linux-kernel - [PATCH] firmware: qcom_scm: Give page

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Date: Fri, 17 May 2024 01:02:56 +0530
From: Mukesh Ojha <quic_mojha@...cinc.com>
To: <andersson@...nel.org>, <konrad.dybcio@...aro.org>
CC: <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        "Mukesh
 Ojha" <quic_mojha@...cinc.com>
Subject: [PATCH] firmware: qcom_scm: Give page_aligned size for dma api's

If we disable CONFIG_ZONE_DMA32 to make the selection of DMA
memory from higher 4GB range. dma_alloc_coherant() api usage
inside qcom_scm_pas_init_image() which usage scm 32bit device
will fail for size of data passed less than PAGE_SIZE and
it will fallback to buddy pool to allocate memory from which
will fail.

Convert the size to aligned to PAGE_SIZE before it gets pass
to dma_alloc_coherant(), so that it gets coherant memory in
lower 4GB from linux cma region.

Signed-off-by: Mukesh Ojha <quic_mojha@...cinc.com>
---
 drivers/firmware/qcom/qcom_scm.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
index 029ee5edbea6..6616048f1c33 100644
--- a/drivers/firmware/qcom/qcom_scm.c
+++ b/drivers/firmware/qcom/qcom_scm.c
@@ -562,6 +562,7 @@ static void qcom_scm_set_download_mode(u32 dload_mode)
 int qcom_scm_pas_init_image(u32 peripheral, const void *metadata, size_t size,
 			    struct qcom_scm_pas_metadata *ctx)
 {
+	size_t page_aligned_size;
 	dma_addr_t mdata_phys;
 	void *mdata_buf;
 	int ret;
@@ -579,7 +580,8 @@ int qcom_scm_pas_init_image(u32 peripheral, const void *metadata, size_t size,
 	 * data blob, so make sure it's physically contiguous, 4K aligned and
 	 * non-cachable to avoid XPU violations.
 	 */
-	mdata_buf = dma_alloc_coherent(__scm->dev, size, &mdata_phys,
+	page_aligned_size = PAGE_ALIGN(size + PAGE_SIZE);
+	mdata_buf = dma_alloc_coherent(__scm->dev, page_aligned_size, &mdata_phys,
 				       GFP_KERNEL);
 	if (!mdata_buf)
 		return -ENOMEM;
@@ -604,11 +606,11 @@ int qcom_scm_pas_init_image(u32 peripheral, const void *metadata, size_t size,
 
 out:
 	if (ret < 0 || !ctx) {
-		dma_free_coherent(__scm->dev, size, mdata_buf, mdata_phys);
+		dma_free_coherent(__scm->dev, page_aligned_size, mdata_buf, mdata_phys);
 	} else if (ctx) {
 		ctx->ptr = mdata_buf;
 		ctx->phys = mdata_phys;
-		ctx->size = size;
+		ctx->size = page_aligned_size;
 	}
 
 	return ret ? : res.result[0];
-- 
2.7.4