(real_dev, etr_buf->size,
+					flat_buf->sgt,
+					DMA_FROM_DEVICE);
+		flat_buf->sgt = NULL;
+		return -ENOMEM;
+	}
+
 	flat_buf->size = etr_buf->size;
 	flat_buf->dev = &drvdata->csdev->dev;
 	etr_buf->hwaddr = flat_buf->daddr;
@@ -640,9 +650,12 @@ static void tmc_etr_free_flat_buf(struct etr_buf *etr_buf)
 	if (flat_buf && flat_buf->daddr) {
 		struct device *real_dev = flat_buf->dev->parent;
 
-		dma_free_noncoherent(real_dev, etr_buf->size,
-				     flat_buf->vaddr, flat_buf->daddr,
+		dma_vunmap_noncontiguous(real_dev, flat_buf->vaddr);
+		dma_free_noncontiguous(real_dev, etr_buf->size,
+				     flat_buf->sgt,
 				     DMA_FROM_DEVICE);
+		flat_buf->vaddr = NULL;
+		flat_buf->sgt = NULL;
 	}
 	kfree(flat_buf);
 }
@@ -651,6 +664,9 @@ static void tmc_etr_sync_flat_buf(struct etr_buf *etr_buf, u64 rrp, u64 rwp)
 {
 	struct etr_flat_buf *flat_buf = etr_buf->private;
 	struct device *real_dev = flat_buf->dev->parent;
+	s64 buf_len;
+	int i;
+	struct scatterlist *sg;
 
 	/*
 	 * Adjust the buffer to point to the beginning of the trace data
@@ -668,12 +684,17 @@ static void tmc_etr_sync_flat_buf(struct etr_buf *etr_buf, u64 rrp, u64 rwp)
 	 * is full.  Sync the entire buffer in one go for this case.
 	 */
 	if (etr_buf->offset + etr_buf->len > etr_buf->size)
-		dma_sync_single_for_cpu(real_dev, flat_buf->daddr,
-					etr_buf->size, DMA_FROM_DEVICE);
-	else
-		dma_sync_single_for_cpu(real_dev,
-					flat_buf->daddr + etr_buf->offset,
-					etr_buf->len, DMA_FROM_DEVICE);
+		dma_sync_sgtable_for_cpu(real_dev, flat_buf->sgt,
+					DMA_FROM_DEVICE);
+	else {
+		buf_len = etr_buf->len;
+		for_each_sg(flat_buf->sgt->sgl, sg, flat_buf->sgt->orig_nents, i) {
+			dma_sync_sg_for_cpu(real_dev, sg, 1, DMA_FROM_DEVICE);
+			buf_len -= sg->length;
+			if (buf_len <= 0)
+				break;
+		}
+	}
 }
 
 static ssize_t tmc_etr_get_data_flat_buf(struct etr_buf *etr_buf,
-- 
2.25.1